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1
Klowden, Marc J. "Endocrine aspects of mosquito reproduction". Archives of Insect Biochemistry and Physiology 35, n.º 4 (1997): 491–512. http://dx.doi.org/10.1002/(sici)1520-6327(1997)35:4<491::aid-arch10>3.0.co;2-5.
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Notter, DR. "Genetic Aspects of Reproduction in Sheep". Reproduction in Domestic Animals 43 (julio de 2008): 122–28. http://dx.doi.org/10.1111/j.1439-0531.2008.01151.x.
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Tomatis, Veronica, Christian Battipaglia y Alessandro D. Genazzani. "Thyroid, Adrenal, PRL Impairments and Ovarian Function". Endocrines 2, n.º 3 (27 de julio de 2021): 212–25. http://dx.doi.org/10.3390/endocrines2030021.
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Endocrine axes (prolactin, thyroid and adrenal axes) directly and indirectly modulate and drive human female central functions, mainly behavior and reproduction. Though having distinct abilities, they greatly act both at peripheral as well as at neuroendocrine levels, so as to participate in the control of reproduction. Any event that changes these balanced activities produces specific peripheral signals that induce abnormal functions centrally, thus triggering menstrual disorders such as oligomenorrhea or amenorrhea. It is clear that the knowledge of the relationships that exist between the different endocrine axes becomes essential for the choice of therapeutical approach. This review aims to focus on the main aspects of the physiopathology of the endocrine diseases that might be at the basis of that interference with female reproductive capacity.
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Wang, Wei, Xiaoyun He, Ran Di, Xiangyu Wang y Mingxing Chu. "Transcriptome Analysis Revealed Long Non-Coding RNAs Associated with mRNAs in Sheep Thyroid Gland under Different Photoperiods". Genes 13, n.º 4 (28 de marzo de 2022): 606. http://dx.doi.org/10.3390/genes13040606.
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The thyroid gland is a vital endocrine organ involved in the reproduction of animals via the regulation of hormone synthesis and secretion. LncRNAs have been proven to play important roles in reproductive regulation; however, the associated mechanism in the thyroid gland has not been clarified. In this study, we investigated to identify photoperiod-induced lncRNAs and mRNAs in the thyroid gland in Sunite ewes by comparing the expression profiles of short photoperiod (SP) and long photoperiods (LP). A total of 41,088 lncRNAs were identified in the thyroid gland through RNA-Seq. Functional analysis of differentially expressed lncRNAs using the R package revealed that reproductive hormone- and photoperiod response-related pathways, including the prolactin signaling, cAMP signaling, and circadian rhythm pathways, were significantly enriched. An mRNA-lncRNA interaction analysis suggested that the lncRNA LOC1056153S88 trans targets ARG2 and CCNB3, and the lncRNA LOC105607004 trans targets DMXL2, both of these might be involved in seasonal sheep breeding reproduction. Together, these results will provide resources for further studies on seasonal reproduction in sheep.
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Vissio, Paula G., María P. Di Yorio, Daniela I. Pérez-Sirkin, Gustavo M. Somoza, Kazuyoshi Tsutsui y Julieta E. Sallemi. "Developmental aspects of the hypothalamic-pituitary network related to reproduction in teleost fish". Frontiers in Neuroendocrinology 63 (octubre de 2021): 100948. http://dx.doi.org/10.1016/j.yfrne.2021.100948.
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Oddy, VH. "Regulation of muscle protein metabolism in sheep and lambs: nutritional, endocrine and genetic aspects". Australian Journal of Agricultural Research 44, n.º 5 (1993): 901. http://dx.doi.org/10.1071/ar9930901.
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Muscle protein accretion, as with the body in general, increases with feed intake. Protein balance across hind limb muscles occurs at energy intakes less than energy balance in the animal as a whole. There is considerable between-sheep variation in muscle protein accretion, and in the relative rates of protein synthesis and degradation, which are in part due to inherent differences in growth potential. Lambs selected for high weight at weaning deposit proportionately more nitrogen in the body than those selected for low weight at weaning. Inherently faster growing lambs have lower rates of protein breakdown in muscle and whole body than those which exhibit slower growth. Differences in sensitivity to insulin and plasma concentration of insulin-like growth factor-1 (IGF-1) indicate that the inherent differences in growth are associated with differences in responsiveness of muscle to hormones, and possible direct effects of IGF-1. Arteriovenous difference methodology, and isotope dilution, have been important tools in improving our understanding of the regulation of muscle protein metabolism.
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He, Xiaoyun, Lin Tao, Yingjie Zhong, Ran Di, Qing Xia, Xiangyu Wang, Xiaofei Guo et al. "Photoperiod induced the pituitary differential regulation of lncRNAs and mRNAs related to reproduction in sheep". PeerJ 9 (21 de abril de 2021): e10953. http://dx.doi.org/10.7717/peerj.10953.
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The pituitary is a vital endocrine organ that regulates animal seasonal reproduction by controlling the synthesis and secretion of the hormone. The change of photoperiod is the key factor affecting the function of the pituitary in animals, but the mechanism is unclear. Here, we studied the transcriptomic variation in pars distalis (PD) of the pituitary between short photoperiod (SP) and long photoperiod (LP) using RNA sequencing based on the OVX+E2 sheep. 346 differentially expressed (DE) lncRNAs and 186 DE-mRNA were found in the PD. Moreover, function annotation analysis indicated that the reproductive hormones and photoperiod response-related pathways including aldosterone synthesis and secretion, insulin secretion, thyroid hormone synthesis, and circadian entrainment were enriched. The interaction analysis of mRNA-lncRNA suggested that MSTRG.240648, MSTRG.85500, MSTRG.32448, and MSTRG.304959 targeted CREB3L1 and DUSP6, which may be involved in the photoperiodic regulation of the PD. These findings provide resources for further study on the seasonal reproductive in ewes.
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De Rensis, Fabio, Giorgio Morini, Irina Garcia-Ispierto y Fernando López-Gatius. "To What Extent Does Photoperiod Affect Cattle Reproduction? Clinical Perspectives of Melatonin Administration – A Review". Annals of Animal Science 20, n.º 3 (1 de julio de 2020): 797–809. http://dx.doi.org/10.2478/aoas-2020-0012.
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AbstractThe seasonality of reproduction in most mammals is dictated by photoperiod, temperature and nutrition. Melatonin, mainly synthesized in the pineal gland, is generally accepted as the active mediator of photoperiod responses including reproduction. While non-pregnant heifers and cows show continuous sexual activity and are therefore not seasonal breeders, it has been suggested that photo-periodicity may influence the appearance of puberty in heifers and the onset of parturition. Further, the light/dark ratio may influence endocrine patterns of gestation and a shorter light period correlates with the incidence of twin pregnancies. This review considers specific aspects of the effects of photoperiod and melatonin on reproduction in dairy cattle and discusses the clinical applications of melatonin.
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Wishy, A. B. "Some aspects of reproduction in fat-tailed sheep in Subtropics IV. Puberty and sexual maturity". Zeitschrift für Tierzüchtung und Züchtungsbiologie 91, n.º 1-4 (26 de abril de 2010): 311–16. http://dx.doi.org/10.1111/j.1439-0388.1974.tb01157.x.
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Blache, Dominique, Song Zhang y Graeme B. Martin. "Dynamic and integrative aspects of the regulation of reproduction by metabolic status in male sheep". Reproduction Nutrition Development 46, n.º 4 (julio de 2006): 379–90. http://dx.doi.org/10.1051/rnd:2006019.
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Brancia, Carla, Paola Nicolussi, Pietro Cappai, Giorgio La Corte, Roberta Possenti y Gian-Luca Ferri. "Differential expression and seasonal modulation of VGF peptides in sheep pituitary". Journal of Endocrinology 186, n.º 1 (julio de 2005): 97–107. http://dx.doi.org/10.1677/joe.1.05992.
