Responses in wool growth, liveweight, glutathione and amino acids, in Merino wethers fed increasing amounts of methionine protected from degradation in the rumen

1995 ◽  
Vol 46 (6) ◽  
pp. 1189 ◽  
Author(s):  
G Mata ◽  
DG Masters ◽  
D Buscall ◽  
K Street ◽  
AC Schlink

The aim of the experiments reported was to evaluate the protection from microbial breakdown of two methionine formulations (Lactet and Mepron) and to measure responses in wool production, liveweight, amino acids and glutathione in blood and tissues when one of these forms of methionine (Lactet) was supplied to merino wethers fed at maintenance. Lactet was well protected against microbial breakdown in the rumen. Peak values for concentrations of methionine in plasma, following administration of the different forms of methionine into the rumen, were 574, 148 and 143pmol L-1 for Lactet, DL-methionine and Mepron. Production responses to dosed levels of Lactet (0, 1, 2, 3, 5, 8 g methionine dayw1) were measured over 63 days in the animal house. Significant linear responses were obtained for wool growth (4-38%), fibre diameter (0.5-2 8m) and liveweight gain (30-1 15%). Concentrations of reduced glutathione in blood, liver and skin were increased, at some times during the experiment, by provision of Lactet. However, responses were inconsistent and highly variable among sheep, Glutathione was of limited use as an indicator of sulfur amino acid intake or status. Sulfate in plasma increased markedly at all levels of Lactet intake, and there was a linear relationship between Lactet intake and the concentration of sulfur in wool. Plasma free methionine and the ratio of methionine to total essential amino acids showed significant linear responses to the supplements. It was concluded that Lactet was an effective method of supplying rumen-protected methionine to ruminants.


1978 ◽  
Vol 90 (1) ◽  
pp. 173-183 ◽  
Author(s):  
P. J. Reis ◽  
D. A. Tunks

SUMMARYMerino sheep were given abomasal infusions of either mixtures of amino acids or protein during periods of 8 or 12 days. Effects on wool growth were measured using autoradiography and a clipping procedure which allowed time for the emergence of the wool fibres. Estimates of volume growth rate, from the autoradiographic measurements, and of mass of wool grown, from clipping, were in good agreement.An infusion of a standard mixture of 13 amino acids, which included ten essential amino acids in approximately the proportions in casein, consistently stimulated wool growth. The mean increases in volume and mass of wool grown, during 30 infusions, were 66 and 67% respectively. A mixture of ten essential amino acids alone appeared to be as effective as the standard mixture for stimulating wool growth, and there were no significant differences between the effects on wool growth of casein and the standard mixture of amino acids.The omission of methionine from an infusion of the standard mixture of amino acids, or from a mixture of essential amino acids only, inhibited wool growth rate; both fibre diameter and length of wool grown per day were reduced to below the control values. In addition, the strength of the fibres was considerably reduced.Infusions of zein and of an amino acid mixture simulating the essential amino acid composition of zein both inhibited wool growth rate, due to a reduction in fibre diameter. Similar effects on wool growth were observed when any one of three essential amino acids (lysine, isoleucine or leucine) was omitted from an infusion of the standard mixture of amino acids. The omission of five other essential amino acids (arginine, histidine, phenylalanine, threonine or valine) from the infusion, or variations in the proportions of leucine, lysine or methionine, had no appreciable effects on wool growth.



1993 ◽  
Vol 44 (5) ◽  
pp. 945 ◽  
Author(s):  
DG Masters ◽  
CA Stewart ◽  
PJ Connell

Pregnancy and lactation result in depressed growth, fibre diameter and tensile strength of wool. Competition for nutrients between wool follicles, maternal tissues and the foetus may cause these changes. Changes in the concentrations of individual free amino acids in plasma, during late pregnancy, were used as indicators of limiting amino acids in this experiment. A group of pregnant ewes was maintained in the animal house during late pregnancy and early lactation and measurements made on amino acids in plasma. Liveweight, wool growth and quality characteristics and sulfur in wool were also measured. Comparisons were made between the different time periods in pregnancy and lactation and between the reproducing ewes and a group of non-reproducing ewes maintained under the same conditions. During the last 3 weeks of pregnancy, there was a 31% decline in the concentration of the total, free essential amino acids in plasma. There was also a significant decline in the concentration of arginine (60%), lysine (55%) and threonine (48%). The concentrations of these amino acids increased during the first 3 weeks of lactation. There was no change in concentration of methionine or cystine. Wool growth rate was lowest in the last 3 weeks of pregnancy and the reproducing ewes had significantly lower wool growth, fibre diameter, staple strength and sulfur in wool than the non-reproducing ewes. The results indicate that a lack of the sulfur-containing amino acids is unlikely to be limiting, but a lack of arginine, lysine or threonine may be limiting wool growth and protein deposition in late pregnancy.



