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1
Tahmasbi, A. M., H. Galbraith e J. R. Scaife. "Development of an In Vitro technique to investigate the role of biotin in regulating wool growth in sheep". Proceedings of the British Society of Animal Science 1996 (marzo 1996): 183. http://dx.doi.org/10.1017/s1752756200593788.
Testo completoAbstract (sommario):
The development of in vitro culture techniques (Ibraheem et al, 1993, 1994) for the study of caprine hair follicles has proved useful in elucidating aspects of the control of cashmere and mohair fibre production. There is a similar need to investigate nutritional and other factors which regulate the growth of sheep wool. The aim of the present study was to develop an in vitro technique to study the role of the B-vitamin biotin in controlling growth and viability of sheep wool follicles.
2
Tahmasbi, A. M., H. Galbraith e J. R. Scaife. "Development of an In Vitro technique to investigate the role of biotin in regulating wool growth in sheep". Proceedings of the British Society of Animal Science 1996 (marzo 1996): 183. http://dx.doi.org/10.1017/s0308229600031494.
Testo completoAbstract (sommario):
The development of in vitro culture techniques (Ibraheem et al, 1993, 1994) for the study of caprine hair follicles has proved useful in elucidating aspects of the control of cashmere and mohair fibre production. There is a similar need to investigate nutritional and other factors which regulate the growth of sheep wool. The aim of the present study was to develop an in vitro technique to study the role of the B-vitamin biotin in controlling growth and viability of sheep wool follicles.
3
Adams, N. R., e S. M. Liu. "Principles of nutrient partitioning for wool, growth and reproduction: implications for nematode parasitism". Australian Journal of Experimental Agriculture 43, n. 12 (2003): 1399. http://dx.doi.org/10.1071/ea03007.
Testo completoAbstract (sommario):
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.
4
Birrell, HA. "Factors associated with the rate of growth of clean wool on grazing sheep". Australian Journal of Agricultural Research 43, n. 2 (1992): 265. http://dx.doi.org/10.1071/ar9920265.
Testo completoAbstract (sommario):
In a grazing study that spanned 2.5 years, the rate of clean wool growth (Wi, g/day) in 4 week periods on Corriedale wether sheep was measured on each side of the animal with dyebands that were applied, alternately, at 2 week intervals. The observations (n = 224) on wool growth from 3 contiguous periods Wi = 1, 2 and 3 with the middle overlapping the other two periods, were related to either the daily rate of organic matter intake (OMI, g/day), the digestible organic matter intake (g DOMI/day), the hourly rate of OMI (IR, g OMI/h) or the hourly rate of digestible organic matter intake (DR, g DOMI/h) in linear or quadratic expressions. The intake data were collected every 4 weeks over the 3 days that correspond to days 6 to 8 of W1. The variance accounted for in each of W1, W2 and W3 increased in the order OMI<DOMI<IR<DR. DR accounted for 33.2% of the variance in W1 with a significant quadratic fit (P < 0.01) and 24.3% and 7.8% with linear fits against W2 and W3, respectively. A relationship that comprised five factors and accounted for 68% of the variance in W1 was developed by nonlinear regression. Three factors that were associated with nutritional aspects, the hourly rate of digestible organic matter intake (DR, g DOMI/h), the organic matter digestibility (OMD %) and the average organic matter intake in a grazing period (M, g OMI/grazing period) accounted for 54.9% of the variance in W1 while the other two factors that were associated with the physiological state of the animal, fleece-free liveweight change (C, g/day) and the fleece-free liveweight (L, kg) accounted for a further 13.1% of the variance of W1. The study suggests that factors associated with phenomena within a daily period may have important effects on wool growth. Management aspects are discussed.
5
Adelson, DL, SG Munro e DA Tunks. "Perturbation of wool fibre cell differentiation by a mixture of bromodeoxyuridine and fluorodeoxyuridine". Australian Journal of Agricultural Research 42, n. 8 (1991): 1293. http://dx.doi.org/10.1071/ar9911293.
Testo completoAbstract (sommario):
As part of investigations into the pattern of cell division and differentiation in the wool follicle bulb, the thymidine analogue 5-bromo-2'-deoxyuridine was used to label cells in S phase. A mixture of 5-bromo-2deoxyuridine and 5-fluoro-2'-deoxyuridine was injected into sheep held at a constant plane of nutrition. fibre length growth rates were measured by injecting the animals with either 35S-labelled methionine or cysteine, followed by autoradiography of individual fibres. Fibres from 5-bromo-2'-deoxyuridine/5-fluoro-2'-deoxyuridine treated animals exhibited both abnormal cuticle scale patterns and disorganized ortho- and paracortex as determined by staining with methylene blue. Orthocortex differentiation in wool follicle bulb keratogenous zones was visualized using a monoclonal antibody specific for orthocortical cells (HiT 96). We determined that the normal pattern of orthocortical cell differentiation was reversibly inhibited by 5-bromo-2'-deoxyuridine/5-fluoro-2'-deoxyuridine treatment. Fibre length growth rate was reversibly decreased very slightly as a result of 5-bromo-2'-deoxyuridine/5-fluoro- 2'-deoxyuridine administration. We conclude that 5-bromo-2'-deoxyuridine/5-fluoro-2'-deoxyuridine can grossly perturb aspects of wool follicle bulb cell differentiation without profoundly affecting fibre length growth rate. Although 5-bromo-2'-deoxyuridine/5-fluoro-2~-deoxyuridine labelling is an inexpensive, nonradioactive method of visualizing S phase nuclei, the possibility of artefacts resulting from such treatment should be borne in mind.
6
Lee, GJ, e AJ Williams. "Nutritional responses in wool growth by four Merino genotypes of differing wool growth performance". Australian Journal of Agricultural Research 45, n. 6 (1994): 1171. http://dx.doi.org/10.1071/ar9941171.
Testo completoAbstract (sommario):
Sheep from four Merino flocks, different in annual clean fleece production when grazed together, were offered a range of nutritional treatments to compare their ability to digest dietary organic matter (experiment 1) and to compare the relationships of wool growth and fibre diameter with nutrient intake (experiment 2). The sheep were selected from a finewool (Fl), a strong wool (S), and two medium-Peppin (MP6 and MP10) flocks. The nutritional treatments varied intakes of two pelleted diets-B and F. Diet B consisted of oat grain, lucerne chaff, and oaten straw, while diet F was as for B but fortified with fishmeal. The digestibility of both diets was negatively related to the level of intake, and there were some differences between the flocks in their ability to digest organic matter. Clean wool growth per unit area of skin was curvilinearly related (P < 0.001) to N intake, but was not influenced by diet per se. The regression coefficient for the relationship of clean wool growth with N intake and the estimated maximum wool growth rate of flock F1 were less than the other flocks. However, flock MP10 grew less wool than flocks S and MP6 at any given intake. Variation in (fibre diameter)2 accounted for 0.6 of the variation in wool growth, with responses in fibre diameter to intake being similar to those observed in wool growth. The responses in plasma cystine of the flocks to N intake differed, with the relationship for flock F1 being curvilinear and reaching a maximum at an intake of 27 g N day-1, while the responses of the other flocks were essentially linear. The relationships between plasma cystine level and wool growth differed between the flocks such that wool growth of sheep from flocks S and MP6 was more responsive to increased plasma concentration of cystine.
7
García-Ruiz, E., V. Marco e I. Pérez-Moreno. "Laboratory rearing and life history of an emerging grape pest, Xylotrechus arvicola (Coleoptera: Cerambycidae)". Bulletin of Entomological Research 102, n. 1 (6 settembre 2011): 89–96. http://dx.doi.org/10.1017/s000748531100040x.
Testo completoAbstract (sommario):
AbstractSeveral aspects of the biology of Xylotrechus arvicola (Olivier), an emerging grape pest, were studied under laboratory conditions. Four diets were tested to rear this species in the laboratory. Among them, only one made rearing from larva to adult possible. The highest mortality, in all cases, was recorded during the first days of larval development. Larvae were kept 45 days at 8°C to break diapause in order to reduce the normal field larval developmental time. The species' developmental time was similar between sexes, while pupal developmental time and weight were significantly greater for females than for males. As part of a complementary study, life table parameters of females obtained from the larvae reared on the artificial diet were compared to those of females emerged from field-infested grape root wood. Both laid the majority of eggs in the first two weeks after emergence, and they had a similar pre-laying period. Nevertheless, the females from the diet-reared larvae lived significantly longer, laid eggs over a longer period of time and showed higher fertility than those emerging from infested grape root, suggesting that diet fulfils larval nutritional needs. The species’ laboratory-reared population exhibited a low intrinsic growth rate value (rm=0.01) as a result of its long egg-to-adult developmental time and its high larval mortality.
8
Hynd, P. I. "The nutritional biochemistry of wool and hair follicles". Animal Science 70, n. 2 (aprile 2000): 181–95. http://dx.doi.org/10.1017/s1357729800054655.