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The inducible gene vgf and its peptide products are relevant to the neuroendocrine regulation of homeostasis and reproduction in rodents. We show here that in the anterior pituitary of female sheep the somatotrope, gonadotrope, and lactotrope/thyrotrope cell populations each expressed vgf mRNA, but displayed a distinct profile of VGF immunoreactive peptides. ProVGF C-terminus and VGF443–588 immunoreactivities were found in lactotropes and thyrotropes, often in a subcellular location restricted to the Golgi area and suggestive of rapid peptide (or proVGF) release upon biosynthesis, while high molecular weight bands consistent with proVGF were shown in pituitary extracts. Distinct seasonal changes were revealed, proVGF C-terminus immunoreactive cells being largely identified as lactotropes during the summer (83.7 ± 2.1% (mean ±s.e.m.) versus 27.0 ± 1.9% during the winter), as opposed to thyrotropes during the winter (73.0 ± 1.9% versus 16.3 ± 2.1% during the summer). Conversely, antisera to peptides adjacent to the ‘Arg-Pro-Arg’ cleavage site, and to the VGF553–555 N-terminus of the proVGF-derived peptide V, selectively labeled gonadotropes, indicating processing to small peptides not retaining the proVGF C-terminus in such cells. Finally, a peptide related to the VGF4–240 region was immunostained in somatotropes, shown in a Western blot as a band of relative molecular mass of approximately 16 000. In conclusion, a complex, endocrine cell-type-specific processing of proVGF was revealed. Further to the known inducibility of vgf mRNA upon a range of stimuli, discreet, selective modulations of VGF-peptide profile/s are suggested, possibly involved in specific neuro/endocrine or modulatory mechanisms.
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Chetrite, Gérard S. y Bruno Fève. "Preface to special issue on Peripheral and Central Control of Human Reproduction: Endocrine Aspects – Part 1". Hormone Molecular Biology and Clinical Investigation 24, n.º 1 (1 de enero de 2015): 1–3. http://dx.doi.org/10.1515/hmbci-2015-0059.
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Chetrite, Gérard S. y Bruno Fève. "Preface to special issue on Peripheral and Central Control of Human Reproduction: Endocrine Aspects – Part 2". Hormone Molecular Biology and Clinical Investigation 25, n.º 1 (1 de enero de 2016): 1–3. http://dx.doi.org/10.1515/hmbci-2016-0011.
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Pascal, Constantin, Traian Stefan Atanasiu, Ionica Nechifor y Costica Cristian. "Precocious Utilisation at Reproduction of Female Youth Sheep From Ţigaie Breed". Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Animal Science and Biotechnologies 73, n.º 2 (28 de noviembre de 2016): 218. http://dx.doi.org/10.15835/buasvmcn-asb:12255.
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Ovine rearing represents a domain being in a full development process in Romania. At the base of this tendency are the solicitation of local and external markets for basic production, respectively meat and milk. To record favourable economical results farmers wants to apply the most optimal technologies so, economical efficiency to reach a maximum level for each female which is part of the livestock (Pascal, 2015, Daraban 2006 ). One of those technologies refers also at precocious utilisation at reproduction of a female youth. So, the aim of effectuated research was represented by studying of possibilities for utilization at reproduction of female youth at an age still from the first year of life.Biologic material was represented by domestic ovine, from Ţigaie breed, reared in different farms situated in the North-East part of Romania. Experimental batches were formed by females with different ages, but all of them being utilized for the first time at mating. Respecting those demands were formed three batches differentially by age between them, which had, at the moment of utilization for reproduction, 9 months (L1), 18 months (L2) and 22 months (L3). Control batch was formed by adult females belonging to the same breed (LM). In the current research were tracked more aspects, the most important being the ones in which were analyzed the influence of sheep’ age on specific indexes of reproduction function, on the total duration of gestation and on further corporal development of youth females. The obtained data were statistically processed using ANOVA software, and for determination of differences and their signification were utilized Fisher and Tukey tests. The obtained results allow us to enlightened the fact that even, in case of batches formed by female youth, the mean values for studied parameters were very close to the ones specific to adult sheep, differences are significant in majority of situations for p >0.01.
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Holmberg, BJ, CD Morrison y DH Keisler. "Endocrine responses of ovariectomized ewes to i.c.v. infusion of urocortin". Journal of Endocrinology 171, n.º 3 (1 de diciembre de 2001): 517–24. http://dx.doi.org/10.1677/joe.0.1710517.
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Urocortin is a novel corticotropin-releasing factor-like peptide, first isolated from the rat midbrain, which has anorexigenic properties, possibly associated with its involvement in the stress axis. Urocortin has been implicated in blood pressure regulation, ACTH release and feed intake, but its role as an integral component of the reproduction-nutrition axis has not been examined. The present experiment was designed to determine the effects of i.c.v. infusion of urocortin on feed intake and endocrine profiles of LH, GH, IGF-I, cortisol and leptin in ovariectomized ewes. Ewes were fitted with two laterocerebroventricular cannulae and urocortin was continuously infused in a linearly increasing manner from 0.001 microg/h on day 0, to a maximum of 31.6 microg/h on day 5. Blood samples were collected via jugular catheters at 10 min intervals for 4 h on day 1, 3 and 5, and assayed by RIA for LH, GH, IGF-I, cortisol and leptin. All ewes were allowed free access to feed and water, and feed intake was recorded daily. Urocortin-infused ewes responded with a significant decrease in feed intake beginning on day 1 (P<0.02) and were aphagic for the remainder of the experiment. Serum concentrations of LH were elevated in individual samples from urocortin-treated compared with saline-treated ewes on day 3 (treatment x day x sample, P=0.05), but were not different on day 1 or 5. Mean serum concentrations of GH increased (P<0.04) over days with urocortin treatment, although concentrations of IGF-I were not influenced by treatment (P>0.5). Serum concentrations of cortisol were markedly increased by urocortin treatment (P<0.001). Leptin tended to be influenced by treatment and day (P=0.08), with leptin levels tending to be elevated in urocortin-treated vs saline-treated ewes on day 5 (P=0.08). The ability of urocortin to decrease feed intake while increasing LH, GH, cortisol and leptin provides evidence that urocortin is not only an integral component of the stress axis, but possibly of the nutrition-reproduction axis in sheep.
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Ferasyi, Teuku R., P. Hugh R. Barrett, Dominique Blache y Graeme B. Martin. "Modeling the Male Reproductive Endocrine Axis: Potential Role for a Delay Mechanism in the Inhibitory Action of Gonadal Steroids on GnRH Pulse Frequency". Endocrinology 157, n.º 5 (24 de febrero de 2016): 2080–92. http://dx.doi.org/10.1210/en.2015-1913.
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Abstract We developed a compartmental model so we could test mechanistic concepts in the control of the male reproductive endocrine axis. Using SAAM II computer software and a bank of experimental data from male sheep, we began by modeling GnRH-LH feed-forward and LH-T feedback. A key assumption was that the primary control signal comes from a hypothetical neural network (the PULSAR) that emits a digital (pulsatile) signal of variable frequency that drives GnRH secretion in square wave-like pulses. This model produced endocrine profiles that matched experimental observations for the testis-intact animal and for changes in GnRH pulse frequency after castration and T replacement. In the second stage of the model development, we introduced a delay in the negative feedback caused by the aromatization of T to estradiol at the brain level, a concept supported by empirical observations. The simulations showed how changes in the process of aromatization could affect the response of the pulsatile signal to inhibition by steroid feedback. The sensitivity of the PULSAR to estradiol was a critical factor, but the most striking observation was the effect of time delays. With longer delays, there was a reduction in the rate of aromatization and therefore a decrease in local estradiol concentrations, and the outcome was multiple-pulse events in the secretion of GnRH/LH, reflecting experimental observations. In conclusion, our model successfully emulates the GnRH-LH-T-GnRH loop, accommodates a pivotal role for central aromatization in negative feedback, and suggests that time delays in negative feedback are an important aspect of the control of GnRH pulse frequency.
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Ralph, C. R., M. N. Lehman, R. L. Goodman y A. J. Tilbrook. "Impact of psychosocial stress on gonadotrophins and sexual behaviour in females: role for cortisol?" Reproduction 152, n.º 1 (julio de 2016): R1—R14. http://dx.doi.org/10.1530/rep-15-0604.
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This review focuses on the importance of cortisol in mediating the inhibitory effects of psychosocial stress on reproduction in females. In particular, we have summarized our research in sheep where we have systematically established whether cortisol is both sufficient and necessary to suppress reproductive hormone secretion and inhibit sexual behaviour. Our findings are put into context with previous work and are used to develop important concepts as well as to identify productive further lines of investigation. It is clear that cortisol is necessary to inhibit some, but not all, aspects of reproduction in female sheep. These actions vary with reproductive state, and there are important interactions with gonadal steroids. The impact of cortisol on the tonic secretion of gonadotrophin-releasing hormone and luteinizing hormone has been investigated extensively, but less is known about the surge secretion of these hormones and their effects on sexual behaviour. Furthermore, there are separate effects of cortisol in the brain (hypothalamus) and at the anterior pituitary, illustrating that there are different mechanisms of action. Thus, although cortisol is important in mediating some of the effects of stress on reproduction, we need to look beyond cortisol and investigate some of the other mechanisms and mediators that relay the effects of stress on reproduction. In this regard, we propose that a group of neurons in the hypothalamus that co-synthesize kisspeptin, neurokinin B and dynorphin, termed KNDy cells, play important roles in mediating the effects of cortisol on reproduction. This hypothesis needs to be rigorously tested.
