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Charrier, Isabelle, Nicolas Mathevon, Mohammed Hassnaoui, Laurent Carraro y Pierre Jouventin. "The subantarctic fur seal pup switches its begging behaviour during maternal absence". Canadian Journal of Zoology 80, n.º 7 (1 de julio de 2002): 1250–55. http://dx.doi.org/10.1139/z02-109.
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Begging signals from the young are used to elicit parental care. Although honest and parent-directed signalling seems to be widely shared characteristic of begging behaviour, offspring might modify their strategy under some ecological or environmental constraints. In the subantarctic fur seal, Arctocephalus tropicalis, mothers forage at sea for 23 weeks at a time throughout the lactation period, resulting in regular separations of mothers and pups. Using playback experiments we investigated modifications of pups' begging behaviour during their mother's absence. From the 1st to the 5th day of maternal absence, pups rarely begged in response to other adult females' vocalizations (17.646.7% of tested pups), but always responded specifically to their mother's. After its mother had been absent for 510 days, the pup's response to playback of strange females' calls was stronger (4669% of tested pups), but the specificity of the response to the mother remained. However, after the 11th day of maternal absence, pups become highly responsive to calls made by any adult female (up to 37% of tested pups). The variation in responsiveness of fur seal pups during their mother's absence may be explained by changes in their motivational state that were linked to their internal nutritional balance.
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Baker, Jason D. y Mary J. Donohue. "Ontogeny of swimming and diving in northern fur seal (Callorhinus ursinus) pups". Canadian Journal of Zoology 78, n.º 1 (28 de febrero de 2000): 100–109. http://dx.doi.org/10.1139/z99-190.
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Time spent in the water and diving behavior of northern fur seal (Callorhinus ursinus) pups were monitored between birth and weaning at St. Paul Island, Alaska. The median age when pups began swimming was 26 days, but prior to 40 days of age they spent virtually all their time on shore and only rarely took brief (15-20 min) swims. Pups began spending substantial time in the water at approximately 40-50 days of age, coinciding both with the early growth of insulating underfur and a seasonal peak in sea surface temperature. This suggests that pups had earlier been constrained to remain on shore by their undeveloped thermoregulatory capabilities. Time in the water increased up to approximately 100 days of age, when molted pups spent about 35% of their time in the water and swim bouts were several hours in duration. Moreover, the presence of a pup's mother on shore, photoperiod, and precipitation also influenced the amount of time pups spent in the water. Pups (mean age = 100 days) dove to very shallow depths (mean = 3 m) for short durations (mean = 11 s). Because pups did not gain mass unless suckled by their mothers, it is unlikely that they fed extensively while diving prior to migration. The pattern of development of swimming and diving in northern fur seals is intermediate between typical phocid and otariid patterns, as is the maternal strategy.
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Gese, Eric M., William T. Waddell, Patricia A. Terletzky, Chris F. Lucash, Scott R. McLellan y Susan K. Behrns. "Cross-fostering as a conservation tool to augment endangered carnivore populations". Journal of Mammalogy 99, n.º 5 (24 de julio de 2018): 1033–41. http://dx.doi.org/10.1093/jmammal/gyy087.
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Abstract Cross-fostering offspring with nonbiological parents could prove useful to augment populations of endangered carnivores. We used cross-fostering to augment captive-born and wild-born litters for the endangered red wolf (Canis rufus). Between 1987 and 2016, 23 cross-fostering events occurred involving captive-born pups fostered into captive litters (n = 8 events) and captive-born pups fostered into wild recipient litters (n = 15 events). Percentage of pups surviving 3 and 12 months was 91.7% for captive-born pups fostered into captive recipient litters. For pups fostered into wild litters, percentage of pups surviving 5 months was > 94% among fostered pups (pups fostered into a wild red wolf litter or replaced a hybrid litter), pups in recipient litters (wild-born litters receiving fostered pups), and pups in control litters (wild-born litters not in a fostering event) when using pups with known fates. Including pups with unknown fates as deaths, percentage of pups surviving 5 months was > 54% among fostered pups, pups in recipient litters, and pups in control litters. Among wild litters, percentage of pups surviving 12 months was > 82% among fostered pups, pups in recipient litters, and pups in control litters when using pups with known fates. Including pups with unknown fates as deaths, percentage of pups surviving 12 months was > 48% among fostered pups, pups in recipient litters, and pups in control litters. Although survival to 12 months was similar among the groups, average life span was different with pups in control litters living 3.3 years, pups in recipient litters living 4.6 years, and fostered pups living 5.6 years. Of fostered pups surviving > 12 months in the wild, 9 animals whelped or sired 26 litters. Cross-fostering was successful at augmenting litter size for red wolves without any deleterious effects on recipient litters, illustrating fostering as a tool for increasing populations of endangered carnivores.
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Bourne, Debra. "Pups and patterns". Companion Animal 22, n.º 8 (2 de agosto de 2017): 433. http://dx.doi.org/10.12968/coan.2017.22.8.433.
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Goebel, Renea. "Pups' tails saved". Australian Veterinary Journal 78, n.º 3 (marzo de 2000): 206. http://dx.doi.org/10.1111/j.1751-0813.2000.tb10612.x.
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Trites, Andrew W. "Does Tagging and Handling Affect the Growth of Northern Fur Seal Pups (Callorhinus ursinus)?" Canadian Journal of Fisheries and Aquatic Sciences 48, n.º 12 (1 de diciembre de 1991): 2436–42. http://dx.doi.org/10.1139/f91-285.
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From 1957 to 1966, samples of tagged and marked northern fur seal pups (Callorhinus ursinus) consistently weighed less than untagged and unmarked pups on the Pribilof Islands, Alaska. At the time, it was concluded that tagging and handling had caused a loss of weight and had slowed the normal rate of pup growth. In re-evaluating the data from this time period, it seems that tagged pups grew at the same rate as untagged pups, but were smaller at the time of tagging than average size pups. The growth curve for tagged pups appears to lag behind that of untagged pups, suggesting that tagged pups were born later in the breeding season and were more susceptible to being captured and tagged than older and heavier pups.
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Osterrieder, Sylvia K. y Randall W. Davis. "Sea otter female and pup activity budgets, Prince William Sound, Alaska". Journal of the Marine Biological Association of the United Kingdom 91, n.º 4 (4 de octubre de 2010): 883–92. http://dx.doi.org/10.1017/s0025315410001426.
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In altricial mammals, mothers' care and attendance are essential for young to acquire survival skills. Despite the crucial importance of this early period for pup survival, not much is known about mother–pup behaviour and time allocation in the wild. To improve our understanding of the critical period of the sea otter development, a total of 240 30-minute focal follows of females with pups of different ages were conducted in four 6-hour-periods (dawn, day, dusk and night) from 4 June to 12 August 2008. Generalized linear models were used to investigate the impact of age, weather, tide and time of day on otters' behaviour. Pups significantly decreased resting behaviour and increased feeding, travelling, interacting and grooming behaviour with increasing age. Females with large pups fed and interacted significantly more, and travelled and groomed the pup less than females with small pups. Foggy conditions were associated with less resting on the water and increased travelling by pups. Tide did not appear to have an effect on sea otter behaviour. Grooming by pups occurred mainly during dawn in medium sized pups whereas large pups groomed themselves mostly during the day and night. Variations due to times of day tended to be apparent only in larger, i.e. older pups. Females and large pups were more active during the day. Mothers of smaller pups spent most of their active time travelling whereas females with large pups were mostly feeding. This study showed how sea otter females with pups adapted their behaviours as their pups grew and matured during the first months of life.
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Job, Damon A., Daryl J. Boness y John M. Francis. "Individual variation in nursing vocalizations of Hawaiian monk seal pups, Monachus schauinslandi (Phocidae, Pinnipedia), and lack of maternal recognition". Canadian Journal of Zoology 73, n.º 5 (1 de mayo de 1995): 975–83. http://dx.doi.org/10.1139/z95-114.
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Vocalizations of individual Hawaiian monk seal pups, Monachus schauinslandi, do not have unique attributes that enable females to recognize their own offspring. Despite low aggregation density during pupping, aggressive encounters are common between females with pups. Fostering is prevalent and may reflect confusion over the identity of pups following aggressive encounters between females. All pup vocalizations were simple in structure and contained true harmonics. The coefficients of variation revealed considerable variance in vocalization structure within pups. Controlling for age, multivariate analyses of variance revealed significant differences among pups in vocalization attributes. Significant developmental changes occurred in vocalization structure for some pups but not for others. Discriminant function analysis suggested that it would be difficult for females to distinguish between the vocalizations of pups. The results of experiments conducted in the field showed that females did not discriminate between filial and alien pups by voice. In addition, females tended not to foster pups that had vocalizations similar to those of their own offspring. Thus, females seem to be unable to recognize their pups by voice. The apparent lack of vocal recognition of pups may contribute to the high frequency of fostering in this species.
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Ibrahim, Ahamed, Sanjay Basak y Nasreen Z. Ehtesham. "Impact of maternal dietary fatty acid composition on glucose and lipid metabolism in male rat offspring aged 105 d". British Journal of Nutrition 102, n.º 2 (23 de enero de 2009): 233–41. http://dx.doi.org/10.1017/s0007114508198993.