Testo completoAbstract (sommario):
AbstractThe rôle of various classes of nutrients (energy substrates, vitamins, minerals, amino acids) in the production of wool and hair from follicles, is considered for a variety of animal species. The wool and hair follicle have evolved a number of interesting features of carbohydrate metabolism including glutaminolysis, aerobic glycolysis, significant activity of the pentose phosphate pathway, and storage and mobilisation of glycogen. Presumably the necessity to continue to produce fibre despite fluctuations in the supply of oxygen and nutrients has resulted in some of these unique features, while others reflect the high level of DNA and protein synthesis occurring in the follicle. While it is considered that energy does not normally limit fibre growth, the relative contributions of aerobic and anerobic metabolism will greatly influence the amount of ATP available for follicle activity, such that energy availability may at times alter fibre growth. Alopecia and deficient fibre growth are consistent outcomes of deficiencies of biotin, riboflavin, pyridoxine, folate and pantothenic acid, but the precise rôles of these vitamins in follicle function await elucidation. Folate, in particular appears to play an important rôle in wool production, presumably reflecting its involvement in methionine metabolism. Cholecalciferol (vitamin D) significantly alters fibre growth in cultured follicles; vitamin D receptors are located in the outer root sheath, bulb, and dermal papilla of the follicle; and alopecia occurs in humans with defects in the vitamin D receptor. Retinol (vitamin A), too, appears to influence follicle function by altering keratinocyte proliferation and differentiation, with direct effects on the expression of keratin genes. The receptors for the retinoids are present in the keratogenous zone, the outer root sheath, the bulb, and the sebaceous glands. Vitamin A may also act indirectly on follicle function by influencing the activity of the insulin-like and epidermal growth factors and by altering vitamin D activity. At present there is little evidence implicating alpha-tocopherol (vitamin E) or phytylmenaquinone (vitamin K) in follicular events. Of the minerals, only copper and zinc have been shown to have direct effects on follicle function, independent of effects on food intake. Copper has direct effects on the activity of an unidentified enzyme on oxidation of thiol groups to form disulphide linkages. Wool produced by copper-deficient sheep lacks crimp, is weak and lustrous. Copper is also necessary for the activity of tyrosinase and the tyrosinase-related proteins involved in melanin synthesis. Zinc, like copper, is required for the normal keratinization of fibres but again, the precise rôle has yet to be elucidated. While the importance of amino acid supply for wool growth has long been established, there are still some unaswered questions such as; what are the effects of amino acids on fibre growth in animals other than sheep; what are the characteristics of the amino acid transport genes and proteins operating in the wool and hair follicle; and what are the specific rôles for amino acids in follicle function.
9
Williams, AJ, e RJ Winston. "A study of the characteristics of wool follicle and fibre in Merino sheep genetically different in wool production". Australian Journal of Agricultural Research 38, n. 4 (1987): 743. http://dx.doi.org/10.1071/ar9870743.
Testo completoAbstract (sommario):
Fourteen Merino ewes from each of two flocks, selectively bred for either high (Fleece Plus) or low (Fleece Minus) clean fleece weight per head, were randomly allotted to two feeding levels (17 v. 34 g kg-1 liveweight) of a good quality diet and offered these levels for 100 days. During the final 42 days, the rate of wool growth and its components were measured in each sheep. The Fleece Plus sheep had a greater density of wool follicles and produced more wool per unit area of skin. The latter trait interacted with the nutritional level; Fleece Plus sheep were more responsive to the higher nutritional level (45 v. 13%). Both the rate of growth of fibre length and the diameters of fibres produced in secondary follicles were the components associated with this interaction. The sulfur content of the wool was 12% less in wool from Fleece Plus ewes, but the difference between the two flocks was unrelated to the nutritional level. The average diameter (c. 83 8m) of the bulbs of the follicles did not differ between flocks or dietary levels, but follicles in the skin of Fleece Plus sheep were deeper (P < 0.05) below the skin surface (1.52 v. 1.38 mm). Despite the similar maximum bulb diameters, random longitudinal sections of follicles from Fleece Plus sheep had a 10% greater area of mitotically active tissue (P < 0.05). The difference was independent of nutritional level. When colchicine (10 8g) was injected intradermally, the number of cells revealing metaphase arrest within the mitotically active area of the follicle increased linearly with time to 6 h after the injection. The rate of increase in these cells expressed per unit volume of bulb tissue was not however influenced by either genotype or nutritional level. The average volume of cortical cells isolated from the fibres did not differ between genotypes or nutritional levels, but as with fibre volume, the volume of the cortical cells of the Fleece Plus sheep was more sensitive to a change in nutritional level (interaction: P < 0.05). Calculation of the rate of incorporation of cortical cells into fibre from both rate of production of fibre and the size of the cortical cells indicated that 20% more cells were incorporated by the Fleece Plus sheep and 17% more cells were incorporated by those sheep offered the greater dietary allowance. There was no significant interaction between genotypes and nutritional level for this trait.
10
Butler, LG, e GM Head. "Photoperiodic rhythm of wool growth and its contribution to seasonal wool production by the Merino, Polwarth, and their reciprocal crosses in southern Australia". Australian Journal of Experimental Agriculture 34, n. 3 (1994): 311. http://dx.doi.org/10.1071/ea9940311.
Testo completoAbstract (sommario):
Twelve wethers of each of the Merino and Polwarth breeds and their reciprocal crosses were fed at1 of 2 levels in individual pens for 14 months. Periodic clean wool weight, yield, fibre diameter, and the coefficient of variation (CV%) for fibre diameter were measured from midside patches harvested every6 weeks.There was a significant effect of time of wool harvest on clean wool weight per cm2, yield, fibre diameter(all P<0.01), and its CV% (P<0.05). A trough in wool production occurred about August-September and a peak in January. The amplitude of the photoperiodic rhythm of wool growth (difference between maximum and minimum wool growth per cm2 per 42 days as a percentage of the average) was 40%. Yield also displayed a substantial photoperiodic rhythm, but that of fibre diameter was less pronounced. Mean staple strength was 32.3 N/ktex, the mean break occurring at a distance of 60% of the staple length from the tip; there was no effect of genotype or level of feeding. From comparison with published Tasmanian field data, the seasonal wool growth pattern of sheep at pasture appears similar to the photoperiodic rhythm but occurs about a month earlier. It was concluded that the photoperiodic rhythm of wool production of Tasmanian Merino-based breeds should not be a barrier to manipulation of wool quality (staple strength and fibre diameter) by nutritional management.
11
Reis, PJ, DA Tunks e SG Munro. "Effects of abomasal protein and energy supply on wool growth in Merino sheep". Australian Journal of Agricultural Research 43, n. 6 (1992): 1353. http://dx.doi.org/10.1071/ar9921353.
Testo completoAbstract (sommario):
The relative importance for wool growth of energy-yielding nutrients compared with amino acids required for incorporation into wool proteins was assessed in an experiment in which most nutrients were supplied via the abomasum. Nine nutritional treatments, providing three levels of protein (53, 99 and 145 g/day) to the intestines at three levels of energy (5.2, 7.5 and 9.7 MJ/day), were given to 12 Merino sheep during three consecutive periods of 3 weeks in a balanced lattice design. Abomasal nutrients consisted of varying proportions of casein, whole milk, glucose and glycerol. There was a large effect of protein supply on all components of wool growth, but there was no significant effect of energy. There was a significant interaction between the effects of protein and energy supply on diameter, length growth rate and volume of wool, but it was small relative to the main effect of protein. Extra energy appeared to enhance wool growth at the highest level of protein but reduce it at the lowest level of protein. The concentration of urea, cystine, methionine and other essential amino acids in plasma increased with protein level. Increasing energy supply reduced the concentration of urea and essential amino acids in plasma but not that of cystine or methionine. The experiment confirmed the major role of amino acid supply in controlling wool growth but indicated that there may be a small interaction with energy supply.
12
Barry, T. N. "The role of condensed tannins in the nutritional value of Lotus pedunculatus for sheep". British Journal of Nutrition 54, n. 1 (luglio 1985): 211–17. http://dx.doi.org/10.1079/bjn19850106.