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Santos, Jadson Pinheiro, Simone de Jesus Melo Almeida, Claryce Cunha Costa, Erick Cristofore Guimarães, Erivânia Gomes Teixeira y Raimunda Nonata Fortes Carvalho-Neta. "Reproductive aspects of freshwater fishes exposed to pesticide-contamined environments: A systematic review". Revista Brasileira de Gestão Ambiental e Sustentabilidade 8, n.º 19 (2021): 1155–68. http://dx.doi.org/10.21438/rbgas(2021)081935.
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Fish are the predominant group of vertebrates in aquatic environments, and they are directly affected by the presence of contaminants in water bodies, which undergo changes in the structure and function of communities and dynamics of the populations. The aim of the present study was to conduct a systematic review of studies that analyze the reproductive aspects of freshwater teleosts in environments contaminated by pesticides. A systematic search for scientific articles was carried out from 2000 to 2019 using the "Web of Science" database, using the descriptors "fish reproduction", "contamination", "toxicology", "ecotoxicity" and "biomonitoring", combined with the use of boolean operators "AND" and "OR". The content analysis was performed based on the titles and the summary, with a first screening. Then, 98 articles were read in full, with 40 being selected. 24 species of fish were recorded, with a predominance of Danio rerio (17.5%). Insecticides were present in 78% of the studies, mainly Endosulfan (35%) and Cypermethrin (13%). Reproductive endocrine disorders were the most reported pathways of action (57.5%). The effects of pesticides on the reproduction of freshwater teleosts are evident, requiring studies on structural changes in gonads and a decrease in the quality of gametes.
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Leyria, Jimena, Samiha Benrabaa, Marcela Nouzova, Fernando G. Noriega, Lilian Valadares Tose, Francisco Fernandez-Lima, Ian Orchard y Angela B. Lange. "Crosstalk between Nutrition, Insulin, Juvenile Hormone, and Ecdysteroid Signaling in the Classical Insect Model, Rhodnius prolixus". International Journal of Molecular Sciences 24, n.º 1 (20 de diciembre de 2022): 7. http://dx.doi.org/10.3390/ijms24010007.
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The rigorous balance of endocrine signals that control insect reproductive physiology is crucial for the success of egg production. Rhodnius prolixus, a blood-feeding insect and main vector of Chagas disease, has been used over the last century as a model to unravel aspects of insect metabolism and physiology. Our recent work has shown that nutrition, insulin signaling, and two main types of insect lipophilic hormones, juvenile hormone (JH) and ecdysteroids, are essential for successful reproduction in R. prolixus; however, the interplay behind these endocrine signals has not been established. We used a combination of hormone treatments, gene expression analyses, hormone measurements, and ex vivo experiments using the corpus allatum or the ovary, to investigate how the interaction of these endocrine signals might define the hormone environment for egg production. The results show that after a blood meal, circulating JH levels increase, a process mainly driven through insulin and allatoregulatory neuropeptides. In turn, JH feeds back to provide some control over its own biosynthesis by regulating the expression of critical biosynthetic enzymes in the corpus allatum. Interestingly, insulin also stimulates the synthesis and release of ecdysteroids from the ovary. This study highlights the complex network of endocrine signals that, together, coordinate a successful reproductive cycle.
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Adams, N. R. y S. M. Liu. "Principles of nutrient partitioning for wool, growth and reproduction: implications for nematode parasitism". Australian Journal of Experimental Agriculture 43, n.º 12 (2003): 1399. http://dx.doi.org/10.1071/ea03007.
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The capacity of sheep to withstand and repel intestinal parasites is a neglected component of effective parasite control. The immune response is strongly influenced by the nutritional status of the sheep. However, we are unable take advantage of this to develop effective control programs because we have neither an adequate understanding nor appropriate quantitative data on the impacts of protein and energy on sheep nutrition. This paper reviews some aspects of current knowledge about the impact on immune responsiveness of nutrient flows within the animal as well as hormonal partitioning mechanisms, and assesses research needs in this area. The availability of nutrients to the immune response in the gut is determined by the supply of nutrients to the sheep from both feed intake and body reserves, and the demands of other physiological processes such as growth, wool growth, pregnancy or lactation. Hormones coordinate nutrient flow among these processes. Breakdowns in immunity appear most severe when animals are faced with a demand for growth or lactation, but no single partitioning mechanism can explain all the observations in the field. Therefore, it is unrealistic to seek to establish a hierarchy of partitioning priorities. Protein appears to have a greater impact on immune responsiveness to parasites than energy. However, energy affects the availability of amino acids through a number of mechanisms including protein deposition and mobilisation, so protein supply cannot be considered in isolation. It is appealing to believe that specific limiting nutrients such as sulfur amino acids might explain the relationship between susceptibility to parasites and wool growth, but the experimental evidence for this view is still inconclusive. Rather, it appears that the total flow of nutrients from feed intake and body reserves is more important than specific partitioning mechanisms, or specific limiting nutrients. The potential conflict between role of the gut as a source of mobilisable protein reserves, and the need for protein in the gut to develop local immune responses, need to be explored experimentally. Practical applications of nutritional knowledge are likely to come through improved timing of management procedures rather than better supplements, which are rarely economic. The conclusions outline a number of research questions that must be answered before we can develop programs that integrate immune competence with drenching and other procedures in a holistic way.
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Sharma, T. P., D. Blache, C. E. Roselli y G. B. Martin. "Distribution of aromatase activity in brain and peripheral tissues of male sheep: effect of nutrition". Reproduction, Fertility and Development 16, n.º 7 (2004): 709. http://dx.doi.org/10.1071/rd04018.
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Conversion of testosterone to oestradiol plays a major role in the feedback inhibition of gonadotrophin secretion in male sheep but little is known of the distribution or control of aromatase activity among central and peripheral tissues. Changes in activity at those sites may mediate alterations in the effectiveness of negative feedback following, for example, a change in nutrition. Using a tritiated-water assay, we quantified aromatase in several tissues in mature male sheep, assessed their contribution to oestradiol production, and tested whether activity at each site was affected by a nutritional treatment that stimulates gonadotrophin secretion. Among the brain tissues, the preoptic area had the highest concentration of activity, followed by the hypothalamus, amygdala and cortex. Among the peripheral tissues, liver and testis had the highest activity and, due to their mass, they are the major sources of circulating oestradiol. Pituitary, muscle, kidney and adipose tissues had very low aromatase levels. The nutritional stimulus increased activity in testis but not in liver or brain. We conclude that changes in aromatase activity do not mediate the effects of nutrition on steroid feedback, but aromatisation in testis, liver and brain is important in the endocrine regulation of reproduction in the mature ram.
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Chalfun Guimaraes Okamoto, Priscylla Tatiana, Ana Luísa Holanda de Albuquerque, Silvano Salgueiro Geraldes, André Nanny Vieira Le Sueur, Alessandra Melchert, Maria Lúcia Gomes Lourenço, Carmel Rezende Dadalto et al. "INTERMITTENT HEMODIALYSIS, AN ALTERNATIVE TREATMENT FOR OVINE WITH ACUTE-ON-CHRONIC KIDNEY DISEASE." Veterinária e Zootecnia 27 (11 de diciembre de 2020): 1–14. http://dx.doi.org/10.35172/rvz.2020.v27.445.
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Chronic Kidney Disease (CKD) is a syndrome composed of numerous comorbidities such as the failure of excretion of toxins and nitrogenous compounds from metabolism, as well as the failure to maintain endocrine, water, electrolyte and acid-base homeostasis in all mammals. As it is a non-regenerative and progressive disease, any endogenous or exogenous insults in the organ in question will lead to the intensification of all these mentioned disorders associated with decreased urinary output. Several studies in humans and animals recommend the use of renal replacement therapy, especially in those who already have CKD, and who are in uremic syndrome. This report aims to demonstrate that the use of intermittent hemodialysis (HI) in sheep is a therapeutic alternative in those in renal failure. A six-year-old Bergamasca sheep was presented with lateral decubitus, dyspnea, dark liquid diarrhea, apathy, anorexia and pulmonary crepitation on auscultation. Laboratory tests showed azotemia and electrolyte changes such as hypocalcemia, hypokalemia, hypochloremia, isosthenuria (1,012), pyuria, glycosuria, and a protein: creatinine ratio of 0.88. In ultrasonography, the real resistivity index was above 0.54, being suggestive of loss of renal perfusion. The treatment chosen consisted of electrolytic and fluid replacement, associated with HI. After HI, the sheep showed great clinical and laboratory improvement as expected, however, despite not having survived, the histopathological findings of the necropsy pointed out segments of glomerulosclerosis, thus reinforcing the hypothesis that the animal already had a CKD which was aggravated due to the association of hypovolemia, hypotension by anesthetic drugs and the indiscriminate use of NSAIDs. Despite the death of the sheep, HI again proved to be a therapy of rapid clinical and laboratory improvement of the patient compared to conventional clinical treatment, thus being an important treatment alternative for sheep with a high impact on reproduction, production, and research.