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In recent years the intake of n-6 PUFA and trans-fatty acids (TFA) has increased, whereas n-3 PUFA intake has decreased. The present study investigated the effects of maternal diet high in n-6 PUFA, n-3 PUFA or TFA on glucose metabolism, insulin sensitivity and fatty acid profile in male offspring. Female weanling Wistar/NIN rats were randomly assigned to receive either a diet high in linoleic acid (LA), or α-linolenic acid (ALA), or long-chain n-3 PUFA (fish oil; FO), or TFA, for 90 d, and mated. Upon weaning, pups were randomly divided into seven groups (mother's diet-pup's diet): LA-LA, LA-ALA, LA-FO, ALA-ALA, FO-FO, TFA-TFA and TFA-LA. At the age of 105 d, an oral glucose tolerance test, adipocyte glucose transport and muscle phospholipid fatty acid composition were measured in the pups. All animals displayed normal insulin sensitivity as evidenced by similar plasma insulin and area under the curve of insulin after an oral glucose load. Maternal intake of n-3 PUFA (ALA or FO) resulted in higher n-3 PUFA in the offspring. Plasma cholesterol and NEFA were significantly higher in the TFA-TFA group compared with the other groups. Adipocyte insulin-stimulated glucose transport and adiponectin mRNA expression were lower in TFA-TFA and TFA-LA offspring compared with the other groups. While most mother-pup fatty acid combinations did not influence the measured variables in the pups, these results indicate that maternal intake of TFA led to an unfavourable profile in the pups through to the age of 105 d, whether the pups consumed TFA, or not.
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Shaughnessy, P. D., R. J. Kirkwood y R. M. Warneke. "Australian fur seals, Arctocephalus pusillus doriferus: pup numbers at Lady Julia Percy Island, Victoria, and a synthesis of the species' population status". Wildlife Research 29, n.º 2 (2002): 185. http://dx.doi.org/10.1071/wr01056.
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The abundance of Australian fur seal pups was determined at Lady Julia Percy Island in early January 2000 when the average age of pups was 5 weeks. A mark-recapture procedure with repeated recapture sessions was used to estimate abundance of pups in six accessible breeding areas. Pups (n = 1836) were marked by clipping guard hair on the head. Recaptures were conducted visually on 2-4 occasions, when a mean of 41% of sighted pups had been marked. Pup numbers were calculated using a modified Petersen estimate and combined by taking their arithmetic mean. The combined estimate in the accessible breeding areas was 4487 380 pups were counted at two inaccessible sites and 347 dead pups were recorded. Overall, the estimate of abundance for Lady Julia Percy Island was 5214 pups. This exceeds three previous estimates of doubtful veracity for pupping seasons in 1935-36, 1975-76 and 1986-87, and is the greatest number of pups recorded at any Australian fur seal colony. Summation of the most recent estimates of abundance of Australian fur seal pups in all colonies indicates pup production of 16 900 per annum in the 1990s. New Zealand fur seals were also breeding on the island (a mating and four new-born pups were recorded) and two adult male Australian sea lions were observed.
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Kraeft, Susanne, Knut Schwarzer, Sandra Eiden, Barbara Nuesslein-Hildesheim, Gerald Preibisch y Ingrid Schmidt. "Leptin responsiveness and gene dosage for leptin receptor mutation (fa) in newborn rats". American Journal of Physiology-Endocrinology and Metabolism 276, n.º 5 (1 de mayo de 1999): E836—E842. http://dx.doi.org/10.1152/ajpendo.1999.276.5.e836.
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To determine the degree to which the leptin receptor mutation ( fa) influences the responsiveness to leptin during the first postnatal week, we injected recombinant leptin (600 pmol ⋅ g−1 ⋅ day−1sc from day 1 to day 7) into wild-type (+/+), heterozygous (+/ fa), and fatty ( fa/fa) rat pups. Growth and final body fat content of these leptin-treated pups were compared with those of saline-treated littermates of the same genotype. The body mass of the leptin-treated +/+ pups, but not that of the +/ fa and fa/fa pups, increased more slowly than that of their respective controls, and fat content at day 7was reduced by 37% in +/+ pups, by 22% in +/ fa pups, but not at all in fa/fa pups. Plasma leptin remained excessively high throughout the day under this treatment, but a 30-fold lower leptin dose, causing only moderate changes of plasma leptin, still reduced the body fat of +/+ pups significantly. We conclude that leptin participates in the control of even the earliest stages of fat deposition and that the response to supraphysiological doses of leptin is markedly reduced in 1-wk-old pups with one fa allele and absent in pups with two fa alleles.
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Gleed, R. D. y J. P. Mortola. "Ventilation in newborn rats after gestation at simulated high altitude". Journal of Applied Physiology 70, n.º 3 (1 de marzo de 1991): 1146–51. http://dx.doi.org/10.1152/jappl.1991.70.3.1146.
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Pregnant rats were kept at a simulated altitude of 4,500 m (PO2 91 Torr) for the whole of gestation and returned to sea level 1 day after giving birth. During pregnancy, body weight gain and food intake were approximately 30% less than in controls at sea level. Measurements were made on the 1-day-old (HYPO) pups after a few hours at sea level. In normoxia, ventilation (VE) measured by flow plethysmography was more (+17%) and O2 consumption (VO2) measured by a manometric method was less (-19%) than in control (CONT) pups; in HYPO pups VE/VO2 was 44% greater than in CONT pups. In acute hyperoxia, VE/VO2 of HYPO and CONT pups decreased by a similar amount (15-20%), indicating some limitation in O2 availability for both groups of pups in normoxia. However, VE/VO2 of HYPO pups, even in hyperoxia, remained above (+34%) that of CONT pups. HYPO pups weighed slightly less than CONT pups, their lungs were hypoplastic, and their hearts were a larger fraction of body weight. An additional group of female rats was acclimatized (8 days) to high altitude before insemination. During pregnancy, body weight gain and food intake of these females were similar to those of pregnant rats at sea level. Measurements on the 1-day-old pups of this group were similar to those of HYPO pups. We conclude that newborn rats born after hypoxic gestation present metabolic adaptation (low VO2) and acclimatization (high VE/VO2), possibly because of hypoxemia. Maternal acclimatization before insemination substantially alters maternal growth in hypoxia but does not affect neonatal outcome.
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Moore, B. J., J. S. Stern y B. A. Horwitz. "Brown fat mediates increased energy expenditure of cold-exposed overfed neonatal rats". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 251, n.º 3 (1 de septiembre de 1986): R518—R524. http://dx.doi.org/10.1152/ajpregu.1986.251.3.r518.
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Genetically lean rat pups, overfed by being raised in small litters of three from day 1 postpartum, rapidly become obese compared with pups raised in standard sized litters of eight. Because of the rapid onset of their obesity, we expected that overfed pups would exhibit defective brown fat thermogenesis as is seen in neonatal genetically obese rodents. O2 consumption (VO2) was measured in 2-, 4-, 6-, and 8-day-old homozygous lean (Fa/Fa) Zucker pups from each treatment. We determined minimum rate of VO2 at thermoneutrality and maximum VO2 in response to progressively colder ambient temperatures. Overfed pups were fatter than standard-fed pups (P less than 0.001). But contrary to our prediction, overfed pups had a significantly increased maximum VO2 in response to acute cold exposure. To test the hypothesis that brown fat mediated the increased VO2 in the overfed pups, scapular brown fat lipectomies were performed on a new group of overfed pups at 2 days of age and compared with sham-operated littermate controls. On day 8, no differences in minimum VO2 were seen at thermoneutrality when brown fat is turned off. But maximum VO2 in response to cold, when brown fat is turned on maximally, was significantly reduced in the lipectomized overfed pups compared with sham-operated overfed littermates. These data suggest that manipulations of diet, accomplished by raising pups in small litters, can increase brown fat thermogenic function. The results of the lipectomy experiment imply that brown adipose tissue is a primary mediator of the increased energy expenditure in response to acute cold exposure in the overfed pups.
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Morales-Velazquez, Gabriela, Blanca Patricia Lazalde-Ramos, Belinda Claudia Gómez-Meda, Guillermo Moisés Zúñiga-González, Yveth Marlene Ortiz-García, Rosalinda Gutiérrez-Hernández, Celia Guerrero-Velazquez, Susana Vanessa Sánchez de la Rosa y Ana Lourdes Zamora-Perez. "Genome Damage in Rats after Transplacental Exposure to Jatropha dioica Root Extract". Evidence-Based Complementary and Alternative Medicine 2019 (3 de noviembre de 2019): 1–9. http://dx.doi.org/10.1155/2019/2962950.
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Jatropha dioica is traditionally used owing to its antiviral, antifungal, and antimicrobial properties. But, toxicological information regarding J. dioica root total extract is currently limited. The aim of this work was to evaluate in a rat model, the transplacental genotoxicity effect of J. dioica aqueous root total extract. Three different J. dioica aqueous root total extract doses (60, 100, and 300 mg/kg) were administered orally to Wistar rats during 5 days through the pregnancy term (16–21 days). Pregnant rats were sampled every 24 h during the last 6 days of gestation, and pubs were sampled at birth. Genome damage in dams and their newborn pups transplacentally exposed to J. dioica was evaluated by in vivo micronuclei assay. We evaluated the frequency of micronucleated erythrocytes (MNE), micronucleated polychromatic erythrocytes (MNPCE), and polychromatic erythrocytes (PCE) in peripheral blood samples from pups and MNPCE and PCE in pregnant rats. No genotoxic effect was observed after oral administration of the three different doses of aqueous root total extract of J. dioica in pregnant or in their newborn pubs, after transplacental exposure. A significant decrease in PCE frequency was noted in samples from pubs of rats treated with the highest dose of J. dioica extract. The aqueous total root extract of J. dioica at the highest dose tested in our research do have cytotoxic effect in pups transplacentally exposed to this plant extract. Moreover, neither a genotoxic nor a cytotoxic effect was observed in pregnant rats. In the present work, there was no evidence of genome damage in the rat model after transplacental exposure to J. dioica aqueous root total extract.