1989 ◽  
Vol 40 (4) ◽  
pp. 889 ◽  
Author(s):  
PD Fenn ◽  
RA Leng

In two experiments, sheep were offered a roughage-based diet supplemented with either cysteine or bentonite as a solid, or bentonite, cysteine or methionine added to their drinking water. Supplementation with cysteine as a solid had no effect on wool growth, while supplementation via drinking water had no effect on wool growth or cysteine entry rate into the blood. Supplementation with methionine via drinking water increased the entry rate of methionine into blood by 69% (P< 0.05) as measured by a continuous infusion of [35S]-methionine. This coincided with subsequent increases in wool growth of 16% (P< 0.05) compared to sheep fed a basal diet alone. Compared with the basal diet alone, supplementation with 30 g/day bentonite as a dry powder or 60 g/day as a suspension in drinking water increased wool growth by 19 and 20% respectively. Bentonite given as sole supplement did not increase the entry rate of either cysteine or methionine into the blood of sheep. When bentonite and sulfur amino acids were complexed or mixed, wool growth was not increased above that for bentonite or the amino acid alone.



1976 ◽  
Vol 86 (3) ◽  
pp. 475-482 ◽  
Author(s):  
P. J. Reis ◽  
D. A. Tunks

SummaryMerino sheep were given abomasal infusions of (i) zein (80 g/day), (ii) zein (80 g/day) supplemented with L-lysine (6 g/day), L-tryptophan (1 g/day) or lysine and tryptophan together, or (iii) L-leucine (20 g/day). Effects on wool growth (length growth rate, fibre diameter, fibre volume growth rate and mass of wool grown) and on plasma amino acids were measured.Zein increased length growth rate and decreased fibre diameter; on average the volume growth rate and mass of wool grown were not significantly altered. The addition of tryptophan to the infusion of zein did not significantly alter wool growth, whereas the addition of lysine significantly increased all aspects of wool growth. The responses to these treatments were rapid and were adequately assessed during 12-day infusion periods. The infusion of leucine did not cause any appreciable changes in wool growth.Leucine supplementation increased the concentration of leucine in blood plasma about six-fold. Zein decreased the concentration of lysine and ornithine in plasma and increased the concentration of several essential amino acids; leucine was increased about seven-fold. The addition of tryptophan to zein had no effects on plasma amino acids, whereas lysine decreased the concentration of several amino acids in plasma and markedly increased lysine.



2001 ◽  
Vol 26 (S1) ◽  
pp. S220-S227 ◽  
Author(s):  
Robert R. Wolfe

In the resting state muscle protein breakdown exceeds the rate of muscle protein synthesis, meaning that the balance between synthesis and breakdown is negative. Resistance exercise improves the net balance by stimulating muscle protein synthesis, but nutrient intake is requiredfor synthesis to exceed breakdown (i.e., an anabolic response). Exercise and exogenous amino acids have an additive effect on muscle protein synthesis. There is a timecourse of the response to a steady-state change in amino acid concentration. The signal for stimulation of muscle protein synthesis appears to be the extracellular concentrations of one or more of the essential amino acids (EAAs). Further, the rate , and direction, of change in extracellular concentrations (rather than the static concentration, per se) may be the important. Ingestion of non-essential AAs is not needed to stimulate muscle protein synthesis. Carbohydrate has, at most, a modest effect to enhance the response to amino acid ingestion after exercise. Finally, a mixture of EAAs + CRO more effectively stimulates muscle protein synthesis when taken before as opposed to after exercise.



Amino Acids ◽  
2018 ◽  
Vol 50 (12) ◽  
pp. 1679-1684 ◽  
Author(s):  
Hiroyuki Kato ◽  
Kimberly A. Volterman ◽  
Daniel W. D. West ◽  
Katsuya Suzuki ◽  
Daniel R. Moore


1973 ◽  
Vol 81 (3) ◽  
pp. 391-401 ◽  
Author(s):  
D. G. Harrison ◽  
D. E. Beever ◽  
D. J. Thomson ◽  
D. F. Osbourn

SUMMARYWether sheep were fed on six forage diets, namely, (1) barn-dried low-N hay, (2) barndried low-N hay plus urea infused intraruminally at 12·6 g/24 h, (3) dried sainfoin, (4) dried lucerne, (5) fresh red clover and (6) dried and pelleted red clover. The proportions of amino acids in the diet and in samples of digesta from the duodenum and ileum were determined.The relative proportions of individual amino acids in the duodenal digesta showed little variation despite the differences in intake and the variation in the proportions of amino acids in the feeds. Only the proportions of methionine, lysine, 2:6 diaminopimelic acid (DAPA) and aminoisobutyric acid (AIB) showed significant (P < 0·01) variation with respect to diet. In the ileal digesta the proportions of methionine, leucine, tyrosine, phenylalanine, glutamic acid, proline, glycine, alanine, AIB and DAPA showed significant variation by diet.With all diets except lucerne the quantity (g/day) of total amino acids presented at the duodenum was higher than the quantity ingested. There was no correlation between the quantity of total amino acids presented at the duodenum and the quantity disappearing within the small intestine.The duodenal digesta contained a significantly higher (P < 0·001) proportion of essential amino acids than did the ileal digesta. This difference was most marked with the diets which supplied a low amino acid intake.With all diets there was little apparent absorption of DAPA in the small intestine.