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Whitlock, BK, JA Daniel, RR Wilborn, TH Elsasser, JA Carroll y JL Sartin. "Comparative Aspects of the Endotoxin- and Cytokine-Induced Endocrine Cascade Influencing Neuroendocrine Control of Growth and Reproduction in Farm Animals". Reproduction in Domestic Animals 43 (julio de 2008): 317–23. http://dx.doi.org/10.1111/j.1439-0531.2008.01180.x.
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Masters, David G. "Practical implications of mineral and vitamin imbalance in grazing sheep". Animal Production Science 58, n.º 8 (2018): 1438. http://dx.doi.org/10.1071/an17761.
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Rapid progress in research on mineral functions in biological systems over the past 20 years has provided new and unexplored implications for health and production in grazing livestock. The strong interaction among calcium (Ca), magnesium (Mg), phosphorus (P), sodium (Na), potassium (K) and vitamin D influences the absorption, utilisation and status of these nutrients, particularly Ca and Mg. An imbalanced intake of Ca, Mg, P, Na, K and vitamin D is common in ruminants grazing pastures and vegetative crops. The interaction may modify susceptibility to clinical hypocalcaemia, hypomagnesaemia and pregnancy toxaemia, or to subclinical and chronic deficiencies of Ca, Mg and Na. However, hypocalcaemia is also associated with endocrine failure. Whether this failure is susceptible to nutritional modulation or even whether supplements of Ca, Mg, Na and vitamin D reduce or exacerbate the risk of metabolic disease in sheep is unclear. Selenium, manganese, zinc, copper, sulfur, vitamin E and vitamin A play synergistic roles in the antioxidant defence mechanism and modulate the consequences of oxidative stress. In extensive grazing systems combined low intakes of these antioxidants are not unusual, particularly in seasonally dry environments and at a time coinciding with the increased oxidative stress that naturally occurs through the reproductive cycle. This oxidative stress is accentuated by heat stress and parasite infection. Oxidative stress in the short-term influences growth, reproduction, offspring survival and health. Long-term, oxidative damage to embryo DNA and changes in RNA expression, may influence lifetime performance of offspring. The high cost of providing mineral supplements to grazing sheep is a deterrence to addressing the implications of multiple mineral deficiencies. New herbaceous and shrub options to increase the botanical and nutritional diversity within pasture and crop-grazing systems may allow livestock to select a heterogeneous diet providing a more balanced mineral intake.
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Robertson, John A. "Oocyte Cytoplasm Transfers and the Ethics of Germ-Line Intervention". Journal of Law, Medicine & Ethics 26, n.º 3 (1998): 211–20. http://dx.doi.org/10.1111/j.1748-720x.1998.tb01422.x.
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The February 1997 announcement of the birth of Dolly, the sheep cloned from a mammary cell of an adult ewe, has drawn attention to the growing ability to select, alter, or otherwise manipulate the genome of offspring. Prior to Dolly, ethical discussion of genes in reproduction had focused on negative selection: carrier screening, prenatal diagnosis, and abortion or embryo discard. After Dolly, ethical debate will have to consider the direct or positive use of genetic selection or alteration technology.The principal use of genetic selection techniques in human reproduction (reprogenetics) likely will be to treat or prevent disease in offspring. In the future, however, such techniques might also be used to enhance or even diminish expected characteristics of progeny. Techniques to accomplish these goals are likely to include: selection of the nuclear genome, as occurs in somatic cell cloning; chromosomal transplants; or direct insertion or deletion of specific genes.
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Silva, Severiano R., Laura Sacarrão-Birrento, Mariana Almeida, David M. Ribeiro, Cristina Guedes, José Ramiro González Montaña, Alfredo F. Pereira et al. "Extensive Sheep and Goat Production: The Role of Novel Technologies towards Sustainability and Animal Welfare". Animals 12, n.º 7 (31 de marzo de 2022): 885. http://dx.doi.org/10.3390/ani12070885.
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Sheep and goat extensive production systems are very important in the context of global food security and the use of rangelands that have no alternative agricultural use. In such systems, there are enormous challenges to address. These include, for instance, classical production issues, such as nutrition or reproduction, as well as carbon-efficient systems within the climate-change context. An adequate response to these issues is determinant to economic and environmental sustainability. The answers to such problems need to combine efficiently not only the classical production aspects, but also the increasingly important health, welfare, and environmental aspects in an integrated fashion. The purpose of the study was to review the application of technological developments, in addition to remote-sensing in tandem with other state-of-the-art techniques that could be used within the framework of extensive production systems of sheep and goats and their impact on nutrition, production, and ultimately, the welfare of these species. In addition to precision livestock farming (PLF), these include other relevant technologies, namely omics and other areas of relevance in small-ruminant extensive production: heat stress, colostrum intake, passive immunity, newborn survival, biomarkers of metabolic disease diagnosis, and parasite resistance breeding. This work shows the substantial, dynamic nature of the scientific community to contribute to solutions that make extensive production systems of sheep and goats more sustainable, efficient, and aligned with current concerns with the environment and welfare.
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Rojas, Joselyn, Mervin Chávez-Castillo, Luis Carlos Olivar, María Calvo, José Mejías, Milagros Rojas, Jessenia Morillo y Valmore Bermúdez. "Physiologic Course of Female Reproductive Function: A Molecular Look into the Prologue of Life". Journal of Pregnancy 2015 (2015): 1–21. http://dx.doi.org/10.1155/2015/715735.
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The genetic, endocrine, and metabolic mechanisms underlying female reproduction are numerous and sophisticated, displaying complex functional evolution throughout a woman’s lifetime. This vital course may be systematized in three subsequent stages: prenatal development of ovaries and germ cells up untilin uteroarrest of follicular growth and the ensuing interim suspension of gonadal function; onset of reproductive maturity through puberty, with reinitiation of both gonadal and adrenal activity; and adult functionality of the ovarian cycle which permits ovulation, a key event in female fertility, and dictates concurrent modifications in the endometrium and other ovarian hormone-sensitive tissues. Indeed, the ultimate goal of this physiologic progression is to achieve ovulation and offer an adequate environment for the installation of gestation, the consummation of female fertility. Strict regulation of these processes is important, as disruptions at any point in this evolution may equate a myriad of endocrine-metabolic disturbances for women and adverse consequences on offspring both during pregnancy and postpartum. This review offers a summary of pivotal aspects concerning the physiologic course of female reproductive function.
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Wiener, G., Carol Woolliams y J. Slee. "A comparison of inbred and outbred sheep on two planes of nutrition. 3. A note on the effects on semen characteristics before and after exposures to acute cold and heat". Animal Science 46, n.º 2 (abril de 1988): 309–12. http://dx.doi.org/10.1017/s0003356100042409.
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Traits associated with fitness such as aspects of reproduction (for a review see Lamberson and Thomas, 1984) and lamb survival (Wiener, Woolliams and Macleod, 1983) are seriously affected by inbreeding. Homeostatic control is an important component of fitness in animals. In an experiment reported by Wiener, Woolliams and Slee (1988) and Slee, Wiener and Woolliams (1988), inbred (I) rams were far less able to resist acute cold than outbred (O) rams. The opportunity was taken in this same experiment to examine the effects of inbreeding, plane of nutrition (high (H) or low (L)) and exposures to acute cold and heat on aspects of semen quality.
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Wójcik-Gładysz, Anna, Marta Wańkowska, Alina Gajewska, Tomasz Misztal, Marlena Zielińska-Górska, Michał Szlis y Jolanta Polkowska. "Effects of intracerebroventricular infusions of ghrelin on secretion of follicle-stimulating hormone in peripubertal female sheep". Reproduction, Fertility and Development 28, n.º 12 (2016): 2065. http://dx.doi.org/10.1071/rd16028.