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Storey, Anne E. y Carolyn J. Walsh. "Are Chemical Cues as Effective as Pup Contact for Inducing Paternal Behaviour in Meadow Voles?" Behaviour 131, n.º 3-4 (1994): 139–51. http://dx.doi.org/10.1163/156853994x00406.
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AbstractWe tested what social cues mediate the transition from non-parental to parental behavior in male meadow voles, based on our previous findings that postpartum interaction with mate and pups was the most effective social experience for making males paternal. Males housed with their mates and pups for a day were more paternal and less aggressive to unrelated pups than males removed from their mates before parturition. Males housed with their mates, but with the litter removed, interacted with pups but were initially as likely to be aggressive as males with no exposure to mates and pups. These results suggest that the mate facilitates interaction with pups, but exposure to pups accelerates the sensitization process. Twenty-four hours of exposure to chemical cues from the mate and pups (mother and litter in cage with wire mesh floor suspended above male's cage) eliminated male aggression towards pups, but physical contact was necessary to enhance positive interactions with pups. Exposure to chemical cues from parturient mates reduced aggression, whereas cues from non-mates were not effective. These results may explain our previous findings that females keep sires removed during pregnancy out of the nest for about a day after reintroduction (while males become sensitized via chemosignals), and continue repelling unfamiliar males (that would not be sensitized by chemical cues from non-mates).
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Thompson, Carl I., John W. Munford, Edward H. Buell, Robert J. Karry, Charles T. Lee, Benjamin L. Morgan y Alexander J. Radnovich. "Plasma constituents and mortality in rat pups given chronic insulin via injection, pellet, or osmotic minipump". Canadian Journal of Physiology and Pharmacology 80, n.º 3 (1 de marzo de 2002): 180–92. http://dx.doi.org/10.1139/y02-020.
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Two studies compared the glucose responses of 9-day-old rats given subcutaneous insulin, either continuously or via daily injection, for 10 days. In Experiment 1, implanted pellets released a total of 0, 1.9, or 5.7 U insulin/kg the first 24 h. Injected doses were larger, 0 or 8 U/kg. Injections caused no deaths, but insulin-releasing pellets caused high mortality within 24 h. Pups surviving the pellets were normoglycemic by treatment day 8. In Experiment 2, pups received 0.184 U of insulin daily, approximately 8 U/kg at 9 days, via either injection or osmotic minipump. All pups survived. Injected pups were hypoglycemic 2 h postinjection through treatment day 10, whereas pups with insulin minipumps were normoglycemic by day 5. Insulin injections, but not minipumps, lowered plasma triglycerides on day 10. To examine age differences in response to insulin, additional pups and adults received daily injections of 0 or 8 U/kg for 10 days. All survived. Insulin lowered plasma glucose more in pups than in adults and reduced triglycerides in pups but not in adults. The rapid development of normoglycemia in pups with insulin minipumps, compared with pups injected daily with the same dose, suggests that continuous early insulin may produce insulin resistance.Key words: route of insulin administration, insulin resistance, mortality, plasma glucose, development.
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Arnbom, T., M. A. Fedak, I. L. Boyd y B. J. McConnell. "Variation in weaning mass of pups in relation to maternal mass, postweaning fast duration, and weaned pup behaviour in southern elephant seals (Mirounga leonina) at South Georgia". Canadian Journal of Zoology 71, n.º 9 (1 de septiembre de 1993): 1772–81. http://dx.doi.org/10.1139/z93-252.
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Female southern elephant seals, Mirounga leonina, assemble in large groups and each gives birth to a single pup which is nursed for some 3 weeks. Weaning mass is highly variable; some pups are three times as heavy as others at weaning. After weaning, the pup fasts for several weeks before departing to sea. The function of this fast is unknown. We examined the relationships between maternal mass, pup weaning mass, and pup behaviour during the postweaning fast in 377 pups and 128 adult females over four breeding seasons at South Georgia. Pup weaning mass was positively related to maternal postpartum mass, which accounted for 55% of the variation in weaning mass. Over all 4 years male pups were significantly heavier at weaning than female pups (130 vs. 123 kg) but this difference disappeared after maternal mass was controlled for. After fasting for 21–66 days, weaned pups went to sea at an average of 68% of weaning mass. Heavier pups remained on the beach longer after weaning than lighter pups. There was no evidence that pups synchronized their departure to sea. Only male pups were observed to take part in mock fights. With increasing age, weaned pups spent more time in the water. Mortality during the postweaning fast was negligible (0.1 %). The timing of departure of weaned pups may involve a trade-off between an early departure with greater fat (energy) stores but poorer foraging ability and a late departure with increased swimming, diving, and social skills but reduced fat stores.
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Mattheij, John A. M. y Hans J. M. Swarts. "Evidence that exteroceptive stimuli other than suckling have no major effect on plasma prolactin in lactating rats". Acta Endocrinologica 114, n.º 3 (marzo de 1987): 417–25. http://dx.doi.org/10.1530/acta.0.1140417.
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Abstract. The ability of exteroceptive stimuli from pups to increase plasma prolactin in lactating dams was investigated. Prolactin profiles were measured during 30 min of suckling followed by complete or partial separation from pups. Prolactin profiles were also measured subsequent to complete or partial isolation from pups in dams which had been with pups permanently before the experiment. In addition, plasma prolactin was measured in dams which after a night of isolation were partially united with pups. Finally, the effect of ether stress on prolactin profiles after interruption of suckling by pups was determined. Vigorous suckling after a period of isolation induced a sharp increase of plasma prolactin. Subsequent to pup removal, either partial or complete, prolactin profiles showed a widespread variation. Also dams which before experimentation were kept permanently with pups, showed a great variation in prolactin profiles subsequent to either complete or partial separation from pups. Plasma prolactin either decreased rapidly or gradually. In several dams a rapid or a gradual decline of plasma prolactin was interrupted by one or more episodes of prolactin release. Partial reunion with pups after a night of isolation, either in mid-lactation or in late lactation, did not induce a rise of plasma prolactin. It is concluded that exteroceptive stimuli from pups are not effective as prolactin releasing signal. Because ether stress did not induce a steep rise of plasma prolactin, we conclude that the episodic rises of plasma prolactin in dams, subsequent to partial or complete removal of pups, are due to spontaneous activity of the hypothalamo-pituitary system.
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Gilbert, Caroline, Stéphane Blanc, Sylvain Giroud, Marie Trabalon, Yvon Le Maho, Martine Perret y André Ancel. "Role of huddling on the energetic of growth in a newborn altricial mammal". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 293, n.º 2 (agosto de 2007): R867—R876. http://dx.doi.org/10.1152/ajpregu.00081.2007.
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Huddling is considered as a social strategy to reduce thermal stress and promote growth in newborn altricial mammals. So far, the role of huddling on the allocation of saved energy has not been quantified nor have the related impacts on body temperature rhythms. To determine the energy partitioning of rabbit pups either raised alone or in groups of eight, four, or two individuals, when thermoregulatory inefficient (TI) and efficient (TE), we first investigated their total energy expenditure and body composition. We then monitored body temperature and activity rhythms to test whether huddling may impact these rhythms, centered on the suckling event. Pups in a group of eight utilized 40% less energy for thermogenesis when TI than did pups alone and 32% less energy when TE. Pups in groups of eight and four had significantly lower thermoregulatory costs in the TI period, whereas pups in groups of two, four, and eight had lower costs during the TE period. Huddling pups could therefore channel the energy saved into processes of growth and accrued more fat mass (on average 4.5 ± 1.4 g) than isolated pups, which lost 0.7 g of fat. Pups in groups of four and eight had a body temperature significantly higher by 0.8°C than pups in groups of two and one when TI, whereas no more differences were noted when the TE period was reached. Moreover, pups alone showed an endogenous circadian body temperature rhythm that differed when compared with that of huddling pups, with no rise before suckling. Thus huddling enables pups to invest the saved energy into growth and to regulate their body temperature to be more competitive during nursing, particularly at the early time when they are TI.
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Bray, Natasha. "Picking up the pups". Nature Reviews Neuroscience 16, n.º 6 (8 de mayo de 2015): 315. http://dx.doi.org/10.1038/nrn3967.
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Schwarzer, K., H. Doring y I. Schmidt. "Different physiological traits underlying increased body fat of fatty (fa/fa) and heterozygous (+/fa) rats". American Journal of Physiology-Endocrinology and Metabolism 272, n.º 1 (1 de enero de 1997): E100—E106. http://dx.doi.org/10.1152/ajpendo.1997.272.1.e100.