Testo completoAbstract (sommario):
1. Lotus pedunculatus (cv. Grasslands Maku) grown on acid low-fertility soil and containing high concentrations of condensed tannin (76–90 g/kg dry matter (DM)) was grazed by growing sheep for 31–42 d periods in three experiments. In Expt 2 an additional group of lambs grazed areas oversown with white clover (Trifolium repens) and red clover (Trifolium pratense). Lambs were transferred from grazing ryegrass (Lolium perenne) – white clover straight on to lotus in all experiments (unconditioned sheep). In Expt 3 a second group was included which had grazed high-tannin lotus for a pre-experimental period of 8 weeks (conditioned sheep).2. Effects of condensed tannin on body and wool growth were assessed by studying responses to daily oral administration of polyethylene glycol (PEG; molecular weight 3350, 75–100 g/d). PEG forms a complex with condensed tannin, which is assumed to be inert in its passage through the digestive system, and so effectively reduces the nutritional effects attributable to high condensed-tannin concentrations.3. Live-weight gain (LWG) in the absence of PEG was low (27–125 g/d) for sheep grazing high-tannin lotus, and PEG administration increased LWG by 41–61 g/d and increased wool growth. In Expt 3, responses to PEG supplementation tended to be less with conditioned than with unconditioned sheep, indicating that conditioned sheep had partially adapted to the high-tannin diet.4. PEG supplementation had no effect on either LWG or wool growth of sheep grazing areas oversown with mixed clovers, confirming its effects as specific to forages containing condensed tannins. These experiments therefore conclusively show that high concentrations of condensed tannin induced by growing Lotus pedunculatus under low soil fertility conditions prevent maximum expression of LWG and wool growth in grazing sheep. These results contrast with high LWG (153–315 g/d) observed in growing sheep grazing the same lotus cultivar grown in high fertility soil and containing 20 g condensed tannin/kg DM, a level considered to be nutritionally beneficial.
13
Stephenson, RGA, GR Suter, DA Pritchard e MDJ Martin. "Studies of wool growth responses to 2-hydroxy-4-(methylthio) butanoic acid, Alimet, an analogue of methionine". Australian Journal of Experimental Agriculture 30, n. 4 (1990): 477. http://dx.doi.org/10.1071/ea9900477.
Testo completoAbstract (sommario):
An analogue of DL-methionine, Alimet, was evaluated for its commercial potential for increasing wool growth in Merino sheep in pen and grazing experiments. This was done by administering Alimet as a drench, in drinking water, or via rumen or abomasal fistula, and measuring wool growth rate and plasma methionine concentrations. In vivo data indicated that significant wool growth responses (23-35%) to Alimet as a drench or in drinking water occurred at low rates (estimated 5-6 g/sheep.day) of basal wool production when sheep were fed a lucerne diet to maintain liveweight. At higher rates of clean wool growth (10-12 g/sheep.day) when sheep were eating above-maintenance diets (lucerne ration or pasture), Alimet treatment was associated with variable and reduced response. A significant (P<0.05) negative correlation (r2 = 0.699, n = 11) between wool growth responses (x � s.d. = 0.11 � 0.067) to the 3 mL dose rate of Alimet and wool growth in control treatments (y �: s.d. = 0.70 � 0.202) confirmed the above trend. Four hours after administration of Alimet via either rumen or abomasal fistula, comparative plasma concentrations of methionine, 28 and 168 �mol/L respectively, suggest that Alimet is susceptible to degradation in the rumen. The corresponding values for DL-methionine, via either rumen or abomasal fistula, were 64 and 350 �mol/L, respectively. The small rises (40%) in plasma methionine values associated with significant increases in wool production indicate that a dose of 3 mL is as effective as 4 mL of Alimet when the basal nutritional regime is limiting. While administration of Alimet in drinking water during dry seasons is possible, the profitability of supplementation would need to be tested further.
14
Stephenson, RGA, GR Suter e CJ Howitt. "Wool growth responses to DL-methionine administration and factors affecting the value of supplementation". Australian Journal of Experimental Agriculture 31, n. 4 (1991): 471. http://dx.doi.org/10.1071/ea9910471.
Testo completoAbstract (sommario):
Wool growth responses to methionine administration were assessed using Peppin Merino wethers on various planes of nutrition. In experiment 1, sheep were fed 700 g/day of lucerne pellets to maintain liveweight. DL-methionine (5.8 g) administered subcutaneously resulted in 0.29 mg/cm2.day (36%) more wool (P<0.01) and a 2.5 �m (15.2%) increase in fibre diameter (P<0.05). In experiment 2, two levels (700 and 1400 g/day) of lucerne pellets were offered, with and without methionine administered subcutaneously (5.8 g). Main treatment analysis indicated a significant (P<0.01) effect of nutrition on wool growth and fibre diameter, with no effect of methionine, except for a reduction (P<0.05) in liveweight gain. Methionine administration was associated with a non-significant increase (39%) in wool growth for the 700 g diet and no change for the 1400 g diet. In experiment 3, two levels (1.75 and 2.5 g/day) of methionine were infused (4 h daily) when sheep were fed a submaintenance ration of Rhodes grass chaff, supplemented with nitrogen and sulfur. Significant (P<0.05) wool growth responses at both levels of methionine infusion were similar, with absolute (0.21 and 0.23 mg/cm2.day) and percentage (52 and 58%) increases for 1.75 and 2.5 g/day methionine treatments, respectively. Methionine administration only increased wool production at nutritional levels of liveweight maintenance or below when wool growth values for control treatments were 0.63,0.59 and 0.40 mg/cm2.day for experiments 1, 2 and 3. Fibre diameters of sheep in untreated groups were 16.4 and 18.8 pm for experiments 1 and 2. These wool growth and fibre diameter values are 25-40% below what might be expected for this strain of Merino. The values of positive correlations between wool growth and fibre diameter were increased with increased nutrition and the administration of methionine in experiment 2. This result and the nil response at high basal wool growth, together with the low potential net return on the cost of methionine, suggest that the use of methionine could be unprofitable.
15
McKay, J. C. "Fibre production in angora rabbits". Proceedings of the British Society of Animal Production (1972) 1990 (marzo 1990): 67. http://dx.doi.org/10.1017/s0308229600018481.
Testo completoAbstract (sommario):
Angora rabbits carry a mutation.which confers continuous wool growth. The use of the wool in textiles was first recorded in 1706 in the U.K. and western Europe dominated world production until the the early 20th century. China now produces 60 percent of the world's 4,000 tonne annual crop.Genetic and nutritional improvements have led to a five-fold increase in annual yields over the last 40 years. Current commercial strains produce up to 1.5 Kg of wool per year from rabbits weighing 4 Kg. To maintain such yields requires concentrate diets with protein contents of at least 16 percent and cystine+methionine contents of 0.8 percent.The wool may be sheared or plucked and consists of three fibre types. The wool hairs (80 percent of the fleece) are among the finest animal fibres at 8-12 microns. They have a hollow medulla which gives important properties of low density (1.23 grams per ml versus 1.3 for sheep wool) and high thermal insulation (2-3 times that of sheep wool).
16
Revell, Dean K., Suzanne K. Baker e D. Barrie Purser. "Nitrogen and sulfur mobilised from body tissue can be used for wool growth". Australian Journal of Agricultural Research 50, n. 1 (1999): 101. http://dx.doi.org/10.1071/a98068.
Testo completoAbstract (sommario):
The hypothesis was tested that when nitrogen (N) and sulfur (S) are mobilised from body tissue the rate of wool growth is determined both by the amount of N and S apparently digested and by the amount of N and S mobilised from body tissue. The experiment consisted of seven 5-day periods (Periods 1–7) and N and S retention were measured during each period in 12 mature Merino wethers. During Periods 2 and 3, casein and methionine were infused into the abomasum of all sheep to increase the amount of N and S absorbed in the small intestine. Three nutritional regimes were used in order to manipulate the amount of N and S mobilised from body tissues after the cessation of the abomasal infusion: one group of sheep (n = 4) was fed ad libitum throughout the experiment (Group A), another group (n = 4) was fed at a level calculated to maintain liveweight throughout the experiment (Group M), and the third group (n = 4) was fed ad libitum pre-infusion and during the infusion but was then fed at a level calculated to maintain liveweight after the infusion ceased (Group AM). The infusion of the supplement increased wool growth, and when the infusion ceased, it took 10 days for wool growth to return to a steady rate of growth. Wool growth per unit of apparently digested N or S increased markedly when N or S was mobilised from body tissue, indicating that mobilised protein was used for wool growth. Based on the relationship between the apparent retention of N and S in body tissues excluding wool, and changes in plasma amino acid concentrations, it appeared that the supply of S-containing amino acids from body tissue limited the use of mobilised protein for wool growth.
17
Terrill, T. H., G. B. Douglas, A. G. Foote, R. W. Purchas, G. F. Wilson e T. N. Barry. "Effect of condensed tannins upon body growth, wool growth and rumen metabolism in sheep grazing sulla (Hedysarum coronarium) and perennial pasture". Journal of Agricultural Science 119, n. 2 (ottobre 1992): 265–73. http://dx.doi.org/10.1017/s0021859600014192.
