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

Murdoch, R. N.

doi:10.1071/bi9701077

Cited by 11 publications

(2 citation statements)

References 4 publications

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“…However, this experiment was too short to achieve a new equilibrium of wool growth. Downes et al (1970) also reported intravenous and intraperitoneal infusions of methionine and cysteine produced the main increase in wool length growth rates and fibre diameter during the first eight days. Examination of their figures shows both length growth rates and fibre diameter increasing beyond the inifial eight days and perhaps plateauing at the end of the 20 day supplementafion trial.…”

Section: Cl36 Wool Growth Lag Periodmentioning

confidence: 81%

“…Oral supplementafion with cystine and methionine usually fails to increase wool growth due to their extensive degradation in the mmen (Reis 1969, Coetzee et al 1995. Infusion of sulphur amino acids or proteins rich in them direcfiy into the abomasum, use of proteins protected from mminal degradation such as formalin treated casein, or intraperitoneal and intravenous administrafion of cystine and methionine, all increased rates of wool growth and the cystine / sulphur content m wool proteins (Reis 1969, Downes et al 1970, Wilhams et al 1972, Hemsley and Reis 1984, Lee and Wilhams 1993, Coetzee et al 1995. Such changes in wool growth are most marked in sheep with a higher genetic potential for wool growth (Wilhams et al 1972, Williams 1995.…”

Section: Cl34 Sulphur Containing Amino Acidsmentioning

confidence: 99%

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Near-real time financial assessment of the Queensland wool industry on a regional basis

Hall

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TJiis thesis describes a systems analysis of the Queensland wool industry at a farm-enterprise level, and development of a computer simulation model designed to provide near real-time physical and financial information to policy makers at a regional level as an aid to decision making.Extensive reviews of the main biological factors affecting the wool enterprise were completed: diet selection and feed intake, protein digestion and metabolism, energy digestion and metabolism, wool growth, reproduction and mortalit}\ A sensitivity analysis of three separate bio-economic models was carried out to identify system components having the greatest impact on the financial performance of wool enterprises. Fleece production, wool price and total variable costs were found to be the most important determinants in each model. Grazfeed, a commercially available software package based on the Australian feeding standards for ruminants, was tested for its ability to simulate animal production as observed in Queensland sheep grazing experiments. A FORTRAN version of the required code for sheep and cattle was written and used in the subsequent analysis. These experiments varied greatly, both temporally and spatially. A number of problems in trial management and methodology were identified, these often required adjustment of recorded data. The collation of trial data was done in a manner that allowed ease of use in computer models. Optimisation software was used to modify parameters and equations within the model in an attempt to improve the agreement between predicted and observed values. Grazfeed was found to be unsuitable using the available test data.Regression analysis techniques were then used to identify climate, soil water, pasture and dietary variables which were able to explain the observed grazing trial variation in annual fleece production and liveweight change. The dietary variables were estimated using a theoretical diet selection subroutine, and a feed intake subroutine based on

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Section: Cl36 Wool Growth Lag Periodmentioning

confidence: 81%

Section: Cl34 Sulphur Containing Amino Acidsmentioning

confidence: 99%

Near-real time financial assessment of the Queensland wool industry on a regional basis

Hall

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Methionine Substitutes in Ruminant Nutrition I: Stability of Nitrogenous Compounds Related to Methionine during In Vitro Incubation with Rumen Microorganisms

Digenis

Amos

Yang

et al. 1974

Journal of Pharmaceutical Sciences

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4:1:2)] were scraped off, eluted into n-hexane, back-extracted into the ceric sulfate-sulfuric acid solution, and examined by the oxidation-UV method. The resulting UV absorption spectra from both the unchanged methadone and the metabolite were identical to that of benzophenone. GLC examination of the heptane following reflux further substantiated that benzophenone was formed from both the parent drug and the metabolite. DISCUSSIONThe extended linearity of the spectrophotometric method permits the use of a single aliquot of the specimen to encompass most urine methadone concentrations encountered in patients receiving methadone maintenance. Analysis by the barium peroxide method required varying specimen volumes since linearity was achieved up to a concentration of 25 pg/ml.A comparison of the procedures and results of the ceric sulfate and barium peroxide methods indicates several advantages of the former in addition to the extended linearity and elimination of the required alkaline wash. Oxidation of methadone by the method of this report gives a 84.6 f 3.2% yield of benzophenone as opposed to a 77.8 f 3.3% yield obtained with the barium peroxide method. In addition to the time saved through the elimination of an extraction step, the proposed spectrophotometric method requires a shorter reaction time; e.g., 20 min reflux with barium peroxide provided only a 48% yield of benzophenone compared to an 82% yield obtained with ceric sulfate. Additionally, reflux conditions were less critical since no significant change in percent yield was observed as the amount of primary oxidant was varied from 200 to 300 mg, the molarity of the sulfuric acid was varied from 5 to 6, or the duration of reflux was varied from 25 to 50 min. Similar variations in the barium peroxide method resulted in significantly decreased yields; changes in the amount of acid, solvent, and heat of reflux produced similar effects in both methods.The proposed methods provide rapid and sensitive quantitative methods for determining methadone a t therapeutic levels in biological specimens. Since other diphenyl-substituted drugs are susceptible to cerium sulfate, utilization of the GLC technique in conjunction with the spectrophotometric method provides a highly specific analytical methodology for methadone in biological specimens. The methods are particularly useful as a quantitative test in suspected methadone overdose cases and as a mechanism to monitor pharmacokinetic studies. In methadone maintenance programs the techniques can be used in collaboration with TLC to confirm on a relative basis that patients are receiving, within broad limits, proper dosages of the drug.Abstract Thirty-one nitrogenous compounds with possible methionine activity were included as potential nitrogen sources in media for in uitro incubation of rumen microorganisms. Compounds not supporting cellulose digestion were included in studies of ammonia release and specific analyses designed to confirm resistance of the compounds to microbial deamination. N-Acetyl-DLmethionine (IV)...

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Preliminary investigations on some potential sources of protected methionine derivatives for ruminant rations

1977

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A series of N-substituted methionine derivatives were investigated for their potential to resist rumen degradation but still to release methionine in the duodenum. The method adopted was (a) to measure rumen methyl mercaptan concentrations in sheep following intraruminal doses of the materials and (b) to measure the ability of the materials to promote the growth of chicks receiving a methionine deficient diet.

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

Cited by 11 publications

References 4 publications

Near-real time financial assessment of the Queensland wool industry on a regional basis

Near-real time financial assessment of the Queensland wool industry on a regional basis

Methionine Substitutes in Ruminant Nutrition I: Stability of Nitrogenous Compounds Related to Methionine during In Vitro Incubation with Rumen Microorganisms

Preliminary investigations on some potential sources of protected methionine derivatives for ruminant rations

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