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To find out whether the most characteristic physiological traits distinguishing suckling-age fa/fa pups from lean littermates also differ between +/+ and +/fa littermates, we analyzed the body composition and cold defense of 7- and 16-day-old pups and the plasma concentrations of insulin, glucose, triglycerides, and free fatty acids in 16-day-old pups. Zucker rat x Brown Norway hybrid pups were genotyped by using a molecular marker within 0.5 cM of the fa gene. At both ages the +/fa pups had significantly more body fat than their +/+ littermates. At 7 days this difference was as large as that between +/fa and fa/fa pups, but at 16 days it was only one-seventh of the fa/fa vs. +/fa difference. In contrast, there were no heterozygote differences for three parameters that show crucial abnormalities in the fa/fa pups: thermoregulatory thermogenesis and plasma concentrations of insulin and triglycerides. The physiological mechanisms underlying the increased fat content of +/fa pups thus differ from those known to fuel most of the excessive fat deposition of their fa/fa littermates.
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McCulloch, Susanne, Patrick P. Pomeroy y Peter JB Slater. "Individually distinctive pup vocalizations fail to prevent allo-suckling in grey seals". Canadian Journal of Zoology 77, n.º 5 (1 de octubre de 1999): 716–23. http://dx.doi.org/10.1139/z99-023.
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In crowded aggregations that occur in breeding colonies, female pinnipeds commonly become separated from their pups and may use spatial, olfactory, or auditory cues to locate them. A system of mutual recognition based on vocalizations is known for otariids. Female phocids are known to use location and olfaction to help identify pups, but evidence for vocal recognition is weak. During the 1997 breeding season on the Isle of May, Scotland, vocalizations were recorded from grey seal, Halichoerus grypus, pups; playback experiments were carried out; and nursing of nonfilial pups was observed. Pup vocalizations were found to be both stereotyped and individually distinctive, features normally associated with a system of individual recognition. However, playback experiments revealed that mothers did not respond more to vocalizations of their own pups than to those of nonfilial pups. Furthermore, seventeen cases of allo-suckling were observed during 68 h of observation on the colony. High densities of animals and frequent separations present challenges to identification of pups by their mothers.
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Bowen, W. D., D. J. Boness y S. J. Iverson. "Diving behaviour of lactating harbour seals and their pups during maternal foraging trips". Canadian Journal of Zoology 77, n.º 6 (10 de octubre de 1999): 978–88. http://dx.doi.org/10.1139/z99-065.
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Female harbour seals (Phoca vitulina) undertake foraging trips during mid to late lactation. We show that they are accompanied by their pup during many of these foraging trips. Time-depth recorder data were obtained from 20 lactating females and 14 of their pups in 1995 and 1996 at Sable Island, Nova Scotia. Overall, females spent 55.4 ± 4.68% (mean ± SE) of their time at sea compared with 39.8 ± 2.29% for pups. Like those of their mothers, pups' dives occurred in clusters or bouts: 71.4 ± 4.4 dives, 2.5 ± 0.15 h in duration. Bouts of diving by females and pups began 0-3 days post partum. Mean dive duration of pups increased from about 1 to 1.5 min over the course of lactation, but was still shorter than that of adult females (1.5-2.25 min). Both females and pups appeared to dive within their theoretical aerobic dive limits (TADL) of 8.9 and 2.6-3.1 min, respectively. Up to 3.6% of dives by some pups may have exceeded their TADL. Pups appeared to compensate for their lesser diving ability by making more and shorter dives per bout than females, particularly during early lactation.
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Modig, Anders, Henri Engström y Tom Arnbom. "Postweaning behaviour in pups of the southern elephant seal (Mirounga leonina) on South Georgia". Canadian Journal of Zoology 75, n.º 4 (1 de abril de 1997): 582–88. http://dx.doi.org/10.1139/z97-072.
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After weaning, southern elephant seal pups (Mirounga leonina) fast for 3 – 8 weeks, for largely unknown reasons. During the postweaning fast we observed daytime behaviour and movements of pups on South Georgia in relation to mass, sex, and tooth eruption. There was variation in behaviour, with the lowest levels of activity from about 09:00 to 15:00. When ashore, weaned pups spent 97% of the time resting. There was no difference in activity between the sexes, except that only male pups were observed fighting. There was a significant difference in tooth eruption between the sexes. In female pups, 87.9% had teeth at weaning, while only 28.7% of male pups had. There was no correlation between mass at weaning and activity in either sex. Weaned pups tended to gather in groups (median group size 3, range 2 – 67). Several factors may affect the behaviour of pups during the postweaning fast: the resting behaviour required to save energy favours spending time ashore during the day (which also enhances vitamin D synthesis), and foraging is more effectively practiced at night because their prey is more active at night.
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Nuesslein, B. y I. Schmidt. "Development of circadian cycle of core temperature in juvenile rats". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 259, n.º 2 (1 de agosto de 1990): R270—R276. http://dx.doi.org/10.1152/ajpregu.1990.259.2.r270.
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To find out whether or not juvenile rats can sustain circadian rhythms of core temperature (Tc) in the absence of diurnal cues, we continuously recorded Tc for 12 days in isolated pups artificially reared in continuous dim light. Possible effects of uncontrolled environmental 24-h cycles were excluded by simultaneously studying pups born on the same day to two mothers entrained to 12:12 h light-dark cycles 180 degrees out of phase. Age-dependent changes were discriminated from the effects of sustained isolation by comparing Tc records between pups isolated from 10 or from 4 days of age (late- or early-isolated pups). Both groups of pups showed Tc cycles in phase with the light cycle in the colony of origin and with highest amplitudes from 10 to 13 days of age. Tc cycles with a period length close to 24 h could be seen through the 12th day of artificial rearing for early-isolated pups but only until the 6th day for late-isolated pups. In the third postnatal week the rhythm faded gradually. Self-sustained circadian Tc rhythms observed in isolated 1- to 2-wk-old pups demonstrate a functional endogenous clock in the juvenile rat.
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Bowen, W. D., O. T. Oftedal, D. J. Boness y S. J. Iverson. "The effect of maternal age and other factors on birth mass in the harbour seal". Canadian Journal of Zoology 72, n.º 1 (1 de enero de 1994): 8–14. http://dx.doi.org/10.1139/z94-002.
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We studied the effects of maternal age, maternal body mass at parturition, year of birth, birth date, pup sex, and developmental stage (as indicated by the presence of a foetal pelage called lanugo) on the birth mass of harbour seals (Phoca vitulina) on Sable Island, Nova Scotia, Canada. Between 1987 and 1992, mass was obtained on 330 newborns and 259 of their mothers. Birth mass was significantly correlated with maternal mass (r = 0.42 for male pups; r = 0.32 for female pups). Among pups that had shed their lanugo, males were significantly heavier at birth (11.4 ± 0.09 kg, n = 107) than females (10.9 ± 0.09, n = 99). Birth mass increased significantly with maternal age (n = 71, range 4–12 years) even after the effects of maternal mass and pup sex were statistically removed. Mean birth mass varied significantly among years, from 10.5 to 11.5 kg. Newborns averaged 12.8% of maternal mass at parturition (84.8 ± 0.49 kg). Most (84%) pups had shed their lanugo before birth. Pups born with extensive lanugo were born earlier in the season and weighed about 20% less than pups born without lanugo. These data suggest that pups born with lanugo may be less developed than pups that had shed their foetal coat. Young mothers (4 and 5 years old) produced most of the underweight, lanugo-covered pups.
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Madden, Joah R., Hansjoerg P. Kunc, Sinead English, Marta B. Manser y Tim H. Clutton-Brock. "Calling in the gap: competition or cooperation in littermates' begging behaviour?" Proceedings of the Royal Society B: Biological Sciences 276, n.º 1660 (6 de enero de 2009): 1255–62. http://dx.doi.org/10.1098/rspb.2008.1660.
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Offspring are frequently raised alongside their siblings and are provisioned early in life by adults. Adult provisioning is stimulated by offspring begging, but it is unclear how each offspring should beg, given the begging behaviour of their siblings. It has previously been suggested that siblings may compete directly through begging for a fixed level of provisioning, or that siblings may cooperate in their begging in order to jointly elevate the level of provisioning by adults. We studied the begging behaviour of meerkat Suricata suricatta pups, explored how it changed as the begging behaviour of their littermates altered, and asked how the adults responded to group-level changes in begging. We found conflicting evidence for classic models of competitive and cooperative begging. Pups reared in larger litters begged at higher rates, yet experimentally increasing begging levels within groups caused individual begging rates to decrease. Pups decreased begging rates when close to other begging pups, and pups spaced further apart were fed more. Adults increased their overall level of provisioning as group levels of begging increased, but per capita provisioning decreased. Adults preferred to provision speakers playing back recordings of two pups begging alternately to recordings of the same two pups begging simultaneously. Therefore, we suggest that meerkat pups avoid some of the costs of direct competition imposed by an escalation of begging as other pups beg, by begging in gaps between the bouts of others or avoiding littermates. Such behaviour is also preferred by provisioning adults, thus providing additional benefits to the pups.
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Guinet, Christophe, Mary-Anne Lea y Simon D. Goldsworthy. "Mass change in Antarctic fur seal (Arctocephalus gazella) pups in relation to maternal characteristics at the Kerguèlen Islands". Canadian Journal of Zoology 78, n.º 3 (1 de abril de 2000): 476–83. http://dx.doi.org/10.1139/z99-231.
