scholarly journals The Influence of Abomasal and Intravenous Supplements of Sulphur-Containing Amino Acids on Wool Growth Rate

1973 ◽  
Vol 26 (1) ◽  
pp. 249 ◽  
Author(s):  
PJ Reis ◽  
DA Tunks ◽  
AM Downes
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Wool Growth ◽  
Intravenous Infusions

Various amounts (0�6-10�0 g/day) of L-cystine, L-cysteine, and L- and DL-methionine were given as abomasal or intravenous infusions to 10 sheep, in three experiments.

The influence of abomasal supplements of methionine on wool growth of wheat-fed sheep

1974 ◽  
Vol 25 (6) ◽  
pp. 919 ◽  
Author(s):  
PJ Reis ◽  
DA Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Blood Plasma ◽  
Fibre Diameter ◽  
Length Growth ◽  
Wool Growth ◽  
Abomasal Infusion ◽  
Mineral Mixture ◽  
In Blood Plasma

Sheep receiving a diet consisting solely of wheat (500 g/day), supplemented with a mineral mixture, were given abomasal infusions of varying amounts of DL-methionine (1.5–6.0 g/day) or of L-cystine (5 g/day). Other sheep received DL-methionine as a supplement to a roughage diet. All levels of methionine infused caused a decrease in the mass of wool grown by sheep consuming the wheat diet. This effect was greatest with 6 g methionine and was due mainly to a considerable depression of fibre diameter. Smaller amounts of methionine decreased fibre diameter and increased length growth rate. The infusion of methionine caused a considerable weakening of the wool grown by most of the sheep, with the result that a 'break' was observed in the fleece after about 1 week of methionine administration. This effect occurred with all levels of methionine but was more pronounced with 6 g/day. The abomasal infusion of cystine (5 g/day) caused little change in the mass of wool grown, but fibre diameter was decreased slightly. There were no appreciable effects on the strength of wool fibres and no wool was shed. Supplementation of the roughage diet (400 g/day) with methionine at 2 g/day stimulated wool growth, whereas with 6 or 10 g/day the mass of wool grown was unchanged but fibre diameter was markedly reduced. The strength of wool fibres was not markedly influenced by methionine infusions on this diet. The levels of amino acids in blood plasma and in abomasal digesta indicated that the mixture of amino acids absorbed was similar with both the roughage and the wheat diets.

scholarly journals The Utilization of Abomasal Supplements of Proteins and Amino Acids by Sheep With Special Reference to Wool. Growth

1972 ◽  
Vol 25 (5) ◽  
pp. 1057 ◽  
Author(s):  
PJ Reis ◽  
WF Colebrook
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Nutritive Value ◽  
Body Weight Gain ◽  
Wheat Gluten ◽  
Nitrogen Retention ◽  
Wool Growth ◽  
Egg Protein ◽  
Egg Albumen ◽  
Whole Egg

Proteins of different amino acid composition (Promine-D, wheat gluten, and zein) were given as abomasal infusions to sheep and effects on wool growth rate, body weight gain, and nitrogen retention were compared with those of casein. These results were considered together with earlier data obtained for whole egg protein, egg albumen, maize gluten, and gelatin. The nutritive value of bloodmeal supplements was also studied. In addition the effects on wool growth of adding lysine and tryptophan to zein, and of adding leucine to casein, were examined.

Effects on wool growth of the infusion of mixtures of amino acids into the abomasum of sheep

1978 ◽  
Vol 90 (1) ◽  
pp. 173-183 ◽  
Author(s):  
P. J. Reis ◽  
D. A. Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Amino Acid ◽  
Volume Growth ◽  
Fibre Diameter ◽  
Essential Amino Acids ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Standard Mixture ◽  
Wool Growth

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.

scholarly journals Metabolic Fate of Parenterally Administered Sulphur-Containing Amino Acids in Sheep and Effects on Growth and Composition of Wool

1970 ◽  
Vol 23 (4) ◽  
pp. 1077 ◽  
Author(s):  
RN Murdoch
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Parenteral Administration ◽  
Metabolic Fate ◽  
Length Growth ◽  
Wool Growth

Intravenous or intraperitoneal infusions of either L-cysteine (2, 0 gjday) or L-methionine (2�5 gjday) for 20 days increased wool diameter and its length growth rate, the main increases occurring during the first 8 days of infusion. Thus parenteral administration of these amino acids is effective in stimulating wool growth.

The influence of abomasal supplements of zein and some amino acids on wool growth rate and plasma amino acids

1976 ◽  
Vol 86 (3) ◽  
pp. 475-482 ◽  
Author(s):  
P. J. Reis ◽  
D. A. Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Volume Growth ◽  
Fibre Diameter ◽  
Essential Amino Acids ◽  
Fibre Volume ◽  
Plasma Amino Acids ◽  
Leucine Supplementation ◽  
Length Growth ◽  
Wool Growth

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.

scholarly journals Effects of Intravenous Infusion of Mimosine on Wool Growth of Merino Sheep

1975 ◽  
Vol 28 (6) ◽  
pp. 483 ◽  
Author(s):  
PJ Reis
Keyword(s):  
Amino Acids ◽  
Intravenous Infusion ◽  
Merino Sheep ◽  
Wool Growth ◽  
Intravenous Infusions

Merino sheep were given continuous intravenous infusions of L-mimosine for periods of It, 2 or 21 days; efficacy as a defleecing procedure and effects on subsequent wool growth were measured. In addition, the amino acids tyrosine, phenylalanine and cystine were investigated as antagonists to the effects of mimosine.

scholarly journals The Influence of Abomasal Supplements of Some Amino Acids and Sulphur-Containing Compounds on Wool Growth Rate

1970 ◽  
Vol 23 (2) ◽  
pp. 441 ◽  
Author(s):  
PJ Reis
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Glutamic Acid ◽  
Sulphuric Acid ◽  
Dietary Supplement ◽  
Wool Growth

Effects on wool growth rate of abomasal supplements of several amino acids (glycine, glutamic acid, arginine, lysine, and threonine) and of some sulphurcontaining compounds (L-cysteamine, sulphuric acid, and methionine hydroxy analogue) were examined. None of the abomasal supplements, apart from methionine hydroxy analogue, was effective for stimulating wool growth. Methionine hydroxy analogue did not influence wool growth rate when given as a dietary supplement.