Testo completoAbstract (sommario):
SUMMARYAreas of sulla (Hedysarum coronarium) and pasture (Lolium perenne/Trifolium repens/Holcus lanatus) were grazed by young sheep (29·5–34·8 kg initial liveweight) in four experiments, and effects upon body growth, wool growth and rumen metabolism were measured.Sulla contained 40–50 g condensed tannins (CT)/kg DM, whilst the pasture contained small amounts of CT (2–6 g/kg DM). After chewing during eating, a lower proportion of total CT was readily extractable and greater proportions were protein-bound and fibre-bound. Nutritional effects attributable to CT were assessed by oral administration of polyethylene glycol (PEG), which binds and inactivates CT, to half the animals grazing each forage. Rates of body growth were consistently higher for lambs grazing sulla than those grazing pasture, with the CT concentration in sulla being neither stimulatory or inhibitory to body growth or voluntary feed intake (VFI). The action of CT reduced carcass fatness in sheep fed both diets, in the one experiment where this was measured. CT present in both sulla and pasture decreased rumen ammonia concentration and decreased molar proportions of iso-butyrate and iso and n-valerate. During spring and early summer, when wool growth rates were highest, CT present in both pasture and sulla increased wool growth rate; when wool growth rates were low during winter, CT had no effect upon the wool growth of sheep grazing either forage. Numbers of protozoa and molar proportions of n-butyrate in rumen fluid were increased by CT in sheep grazing sulla but not pasture.It was concluded that the higher rates of body growth and VFI in lambs grazing sulla was most likely to be due to its very high ratio of readily fermentable: structural carbohydrate.
18
Di Chio, Teresa, Christiane Sokollik, Diego G. Peroni, Lara Hart, Giacomo Simonetti, Franziska Righini-Grunder e Osvaldo Borrelli. "Nutritional Aspects of Pediatric Gastrointestinal Diseases". Nutrients 13, n. 6 (19 giugno 2021): 2109. http://dx.doi.org/10.3390/nu13062109.
Testo completoAbstract (sommario):
In the last decade, the role of nutritional management in pediatric gastrointestinal diseases has gained increasing popularity. Disease-specific diets have been introduced as conventional treatments by international guidelines. Patients tend to more willingly accept food-based therapies than drugs because of their relatively “harmless” nature. Apart from a diet’s therapeutic role, nutritional support is crucial in maintaining growth and improving clinical outcomes in pediatric patients. Despite the absence of classical “side effects”, however, it should be emphasized that any dietary modification might have negative consequences on children’s growth and development. Hence, expert supervision is always advised, in order to support adequate nutritional requirements. Unfortunately, the media provide an inaccurate perception of the role of diet for gastrointestinal diseases, leading to misconceptions by patients or their caregivers that tends to overestimate the beneficial role of diets and underestimate the potential adverse effects. Moreover, not only patients, but also healthcare professionals, have a number of misconceptions about the nutritional benefits of diet modification on gastrointestinal diseases. The aim of this review is to highlight the role of diet in pediatric gastrointestinal diseases, to detect misconceptions and to give a practical guide for physicians on the basis of current scientific evidence.
19
Lohan, Anjana. "Integration of Auxology and Nutritional Aspects for Human Growth". Asian Journal of Research in Social Sciences and Humanities 11, n. 9 (2021): 77–82. http://dx.doi.org/10.5958/2249-7315.2021.00044.7.
Testo completo
20
Fry, JM, MC McGrath, M. Harvey e EJ Speijers. "Vitamin E treatment of weaner sheep. II. The effect of vitamin E responsive subclinical myopathy on liveweight and wool production". Australian Journal of Agricultural Research 47, n. 6 (1996): 869. http://dx.doi.org/10.1071/ar9960869.
Testo completoAbstract (sommario):
Nutritional myopathy occurs as both a clinical and subclinical disease in weaner sheep in Western Australia during summer and autumn. The effect of subclinical nutritional myopathy (SCNM), caused by vitamin E deficiency or combined vitamin E and selenium deficiency, on liveweight and wool was investigated. During the period of SCNM there was no significant difference in liveweight gain in sheep with and without the disease in any of the experiments. Initial liveweight in one experiment was significantly (P < 0.05) higher in sheep that were to develop SCNM during the course of the experiment. In vitamin E deficient-selenium adequate SCNM, there was no difference in wool growth over the period of the disease and no differences in any of the wool measurements at shearing. At 2 sites, the greasy and clean fleece weights were significantly (P < 0.05) greater in a group of sheep diagnosed with more severe SCNM compared with sheep without SCNM. It was concluded that unlike the clinical disease, SCNM was unlikely to cause any economic loss.
21
Pritchard, DA, PR Martin e PK O'Rourke. "The role of condensed tannins in the nutritional value of mulga (Acacia aneura) for sheep". Australian Journal of Agricultural Research 43, n. 8 (1992): 1739. http://dx.doi.org/10.1071/ar9921739.
Testo completoAbstract (sommario):
Sheep were fed mulga (Acacia aneura) ad libitum and supplemented with 0, 12 or 24 g/day of polyethylene glycol molecular weight 4000 (PEG), with or without an additional supplement of 1.5 g/day of each of nitrogen (N), phosphorus (P) and sulfur (S) (NPS). Supplementation with either 12 g/day PEG or 24 g/day PEG increased dry matter intake by 56 and 78% respectively and clean wool growth per unit surface area by 166 and 178% respectively. Supplementation with 24 g/day PEG increased wool fibre diameter, linear growth rate and volumetric growth rate by 32, 29 and 143% respectively. Sheep receiving 24 g/day PEG retained more N (1.80 g/day) and S (254 mg/day) and digested more N (218 g/kg) and S (229 g/kg) when compared with non-supplemented animals. These parameters were further enhanced when NPS was supplemented in conjunction with 24 g/day PEG. Maximum precipitation (77%) of mulga condensed tannins (CT) occurred at a PEG to CT ratio of 0.7:l.
22
Clark, J. E., J. A. Roden, O. Macpherson e P. R. English. "A study of premature wool loss in sheep". Proceedings of the British Society of Animal Production (1972) 1991 (marzo 1991): 88. http://dx.doi.org/10.1017/s0308229600020389.
Testo completoAbstract (sommario):
Premature loss of wool from fleece casting prior to shearing is a problem in some sheep genotypes, in particular in the North Country Cheviot. The reasons for this ocurrence are not fully understood, but it is believed that it is due to a complex of factors including heredity, nutritional and managerial (stress) practices, the wool growth cycle, and physiological parameters such as pregnancy. Prolonged stress is reported to be particularly important in the case of wool slip in ewes which are housed and shorn (Morgan et al, 1986).The present study aimed to investigate the incidence of visible fleece casting in the North Country Cheviot (NCC), Scotch Halfbred (HB) (Border Leicester x NCC), and Border Leicester (BL), which has no history of premature wool loss. The study was implemented on 8 commercial farms in Scotland, and links between key productive parameters and wool loss were studied, and an attempt to identify fleece types most liable to cast was also made.
23
Alam, Shaan E., R. B. Singh, Siddharth Gupta, Parinita Dherange, Fabien De Meester, Agnieszka Wilczynska, Suniti Dharwadkar, Douglas Wilson e Pali Hungin. "Nutritional aspects of epigenetic inheritance". Canadian Journal of Physiology and Pharmacology 90, n. 8 (agosto 2012): 989–94. http://dx.doi.org/10.1139/y2012-105.
Testo completoAbstract (sommario):
The impact of diet and environmental factors on genes concerned with epigenetic inheritance and the mechanism of evolution has grown significantly beyond the Modern Synthesis period. Epigenetic inheritance is the passing of phenotypic change to subsequent generations in ways that are outside the genetic code of DNA. Recently, polymorphisms of the human Delta-5 (fatty acid desaturase, FADS1) and Delta-6 (FADS2) desaturase genes have been described as being associated with the level of several long-chain n-3 and n-6 polyunsaturated fatty acids (PUFAs) in serum phospholipids. Increased consumption of refined starches and sugar increases the generation of superoxide anion in the tissues and free fatty acids (FFA) in the blood. There is an increased amount and activity of nuclear factor-κB (NF-κB), a transcriptional factor regulating the activity of at least 125 genes, most of which are pro-inflammatory. The consumption of glucose may be associated with an increase in 2 other pro-inflammatory transcription factors: activating protein-1 (AP-1), and early growth response protein-1 (Egr-1). AP-1 regulates the transcription of matrix metallo-proteinases and Egr-1 modulates the transcription of tissue factor and plasminogen activator inhibitor-1. It is possible that a complex set of factors, including nutritional factors, come into play during epigenetic inheritance.
24
Adams, N. R., J. R. Briegel, R. D. G. Rigby, M. R. Sanders e R. M. Hoskinson. "Responses of sheep to annual cycles in nutrition 1. Rôle of endogenous growth hormone during undernutrition". Animal Science 62, n. 2 (aprile 1996): 279–86. http://dx.doi.org/10.1017/s1357729800014582.