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Reproduction depends on mechanisms responsible for the regulation of energy homeostasis and puberty is a developmental period when reproductive and somatic maturity are achieved. Ghrelin affects the activity of the hypothalamo–pituitary–gonadal axis under conditions of energy insufficiency. An in vivo model based on intracerebroventricular (i.c.v.) infusions was used to determine whether centrally administered acyl ghrelin affects transcriptional and translational activity of FSH in peripubertal lambs and whether ghrelin administration mimics the effects of short-term fasting. Standard-fed lambs received either Ringer–Lock (R-L) solution (120 µL h–1) or ghrelin (120 µL h–1, 100 µg day–1). Animals experiencing a short-term (72 h) fast were treated only with R-L solution. In each experimental group, i.c.v. infusions occurred for 3 consecutive days. Immunohistochemistry, in situ hybridisation and real-time reverse transcription quantitative polymerase chain reaction analyses revealed that short-term fasting, as well as exogenous acyl ghrelin administration to standard-fed peripubertal lambs, augmented FSHβ mRNA expression and immunoreactive FSH accumulation. In addition to the effects of ghrelin on FSH synthesis in standard-fed animals, effects on gonadotrophin release were also observed. Acyl ghrelin increased the pulse amplitude for gonadotrophin release, which resulted in an elevation in mean serum FSH concentrations. In conclusion, the present data suggest that ghrelin participates in an endocrine network that modulates gonadotrophic activity in peripubertal female sheep.
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Comninos, Alexander N. y Waljit S. Dhillo. "Emerging Roles of Kisspeptin in Sexual and Emotional Brain Processing". Neuroendocrinology 106, n.º 2 (31 de agosto de 2017): 195–202. http://dx.doi.org/10.1159/000481137.
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The emergence of kisspeptin as a crucial regulator of the hypothalamo-pituitary-gonadal (HPG) axis over the last 14 years has answered many questions as to the control of reproductive hormone secretion from the hypothalamus. More recently, the role of kisspeptin outside the HPG axis has received increasing attention in the hope of delineating the pathways linking various sensory and social behaviours to reproduction. These studies, in a range of species from zebrafish to humans, have identified a role for kisspeptin in behavioural networks related to reproduction including olfaction, audition, fear, anxiety, mood, and sexual arousal. The available evidence suggests that extrahypothalamic kisspeptin signalling encourages positive aspects of emotional and sexual brain processing in a presumed drive towards reproduction and ultimately maintenance of the species at a population level. In this review, we examine these studies, which collectively propose that kisspeptin may integrate sexual and emotional brain processing with the control of the HPG axis.
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Meier, Ursula y Axel M. Gressner. "Endocrine Regulation of Energy Metabolism: Review of Pathobiochemical and Clinical Chemical Aspects of Leptin, Ghrelin, Adiponectin, and Resistin". Clinical Chemistry 50, n.º 9 (1 de septiembre de 2004): 1511–25. http://dx.doi.org/10.1373/clinchem.2004.032482.
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Abstract Background: Recent studies point to the adipose tissue as a highly active endocrine organ secreting a range of hormones. Leptin, ghrelin, adiponectin, and resistin are considered to take part in the regulation of energy metabolism. Approach: This review summarizes recent knowledge on leptin and its receptor and on ghrelin, adiponectin, and resistin, and emphasizes their roles in pathobiochemistry and clinical chemistry. Content: Leptin, adiponectin, and resistin are produced by the adipose tissue. The protein leptin, a satiety hormone, regulates appetite and energy balance of the body. Adiponectin could suppress the development of atherosclerosis and liver fibrosis and might play a role as an antiinflammatory hormone. Increased resistin concentrations might cause insulin resistance and thus could link obesity with type II diabetes. Ghrelin is produced in the stomach. In addition to its role in long-term regulation of energy metabolism, it is involved in the short-term regulation of feeding. These hormones have important roles in energy homeostasis, glucose and lipid metabolism, reproduction, cardiovascular function, and immunity. They directly influence other organ systems, including the brain, liver, and skeletal muscle, and are significantly regulated by nutritional status. This newly discovered secretory function has extended the biological relevance of adipose tissue, which is no longer considered as only an energy storage site. Summary: The functional roles, structures, synthesis, analytical aspects, and clinical significance of leptin, ghrelin, adiponectin, and resistin are summarized.
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Zoltán, Kun Imre, Kun Ildikó y Kolcsár Melinda. "Current aspects of polycystic ovary syndrome I: definition, pathophysiology, clinical manifestations, diagnosis and complications". Bulletin of Medical Sciences 91, n.º 1 (1 de julio de 2018): 5–18. http://dx.doi.org/10.2478/orvtudert-2018-0011.
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Abstract Polycystic ovary syndrome (PCOS) is the most frequent endocrine disease among women with childbearing potential, the best-known cause of hirsutism, with a hypothesized prevalence of 8-22%. The first part of the paper discusses the conceptional evolution of the syndrome, from its description in 1935 by Stein and Leventhal till today. It describes the changes in the criteria systems, emphasizing that the Rotterdam criteria, proposed in 2003 by the European Society for Human Reproduction and Embryology/American Society for Reproductive Medicine, are still valid today. This system basically differs from earlier (1990) NIH-criteria in one aspect: it introduced two newer phenotypes, one without hyperandrogenism and the other with ovulatory cycles, so it distinguishes 4 phenotypes. The etiology and pathogenesis of PCOS is heterogeneous, multifactorial, poorly understood. We present the 3 leading hypotheses (1 - hypothalamo-hypophyseal disturbances, 2 – primary enzyme disorders in ovarian, or ovarian/adrenal steroidogenesis, resulting primarily in hyperactivity of 17alpha-hydroxylase/17,20-lyase, 3 – insulin resistance-hyperinsulinism and other metabolic dysfunctions). We emphasize the role of genetically determined hyperandrogenism, that of insulin resistance-hyperinsulinism and the importance of reinforcing each other. Subsequently, the aggravating aspects of the frequently associated metabolic syndrome are discussed, and then the effects of the mentioned pathological processes on the endocrine and other organ structures participating in the regulation of sexual functions. We stress the hypothetical role of perinatal and pubertal androgen exposition in the pathogenesis of PCOS. The mechanisms of anovulation and those of the endometrial lesions are discussed, too. The clinical manifestations, the paraclinical and laboratory examinations, the positive and differential diagnosis and the complications are also presented. We intend to deal with the therapeutic aspects of PCOS in an upcoming paper.
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Sharan, M. y K. Grymak. "Curent state and futyre of using the biotechnological methods of reproduction in sheeps breeding". Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 19, n.º 74 (3 de marzo de 2017): 67–70. http://dx.doi.org/10.15421/nvlvet7415.
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The analysis of publication related to the usage of embryo transplantation method in breeding sheep had been conducted. It is proved that the theoretical basis of the method of embryo transplantation is the large number of germ cells in the ovaries of females, most of which during the usual method of reproduction does not participate in these processes, and the high probability of inheriting genetic characteristics of embryos after transplantation by recipient. On this basis, from females throughout her life we can get a few dozen of descendants. The main aspects of embryos transplantation technology is to development of new methods that will ensure obtaining of the greatest number of good-quality embryos with desirable genotypes, both by the induction of multiple ovulation and by cultivation of follicular oocytes outside the body. It has been defined, that its usage is limited by a number of factors that are not well studіed and many of them are contradictional, in particular unpredictable results of the multiple ovulation induction. The development of the method of predicting the results of polyovulation will significantly increase the efficiency of embryos transplantation and significantly reduce the cost of labor and financial resources. It has been shown, that one of the main factors of making transplantation more practical is to develop the methods of embryos cryopreservation. This will simplify the selection of recipients and donors by the sexual cycle, will further long distance transportation and will enable the transplantation in the planned breeding herds. The further of the method, along with modern advances of genetics, embryology, endocrinology, will in the near future lead to develop a comprehensive method for the accelerated creation in sheep breeding flocks of high performance animals.
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Fernandez-Novo, Aitor, Sonia S. Pérez-Garnelo, Arantxa Villagrá, Natividad Pérez-Villalobos y Susana Astiz. "The Effect of Stress on Reproduction and Reproductive Technologies in Beef Cattle—A Review". Animals 10, n.º 11 (11 de noviembre de 2020): 2096. http://dx.doi.org/10.3390/ani10112096.