The influence of nutrition on the effectiveness of mimosine for defleecing sheep

1978 ◽  
Vol 29 (5) ◽  
pp. 1057 ◽  
Author(s):  
PJ Reis ◽  
DA Tunks
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Intravenous Infusion ◽  
Continuous Intravenous Infusion ◽  
High Intake ◽  
Wool Growth ◽  
Abomasal Infusion ◽  
High Feed ◽  
Standard Rate ◽  
Small Intestines

The effectiveness of mimosine as a chemical defleecing agent was assessed in adult sheep that were subjected to a variety of nutritional treatments prior to administration of mimosine, and in lambs receiving relatively high feed intakes. Mimosine was given as a continuous intravenous infusion over a period of 2 days. Sheep receiving 600 g of a roughage-based diet per day were consistently defleeced following an infusion of mimosine at the rate of 80 mg/kg/day (designated the standard infusion). The prior feeding of a reduced intake of this diet (300 g/day) did not alter the amount of mimosine required to defleece sheep. Likewise, the prior abomasal infusion of an imbalanced mixture of amino acids, which depressed the wool growth rate, did not allow defleecing with a reduced amount of mimosine. A 4-day fast, commenced 3 days before the start of mimosine infusion, approximately halved the amount of mimosine required to defleece sheep. The provision of a high intake of energy, together with large amounts of amino acids available for absorption from the small intestines (supplied by casein), for at least 1 week prior to mimosine infusion, completely prevented defleecing with the standard infusion of mimosine. The effects of these nutritional treatments could be obviated by a 4-day fast as described above. Also, increasing the rate of infusion of mimosine to 120 mg/kg/day largely overcame the effects of previous high nutrition. Relatively greater amounts of mimosine were required to defleece lambs than adults. The concentration of mimosine in plasma was related to the rate of infusion of mimosine. However, fasting and a low dietary intake tended to enhance the concentration of mimosine in plasma for a given rate of infusion. Infusion of mimosine at the standard rate resulted in plasma mimosine concentrations of the order of 100 µmoles/l, but this concentration did not ensure that defleecing would be possible.

Quantitative analysis of methionine and cysteine requirements for wool production of sheep

2000 ◽  
Vol 71 (1) ◽  
pp. 175-185 ◽  
Author(s):  
S. M. Liu ◽  
D. G. Masters
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Amino Acid ◽  
Nitrogen Loss ◽  
Utilization Efficiency ◽  
Body Protein ◽  
Wool Production ◽  
Protein Retention ◽  
Oxidation Rates ◽  
Wool Growth

AbstractThe conventional system of estimating metabolizable protein requirement is unsuitable for defining amino acid requirements because nitrogen loss cannot be converted to amino acid loss, and because there is a lack of data on the utilization efficiencies of individual amino acids for various productive purposes. Therefore, we are proposing an alternative approach. In this review, we use methionine (Met) and cysteine (Cys) for wool production in sheep as examples, and define requirement as retention in both body and wool protein, plus the amount of obligatory oxidation that accompanies the retention. The requirements are expressed in terms of the net absorption. Mathematical models for the calculation of the requirements of both amino acids are established based on the level of absorption, endogenous contribution from body protein breakdown, oxidation rates and the amino acid composition of body and wool proteins. The flows and oxidation of Met and Cys, and Cys synthesis de novo as well are quantified using their plasma kinetics data. Wool growth rate is predicted from the amount of the amino acid available for protein retention and the partition ratio to wool growth. The estimated requirements for Met and Cys absorption for Merino sheep at maintenance are 0·45 to 0·75 g/day and 0·52 to 0·63 g/day depending on the live weight of the sheep. When wool growth rate increases to 10 g/day, the requirements increase to 0·91 to 1·24 g/day and 1·97 to 2·02 g/day respectively. The utilization efficiency for protein retention varies with the level of absorption, and is 0·02 to 0·55 for Met, and 0·09 to 0·55 for Cys. The model shows that wool growth rate is restricted by the lack of Cys supplied in conventional diets and is very sensitive to changes in oxidation of the amino acids.

scholarly journals Effects of Growth Hormone Administration on Wool Growth in Merino Sheep

1988 ◽  
Vol 41 (2) ◽  
pp. 177 ◽  
Author(s):  
PC Wynn ◽  
ALC Wallace ◽  
AC Kirby ◽  
EF Annison
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Energy Intake ◽  
Nitrogen Balance ◽  
Daily Administration ◽  
Maintenance Energy ◽  
Merino Sheep ◽  
Growth Hormone Administration ◽  
Hormone Administration ◽  
Wool Growth

The effects of daily administration of 10 mg of highly purified ovine growth hormone (GH) for a period of 4 weeks on wool growth have been measured in 12 Merino ewes fed either a calculated maintenance energy intake or 1�6 times this amount (six on each ration). Concentrations of hormones, glucose, urea, a-amino N and amino acids in the blood were monitored and faeces and urine collected for measurement of nitrogen balance.

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