Testo completoAbstract (sommario):
AbstractPlasma concentrations of growth hormone (GH) are elevated in sheep during undernutrition. The present study attempted to determine whether this increased secretion mediated nutritional effects on reproduction or wool growth, using sheep immunized against growth hormone-releasing hormone and given a low-quality, sub-maintenance diet. Immunization reduced plasma concentrations of GH at all times measured (P < 0·01), through reduced pulse frequency, reduced pulse amplitude, and reduced baseline concentrations. Plasma insulin-like growth factor-1 (1GF-1) was also reduced in the immunized sheep (P < 0·01). Despite this, rates of live-weight loss and wool growth were similar in immunized and control ewes. Plasma concentrations ofLH and FSH were also similar in immunized and control ewes, both during the late luteal phase and after ovariectomy and supplementation with oestradiol and progesterone. Numbers of ovarian follicles and corpora lutea were also unaffected by immunization. It is concluded that high endogenous concentrations of GH in sheep given food below maintenance are necessary to maintain plasma IGF-1, but do not affect the concentration of gonadotropins or ovarian follicular growth. Furthermore, rates of live-weight loss and the depression in wool growth in such animals were also independent of concentrations ofGH or IGF-1.
25
Williams, AJ, e J. Butt. "Wool growth of pregnant Merino ewes fed to maintain maternal liveweight". Australian Journal of Experimental Agriculture 29, n. 4 (1989): 503. http://dx.doi.org/10.1071/ea9890503.
Testo completoAbstract (sommario):
The wool production at the midside of 15 non-mated Merino ewes was compared with that of their monoctocous (n = 20) and dioctocous (n = 13) flockmates during the second half of pregnancy. The ewes were compared under experimentally controlled feeding conditions designed to maintain the liveweight of each ewe, exclusive of the weights of fleece and conceptus, by progressively increasing the quantities of a sorghum grain and lucerne chaff diet (1:1 by weight) offered to the pregnant ewes. During the latter half of pregnancy, each non-mated ewe consumed 42.1 kg of the diet. The single- and twinbearing ewes consumed 27 and 44% more of the diet than did the non-mated ewes. The adjusted liveweight of the non-pregnant ewes increased by 0.03 kg/week, while those of the monoctocous and dioctocous ewes changed by 0.11 and -0.05 kg/week (s.e.= � 0.04). These changes in liveweight were small but differed between the ewe classes (P<0.05). The rate of wool production per unit area of skin at the midside was 411 �g/cm2.day, with no significant differences between the ewe classes, and with no interactions between ewe classes and period of measurement. The wool produced on the midside had an average fibre diameter of 19.0 �m, again with no significant differences between ewe classes or periods. The length of fibre grown during the latter half of pregnancy was 26.1 mm, with no difference between the ewe classes. We conclude that a loss of wool production is not an obligate consequence of pregnancy, but can be prevented by nutritional management that recognises the additional requirements of the pregnant ewe for nutrients.
26
Cropper, M., M. D. Lloyd e G. C. Emmans. "Nutritional manipulation of lamb growth and its effect on body composition and carcase quality". Proceedings of the British Society of Animal Production (1972) 1986 (marzo 1986): 71. http://dx.doi.org/10.1017/s0308229600015804.
Testo completoAbstract (sommario):
The growth rate and body composition of lambs depend on their rate of feed intake and the composition of the feed given. The purpose of the experiment described here was to test predictions of the growth and composition of lambs given feeds of two protein contents at three levels of feeding.73 Scottish Blackface wethers were abruptly weaned at 49 days of age and an average live weight (LW) of 18 (sd 2.2) kg. Six, chosen to cover the range in initial liveweight, were killed and those remaining were put into individual pens and fed in one of six ways. Two feeds with 140g CP/kg fresh weight (FW), called LP, and 220 g CP/kg FW, called HP, were used. They were formulated using barley, maize and soyabean meal, and hay at 150g/kg FW, and were calculated to yield 11.8 MJ ME/kg FW. Each feed was given ad libitum (AL) and at daily rates of 1.2 or 0.8 kg FW. The numbers of sheepstarted were: ALHP, n = 8; ALLP, n = 8; 1.2 HP, n = 12, 1.2 LP, n = 13, 0.8 HP, n = 14, 0.8 LP, n = 12. Sheep were killed from each treatment at 5 kg LW intervals from 25 to 50 kg. After slaughter the weights of gut-fill and organs were taken and the carcase physically dissected into lean, bone and fat. The chemical composition - dry matter and the ash, N, lipid and gross energy contents of the dry matter - of the whole empty body, excluding wool, was measured. Wool weights were determined. The intakes and weights of each sheep were measured twice weekly.
27
Liu, S. M., G. Mata, H. O'Donoghue e D. G. Masters. "The influence of live weight, live-weight change and diet on protein synthesis in the skin and skeletal muscle in young Merino sheep". British Journal of Nutrition 79, n. 3 (marzo 1998): 267–74. http://dx.doi.org/10.1079/bjn19980044.
Testo completoAbstract (sommario):
Wool growth is derived directly from protein synthesis in the skin of sheep, and is affected by the nutritional status of the animals. The present experiment examined both protein synthesis in the skin and muscle and wool growth in Merino lambs differing in live weight, intake and dietary protein source. The experiment was a 23 factorial design: twenty-four 5-month-old lambs initially weighing 33 kg (heavy) or 25 kg (light) were fed on a hay-based diet with either lupin seed or rapeseed meal as the major protein sources to maintain live weight (M) for 56 d, or were fed at 0.6M for 28 d (period 1) followed by 28 d at 1.6M (period 2). Fractional protein synthesis rates (FSR, % per d) in the skin and the m. longissimus dorsi on days 4 and 24 of period 1 and day 4 of period 2 were measured by means of a flooding dose of l-[ring-d5]phenylalanine, and wool growth on a skin patch over period 1 was also measured. The FSR ranged from 13.2 to 20.2% per d in the skin, higher than reported for other breeds, and 1.53–3.07% per d in the muscle. Sheep on the low intake (0.6M) had significant reductions in FSR, protein content (g), protein synthesis (g/d) in the skin, and wool growth (g/d). The heavy lambs had similar FSR to the light lambs, but had a higher skin protein content and total protein synthesis per unit of skin area (100 cm2) and, therefore, grew more wool. The rapeseed-meal diet increased FSR and wool growth only in the light lambs over the short term. The protein deposited in wool over period 1 was 0.185 of the total protein synthesis in the skin, regardless of live weight, intake or diet, a result similar to other breeds. With the changes in dietary intake, protein synthesis in the skin and muscle responded differentially, with nutrient partitioning at sub-maintenance in favour of wool growth but at supra-maintenance, following a nutrient restriction, in favour of weight gain in young growing sheep.
28
Butler, M., e H. Jenkins. "Nutritional aspects of the growth of animal cells in culture". Journal of Biotechnology 12, n. 2 (novembre 1989): 97–110. http://dx.doi.org/10.1016/0168-1656(89)90009-6.
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29
Khadega .A. Abdalraouf *, Eltayeb S. Elamin e Lamia Gadien. "Extraction and Formulation of hydrolyzed-wool keratin solution for hair growth". Omdurman Journal of Pharmaceutical Sciences 2, n. 3 (28 dicembre 2022): 286–99. http://dx.doi.org/10.52981/ojps.v2i3.2876.
Testo completoAbstract (sommario):
Hair growth is controlled by hair Follicles which show patterns of cyclic activity with periods of active growth and hair production (anagen), apoptosis-driven involution (catagen) and relative resting (telogen). These transformations are regulated by different variations like endocrine, vascular, neural, age and nutritional. Keratin biomaterial has been used in regenerative medicine owing to its in-vivo and in-vitro biocompatibility. The present study aimed at extracting keratin from wool by sulfitolysis, filtration by dialysis tube and freeze drying. Qualitative analysis of the keratin extract powder ensured the presence of cysteine, Keratin powder formulated as solution dosage form and pharmaceutically evaluated, Keratin extract was topically applied on the synchronized depilated dorsal skin of telogenic 4 mice and promoted hair growth by changing Hair growth initiation and completion time and quality of hair result, in wool keratin extract solution-treated groups hair growth initiation and completion time reduced and the hair result was hard, long, thick and healthy. Besides, that the keratin extract solution was a safe agent for topical administration, our study demonstrated that keratin extract stimulating hair growth by inducing the growth phase. The topical application of keratin extract may represent a promising biomaterial for the management and applications of hair follicle disorder.
30
Wheeler, JL, HI Davies, DA Hedges e PJ Reis. "Effects of nutrition and paring on linear hoof growth in sheep". Australian Journal of Agricultural Research 41, n. 1 (1990): 197. http://dx.doi.org/10.1071/ar9900197.
Testo completoAbstract (sommario):
Paring increased the linear hoof growth on the forefeet of Merino wethers by an average of 4.1% (P < 0.05) with a tendency for paring to promote faster growth on the medial digits. Effects of feeding these sheep with 400, 600, or 1000 g pelleted ration day-1 were assessed in a 4 X 4 Latin square design with 28-day periods using four measures of response. An extra (fifth) period was used to determine residual effects. The proportion of residual (carryover) to direct effect was much smaller for hoof growth than for wool. Hoof growth was not related to wool production. In another experiment, hoof growth rate of sheep increased from 103 to 136 8m day-1 when the intake of digestible dry matter was increased from 400 to 600 g day-1 (P< 0.001), and from 115 to 125 8m day -1 (P> 0.05) when the intake of digestible nitrogen was increased from 12 to 25 g day-1. Hoof growth rates of Merino wethers grazing native or sown pasture were not significantly affected by injecting DL-methionine daily into the abomasum. Hoof growth is not an appropriate index of wool growth. It may provide an easily measured, rapidly responsive and cumulative measure of nutritional changes, but its use cannot be recommended until more information is available on the factors that affect it and their interaction with ambient temperature.
