Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-28T00:54:07.777Z Has data issue: false hasContentIssue false

Evaluation of hypotheses regarding mechanisms of action of growth promotants and repartitioning agents using a simulation model of lamb metabolism and growth

Published online by Cambridge University Press:  02 September 2010

R. D. Sainz
Affiliation:
Growth Physiology Group, Ruakura Agriculture Centre, Ministry of Agriculture and Fisheries, Hamilton, New Zealand
J. E. Wolff
Affiliation:
Growth Physiology Group, Ruakura Agriculture Centre, Ministry of Agriculture and Fisheries, Hamilton, New Zealand
Get access

Abstract

Responses of lambs to cimaterol (CIM), diethylstylbestrol (DES) and ovine growth hormone (GH) were examined using a mechanistic model of growing lamb metabolism. All three compounds increase growth of lean tissue (protein) and decrease fat gain, although the magnitudes of these responses vary. Our working hypothesis was that observed changes in nutrient partition between lean and fat gain were caused by alteration of rate constants for turn-over of muscle protein and fat. Individual experiments were simulated whilst varying values of the protein degradation constant (Kprolein) and Vmax for lipolysis (Kfat). Optimal parameter values were found by minimizing residual errors, calculated as the deviations of model predictions from experimental values for carcass protein and fat. Fitted values of Kfat and Kprotein (expressed as proportions of controls) for each simulation were: CIM (grazing), 1·20 (s.d. 0·05) and 0·86 (s.d. 0·025); CIM (pellet-fed), 1·11 (s.d. 0·115) and 0·87 (s.d. 0·032); DES, 1·33 (s.d. 0·111) and 0·94 (s.d. 0·024); GH, 1·77 (s.d. 0·139) and 0·97 (s.d. 0·025) respectively. These results demonstrate that different mechanisms may be responsible for the changes in carcass composition due to 3-adrenergic agonists, anabolic steroids and growth hormone. CIM probably exerts its effects via changes in protein and fat metabolism, whereas DES and GH appear to act mainly through changes in adipose tissue, with little or no effect on the rate constant for protein turn-over. Carcass composition is less sensitive to manipulation of adipose tissue metabolism than to changes in muscle protein metabolism.