2016 ◽  
Vol 5 (10) ◽  
pp. 4972
Author(s):  
Lata Birlangi

The date palm (Phoenix dactylifera L.) is one of mankind’s oldest cultivated plants. The fruit of the date palm is an important crop of the hot arid and semi-arid regions of the world. It has always played a genuine economic and social part in the lives of the people of these areas. The present objective in examining the amino acid content of different varieties of date palm fruits from Middle-East region; is to determine whether its protein could effectively supplement the nutritional value and it is also aimed in finding which variety is rich in number of amino acids. The phytochemical screening revealed the presence of eight essential amino acids and five non-essential amino acids in the date fruits. Among all the date fruit varieties taken as samples for the study, Dabbas cultivar of United Arab Emirates found to exhibit eight types of amino acids which includes five as non-essential ones. Total of thirteen amino acids were detected in the seven date cultivars. Determination of amino acid can serve as a guide to the possible nutritional value.



2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sonia Yun Liu ◽  
Shemil P. Macelline ◽  
Peter V. Chrystal ◽  
Peter H. Selle

AbstractThe prime purpose of this review is to explore the pathways whereby progress towards reduced-crude protein (CP) diets and sustainable chicken-meat production may be best achieved. Reduced-CP broiler diets have the potential to attenuate environmental pollution from nitrogen and ammonia emissions; moreover, they have the capacity to diminish the global chicken-meat industry’s dependence on soybean meal to tangible extents. The variable impacts of reduced-CP broiler diets on apparent amino acid digestibility coefficients are addressed. The more accurate identification of amino acid requirements for broiler chickens offered reduced-CP diets is essential as this would diminish amino acid imbalances and the deamination of surplus amino acids. Deamination of amino acids increases the synthesis and excretion of uric acid for which there is a requirement for glycine, this emphasises the value of so-called “non-essential” amino acids. Starch digestive dynamics and their possible impact of glucose on pancreatic secretions of insulin are discussed, although the functions of insulin in avian species require clarification. Maize is probably a superior feed grain to wheat as the basis of reduced-CP diets; if so, the identification of the underlying reasons for this difference should be instructive. Moderating increases in starch concentrations and condensing dietary starch:protein ratios in reduced-CP diets may prove to be advantageous as expanding ratios appear to be aligned to inferior broiler performance. Threonine is specifically examined because elevated free threonine plasma concentrations in birds offered reduced-CP diets may be indicative of compromised performance. If progress in these directions can be realised, then the prospects of reduced-CP diets contributing to sustainable chicken-meat production are promising.



2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Andrew Matchado ◽  
Kathryn Dewey ◽  
Christine Stewart ◽  
Per Ashorn ◽  
Ulla Ashorn ◽  
...  

Abstract Objectives 1) to estimate the probability of inadequate amino acid intake among infants 9–10 months of age in rural Malawi 2) to evaluate whether dietary amino acid intake or protein quality are associated with length gain from 6 to 12 months of age Methods We assessed total amino acid intake from breast milk and complementary foods in 285 infants. Breast milk intake and complementary foods were estimated using dose-to-mother deuterium oxide dilution method and repeat 4-pass interactive 24-hour recall interviews, respectively. Amino acid composition values were taken from FAO human milk profile, Tanzania Food Composition table and International Minilist. Protein quality was estimated using Digestible Indispensable Amino Acid Score (DIAAS). Probability of intake below Estimated Average Requirement (EAR) for each amino acid was estimated using National Cancer Institute (NCI) method. We estimated protein quality of complementary food using median DIAAS. We assumed a DIAAS of ≥0.75 to represent a diet or food with good protein quality. Relationships between amino acid intake or protein quality with length gain were assessed using regression models. Length was measured at 6 and 12 months of age and length for age z-score (LAZ) velocity was calculated (ΔLAZ/months). Results The probability of inadequate amino acid intake from breast milk and complementary food that included a lipid-based nutrient supplement (LNS) was 3% for lysine, 0% for tryptophan, threonine, valine, histidine, isoleucine, leucine, sulfur containing amino acids (SAA), and aromatic amino acids (AAA). Without LNS, the probability was 7% for lysine and 0–2% for the other amino acids. The median (interquartile range) DIAAS for complementary food with and without LNS was 0.70 (0.28) and 0.64 (0.32), respectively. Dietary amino acid intake and protein quality were not significantly associated with length gain velocity from 6 to 12 months even after adjusting for confounding factors. Conclusions The prevalence of inadequate amino acid intake in 9–10 months old infants in rural Malawi is very low. However, in conditions of frequent clinical or sub-clinical infections this situation may be different. Linear growth at 6–12 months does not appear to be limited by dietary amino acid intake or protein quality in this setting. Funding Sources The Bill & Melinda Gates Foundation.



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