31
Rylova, N. V., A. S. Samoylov, A. V. Zholinsky e I. V. Bolshakov. "Actual aspects of sports nutrition in children". Rossiyskiy Vestnik Perinatologii i Pediatrii (Russian Bulletin of Perinatology and Pediatrics) 66, n. 5 (9 dicembre 2021): 240–45. http://dx.doi.org/10.21508/1027-4065-2021-66-5-240-245.
Testo completoAbstract (sommario):
The article highlights the modern problems of nutrition for junior athletes. The authors outline the role of the nutritional plan as an integral part of sports training, as well as a factor in the healthy growth and development of a young athlete. They describe the features of the nutritional status of athletes. The article notes the need for educational programs in the field of balanced nutrition, the use of nutritional supplements and sports products among junior athletes.
32
Moise, Lavinia. "Observations Regarding the Growth and Exploitation of “Turcana” Breed Sheep on Small and Medium Farms". Annals ”Valahia” University of Targoviste - Agriculture 11, n. 1 (1 aprile 2017): 34–40. http://dx.doi.org/10.1515/agr-2017-0007.
Testo completoAbstract (sommario):
Abstract The exploitation directions in sheep race is determined by the national economic demanding, and the achievement possibilities by the productive potential of the races and also by the system and growth technology, improvement and exploitation of the races. The necessity of combining knowledge which contains a fundamental scientific profile with the applicative knowledge led to an approach of the complex applicative knowledge led to an approach of the complex aspects of the development and modernization of growth and exploitation technologies in import sheep race. Ţurcana continues to be the race that has the highest proportion of about 40% of the total. Milk production, birth weight of lambs, wool production and meat production were analized. Morpho characteristics of the breed Turcan highlights skills towards wool, milk, meat, and leather, which may improve the ability of the existence of a significant variability especially regarding the quantity and quality of milk and wool.
33
Graetz, RD. "A Comparative Study of Sheep Grazing a Semi-Arid Saltbush Pasture in Two Condition Classes." Rangeland Journal 8, n. 1 (1986): 46. http://dx.doi.org/10.1071/rj9860046.
Testo completoAbstract (sommario):
Measurements were made of the wool growth, body weight gain and diet of sheep grazing a saltbush pasture near Broken Hill, N.S.W. The experiment utilized a fenceline contrast in saltbush (Atriplex vesrcarra) density that was visible on Landsat imagery. It ran for five years (1976-1981) with a design of two pasture types by two stocking rates. Fleece weights varied from 3.9-6.0 kg/head and wool production from 0.6-2.9 kg/ha. Neither wool production per head nor bodyweight were substantially affected by stocking rate or pasture type. The composition and quality of the diets selected by sheep on both pastures were identical and of high nutritional value indicating their capability to accommodate differences in pasture composition. Pasture quality was not limiting between stocking rates or determined by the abundance of saltbush. Changes in pasture composition resulting from grazing and exclosure were small and of no significance.
34
Robertson, S. M., G. E. Robards e E. C. Wolfe. "Grazing management of reproducing ewes affects staple strength". Australian Journal of Experimental Agriculture 40, n. 6 (2000): 783. http://dx.doi.org/10.1071/ea99094.
Testo completoAbstract (sommario):
A grazing study was conducted on irrigated pastures to assess the influence of manipulating the availability of green pasture at different stages of pregnancy and lactation on the staple strength of broad-wool Merino ewes lambing in July. Sheep subjected to different treatments produced wool ranging between 14 and 48 N/ktex for single-rearing and 22 and 53 N/ktex for non-lambing ewes. Single-bearing/rearing ewes produced wool of strength +4.7 (P>0.05) to –23 N/ktex (P<0.001) in comparison with non-lambing ewes. Reproduction was associated with a reduction in staple strength of 51, 24 and 9% for ewes grazed throughout the experiment at low, medium and high pasture levels, respectively. A staple strength greater than 40 N/ktex was achieved in single-rearing ewes which grazed high pasture mass throughout pregnancy and lactation, during late pregnancy and early lactation, or during mid-pregnancy. Single-rearing ewes, which grazed low pasture biomass throughout either mid, late or all of pregnancy, or during lactation, produced wool with staple strength less than 30 N/ktex. In comparison to grazing the medium pasture allowance throughout the experiment, manipulation of pasture availability had relatively small effects on lamb growth and average fleece measurements, compared with the effects on staple strength. The exception was ewes grazing only the low pasture allowance. The interaction between reproduction and nutritional management influenced staple strength by altering the minimum fibre diameter and the uniformity of along-staple fibre diameter and rate of wool growth. It was concluded that managing pasture availability to promote a uniform along-staple fibre diameter or rate of wool growth can prevent reductions in staple strength associated with reproduction.
35
Reis, P. J., e T. Sahlu. "The nutritional control of the growth and properties of mohair and wool fibers: a comparative review2". Journal of Animal Science 72, n. 7 (1 luglio 1994): 1899–907. http://dx.doi.org/10.2527/1994.7271899x.
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36
McGuirk, B. J. "Effects of weaner nutrition on sire and flock rankings: a re-analysis of historical data". Animal Production Science 49, n. 12 (2009): 1100. http://dx.doi.org/10.1071/an09032.
Testo completoAbstract (sommario):
Early work in the 1950s on the wool growth response of sheep from diverse genotypes for wool production in response to varying planes of nutrition at pasture did not show the significant genotype × environment interactions exhibited in later pen studies with the same or very similar genotypes. However, this early study used a log-transformation on all traits to adjust nutritional effects for scale. Re-analysis of the original (i.e. untransformed) data shows that superior genetic merit for clean fleece weight, different sire progeny groups or selection flocks is more apparent when hogget ewes are fed a high plane of nutrition at pasture. However, only in the case of flocks was the interaction statistically significant, and this interaction was insignificant when data were either log-transformed, or when an appropriate test that accounts for scale-type effects was applied. When left untransformed, the data are, thus, in agreement with the subsequent pen studies that examined data on untransformed clean wool production.
37
de Souza Osório, Christian Rones Wruck, Gelza Carliane Marques Teixeira, Rafael Ferreira Barreto, Cid Naudi Silva Campos, Aguinaldo José Freitas Leal, Paulo Eduardo Teodoro e Renato de Mello Prado. "Macronutrient deficiency in snap bean considering physiological, nutritional, and growth aspects". PLOS ONE 15, n. 6 (8 giugno 2020): e0234512. http://dx.doi.org/10.1371/journal.pone.0234512.
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38
Thompson, A. N., e P. I. Hynd. "Wool growth and fibre diameter changes in young Merino sheep genetically different in staple strength and fed different levels of nutrition". Australian Journal of Agricultural Research 49, n. 5 (1998): 889. http://dx.doi.org/10.1071/a97129.
Testo completoAbstract (sommario):
The wool growth response to nutrition by Merino weaners (liveweight 33· 2±0·58 kg) bred for high or low staple strength (SS) and fed to produce changes in liveweight was examined. The hypothesis tested was that genetic differences in SS are associated with differences in along-fibre variation in diameter. Sheep fed to maintain liveweight produced wool at a more constant rate with smaller and less rapid changes in fibre diameter than that produced by sheep which lost and then gained liveweight (P < 0·001). There were significant (P < 0·05) but relatively small differences in wool growth rate and fibre diameter between the SS selection flocks, and wool from sheep selected for high SS had less (P < 0 ·001) variation in diameter between individual fibres than wool from sheep selected for low SS Minimum fibre diameter was most closely associated with SS, accounting for 66% (P < 0·001) of the total variance in SS generated by selective breeding and nutrition. An increase in minimum fibre diameter of 1µm was associated with an increase in SS of about 5 N/ktex. Minimum fibre diameter and the rate of change in fibre diameter to the point of break along the staple collectively accounted for 72% (P < 0·001) of the total variance in SS. Addition of a term for between-fibre variation in diameter measured at the point of break removed an additional 8% (P < 0·001) of the variance in SS. We conclude that the mechanisms responsible for nutritionally induced and genetic differences in SS are not the same. Nutrition influences SS by affecting along-fibre diameter changes, whereas genetic differences in SS, at least as far as they are represented by the flocks used here, are largely attributable to between-fibre variations in diameter. The independence of nutritional and genetic effects on SS means that they should be exploited concurrently to reduce the incidence of tender wool production.
39
Zandonadi, Renata Puppin. "An Overview of Nutritional Aspects in Juvenile Idiopathic Arthritis". Nutrients 14, n. 20 (20 ottobre 2022): 4412. http://dx.doi.org/10.3390/nu14204412.