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Researchers have contributed by increasing our understanding of the factors affecting reproduction in beef, mainly physical health and nutrition aspects, which have been main concerns during decades. Animal welfare is of outmost relevance in all animal production systems and it is strongly associated to stress. Stress responses involve endocrine, paracrine and neural systems and the consequences of this stress on the reproductive efficiency of specifically, beef cattle and bulls, need to be highlighted. We, therefore, describe the fundamentals of stress and its quantification, focusing in beef herds, reviewing the highly valuable pieces of research, already implemented in this field. We examine major factors (stressors) contributing to stress in beef cattle and their effects on the animals, their reproductive performance and the success of reproductive biotechnologies. We include terms such as acclimatization, acclimation or temperament, very relevant in beef systems. We examine specifically the management stress due to handling, social environment and hierarchy or weaning effects; nutritional stress; and thermal stress (not only heat stress) and also review the influence of these stressors on reproductive performance and effectiveness of reproductive biotechnologies in beef herds. A final message on the attention that should be devoted to these factors is highlighted.
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Khan, Usman Mir, Ali Murad Khan, Umar Murad Khan y Zeliha Selamoğlu. "Effects of Seasonal Factors in The Goats’ Reproductive Efficiency". Turkish Journal of Agriculture - Food Science and Technology 7, n.º 11 (23 de noviembre de 2019): 1937. http://dx.doi.org/10.24925/turjaf.v7i11.1937-1940.2899.
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Interest in goat farming is at its peak since the last decade of 20th century because the role of goat is well established in animal protein as well as in economic uplift of poor masses in the tropics and subtropics, but also constitutes an important component of traditional farming systems. Goat is a better option as farm animal in the tropics and subtropics as it can withstand dehydration and has better browsing habit which enables it to survive where cattle and sheep farming is difficult. Reproductive performance of does is of immense importance as contributing factor towards increased meat production and in finding out more prolific animals. This is the main factor affecting productivity of goats. Therefore, an improved reproduction rate will be an approach to increase in numbers. Reproductive seasonality represents a natural adaptation that provides important advantages for birth and offspring survival and development, as lambing/kidding coincides with good weather and maximum availability of forage. It is believed that photoperiod is the environmental factor other than food availability that determines the sexual activity in sheep and goat. This review paper focuses on the general aspects of seasonal factors influencing the goat’s reproductive efficiency.
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Córdova Izquierdo, Alejandro, Adrian E. Iglesias Reyes, Gustavo Ruiz Lang, Jorge Saltijeral Oaxaca, Juan Eulogio Guerra Liera, Edmundo Abel Villa Mancera, Ma de Lourdes Juárez Mosqueda et al. "Nutrition and Food in the Reproduction of Cattle". European Journal of Agriculture and Food Sciences 3, n.º 3 (7 de mayo de 2021): 21–33. http://dx.doi.org/10.24018/ejfood.2021.3.3.184.
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At the beginning of the 1980s, a series of very profound changes were initiated in the milk cow nutrition approaches, as a consequence of the highest levels of production per cow that were reached by the productive systems of the northern hemisphere. Nutrition is defined as the series of processes through which an organism acquires and assimilates food to promote its growth and replace worn or damaged tissues. The nutrients are fundamental for the animals to carry out their different productive functions. When we consider the aspects that touch the field of nutrition of ruminants, we understand the importance of this group of animals of zootechnical interest, which are able to process plant components that are not consumed by other mammals, the structural carbohydrates (fiber). Ruminant comes from the word "rumen", which is the largest of the compartments in the stomach of four compartments of a bovine, sheep or goat. This structure is where microbial fermentation takes place. The ruminants, through evolutionary processes, developed life relationships with microorganisms which enabled them to use fiber as food, that is, they developed in some way their "food factory". They eat the forage to be transformed by the rumen's microbiota into substances that are the source of energy for the animal and for the microbial synthesis, the microbial cells are an excellent source of proteins for the animal. However, the processes that make the ruminal microbiota are, in a certain way, inefficient. Grass degradation produces volatile fatty acids, microbial protein and gases. Within these gases, some are environmental pollutants such as CO2, methane and nitrous oxide. Millions of bacteria, protozoa, and fungi live in the rumen and degrade parts of the plant rich in energy, making them digestible to the animal host. After the forage has been digested in the rumen and degraded to smaller parts, it can pass through the reticulum and omasum, which function as colanders that trap large pieces of material preventing them from reaching the abomasum, or "true stomach", where digestion continues. The nutritional concern for ruminants focuses on energy (ie, carbohydrates), protein, minerals, vitamins, and water. The energy (carbohydrates) is responsible for the functions of growth and maintenance of the animal, and the generation of heat. The protein makes the tissue grow and performs other vital functions. Other nutrients and minerals such as vitamin A and E, calcium, phosphorus, and selenium can be fed to "free choice" as a mineral supplement. Dairy cows of high productive potential (9000-12000 / liters / lactation) currently represent a real challenge for nutrition. For many years, there has been evidence of the impact of nutrition on the reproductive behavior of the bovine female. The main factor that affects reproduction is the undernourishment due to the scarcity and quality of the food. Subsequent research has shown that nutritional effects are exerted through complex interrelations between various aspects such as: content and use of body reserves, distribution of nutrients between different systems and organs and prioritization of the use of nutrients for various functions in addition to reproduction.
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Handgraaf, Sandra y Jacques Philippe. "The Role of Sexual Hormones on the Enteroinsular Axis". Endocrine Reviews 40, n.º 4 (10 de mayo de 2019): 1152–62. http://dx.doi.org/10.1210/er.2019-00004.
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AbstractSex steroid estrogens, androgens, and progesterone, produced by the gonads, which have long been considered as endocrine glands, are implicated in sexual differentiation, puberty, and reproduction. However, the impact of sex hormones goes beyond these effects through their role on energy metabolism. Indeed, sex hormones are important physiological regulators of glucose homeostasis and, in particular, of the enteroinsular axis. In this review, we describe the roles of estrogens, androgens, and progesterone on glucose homeostasis through their effects on pancreatic α- and β-cells, as well as on enteroendocrine L-cells, and their implications in hormonal biosynthesis and secretion. The analysis of their mechanisms of action with the dissection of the receptors implicated in the several protective effects could provide some new aspects of the fine-tuning of hormonal secretion under the influence of the sex. This knowledge paves the way to the understanding of transgender physiology and new potential therapeutics in the field of type 2 diabetes.
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van der Veen, Daan R., Sjaak J. Riede, Paul D. Heideman, Michaela Hau, Vincent van der Vinne y Roelof A. Hut. "Flexible clock systems: adjusting the temporal programme". Philosophical Transactions of the Royal Society B: Biological Sciences 372, n.º 1734 (9 de octubre de 2017): 20160254. http://dx.doi.org/10.1098/rstb.2016.0254.
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Under natural conditions, many aspects of the abiotic and biotic environment vary with time of day, season or even era, while these conditions are typically kept constant in laboratory settings. The timing information contained within the environment serves as critical timing cues for the internal biological timing system, but how this system drives daily rhythms in behaviour and physiology may also depend on the internal state of the animal. The disparity between timing of these cues in natural and laboratory conditions can result in substantial differences in the scheduling of behaviour and physiology under these conditions. In nature, temporal coordination of biological processes is critical to maximize fitness because they optimize the balance between reproduction, foraging and predation risk. Here we focus on the role of peripheral circadian clocks, and the rhythms that they drive, in enabling adaptive phenotypes. We discuss how reproduction, endocrine activity and metabolism interact with peripheral clocks, and outline the complex phenotypes arising from changes in this system. We conclude that peripheral timing is critical to adaptive plasticity of circadian organization in the field, and that we must abandon standard laboratory conditions to understand the mechanisms that underlie this plasticity which maximizes fitness under natural conditions. This article is part of the themed issue ‘Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals’.
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Giommi, Christian, Hamid R. Habibi, Michela Candelma, Oliana Carnevali y Francesca Maradonna. "Probiotic Administration Mitigates Bisphenol A Reproductive Toxicity in Zebrafish". International Journal of Molecular Sciences 22, n.º 17 (27 de agosto de 2021): 9314. http://dx.doi.org/10.3390/ijms22179314.