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Maternal allocation to growth of the pup was measured in Antarctic fur seals (Arctocephalus gazella) at the Kerguèlen Islands during the 1997 austral summer. Absolute mass gain of pups following a maternal foraging trip was independent of the sex of the pup but was positively related to foraging-trip duration and maternal length. However, daily mass gain (i.e., absolute mass gain of the pup divided by foraging-trip duration) decreased with increasing foraging-trip duration but increased with maternal length. While the pup were fasting, their daily mass loss was related to their sex and initial body mass: both heavier pups and female pups lost more mass per day than lighter pups and male pups. The mass-specific rate of mass loss was significantly higher in female than in male pups. Over the study period, the mean growth rate was zero, with no difference between female and male pups. The growth rate in mass of the pup was positively related to maternal length but not to maternal condition, and negatively related to the foraging-trip duration of the mother and the initial mass of the pup. This indicates that during the study period, heavier pups grew more slowly because of their higher rate of daily mass loss during periods of fasting. Interestingly, for a given maternal length, the mean mass of the pup during the study period was higher for male than for female pups, even though the rate of daily mass gain was the same. Such differences are likely to result from sex differences in the mass-specific rate of mass loss. As female pups lose a greater proportion of their mass per day, a zero growth rate (i.e., mass gain only compensating for mass loss) is reached at a lower mass in female pups than in male pups. Our results indicate that maternal allocation does not differ according to the sex of the pup, but suggest that the two sexes follow different growth strategies.
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Donohue, M. J., D. P. Costa, M. E. Goebel y J. D. Baker. "The ontogeny of metabolic rate and thermoregulatory capabilities of northern fur seal, Callorhinus ursinus, pups in air and water". Journal of Experimental Biology 203, n.º 6 (15 de marzo de 2000): 1003–16. http://dx.doi.org/10.1242/jeb.203.6.1003.
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Young pinnipeds, born on land, must eventually enter the water to feed independently. The aim of this study was to examine developmental factors that might influence this transition. The ontogeny of metabolic rate and thermoregulation in northern fur seal, Callorhinus ursinus, pups was investigated at two developmental stages in air and water using open-circuit respirometry. Mean in-air resting metabolic rate (RMR) increased significantly from 113+/−5 ml O(2)min(−)(1) (N=18) pre-molt to 160+/−4 ml O(2)min(−)(1) (N=16; means +/− s.e.m.) post-molt. In-water, whole-body metabolic rates did not differ pre- and post-molt and were 2.6 and 1.6 times in-air RMRs respectively. Mass-specific metabolic rates of pre-molt pups in water were 2.8 times in-air rates. Mean mass-specific metabolic rates of post-molt pups at 20 degrees C in water and air did not differ (16.1+/−1.7 ml O(2)min(−)(1)kg(−)(1); N=10). In-air mass-specific metabolic rates of post-molt pups were significantly lower than in-water rates at 5 degrees C (18.2+/−1.1 ml O(2)min(−)(1)kg(−)(1); N=10) and 10 degrees C (19.4+/−1.7 ml O(2)min(−)(1)kg(−)(1); N=10; means +/− s.e.m.). Northern fur seal pups have metabolic rates comparable with those of terrestrial mammalian young of similar body size. Thermal conductance was independent of air temperature, but increased with water temperature. In-water thermal conductance of pre-molt pups was approximately twice that of post-molt pups. In-water pre-molt pups matched the energy expenditure of larger post-molt pups while still failing to maintain body temperature. Pre-molt pups experience greater relative costs when entering the water regardless of temperature than do larger post-molt pups. This study demonstrates that the development of thermoregulatory capabilities plays a significant role in determining when northern fur seal pups enter the water.
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Vasu, Jayalakshmi, Mouttou Vivek Srinivas, Prabhakar Xavier Antony, Jacob Thanislass, Vijayalakshmi Padmanaban y Hirak Kumar Mukhopadhyay. "Comparative immune responses of pups following modified live virus vaccinations against canine parvovirus". Veterinary World 12, n.º 9 (septiembre de 2019): 1422–27. http://dx.doi.org/10.14202/vetworld.2019.1422-1427.
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Background and Aim: Canine parvovirus (CPV) is the most important viral cause of enteritis and mortality in pups. Evaluation and monitoring of pre- and post-vaccine immune responses may help to determine the efficacy of the current vaccination schedule being followed in pups in India. This study aimed to evaluate and monitor the pre- and post-vaccine immune responses of CPV vaccinated pups using hemagglutination inhibition (HI) assay. The neutralizing antibody titer levels were also detected using serum neutralization test (SNT). Materials and Methods: The pups were categorized into two groups, the double booster and the single booster groups. In this study, serum samples were subjected to HI and SNT for measuring the CPV antibody titer at frequent intervals for up to 6 months from 27 healthy pups following primary and booster CPV vaccinations. Results: The antibody titers in double booster pups reached their peaks at the 21st day after the second booster vaccination with a geometric mean (GM) of 3.57. The antibody titers in single booster pups reached their peaks at the 21st day after the first booster vaccination with a lower GM of 3.18. Conclusion: The double booster pups maintained a higher immune response throughout the period of the study compared to single booster pups though the difference in titers was not statistically significant. SNT results indicated that the raised antibody titer was also able to yield virus-neutralizing antibodies. No interfering maternally derived antibodies were found in the pups at the age of primary vaccination (45th day) in our study. Therefore, the second booster vaccination may be useful in maintaining the protective titer for a prolonged period.
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OBREGÓN, María-Jesus, Barbara CANNON y Jan NEDERGAARD. "Postnatal selective suppression of lipoprotein lipase gene expression in brown adipose tissue (relative to the expression of the gene for the uncoupling protein) is not due to adrenergic insensitivity: a possible specific inhibitory effect of colostrum". Biochemical Journal 314, n.º 1 (15 de febrero de 1996): 261–67. http://dx.doi.org/10.1042/bj3140261.
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The levels of mRNA coding for the uncoupling protein (UCP) and for lipoprotein lipase (LPL) were monitored in the brown adipose tissue of newborn rat pups. At 5 h after birth, the mRNA levels of UCP and LPL were high in pups exposed singly to 28 °C and low in pups kept singly at thermoneutrality (36 °C); in pups staying with the dam, the UCP mRNA levels were intermediate. However, the LPL mRNA levels were lower in pups staying with the dam than in pups at 36 °C, implying that factors additional to environmental temperature influenced LPL gene expression. Injection of noradrenaline into pups at thermoneutrality (36 °C) led to increases in UCP and LPL gene expression, but noradrenaline injections had no further effect in cold-exposed pups. The adrenergic effects were mediated via β-adrenergic receptors. The cold-induced increases in both UCP and LPL gene expression were abolished by the β-adrenergic antagonist propranolol. Thus differences in adrenergic responsiveness could not explain the differential expression of the UCP and LPL genes observed in pups staying with the dam. The presence of a physiological suppressor was examined by feeding single pups at 28 °C with different foods: nothing, water, Intralipid, cow's milk, rat milk and rat colostrum. None of these agents led to suppression of UCP gene expression, but colostrum led to a selective suppression of LPL gene expression. It was concluded that the genes for UCP and LPL were responsive to adrenergic stimuli immediately after birth, and it is suggested that a component of rat colostrum can selectively suppress LPL gene expression.
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Shilton, Cathy M. y Ronald J. Brooks. "Paternal care in captive collared lemmings (Dicrostonyx richardsoni) and its effect on development of the offspring". Canadian Journal of Zoology 67, n.º 11 (1 de noviembre de 1989): 2740–45. http://dx.doi.org/10.1139/z89-388.
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We examined parental care in captive collared lemmings (Dicrostonyx richardsoni) to determine how this behavior differed between sexes and to test the hypothesis that presence of the male with the litter from parturition to weaning (17 d) would affect preweaning rates of growth, behavioral development, and body size and aggression at sexual maturity. Also, we tested whether stressing the litter, by removal of the female for 8 h/d, would alter the effect of the male on the development of pups. We compared four treatments: pups raised with mother only, pups raised with both parents, stressed pups raised with mother only, and stressed pups raised with both parents. Parental behavior was recorded from parturition to weaning. Preweaning development of pups was measured by rate of weight gain, age of eye opening, and development of thermoregulation and righting ability. Comparisons were made between stressed and unstressed litters raised with or without the sire. At 25 d, pups were weighed again and isolated, and at 60–75 d, their intrasexual aggressive behavior was measured. Presence of the sire did not alter behavior of the dam, and except for lactation, males and females cared equally for the pups. At weaning, stressed pups weighed less than unstressed pups, but this difference disappeared by 25 d. Presence of the sire had no effect on aggression of male or female offspring at 75 d. We concluded that the paternal care shown in this species is either an artifact of laboratory conditions or that it has effects, such as protection of offspring from infanticide or alleviation of thermal stress, that were not examined in this study.
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Böhm, A. y S. Hoy. "Untersuchungen zum Einfluß der Geburtsmasse auf die Lebendmasseentwicklung von Hundewelpen bis zum 20. Lebenstag". Archives Animal Breeding 43, n.º 6 (10 de octubre de 2000): 655–62. http://dx.doi.org/10.5194/aab-43-655-2000.