Testo completoAbstract (sommario):
There is evidence that nutritional impairment can complicate juvenile idiopathic arthritis (JIA). It is also recognized that the JIA drug treatment may affect the nutritional aspects of patients. It is crucial to understand the impacts that nutritional aspects can have on a patient’s treatment, health, and life. Therefore, this review explores how nutrition influences juvenile idiopathic arthritis. Dietary aspects play essential roles in JIA patients’ growth, body mass index (BMI), bone mineral density (BMD), inflammation, and recovery. Suboptimal nutrition seems to adversely affect the long-term outcome of JIA patients. Nutritional deficiency potentially affects JIA patients’ general wellbeing and disease control and contributes to growth, inflammation, BMI, and BMD disturbances. It was also possible to verify that the correct status of nutrients helps the body recover and reduce inflammation in JIA patients, since nutritional status and nutrients play an important role in regulating immune function. Studies are diverse, and most analyze the effects of a single nutrient on JIA. Moreover, the diet and nutrition impacts are difficult to interpret in the pediatric population due to family influence, dietary regulation, and data collection in children/adolescents. Despite the lack of standardization among studies, the potential benefits of a healthy diet on short- and long-term health and wellbeing in JIA patients are noteworthy.
40
Moeeni, V., e A. S. Day. "Impact of Inflammatory Bowel Disease upon Growth in Children and Adolescents". ISRN Pediatrics 2011 (5 aprile 2011): 1–5. http://dx.doi.org/10.5402/2011/365712.
Testo completoAbstract (sommario):
The inflammatory bowel diseases (IBDs) are chronic inflammatory processes affecting the gastrointestinal tract. When diagnosed in childhood and adolescence, IBD almost always impacts adversely upon the nutritional state of the patient. Weight loss and impaired linear growth may be present at diagnosis or subsequently. Further potential nutritional consequences in childhood IBD include malnutrition, anaemia, osteopaenia, and delayed puberty. Understanding the nutritional aspects of IBD is paramount in growing children, especially those entering and advancing through puberty. This paper focuses upon the nutritional impacts of IBD in children and adolescents.
41
Hegarty, R. S., R. D. Warner e D. W. Pethick. "Genetic and nutritional regulation of lamb growth and muscle characteristics". Australian Journal of Agricultural Research 57, n. 6 (2006): 721. http://dx.doi.org/10.1071/ar06105.
Testo completoAbstract (sommario):
Combined actions of nutrition and genetic regulation of the growth rate of lambs as well as the physical, biochemical, and eating quality characteristics of their skeletal muscle were assessed in a major field experiment. Data arising were collated and integrated to consolidate findings made at the farm, animal, tissue, cellular, and gene expression levels. At the farm level, increased nutrient availability significantly increased the growth rate of crossbred lambs and increased the growth advantage resulting from the use of sires with high estimated breeding values (EBV) for growth. In contrast, the extra depth of the M. longissimus thoracis et lumborum (EMD) arising from sires with a higher EBV for this trait was constant irrespective of nutrition. Ewe liveweight and body condition were critical in determining the pre-weaning nutrition and growth of lambs, with the LOW plane of nutrition causing stunting of forelimb bones and changes to the allometric growth coefficients for carcass lean and fat. The EBV of the sire for muscling (PEMD) influenced several non-muscling traits, and interactions with nutrition suggested that on HIGH nutrition, absorbed nutrients were partitioned away from wool and fat accretion and towards protein accretion in lambs having superior muscling genetics. Expression levels of known myogenic factors in muscle, together with a suite of peptides and proteins whose identity and levels were determined by proteomic screening, contributed to improved understanding of the mechanisms underpinning nutritional and genetic regulation of skeletal muscle development. The study revealed the need for caution in the use of indirect markers of growth or composition, with their usefulness being constrained if the localisation of the response to selection is specific to parts of the carcass where the selection had initially been concentrated. As well, the possibility that much of the variation explained by potential physiological markers can be accounted for by non-invasive measures of growth and fatness currently used by Australian farmers must be considered.
42
Adams, N. R., J. R. Briegel e J. C. Greeff. "Responses of wool growth rate and body reserves to nutrition in Merino ewes: a potential biological link between production and fitness". Australian Journal of Agricultural Research 58, n. 9 (2007): 913. http://dx.doi.org/10.1071/ar06386.
Testo completoAbstract (sommario):
This study examined whether the low body-fat reserves in sheep with high estimated breeding values (EBVs) for clean fleece weight (CFW) reported previously are affected by nutritional history, and second whether the effect may be related to differences in the variation in fibre diameter (CVfd). Groups of 11 20-month-old Merino ewes with high and low EBVs for CFW and for CVfd were compared in a 2 × 2 design at low bodyweight, then fed ad libitum for 100 days and re-measured. The response of wool growth rate to feed supply (WRF) was estimated as the slope of the regression against time of clean wool mass collected from mid-side patches at intervals of 30–40 days throughout the experiment. High CFW sheep had greater feed intake relative to liveweight and liveweight gain (P = 0.02), but did not differ significantly in other characteristics from low CFW sheep. High CVfd sheep had lower plasma concentrations of insulin (P = 0.02), IGF-1 (P = 0.03), and albumin (P = 0.02) throughout the study, and had less fat when in poor body condition (P = 0.02). The WRF was greater in both the high CFW (P = 0.003) and the high CVfd (P = 0.004) genotypes. When studied in poor body condition, sheep with a high WRF had lower liveweight (P < 0.001), lower body condition score (P < 0.001), lower plasma albumin (P < 0.001), and higher plasma growth hormone (P = 0.02), but these relationships weakened or disappeared after ad libitum feeding. Sheep with high WRF also had lower plasma concentrations of insulin (P = 0.002) and IGF-1 (P = 0.008) throughout the study, which may have brought about the increased responsiveness of protein and energy metabolism to nutrition. The results indicate that genetic selection for wool characteristics can affect the responsiveness of wool growth rate to nutrient supply. Sheep that are highly responsive grow more wool when offered abundant feed, but may have lower body nutrient reserves when on limited feed.
43
Motil, Kathleen J., Mary Fete e Timothy J. Fete. "Growth, nutritional, and gastrointestinal aspects of focal dermal hypoplasia (Goltz-Gorlin syndrome)". American Journal of Medical Genetics Part C: Seminars in Medical Genetics 172, n. 1 (1 febbraio 2016): 29–33. http://dx.doi.org/10.1002/ajmg.c.31468.
Testo completo
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KORNIENKO, Р. P. "RESULTS OF THE USE OF SUGAR BEET AND ITS PROCESSED PRODUCTS IN FEEDING LACTATING SHEEP". Sheep, goats, woolen business, n. 3 (2021): 39–42. http://dx.doi.org/10.26897/2074-0840-2021-3-39-42.
Testo completoAbstract (sommario):
In the beet-growing regions of our country, when producing sugar beet as a technical crop, it is advisable to use it to replace concentrates in feeding lactating sheep in up to 1.5-2.0 kg per head per day. This helps to increase the nutritional value and sugar level in the eaten feed with a stable receipt of metabolic energy and digestible protein. The replacement of a signifi cant part of the concentrates with sugar beet has a positive eff ect on milk production and wool growth.
45
Croker, KP, MA Johns, SH Bell, GA Brown e JF Wallace. "The influence of vaccination with Fecundin and supplementation with lupin grain on the reproductive performance of Merino ewes in Western Australia". Australian Journal of Experimental Agriculture 30, n. 4 (1990): 469. http://dx.doi.org/10.1071/ea9900469.
Testo completoAbstract (sommario):
The reproductive performances of groups of 4-6-year-old medium wool Merino ewes that were vaccinated with Fecundin and/or fed sweet lupin grain prior to and during the early part of the joining period were compared with untreated ewes over 2 years. The rams were joined with the ewes in early January of each year. In both years the Fecundin and lupin treatments increased ovulation rates (between 0.13 and 0.56) and the incidence of multiple pregnancies (between 1 and 36%). The proportions of lambs born following treatment with Fecundin were larger than those from the ewes fed only lupins. When the treatments were combined, there were no increases in lambs born above that of Fecundin alone. Pregnancy significantly depressed wool production from individual ewes, while those with more than 1 lamb produced less wool than those with only 1 lamb. However, the average quantity (4.6 kg greasy) and quality of wool produced by the ewes each year was similar for all groups, indicating that the variation in the incidence of multiple pregnancies had not affected flock wool production. The average rate of growth of the progeny from marking to weaning was also similar for each group (191 and 238 g/head.day for years 1 and 2, respectively) even though there were more multiple-born lambs in the Fecundin-treated groups. On a flock basis, it would appear that the nutritional conditions experienced during this study were adequate to avoid significant penalties associated with multiple pregnancies.
46
Read, D. J., e R. Bajwa. "Some nutritional aspects of the biology of ericaceous mycorrhizas". Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 85, n. 3-4 (1985): 317–31. http://dx.doi.org/10.1017/s0269727000004097.