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Although the use of bisphenol A (BPA) has been banned in a number of countries, its presence in the environment still creates health issues both for humans and wildlife. So far, BPA toxicity has been largely investigated on different biological processes, from reproduction to development, immune system, and metabolism. In zebrafish, Danio rerio, previous studies revealed the ability of environmentally relevant concentrations of this contaminant to significantly impair fertility via epigenetic modification. In addition, several studies demonstrated the ability of different probiotic strains to improve organism health. This study provides information on the role of the probiotic mixture SLAb51 to counteract adverse BPA effects on reproduction. A 28-day trial was set up with different experimental groups: BPA, exposed to 10 µg/L BPA; P, receiving a dietary supplementation of SLAb51 at a final concentration of 109 CFU/g; BPA+P exposed to 10 µg/L BPA and receiving SLAb51 at a final concentration of 109 CFU/g and a C group. Since oocyte growth and maturation represent key aspects for fertility in females, studies were performed on isolated class III (vitellogenic) and IV (in maturation) follicles and liver, with emphasis on the modulation of the different vitellogenin isoforms. In males, key signals regulating spermatogenesis were investigated. Results demonstrated that in fish exposed to the combination of BPA and probiotic, most of the transcripts were closer to C or P levels, supporting the hypothesis of SLAb51 to antagonize BPA toxicity. This study represents the first evidence related to the use of SLAb51 to improve reproduction and open new fields of investigation regarding its use to reduce endocrine disrupting compound impacts on health.
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CARVER, F. J. y H. HURD. "The effect of metacestodes of Hymenolepis diminuta on the bean-shaped accessory glands in male Tenebrio molitor". Parasitology 116, n.º 2 (febrero de 1998): 191–96. http://dx.doi.org/10.1017/s0031182097002126.
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Metacestodes of Hymenolepis diminuta affect several aspects of female reproductive physiology in Tenebrio molitor and such effects are mediated via the endocrine system. The effects on male reproduction are less well known and were studied with respect to the Bean-Shaped Accessory Glands (BAGs). The size and wet and dry weight of BAGs from infected and uninfected beetles were compared and rose to a plateau from 0–6 days post-emergence in uninfected beetles but in infected individuals continued to increase in both size and weight. These effects were density independent. Glands from both infected and uninfected beetles were assayed for trehalase activity measured by its ability to convert the sugar trehalose to glucose. The activity of this enzyme, per mg wet weight, was not affected by the parasite. However, total activity per gland increased in infected males. Total protein content and electrophoretic profiles of BAGs from infected and uninfected individuals showed no change in profile but showed an increase in all protein subunits per gland over a broad molecular weight range.
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Matthews, S. G., M. Fraser y J. R. G. Challis. "Dopaminergic regulation of pituitary function in the late-gestation fetal sheep". Journal of Endocrinology 150, n.º 2 (agosto de 1996): 187–94. http://dx.doi.org/10.1677/joe.0.1500187.
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Abstract Development of the fetal ovine pituitary is essential for normal maturation and initiation of the parturition process, as well as for orchestrating endocrine responses to stress in utero. Increases in the biosynthesis of ACTH and prolactin (PRL) occur in the late-gestation fetal sheep pituitary. In the anterior lobe (AL) of the pituitary, pro-opiomelanocortin (POMC) biosynthesis and processing are primarily regulated by corticotrophin-releasing hormone and vasopressin. However, POMC in the intermediate lobe (IL) and PRL in the AL are known to be primarily regulated by dopamine, via the D2 receptor, in adult sheep. Because of the importance of ACTH and PRL during gestation we have investigated a potential role of dopamine in the control of both IL melanotrophs and AL lactotrophs and corticotrophs, in late gestation. Catheters were implanted into a maternal femoral artery and vein, fetal carotid artery and jugular vein as well as into the amniotic cavity. At day 130 of gestation, fetuses were infused intravenously with either the specific D2 receptor agonist bromocriptine (n = 5) or vehicle (n=5), for 5 days. Blood samples were taken throughout the experiment and pituitaries were removed at the end of the treatment period. Bromocriptine caused a significant decrease (>50%) in POMC mRNA levels in the IL. In contrast, bromocriptine had no significant effect on POMC mRNA levels or distribution in the AL. Fetal arterial ACTH and cortisol concentrations were unaffected by the bromocriptine infusion, compared with vehicle-infused controls. There was a dramatic decrease (>80%) in plasma PRL concentrations, compared with the control fetuses. However, PRL mRNA levels in the AL were not significantly affected by bromocriptine. In conclusion, we have found that bromocriptine inhibits aspects of both melanotroph and lactotroph function in late-gestation fetal sheep. The data indicate that the fetal pituitary possesses functional D2 receptors in late gestation. Journal of Endocrinology (1996) 150, 187–194
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Bell, Alan W. y Paul L. Greenwood. "Prenatal origins of postnatal variation in growth, development and productivity of ruminants". Animal Production Science 56, n.º 8 (2016): 1217. http://dx.doi.org/10.1071/an15408.
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This review provides an update on recent research into the effects of maternal nutrition on fetal biology and the growth, development and productivity of progeny in postnatal life of ruminant livestock. Evidence is summarised for effects on postnatal growth and body composition, feed intake and efficiency, carcass characteristics and meat quality, wool production, reproduction and lactation performance. In general, these demonstrated effects are not large in relation to the effects of postnatal nutrition and other environmental influences. The mechanisms underpinning the above production outcomes are briefly discussed in terms of systemic endocrine and metabolic responses, and cellular and molecular effects in skeletal muscle, bone, adipose tissue, wool follicles and brain of fetal, neonatal and adult progeny. Treatments observed to elicit tissue responses include maternal under- and overnutrition at various stages of pregnancy and placental insufficiency caused by increased litter size, chronic maternal heat stress and premating carunclectomy in sheep. The as yet meagre evidence for epigenetic mediation of intergenerational effects in ruminants is considered, as is the likelihood that other, more conventional explanations may suffice in some cases. Finally, evidence is summarised for the proposition that the placenta is not merely a passive conduit for nutrient transfer from dam to fetus, but plays an active role in buffering the effects of variations in maternal nutrition on fetal growth and development, and thence, postnatal outcomes.
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Gandolfi, Fulvio y Tiziana A. L. Brevini. "RFD Award Lecture 2009.In vitro maturation of farm animal oocytes: a useful tool for investigating the mechanisms leading to full-term development". Reproduction, Fertility and Development 22, n.º 3 (2010): 495. http://dx.doi.org/10.1071/rd09151.
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Due to logistical and economic reasons, assisted reproduction of domestic animals has been based mostly on the use of oocytes isolated from ovaries collected at the slaughterhouse. In order to propagate valuable or rare genetic material, perform somatic cell nuclear transfer or generate genetically modified animals, it is essential to obtain fully competent oocytes that will allow full-term development of the in vitro-produced embryos. Such a need makes clear the crucial role played by oocyte quality. In fact, it is easy to compromise the oocyte’s developmental potential but it is impossible to restore once it has been lost. Almost three decades after the first cow, sheep, goat, horse and pig in vitro-generated offspring were born, a large body of information has accumulated on the mechanisms regulating oocyte competence and on how the latter may be preserved during all the required manipulations. The amount of knowledge is far from complete and many laboratories are actively working to further expand it. In this review we will highlight the aspects of the ongoing research in which we have been actively involved.
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Mills, Edouard G. A., Kevin T. O'Byrne y Alexander N. Comninos. "Kisspeptin as a Behavioral Hormone". Seminars in Reproductive Medicine 37, n.º 02 (marzo de 2019): 056–63. http://dx.doi.org/10.1055/s-0039-3400239.
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AbstractSuccessful reproduction is dependent not only on hormonal endocrine responses but also on suitable partner selection, copulatory acts, as well as associated emotional, behavioral, and cognitive processes many of which are supported by the limbic system. The reproductive hormone kisspeptin (encoded by the KISS1/kiss1 gene) is now recognized as the key orchestrator of the reproductive axis. In addition to the hypothalamus, prominent kisspeptin neuronal populations have been identified throughout limbic and paralimbic brain regions across an assortment of species. In this review, we detail the emerging roles of kisspeptin signaling in the broader aspects of behavioral, emotional, and cognitive control. Recent studies from zebrafish through humans have provided new molecular and neural insights into the complex role of kisspeptin in interpreting olfactory and auditory cues to govern sexual partner preference, in regulating copulatory behaviors and in influencing mood and emotions. Furthermore, emerging roles for kisspeptin in facilitating memory and learning are also discussed. To this end, these findings shed new light onto the importance of kisspeptin signaling, while informing the pharmacological development of kisspeptin as a potential therapeutic strategy for individuals suffering from associated reproductive, emotional, and cognitive disorders.
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Gandolfi, F. y T. Brevini. "020. IN VITRO MATURATION OF FARM ANIMALS OOCYTES: A USEFUL TOOL FOR INVESTIGATING THE MECHANISMS LEADING TO FULL TERM DEVELOPMENT". Reproduction, Fertility and Development 21, n.º 9 (2009): 7. http://dx.doi.org/10.1071/srb09abs020.