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Abstract. Title of the paper: Investigations on influence of birth weight on live weight development up to 20th day of age in dog pups Investigations with 102 litters and 715 alive born and 581 individually controlled up to 20th day of age dog pups have shown a highly significant influence of birth weight (x) on weight at the end of third week of age (y) (r = .457; y = 299.9 + 1.99x; p < 0.01). Birth weight of pups died (281 g) was highly significant lower compared to pups who were not lost up to 20th day of age (328 g). Pups with birth weight of more than 451 g reached without losses live weight at day 20 of age which was appr. twice higher compared to pups with birth weight of less than 200 g. Those pups with low birth weight (< 200 g) had a percentage of losses of 83.3 %. Increasing litter size leads to highly significant reduce both in birth weight from 361 to 396 g (litter size = 2 to 5) to 286 g (litter size = 12) and live weight at day 20 of age from 1292 g (litter size = 3) to 748 g (litter size =11). Male dog pups had a less higher live weight compared to female siblings at all points.
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Seguel, Mauricio, Francisco Muñoz, Felipe Montalva, Diego Perez-Venegas, Héctor Pavés y Nicole Gottdenker. "Kelp and dolphin gulls cause perineal wounds in South American fur seal pups ( Arctocephalus australis ) at Guafo Island, Chilean Patagonia". Royal Society Open Science 4, n.º 7 (julio de 2017): 170638. http://dx.doi.org/10.1098/rsos.170638.
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During five reproductive seasons, we documented the presence, extent and origin of perineal wounds in South American fur seal pups ( Arctocephalus australis ) on Guafo Island, Northern Chilean Patagonia. The seasonal prevalence of perineal wounds ranged from 5 to 9%, and new cases were more common at the end of the breeding season (February), when pups were on average two months old and were actively expelling hookworms ( Uncinaria sp). Histologically, wounds corresponded to marked ulcerative lymphoplasmacytic and histiocytic dermatitis with granulation tissue and mixed bacterial colonies. In 2015 and 2017, kelp gulls ( Larus dominicanus ) and dolphin gulls ( Leucophaeus scoresbii ) were observed picking and wounding the perineal area of marked pups. This behaviour occurred more frequently after the pups' defecation, when sea gulls engaged in consumption of pups' faeces. The affected pups usually had moderate to marked hookworm infections along with bloody diarrhoea and anaemia. Pups with severe wounds (23% of affected animals) had swollen perineal areas and signs of secondary systemic bacterial infection. We propose that seagulls on Guafo Island have learned to consume remains of blood and parasites in the faeces of pups affected by hookworm infection, causing perineal wounds during this process. We conclude that this perineal wounding is an unintentional, occasional negative effect of an otherwise commensal gull–fur seal relationship.
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Fiorotto, M. L., D. G. Burrin, M. Perez y P. J. Reeds. "Intake and use of milk nutrients by rat pups suckled in small, medium, or large litters". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 260, n.º 6 (1 de junio de 1991): R1104—R1113. http://dx.doi.org/10.1152/ajpregu.1991.260.6.r1104.
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We investigated the extent to which the altered weight gain of rat pups suckled in litters of varying sizes (4, 10, and 16 pups/litter) is attributable to differences in milk nutrient intake. Milk intake was estimated from the rate of dilution over 2 days of a dose of 3H2O administered at 4, 8, and 14 days of age after correction for the water and milk carbon deposited in body tissues over the measurement period. Protein and energy intakes were estimated from the volume of milk consumed by individual pups and the composition of milk from each dam. Significant effects of litter size on milk fat and protein concentration were observed. Weight gain was highly correlated with energy intake in pups suckled in litters of 4 and 10 but not 16. These findings were attributed to a higher energy expenditure of pups less than 10 days old suckled in litters of 16; specifically these pups had higher maintenance energy needs than pups suckled in litters of 4 and 10 and a higher energy cost of tissue synthesis. The latter was ascribed to an ability of immature pups to maximize the efficiency of protein utilization, thereby blunting the deleterious effects of a reduced nutrient intake on protein deposition.
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Kirkwood, Roger, David Pemberton, Rosemary Gales, Andrew J. Hoskins, Tony Mitchell, Peter D. Shaughnessy y John P. Y. Arnould. "Continued population recovery by Australian fur seals". Marine and Freshwater Research 61, n.º 6 (2010): 695. http://dx.doi.org/10.1071/mf09213.
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Australian fur seals (Arctocephalus pusillus doriferus) are conspicuous, top-level predators in coastal waters of south-eastern Australia that were over-harvested during the 1800s and have had a delayed recovery. A previous species-wide estimate of live pups in 2002 recorded a near-doubling of annual pup production and a 5% annual growth rate since the 1980s. To determine if pup production increased after 2002, we estimated live pup numbers in 2007. Pups were recorded at 20 locations: 10 previously known colonies, three newly recognised colonies and seven haul-out sites where pups are occasionally born. Two colonies adjacent to the Victorian coast accounted for 51% of live pups estimated: Seal Rocks (5660 pups, 25.9%) and Lady Julia Percy Island (5574 pups, 25.5%). Although some colonies were up and some were down in pup numbers, the 2007 total of 21 882 ± 187 (s.e.) live pups did not differ significantly from a recalculated estimate of 21 545 ± 184 in 2002, suggesting little change to overall population size. However, the colonisation of three new sites between 2002 and 2007 indicates population recovery has continued.
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Buchberger, P. y I. Schmidt. "Is the onset of obesity in suckling fa/fa rats linked to a potentially larger milk intake?" American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 271, n.º 2 (1 de agosto de 1996): R472—R476. http://dx.doi.org/10.1152/ajpregu.1996.271.2.r472.
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We wanted to find out whether fatty (fa/fa) sucklings show abnormal intake when given access to an abundant milk reservoir. To do this, we gravimetrically determined the milk ingested by small groups (4-5 pups) of 5- to 15-day-old lean (+/fa) and fatty littermates allowed to suckle for 30 min after their mother had not been nursing for periods of between 1 and 7 h. The pups were grouped randomly and their phenotypes retrospectively identified. Within both genotypes, the intakes of simultaneously tested pups were significantly higher in pups deprived for longer periods. Deprived and undeprived fa/fa pups ingested, however, slightly but significantly less milk than +/fa littermates did in the same nursing bout. In the first 2 wk of life, when fa/fa pups deposit nearly twice as much body fat as their +/fa littermates do, fa/fa pups will thus suckle less rather than more milk. This extends previous findings showing that the onset of fa/fa obesity is independent of larger intakes and thus questions that fa impairs a receptor primarily controlling food intake.
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Lea, Mary-Anne y Mark A. Hindell. "Pup Growth and Maternal Care in New Zealand Fur Seals, Arctocephalus forsteri, at Maatsuyker Island, Tasmania". Wildlife Research 24, n.º 3 (1997): 307. http://dx.doi.org/10.1071/wr96054.
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The growth, maternal attendance and sucking behaviour of 11 New Zealand fur seal pups, Arctocephalus forsteri, on Maatsuyker Island, Tasmania, were studied during the first six months of lactation. Early growth rates (0–50 days) ranged from 78 to 138 g day-1 and were amongst the highest recorded for any fur seal. Male pups from Maatsuyker Island in 1993 grew at double the rate reported from Kangaroo Island in 1989 and 1990. Growth of pups was influenced by the attendance behaviour of mothers. Mothers that spent relatively long periods at sea had pups that grew more slowly. The proportion of time spent sucking by pups decreased during the attendance period of mothers. Distinct interannual variability was also determined for body masses of pups weighed in March in five successive years, 1990–94, with mean body mass differing by up to 20% between years.
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Seguel, M., F. Muñoz, M. J. Navarrete, E. Paredes, E. Howerth y N. Gottdenker. "Hookworm Infection in South American Fur Seal (Arctocephalus australis) Pups". Veterinary Pathology 54, n.º 2 (14 de diciembre de 2016): 288–97. http://dx.doi.org/10.1177/0300985816677151.
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Tissues of South American fur seal pups naturally infected with hookworms ( Uncinaria sp) were examined. Hookworm infection was found in nearly all pups examined (132/140, 94%), and hookworm enteritis with secondary bacteremia was considered the cause of death in 46 (35%) pups. Common findings in these pups included severe hemorrhagic enteritis and numerous (mean intensity = 761.8) hookworms in the jejunum. Hookworms were recovered from the abdominal cavity in 12 of 55 pups (22%) examined through peritoneal wash; these pups had an average of 1343.3 intestinal hookworms and marked fibrinohemorrhagic peritonitis. In all pups that died as a consequence of hookworm infection, the intestinal villi were short, blunt, and fused, and there were variable numbers of free and intrahistiocytic gram-negative bacteria in submucosal hookworm feeding tracks, mesenteric lymph nodes, spleen, blood vessels, and liver sinusoids. Pups that died of causes unrelated to the hookworm infection (trauma) had hookworm feeding tracks confined to the apical portions of the mucosa, and moderate to marked catarrhal eosinophilic enteritis. The number of hookworms was negatively correlated with intestinal villous length and number of leukocytes in the intestine. Pups with hookworm peritoneal penetration had nematodes with little or no blood in the hookworm intestine, suggesting that lack of food for the nematode could be associated with peritoneal penetration. Findings suggest that the initial burden of larval infection, the level of the host tissue response, or a combination determine the number of nematodes in the intestine, the severity of hookworm tissue damage, and pup mortality.
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Kim, Sang-Hoon, Il-Gyu Ko, Jun-Jang Jin, Lakkyong Hwang y Seung-Soo Baek. "Treadmill exercise ameliorates impairment of spatial learning memory in pups born to old and obese mother rats". Journal of Exercise Rehabilitation 17, n.º 4 (23 de agosto de 2021): 234–40. http://dx.doi.org/10.12965/jer.2142466.233.