Testo completoAbstract (sommario):
SynopsisSome aspects of the role of the ericoid mycorrhizal symbiosis in the ecology and physiology of ericaceous plants are described. Mycorrhizal infection leads to enhancement of plant nitrogen content and an experimental analysis of the basis of this effect is reported. In addition to improving the efficiency of ammonium absorption at low concentrations, the mycorrhizal endophyte utilises amino acids, peptides and proteins as nitrogen substrates for growth. These are the predominant nitrogen sources in organic heathland soil. It is suggested that the success of ericaceous plants in such soils may arise through the capacity of the mycorrhizal fungus to provide its host with access to this nutrient resource. A model is described in which absorption of ammonium and amino nitrogen leads to soil acidification, increased acid protease activity and improved vigour of the ericaceous plants.
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Hynd, PI, e BK Everett. "Estimation of Cell Birth Rate in the Wool Follicle Bulb using Colchicine Metaphase Arrest or DNA Labelling with Bromodeoxyuridine". Australian Journal of Agricultural Research 41, n. 4 (1990): 741. http://dx.doi.org/10.1071/ar9900741.
Testo completoAbstract (sommario):
The birth rate of cells in the wool follicle cells (CBR) was measured in two experiments on sheep differing widely in wool growth rate as a consequence of differences in nutritional regime. In Experiment 1, CBR was determined in one sheep on a high and one on a low plane of nutrition by two methods: the colchicine-metaphase arrest method, or from the product of total cell number and cell cycle time (the latter determined by DNA labelling with 5-bromo-2'-deoxyuridine (BrdU) and analysis of the fraction of mitoses labelled curve). CBR by colchicine was 0.73 and 0.56 of that determined using BrdU for the low- and high-plane sheep respectively. Cell cycle times were 26.5 h (low nutrition) to 18.6 h (high nutrition). In Experiment 2, CBR was again measured by the colchicine method, and from the rate of increase in labelled cells following a pulse dose of BrdU, in sheep on two levels of nutrition (n = 4llevel) and with a 3.7-fold difference in wool growth rate. Again, CBR by colchicine was only 0.41 (high nutrition) to 0.74 (low nutrition) of estimates made using the BrdU method, this difference being statistically significant only for sheep on the high plane of nutrition. Nutrition significantly altered CBR determined by colchicine (Pc0.001) and by BrdU (Pc0.034). The rate of fibre growth per follicle measured on two separate occasions was closely related to CBR measured using colchicine (r= 0.83, P< 0.01 and 0.8 1, P c 0.02) or BrdU (r= 0.73, P c 0.04 and 0.64, P< 0.08). It is concluded that CBR is a major determinant of fibre growth, but that colchicine depresses CBR. Previous estimates of mitotic activity in wool follicle bulbs have been made using colchicine and are thus probably underestimated. The technique using BrdU labelling and the subsequent rate of increase in labelled cells appears to be a useful one for estimating follicle cell kinetics.
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Souza, Aline das G., Cristina W. Ritterbusch, Renata D. Menegatti, Oscar J. Smiderle e Valmor J. Bianchi. "Nutritional Efficiency and Morphophysiological Aspects With Growth in the ‘Okinawa Roxo’ Peach Rootstock". Journal of Agricultural Science 11, n. 9 (30 giugno 2019): 221. http://dx.doi.org/10.5539/jas.v11n9p221.
Testo completoAbstract (sommario):
The aim of this study was to evaluate the efficiency of nutrient uptake, accumulation, distribution and use, and its relationship with growth variables, chlorophyll content, and root and shoot dry-weight partitioning in the ‘Okinawa Roxo’ peach rootstock, submitted to different nutrient solutions and substrates. The experimental design was completely randomised, with four treatments and five replications. The treatments were T1: Ns1 = Souza et al. nutrient solution (2011), applied to a sand substrate; T2: Ns2 = Hoagland and Arnon (1950), applied to a sand substrate; T3: Commercial Substrate + H2O; and T4: Control, Sand + H2O. Ninety days after transplanting (DAT), morphological, physiological and nutritional parameters were determined in the ‘Okinawa Roxo’ rootstock, together with the correlation between nitrogen concentration and nitrogen balance index, and the chlorophyll content and index. The greatest zinc content was detected in the shoots of the ‘Okinawa Roxo’ plants, at more than 80% of the accumulated total. Treatments T1 and T2 (nutrient solutions Ns1 and Ns2 respectively) made it possible to obtain ‘Okinawa Roxo’ plants with the best morphophysiological characteristics, being ready for grafting three months after transplanting in a greenhouse. The use of the Ns1 nutrient solution resulted in greater efficiency in the uptake and use of the nutrients nitrogen (N), potassium (K) and iron (Fe). The N and Total Chlorophyll concentrations in the leaves of the red-leaved peach tree can be estimated indirectly with a chlorophyll meter, and are an accurate indication of the nutritional status of the plant in relation to nitrogen content.
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Reis, Mateus Neri Oliveira, Luciana Cristina Vitorino, Lucas Loram Lourenço e Layara Alexandre Bessa. "Microbial Inoculation Improves Growth, Nutritional and Physiological Aspects of Glycine max (L.) Merr." Microorganisms 10, n. 7 (10 luglio 2022): 1386. http://dx.doi.org/10.3390/microorganisms10071386.
Testo completoAbstract (sommario):
Considering a scenario where there is a low availability and increasing costs of fertilizers in the global agricultural market, as well as a finitude of important natural resources, such as phosphorus (P), this study tested the effect of the inoculation of rhizospheric or endophytic microorganisms isolated from Hymenaea courbaril and Butia purpurascens on the growth promotion of Glycine max (L.) Merr. The tests were conducted in a controlled greenhouse system, and the effects of biofertilization were evaluated using the following parameters: dry biomass, nutritional content, and photochemical and photosynthetic performance of plants. Seed biopriming was performed with four bacterial and four fungal isolates, and the results were compared to those of seeds treated with the commercial product Biomaphos®. Overall, microbial inoculation had a positive effect on biomass accumulation in G. max, especially in strains PA12 (Paenibacillus alvei), SC5 (Bacillus cereus), and SC15 (Penicillium sheari). The non-inoculated control plants accumulated less nutrients, both in the whole plant and aerial part, and had reduced chlorophyll index and low photosynthetic rate (A) and photochemical efficiency. Strains PA12 (P. alvei), SC5 (B. cereus), and 328EF (Codinaeopsis sp.) stood out in the optimization of nutrient concentration, transpiration rate, and stomatal conductance. Plants inoculated with the bacterial strains PA12 (P. alvei) and SC5 (B. cereus) and with the fungal strains 328EF (Codinaeopsis sp.) and SC15 (P. sheari) showed the closest pattern to that observed in plants treated with Biomaphos®, with the same trend of direction of the means associated with chlorophyll index, (A), dry mass, and concentration of important nutrients such as N, P, and Mg. We recommend the use of these isolates in field tests to validate these strains for the production of biological inoculants as part of the portfolio of bioinputs available for G. max.
50
Reis, PJ. "Variations in the strength of wool fibres - A review". Australian Journal of Agricultural Research 43, n. 6 (1992): 1337. http://dx.doi.org/10.1071/ar9921337.
Testo completoAbstract (sommario):
This review outlines the factors that may influence the strength of wool fibres and the associated changes in structure and protein composition that have been observed in weakened fibres. The strength of a wool staple is dependent on the intrinsic strength of the fibres that it contains and the total cross-sectional area of fibre being tested. The minimum fibre diameter and the rate of change of diameter along a staple are important determinants of strength. Different sheep kept under similar conditions show a large range of staple strengths. Estimates of heritability for staple strength are sufficiently high (0.17 to 0.49 in Merinos; 0.20 to 0.58 in Romneys) to prompt the establishment of selection programmes in both breeds. A variety of physiological and environmental factors influence the strength of wool fibres. Nutrient supply exerts a major influence via effects on fibre diameter. In addition, there are specific effects of some amino acids (methionine and lysine), trace elements (copper and zinc) and vitamins (folic acid). Seasonal effects are important in breeds which exhibit a large annual rhythm of wool growth, e.g. Romneys, but not in Merinos. Pregnancy and lactation influence fibre strength through competition for essential nutrients but hormonal factors may also be involved. Fibre strength may also be influenced by stress involving excessive secretion of glucocorticoids and by various parasites and diseases which can influence nutrient supply and cause stress. No clear association has been established between the strength of wool fibres and the proportions of the constituent proteins. The content of high-tyrosine proteins in the matrix of weak fibres is frequently, but not invariably, reduced. Likewise, fibre strength has been associated with the proportions of components of the high-sulfur proteins in some studies, but not in others. Thus in Romneys, but not Merinos, tender (weak) wool contained a higher proportion of orthocortex than sound wool, and hence contained less ultra-high-sulfur proteins. Weak fibres produced by specific nutritional treatments in adult sheep and lambs show a loss of cuticle scale pattern and malformed or degraded fibres.