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Due to logistical and economical reasons assisted reproduction of domestic animals has been based mostly on the use of oocytes isolated from ovaries collected at the slaughterhouse. In order to propagate valuable or rare genetic material, perform somatic cell nuclear transfer, generate genetically modified animals it was essential to obtain fully competent oocytes that would allow full term development of the in vitro produced embryos. Such demanding need has soon made clearly evident the crucial role played by oocyte quality, how easy it is to compromise its developmental potential and the fact that it is impossible to restore it once it has been lost. Almost three decades after the first bovine, sheep, goat, horse and pig in vitro generated offsprings were born, a large body of information has accumulated on the mechanisms regulating oocyte competence and on how the latter may be preserved during all the required manipulations. The amount of knowledge is far from being complete and many laboratories are actively working to further expand it. In this review we will highlight the aspects of the ongoing research in which we have been actively involved.
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Symonds, Michael E., Sylvain P. Sebert y Helen Budge. "The impact of diet during early life and its contribution to later disease: critical checkpoints in development and their long-term consequences for metabolic health". Proceedings of the Nutrition Society 68, n.º 4 (1 de septiembre de 2009): 416–21. http://dx.doi.org/10.1017/s0029665109990152.
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Changes in maternal diet at different stages of reproduction can have pronounced influences on the health and well-being of the resulting offspring, especially following exposure to an obesogenic environment. The mechanisms mediating adaptations in development of the embryo, placenta, fetus and newborn include changes in the maternal metabolic environment. These changes include reductions in a range of maternal counter-regulatory hormones such as cortisol, leptin and insulin. In the sheep, for example, targeted maternal nutrient restriction coincident with the period of maximal placental growth has pronounced effects on the development of the kidney and adipose tissue. As a consequence, the response of these tissues varies greatly following adolescent-onset obesity and ultimately results in these offspring exhibiting all the symptoms of the metabolic syndrome earlier in young adult life. Leptin administration to the offspring after birth can have some long-term differential effects, although much higher amounts are required to cause a response in small compared with large animal models. At the same time, the responsiveness of the offspring is gender dependent, which may relate to the differences in leptin sensitivity around the time of birth. Increasing maternal food intake during pregnancy, either globally or of individual nutrients, has little positive impact on birth weight but does impact on liver development. The challenge now is to establish which components of the maternal diet can be sustainably modified in order to optimise the maternal endocrine environment through pregnancy, thus ensuring feto–placental growth is appropriate in relation to an individual's gender and body composition.
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Senthilkumaran, Balasubramanian y Sonika Kar. "Advances in Reproductive Endocrinology and Neuroendocrine Research Using Catfish Models". Cells 10, n.º 11 (20 de octubre de 2021): 2807. http://dx.doi.org/10.3390/cells10112807.
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Catfishes, belonging to the order siluriformes, represent one of the largest groups of freshwater fishes with more than 4000 species and almost 12% of teleostean population. Due to their worldwide distribution and diversity, catfishes are interesting models for ecologists and evolutionary biologists. Incidentally, catfish emerged as an excellent animal model for aquaculture research because of economic importance, availability, disease resistance, adaptability to artificial spawning, handling, culture, high fecundity, hatchability, hypoxia tolerance and their ability to acclimate to laboratory conditions. Reproductive system in catfish is orchestrated by complex network of nervous, endocrine system and environmental factors during gonadal growth as well as recrudescence. Lot of new information on the molecular mechanism of gonadal development have been obtained over several decades which are evident from significant number of scientific publications pertaining to reproductive biology and neuroendocrine research in catfish. This review aims to synthesize key findings and compile highly relevant aspects on how catfish can offer insight into fundamental mechanisms of all the areas of reproduction and its neuroendocrine regulation, from gametogenesis to spawning including seasonal reproductive cycle. In addition, the state-of-knowledge surrounding gonadal development and neuroendocrine control of gonadal sex differentiation in catfish are comprehensively summarized in comparison with other fish models.
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Hasiec, Malgorzata y Tomasz Misztal. "Adaptive Modifications of Maternal Hypothalamic-Pituitary-Adrenal Axis Activity during Lactation and Salsolinol as a New Player in this Phenomenon". International Journal of Endocrinology 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/3786038.
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Both basal and stress-induced secretory activities of the hypothalamic-pituitary-adrenal (HPA) axis are distinctly modified in lactating females. On the one hand, it aims to meet the physiological demands of the mother, and on the other hand, the appropriate and stable plasma cortisol level is one of the essential factors for the proper offspring development. Specific adaptations of HPA axis activity to lactation have been extensively studied in several animal species and humans, providing interesting data on the HPA axis plasticity mechanism. However, most of the data related to this phenomenon are derived from studies in rats. The purpose of this review is to highlight these adaptations, with a particular emphasis on stress reaction and differences that occur between species. Existing data on breastfeeding women are also included in several aspects. Finally, data from the experiments in sheep are presented, indicating a new regulatory factor of the HPA axis—salsolinol—which typical role was revealed in lactation. It is suggested that this dopamine derivative is involved in both maintaining basal and suppressing stress-induced HPA axis activities in lactating dams.
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Gillette, Ross, Michelle Dias, Michael P. Reilly, Lindsay M. Thompson, Norma J. Castillo, Erin L. Vasquez, David Crews y Andrea C. Gore. "Two Hits of EDCs Three Generations Apart: Effects on Social Behaviors in Rats, and Analysis by Machine Learning". Toxics 10, n.º 1 (11 de enero de 2022): 30. http://dx.doi.org/10.3390/toxics10010030.
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All individuals are directly exposed to extant environmental endocrine-disrupting chemicals (EDCs), and indirectly exposed through transgenerational inheritance from our ancestors. Although direct and ancestral exposures can each lead to deficits in behaviors, their interactions are not known. Here we focused on social behaviors based on evidence of their vulnerability to direct or ancestral exposures, together with their importance in reproduction and survival of a species. Using a novel “two hits, three generations apart” experimental rat model, we investigated interactions of two classes of EDCs across six generations. PCBs (a weakly estrogenic mixture Aroclor 1221, 1 mg/kg), Vinclozolin (antiandrogenic, 1 mg/kg) or vehicle (6% DMSO in sesame oil) were administered to pregnant rat dams (F0) to directly expose the F1 generation, with subsequent breeding through paternal or maternal lines. A second EDC hit was given to F3 dams, thereby exposing the F4 generation, with breeding through the F6 generation. Approximately 1200 male and female rats from F1, F3, F4 and F6 generations were run through tests of sociability and social novelty as indices of social preference. We leveraged machine learning using DeepLabCut to analyze nuanced social behaviors such as nose touching with accuracy similar to a human scorer. Surprisingly, social behaviors were affected in ancestrally exposed but not directly exposed individuals, particularly females from a paternally exposed breeding lineage. Effects varied by EDC: Vinclozolin affected aspects of behavior in the F3 generation while PCBs affected both the F3 and F6 generations. Taken together, our data suggest that specific aspects of behavior are particularly vulnerable to heritable ancestral exposure of EDC contamination, that there are sex differences, and that lineage is a key factor in transgenerational outcomes.
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Seshagiri, Polani B. y Venkatappa Vani. "Research on early mammalian development in India". International Journal of Developmental Biology 64, n.º 1-2-3 (2020): 109–21. http://dx.doi.org/10.1387/ijdb.190189ps.
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Historically, research in India on early mammalian development had only begun, rather modestly, in the last century, unlike the USA and UK. In India, initial studies were on gonadal and reproductive tissue development and function and they were limited to anatomical and histological characterization. This was followed by research on fertility regulation and contraception. Since the 1960s, a major initiative took place regarding endocrine biochemistry and the use of antifertility agents in inhibiting gonadal function and early development. Post-independence, the Indian government´s funding support enabled universities and institutions to embark on various research disciplines in biology but with no particular emphasis on developmental biology per se. Subsequently, India made significant progress in the area of mammalian reproduction and development, but not specifically in the core aspects of developmental biology. Reasons for this could be due to the nation’s compulsion to invest and embark on socio-economic and infrastructure development and on research involving family planning methods for reversible-affordable contraceptives to curtail population growth. With regard to the latter, biologists were involved in hormone-based contraception research. During this pursuit, insights were achieved into basic aspects of the development of gonads, gametes and embryos. Notwithstanding this, in the post-1980s through to the present time, Indian scientists have contributed to (i) the understanding of the cellular and molecular regulation of early development, (ii) developing genetically modified mouse models, (iii) using assisted reproductive technologies, generating mammalian progeny, including humans and (iv) deriving pluripotent stem cell lines for developmental studies. This article provides a perspective on the past and current status of early mammalian development research in India.