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Memory state of rat pups born to old and obese mother rats and the effect of a treadmill running of mother rats on the memory of rat pups were studied. The radial 8-arm maze test was performed to detect spatial learning memory, and the level of tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 in the hippocampus was measured by enzymelinked immunoassay. Western blotting was performed for the expression of nuclear factor kappa-light-chain-enhancer (NF-κB), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκB-α), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), matrix metalloproteinase (MMP)-9, and immunohistochemistry for caspase-3 was conducted. The newborn rats were classified into following groups: pups born to old mother rats, pups born to old mother rats with exercise, pups born to old and obese mother rats, and pups born to old and obese mother rats with exercise. Exercise of mother ameliorated spatial learning memory impairment, inhibited proinflammatory cytokines production, NF-κB expression, and IκB-α phosphorylation of the pups born to old and obese mother rats. Maternal exercise suppressed Bax expression, the number of caspase-3, the level of MMP-9, and enhanced Bcl-2 expression of the pups born to old and obese mother rats. When the maternal exercise was performed, the impairment of spatial learning memory in pups was ameliorated. Therefore, it can be seen that exercise during pregnancy of older and obese mothers is an important factor in fetal health management.
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Haug, Tore, Kjell T. Nilssen y Lotta Lindblom. "First independent feeding of harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) pups in the Greenland Sea". NAMMCO Scientific Publications 2 (25 de mayo de 2000): 29. http://dx.doi.org/10.7557/3.2969.
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Data were collected from harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) pups belonging to the Greenland Sea (or "West Ice") stocks in 1995-1997. Pups of both species were observed to feed independently shortly after weaning, and their first food was almost exclusively crustaceans. Parathemisto sp., particularly P. libellula, dominated the diet of both the harp and the hooded seal pups, but the diet also contained sympagic amphipods of the genus Gammarus. Krill (Thysanoessa sp.) was of minor importance as food for seal pups in 1995, but occurred more frequentlyin the diet of both species in 1996 and 1997. Considerable niche overlap may suggest some interspecific competition between harp and hooded seal pups in the West Ice.
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McMahon, Clive R. y Mark A. Hindell. "Twinning in southern elephant seals: the implications of resource allocation by mothers". Wildlife Research 30, n.º 1 (2003): 35. http://dx.doi.org/10.1071/wr01069.
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Southern elephant seals (Mirounga leonina) typically give birth to a single pup and raise it over a short 24-day lactation period. Lactation is characterised by: maternal fasting, rapid pup growth and abrupt weaning after which the weaned pups rely on stored fat for growth and survival. Females are not able to transfer all of their stored resources to their pups because they themselves need to use some to return to their remote foraging grounds after the breeding effort. Therefore the amount of energy expended by a female during lactation may affect not only the survival of her pup, but her own survival and future reproductive success. Female southern elephant seals are therefore under strong selective pressure to allocate finite amounts of resources to their pups. In the rare event of producing twins, females that wean both pups are likely to experience reduced reproductive success. Twin births accounted for 0.38% of all the observed elephant seal births at Macquarie Island in 1999. The mean birth masses, weaning lengths and lactation duration for twin and singleton pups did not differ significantly but weaning mass, weaning girths and lactation growth rates did differ significantly. In all cases, singleton pups were larger and grew faster than twin pups. Twin pups suffered greater pre-weaning mortality than singletons (16.7% and 4.6% respectively) and fewer were seen alive after 18 months (20% compared with 47% respectively).
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Poran, Naomie S. y Richard G. Coss. "Development of Antisnake Defenses in California Ground Squirrels (Spermophilus Beecheyi): I. Behavioral and Immunological Relationships". Behaviour 112, n.º 3-4 (1990): 222–44. http://dx.doi.org/10.1163/156853990x00211.
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AbstractThe development of antisnake behavioral and immunological defenses was investigated in laboratory born California ground squirrels (Spermophilus beecheyi) from an area in California where Northern Pacific rattlesnakes (Crotalus viridis oreganus) and Pacific gopher snakes (Pituophis melanoleucus catenifer) are abundant. Previous studies have shown that adult ground squirrels from this area possess innate physiological resistance to rattlesnake venom while pups are highly vulnerable to predation from snakes. Pups from other areas are known to exhibit snake recognition and adult-like antisnake behaviors on first encounter, a finding that prompted further study of pups from this area. The present study had four objectives: 1) to determine if inexperienced pups can distinguish rattlesnakes from gopher snakes, 2) to determine what role mothers play in shaping their pups' behavior during their first encounters with snakes, 3) to determine if maturational factors affect the expression of antisnake behaviors, and 4) to determine if maturational factors affect rattlesnake venom resistance, especially during the first weeks of life. Two groups of 63-70 day-old pups were studied during their first encounters with both a rattlesnake and a gopher snake. The snakes were presented separately in a wire-screened compartment positioned in the center of the experiment room containing sand substratum. Pups in this setting were either alone or with their mothers during 5-min encounters with the snakes, which were video taped from an overhead mirror. Two years later, pups which had previously engaged the snakes with their mothers were retested with the same snakes as adults and their behavior was compared to that of the earlier group of pups encountering the snakes alone. In another group of pups, radioimmunoassays of serum-to-venom binding examined changes in venom resistance at 14, 30, 48, and 80 days of age. The results indicated that pups do indeed differentiate rattlesnakes from gopher snakes irrespective of whether the mother is present or absent as inferred from the greater time that they spent near the rattlesnake. When the mothers were present, pups spent much less time investigating the rattlesnake or gopher snake closely as compared with the condition in which pups were alone. Except for displacing pups interacting with the snakes at close range, which could theoretically reduce the probability of pup injury, mothers exhibited very little overt protection of pups. Pups and adults behaved similarly when they engaged the snakes as evinced by their close-range investigative behavior, substrate throwing, and tail-flagging activity with the exception that adults were less vigilant in monitoring the snake's activity from anywhere in the experiment room. Analysis of developmental changes in venom resistance revealed that serum-to-venom binding achieves adult levels at 30 days of age which is about 15 days prior to burrow emergence. Despite adult serum-to-venom binding levels, pups are vulnerable to envenomation due to their reduced body mass and serum volume available to neutralize rattlesnake venom. From an over-all perspective, recently emerged ground squirrel pups from a population in which adults are highly resistant to rattlesnake venom are vulnerable to snake predation. Yet, enigmatically, they exhibit adult-like patterns of antisnake behaviors that are very risky, such as close-range investigation and substrate throwing. Tail flagging at the pup stage of development is more easily interpretable as providing some protection from snakes because it attracts the mother's attention and that of nearby adults who are likely to intervene. We interpret the early appearance in pups of risky adult-like investigative and snake-harassment behaviors as a by-product of epigenetic processes aimed at older, less vulnerable stages of development in which these behaviors are likely to have greater defensive utility.
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Rivkees, S. A. y S. M. Reppert. "Entrainment of circadian phase in developing gray short-tailed opossums: mother vs. environment." American Journal of Physiology-Endocrinology and Metabolism 259, n.º 3 (septiembre de 1990): E384. http://dx.doi.org/10.1152/ajpendo.1990.259.3.e384.
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In a marsupial species, the gray short-tailed opossum (Monodelphis domestica), the suprachiasmatic nuclei (SCN), the site of a circadian clock, are formed postnatally and begin oscillating as a circadian clock on day 20. In this study, we examined how the timing (phase) of the SCN clock in the developing opossum is coordinated to the environmental light-dark cycle. When pups were reared from birth in darkness by intact dams, the circadian phases in SCN metabolic activity (monitored by 2-deoxy-D-[14C]glucose autoradiography) in 27-day-old pups were desynchronized. When pups were reared in a light-dark cycle that was 12 h out of phase with the circadian time of blinded dams, the pattern of SCN metabolic activity on day 20 was rhythmic and in phase with the light-dark cycle but out of phase with the circadian time of the dam. On day 20, retina-mediated light activation of SCN metabolic activity was also demonstrated, and anterograde tract-tracing studies revealed the presence of the retinohypothalamic tract within the SCN. These results show there is no influence of the opossum dam on the timing of the pup's biological clock. Instead, from the inception of the daily rhythm in SCN metabolic activity, its timing is regulated by retina-mediated light-dark entrainment.
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Wydooghe, E., E. Berghmans, T. Rijsselaere y A. Van Soom. "International breeder inquiry into the reproduction of the English bulldog". Vlaams Diergeneeskundig Tijdschrift 82, n.º 1 (27 de febrero de 2013): 38–43. http://dx.doi.org/10.21825/vdt.v82i1.16726.
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Dystocia may occur in all dog breeds, but the English bulldog is predisposed because of its conformation and specific problems such as anasarca pups. In this study, the frequency of abnormal pups and breeding problems in English bulldogs was investigated by a questionnaire containing information on 39 bitches in total. In 74.4% of these bitches, artificial insemination was performed. At the end of gestation, 25.8% of the bitches suffered from respiratory problems and partial anorexia. The average duration of gestation was 58.7 days counted from the first day of mating. Caesarean section was performed in 94.8% of the cases, with natural delivery in only 5.2% of the bitches. In this study, the average litter size was six pups. Thirteen percent of the pups were stillborn, 8.2% of the pups alive were deformed, with palatoschisis (38.8%) and anasarca (27.7%) being the most commonly observed abnormalities. Ten percent of the pups died before the age of weaning.