Type
Research Article
Copyright
Copyright © British Society of Animal Science 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Agricultural Research Council. 1980. The Nutrient Requirements of Ruminant Livestock. Commonwealth Agricultural Bureaux, Farnham Royal.Google Scholar
Agricultural Research Council. 1984. Report of the Protein Group of the Agricultural Research Council Working Party on the Nutrient Requirements of Ruminant Livestock. Commonwealth Agricultural Bureaux, Farnham Royal.Google Scholar
Baker, P. K., Dalrymple, R. H., Ingle, D. L. and Ricks, C. A. 1984. Use of a (3-adrenergic agonist to alter muscle and fat deposition in lambs. Journal of Animal Science 59: 12561261.CrossRefGoogle Scholar
Baldwin, R. L. and Black, J. L. 1979. Simulation of the effects of nutritional and physiological status on the growth of mammalian tissues: description and evaluation of a computer program. Animal Research Laboratory Technical Paper 6. Commonwealth Scientific and Industrial Research Organization, Melbourne.Google Scholar
Berg, R. T. and Butterfield, R. M. 1976. Current Concepts of Cattle Growth. Wiley, New York.Google Scholar
Black, J. L. 1984. Regulation of fat and protein deposition in animals. Proceedings of the Nutrition Society of New Zealand 9: 7683.Google Scholar
Bohorov, O., Buttery, P. J., Correia, J. H. R. D. and Soar, J. B. 1987. The effect of the P-2-adrenergic agonist clenbuterol or implantation with oestradiol plus trenbolone acetate on protein metabolism in wether lambs. British Journal of Nutrition 57: 99107.CrossRefGoogle ScholarPubMed
Buttery, P. J. and Dawson, J. M. 1987. The mode of action of beta-agonists as manipulators of carcass composition. In Beta-Agonists and their Effects on Animal Growth and Carcass Quality (ed. Hanrahan, J. P.), pp. 2943. Elsevier Applied Science, London.Google Scholar
Coelho, J. F. S., Galbraith, H. and Topps, J. H. 1981. The effect of a combination of trenbolone acetate and oestradiol-1755 on growth performance and blood, carcass and body characteristics of wether lambs. Animal Production 32: 261266.Google Scholar
Dent, J. B. and Blackie, M. J. 1979. Systems Simulation in Agriculture. Applied Science Publishers, London.CrossRefGoogle Scholar
Eisemann, J. H., Hammond, A. C., Bauman, D. E., Reynolds, P. J., McCutcheon, S. N., Tyrrell, H. F. and Haaland, G. L. 1986. Effect of bovine growth hormone administration on metabolism of growing Hereford heifers: protein and lipid metabolism and plasma concentrations of metabolites and hormones. Journal of Nutrition 116: 25042515.CrossRefGoogle ScholarPubMed
France, J. and Thornley, J. H. M. 1984. Mathematical Models in Agriculture. A Quantitative Approach to Problems in Agriculture and Related Sciences. Butterworths, London.Google Scholar
Gluckman, P. D. and Bass, J. J. 1987. Manipulation of growth in livestock. Proceedings of the 4th Asian- Australasian Association of Animal Production and Animal Science Congress, pp. 119121. The AAAP Organizing Committee, Hamilton, New Zealand.Google Scholar
Gluckman, P. D., Breier, B. H. and Davis, S. R. 1987. Physiology of the somatotropic axis with particular reference to the ruminant. Journal of Dairy Science 70: 442466.CrossRefGoogle Scholar
Gopinath, R. and Krrrs, W. D. 1984. Growth, NTmethylhistidine excretion and muscle protein degradation in growing beef steers. Journal of Animal Science 59: 12621269.CrossRefGoogle Scholar
Goldspink, D. F. 1978. The influence of passive stretch on the growth and protein turnover of the denervated extensor digitorum longus muscle. Biochemical Journal 174: 595602.CrossRefGoogle ScholarPubMed
Isaksson, O. G., Lindahl, A., Nilsson, A. and Isgaard, J. 1987. Mechanism of the stimulatory effect of growth hormone on longitudinal bone growth. Endocrine Reviews 8: 426438.CrossRefGoogle ScholarPubMed
Johnsson, I. D., Hart, I. C. and Butler-Hogg, B. W. 1985. The effects of exogenous bovine growth hormone and bromocriptine on growth, body development, fleece weight and plasma concentrations of growth hormone, insulin and prolactin in female lambs. Animal Production 41: 207217.Google Scholar
Martinez, J. A., Buttery, P. J. and Pearson, J. T. 1984. The mode of action of anabolic agents: the effect of testosterone on muscle protein metabolism in the female rat. British Journal of Nutrition 52: 515521.CrossRefGoogle ScholarPubMed
Muir, L. A., Wien, S., Duquette, P. F., Rickes, E. L. and Cordes, E. H. 1983. Effects of exogenous growth hormone and diethylstilbestrol on growth and carcass composition of growing lambs. Journal of Animal Science 56: 13151323.CrossRefGoogle ScholarPubMed
Pell, J. M. and Bates, P. C. 1987. Collagen and noncollagen protein turnover in skeletal muscle of growth hormone-treated lambs. Journal of Endocrinology 115: R1–R4.CrossRefGoogle ScholarPubMed
Reeds, P. J. 1987. Metabolic control and future opportunities for growth regulation. Animal Production 45: 149169.Google Scholar
Ricks, C. A., Dalrymple, R. H., Baker, P. K. and Ingle, D. L. 1984. Use of a p“-agonist to alter fat and muscle deposition in steers. Journal of Animal Science 59: 12471255.CrossRefGoogle Scholar
Sainz, R. D. and Wolff, J. E. 1987. Mechanisms of action of repartitioning agents: quantitative and dynamic evaluation of alternative hypotheses. Proceedings of the 2nd International Symposium on the Nutrition of Herbivores, pp. 153154. Australian Society of Animal Production, Brisbane.Google Scholar
Sainz, R. D. and Wolff, J. E. 1990. Development of a dynamic, mechanistic model of lamb metabolism and growth. Animal Production 51: 535549.Google Scholar
Schimke, R. T. 1969. Regulation of protein degradation in mammalian tissues. In Mammalian Protein Metabolism (ed. Munro, H. N.), pp. 178228. Academic Press, New York.Google Scholar
Sharpe, P. M., Buttery, P. J. and Haynes, N. B. 1986. The effect of manipulating growth in sheep by diet or anabolic agents on plasma cortisol and muscle glucocorticoid receptors. British Journal of Nutrition 56: 289304.CrossRefGoogle ScholarPubMed
Sinnett-Smith, P. A., Dumelow, N. W. and Buttery, P. J. 1983. Effects of trenbolone acetate and zeranol on protein metabolism in male castrate and female lambs. British Journal of Nutrition 50: 225234.Google ScholarPubMed
Thornton, R. F., Tume, R. K., Larsen, T. W., Johnson, G. W. and Wynn, P. C. 1986. The effects of ovine growth hormone on lipid metabolism of isolated ovine subcutaneous adipocytes. Proceedings of the Nutrition Society of Australia 11: 152.Google Scholar
Thornton, R. F., Tume, R. K., Payne, G., Larsen, T. W., Johnson, G. W. and Hohenhaus, M. A. 1985. The influence of the pvadrenergic agonist, clenbuterol, on lipid metabolism and carcass composition of sheep. Proceedings of the New Zealand Society of Animal Production 45: 97101.Google Scholar
Wagner, J. F. and Veenhuizen, E. L. 1978. Growth performance, carcass deposition and plasma hormone levels in wether lambs when treated with growth Hormone and thyroprotein. Journal of Animal Science 45: Suppl. 1, p. 361 (Abstr.).Google Scholar
Wang, S. Y. and Beermann, D. H. 1988. Reduced calcium-dependent proteinase activity in cimaterolinduced muscle hypertrophy in lambs. Journal of Animal Science 66: 25452550.CrossRefGoogle ScholarPubMed