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Hood, Wendy R. y Kathryn A. Ono. "Variation in maternal attendance patterns and pup behaviour in a declining population of Steller sea lions (Eumetopias jubatus)". Canadian Journal of Zoology 75, n.º 8 (1 de agosto de 1997): 1241–46. http://dx.doi.org/10.1139/z97-146.
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Maternal attendance patterns of lactating female Steller sea lions (Eumetopias jubatus) and the activity budgets of pups on Año Nuevo Island, California, were compared between the 1973 and 1992 breeding seasons to investigate temporal changes in behaviour that may be associated with population decline. Females were absent from the breeding area longer in 1992, which may reflect increased foraging effort. Pups also spent significantly less time sucking and more time swimming in 1992. Suckling time is correlated with milk intake in some otariid species, thus the decreased amount of time 1992 pups spent sucking could reflect a reduction in the total volume of milk produced by females. Pups in 1992 are likely to have spent more time swimming than pups in 1973 because high tide covered a greater proportion of the study site in 1992 than in 1973. An increase in time females spent at sea and a decrease in time pups spent sucking are consistent with behavioural changes associated with reduced prey availability.
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Taya, K. y S. Sasamoto. "Mechanisms responsible for suppression of FSH and LH during lactation in the rat". Journal of Endocrinology 129, n.º 1 (abril de 1991): 119–30. http://dx.doi.org/10.1677/joe.0.1290119.
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ABSTRACT Mechanisms responsible for suppression of FSH and LH secretion during lactation were investigated in rats, with special reference to the suckling stimulus and ovarian inhibin. Concentrations of immunoreactive inhibin in the peripheral plasma and bioactive inhibin in ovarian venous plasma were always low on days 3 and 5 of lactation in dams nursing eight pups, whereas values were always high on days 17 and 20 of lactation in dams nursing eight pups and on day 5 of lactation in dams nursing two pups. There was an FSH surge within 48 h after removal of litters on days 3 and 5 of lactation in dams nursing eight pups, whereas plasma concentrations of FSH were unchanged within 48 h by removal of litters on days 17 and 20 of lactation in dams nursing eight pups and on day 5 of lactation in dams nursing two pups. Plasma LH concentrations increased significantly compared with those of control animals within 24 h after removal of the litter on any day of lactation, regardless of the litter size. Plasma FSH levels increased within 6 h after bilateral or unilateral ovariectomy in lactating rats only on the days when plasma concentrations of inhibin were high before ovariectomy, such as day 17 of lactation in dams nursing eight pups and on day 5 of lactation in dams nursing two pups, whereas the mean concentrations of plasma LH showed no significant increase within 12 h after bilateral ovariectomy in these lactating rats. Treatment with progesterone or oestradiol-17β after unilateral ovariectomy did not inhibit the increase in plasma FSH levels, while the increase in plasma concentrations of FSH after surgery was completely inhibited by injecting inhibin (porcine follicular fluid). Treatment with steroid hormones inhibited the basal levels of LH in unilateral ovariectomized lactating rats. Plasma FSH concentrations increased sharply within 6 h after a single i.v. injection of anti-inhibin serum on days 10, 15 and 20 of lactation in dams nursing eight pups and on day 5 of lactation in dams nursing two pups, whereas only a small but significant increase in concentrations of FSH was noted 6 h after the antiserum treatment on day 5 of lactation in dams nursing eight pups. Concentrations of plasma LH were unchanged by treatment with antiserum in lactating rats throughout lactation. These findings indicate that the suckling stimulus, rather than ovarian factors, is mainly responsible for the suppression of FSH as well as LH secretion during the first half of lactation in rats nursing eight pups. On the other hand, during the second half of lactation in rats nursing eight pups and throughout lactation in rats nursing two pups, ovarian inhibin plays a primary role in the suppression of FSH secretion, whereas ovarian steroids act to suppress LH secretion. Journal of Endocrinology (1991) 129, 119–130
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Kidder, Ian J., Jordan A. Mudery, Santiago Barreda, David J. Taska y E. Fiona Bailey. "Evaluating the control: minipump implantation and breathing behavior in the neonatal rat". Journal of Applied Physiology 121, n.º 3 (1 de septiembre de 2016): 615–22. http://dx.doi.org/10.1152/japplphysiol.00080.2016.
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We evaluated genioglossus (GG) gross motoneuron morphology, electromyographic (EMG) activities, and respiratory patterning in rat pups allowed to develop without interference (unexposed) and pups born to dams subjected to osmotic minipump implantation in utero (saline-exposed). In experiment 1, 48 Sprague-Dawley rat pups (Charles-River Laboratories), ages postnatal day 7 (P7) through postnatal day 10 (P10), were drawn from two experimental groups, saline-exposed ( n = 24) and unexposed ( n = 24), and studied on P7, P8, P9, or P10. Pups in both groups were sedated (Inactin hydrate, 70 mg/kg), and fine-wire electrodes were inserted into the GG muscle of the tongue and intercostal muscles to record EMG activities during breathing in air and at three levels of normoxic hypercapnia [inspired CO2 fraction (FiCO2): 0.03, 0.06, and 0.09]. Using this approach, we assessed breathing frequency, heart rate, apnea type, respiratory event types, and respiratory stability. In experiment 2, 16 rat pups were drawn from the same experimental groups, saline-exposed ( n = 9) and unexposed ( n = 7), and used in motoneuron-labeling studies. In these pups a retrograde dye was injected into the GG muscle, and the brain stems were subsequently harvested and sliced. Labeled GG motoneurons were identified with microscopy, impaled, and filled with Lucifer yellow. Double-labeled motoneurons were reconstructed, and the number of primary projections and soma volumes were calculated. Whereas pups in each group exhibited the same number ( P = 0.226) and duration ( P = 0.093) of respiratory event types and comparable motoneuron morphologies, pups in the implant group exhibited more central apneas and respiratory instability relative to pups allowed to develop without interference.
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Gallant, Karen R. y M. George Cherian. "Influence of maternal mineral deficiency on the hepatic metallothionein and zinc in newborn rats". Biochemistry and Cell Biology 64, n.º 1 (1 de enero de 1986): 8–12. http://dx.doi.org/10.1139/o86-002.
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The effects of maternal Zn, Cu, or Fe deficiencies during late gestation on hepatic levels of metals and metallothionein (MT) and the binding of Zn and Cu to protein fractions were investigated in newborn rats. Timed pregnant rats were fed one of the following diets: Zn deficient (Zn-D), Cu-D, Fe-D, or control from day 12 of gestation until birth. The specific nutritional deficiency status of the dams was confirmed by low plasma levels of the deficient metal. Livers from pups were analyzed for MT, metal content, and metal–protein binding. Maternal Zn-D resulted in a greater than 50% reduction of hepatic MT levels in pups, whereas Cu-D and Fe-D had no significant effects. Pups in each deficient group showed a significant decrease in the hepatic levels of the respective metals. Fractionation of hepatic cytosols from the pups by Sephadex G-75 gel filtration showed that in both Fe-D and Cu-D pups the respective metals were depleted from the high molecular weight protein fraction, whereas in Zn-D pups the Zn was depleted mainly from the MT fraction (Ve/V0 ~ 2). Incorporation of [35S]cysteine into MT fractions was significantly lower in Zn-D pups as compared with control pups. These results indicate that there is a specific effect of the maternal Zn-D on the hepatic storage of Zn as MT in newborn rats.
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Bodager, Jonathan, Thomas Gessert, Eric D. Bruder, Ashley Gehrand y Hershel Raff. "Adrenocortical sensitivity to ACTH in neonatal rats: correlation of corticosterone responses and adrenal cAMP content". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 307, n.º 3 (1 de agosto de 2014): R347—R353. http://dx.doi.org/10.1152/ajpregu.00125.2014.
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A coordinated hypothalamic-pituitary-adrenal axis response is important for the survival of newborns during stress. We have previously shown that prior to postnatal day (PD) 5, neonatal rats exposed to hypoxia (one of the most common stressors effecting premature neonates) exhibit a large corticosterone response with a minimal increase in immunoassayable plasma ACTH and without a detectable increase in adrenal cAMP content (the critical second messenger). To explore the phenomenon of ACTH-stimulated steroidogenesis in the neonate, we investigated the adrenal response to exogenous ACTH in the normoxic neonatal rat. Rat pups at PD2 and PD8 were injected intraperitoneally with porcine ACTH at low, moderate, or high doses (1, 4, or 20 μg/kg body wt). Trunk blood and whole adrenal glands were collected at baseline (before injection) and 15, 30, or 60 min after the injection. ACTH stimulated corticosterone release in PD2 and PD8 pups. In PD2 pups, plasma corticosterone at baseline and during the response to ACTH injection was greater than values measured in PD8 pups, despite lower adrenal cAMP content in PD2 pups. Specifically, the low and moderate physiological ACTH doses produced a large corticosterone response in PD2 pups without a change in adrenal cAMP content. At extremely high, pharmacological levels of plasma ACTH in PD2 pups (exceeding 3,000 pg/ml), an increase in adrenal cAMP was measured. We conclude that physiological increases in plasma ACTH may stimulate adrenal steroidogenesis in PD2 pups through a non-cAMP-mediated pathway.