Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-28T15:33:43.191Z Has data issue: false hasContentIssue false
  • English
  • Français

The effect of restricted feeding on growth hormone (GH) secretory patterns in genetically lean and fat wether lambs

Published online by Cambridge University Press:  18 August 2016

S. M. Francis ,
R. P. Littlejohn ,
S. K. Stuart ,
B. A. Veenvliet  and
J. M. Suttie
S. M. Francis
Affiliation:
AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand
R. P. Littlejohn
Affiliation:
AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand
S. K. Stuart
Affiliation:
AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand
B. A. Veenvliet
Affiliation:
AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand
J. M. Suttie
Affiliation:
AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand
Get access

Abstract

The aim of this work was to determine whether developmental changes in growth hormone (GH) secretory patterns and carcass composition were influenced by nutrition and genotype in sheep. Four-month-old wether lambs from lean (low backfat), fat (high backfat) and control selection lines were nutritionally restricted to maintain a 28 kg live weight or given food ad libitum for 24 weeks. Plasma concentrations of GH and insulin-like growth factor 1 (IGF-1) were measured at predetermined times and carcass composition of the animals determined at the end of the trial.

From week 3 on, restrictions in dry matter (DM) intake were observed as the ad libitum treatment group had a significantly greater intake than the restricted treatment group (7·70 v. 5·80 kg DM per week, s.e.d. = 0·81). Differences in live weight between the feeding treatments were significant (P < 0·05) at week 9. The restricted feeding regime was associated with significant reductions in plasma levels of IGF-1 but had no effect (P > 0·05) on carcass weight-adjusted carcass fat proportion at the close of the trial. The effect of food restriction on GH secretory patterns was variable. Although there was initially a suppression in mean plasma GH, there was subsequently significantly higher mean plasma GH in the restricted feeding treatment. Periodogram analysis indicated that both the absolute levels of GH and the GH secretory pattern were altered by restricted feeding. In all animals, mean and basal GH concentrations, as well as the frequency and amplitude of pulses, declined from February to March and then increased from May to July (P < 0·001).

DM intake and live weight did not differ (P > 0·05) between genotypes, however the fat genotype had greater carcass fatness than lean or control genotypes (P < 0·01). There were no consistent differences between genotypes in plasma IGF-1 concentrations. In the ad libitum treatment, the lean and control genotypes had higher plasma GH levels than the f at genotype but the pattern of GH release did not vary. Under restricted feeding, both the pattern and the level of plasma GH varied between genotypes.

It is concluded that the developmental change in GH secretory patterns is affected by nutrition but not in a consistent manner. Although restricted feeding resulted in higher mean plasma GH concentrations later in the trial, this did not result in a change in carcass composition. The biological cues which lead to increased fat deposition in older lambs need further study but plasma GH levels may not he an important mechanism in this process.

Keywords

backfatbody compositioninsulin-like growth factorsheepsomatotropin
Type
Growth, development and meat science
Information
Animal Science , Volume 70 , Issue 3 , June 2000 , pp. 425 - 433
Copyright
Copyright © British Society of Animal Science 2000

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

Ball, A. J., Thompson, J. M., Hinch, G. N., Fennessy, P. E. and Blakely, A. R. 1995. Feed requirements for maintenance of mature rams and ewes from lines selected for differences in body composition. Proceedings of the New Zealand Society of Animal Production 55: 133–136.Google Scholar
Bass, J. J., Oldham, J. M., Hodgkinson, S. C., Fowke, P. J., Sauerwein, H., Molan, P., Breier, B. H. and Gluckman, P.D. 1991. Influence of nutrition and bovine growth hormone (GH) on hepatic GH binding, insulin-like growth factor-I and growth of lambs, journal of Endocrinology 128: 181–186.CrossRefGoogle ScholarPubMed
Breier, B. H., Bass, J. J., Butler, J. H. and Gluckman, P. D. 1986. The somatotrophic axis in young steers: influence of nutritional status on pulsatile release of growth hormone and circulating concentrations of insulin-like growth factor 1. Journal of Endocrinology 111: 209–215.Google Scholar
Diggle, P. J. 1990. Time series: a biostatistical introduction. Clarendon, Oxford.Google Scholar
Dodson, M., Davis, S., Ohlson, D. and Ercanbrack, S. 1983. Temporal patterns of growth hormone, prolactin and thyrotropin secretion in Targhee rams selected for rate and efficiency of gain. Journal of Animal Science 57: 338–342.Google Scholar
Driver, P.M. and Forbes, J.M. 1981. Episodic growth hormone secretion in sheep in relation to time of feeding, spontaneous meals and short term fasting. Journal of Physiology 317: 413–424.Google Scholar
Forbes, J. M., Driver, P. M., Brown, W. B., Scanes, C. G. and Hart, I. C. 1979a. The effect of daylength on the growth of lambs. 2. Blood concentrations of growth hormone, prolactin, insulin and thyroxine, and the effect of feeding. Animal Production 29: 43–51.Google Scholar
Forbes, J. M., El Shahat, A. A., Jones, R., Duncan, J. G. S. and Boaz, T. G. 1979b. The effect of daylength on the growth of lambs. 1. Comparisons of sex, level of feeding, shearing and breed of sire. Animal Production 29: 33–42.Google Scholar
Francis, S. M., Jopson, N. B., Littlejohn, R. P., Stuart, S. K., Veenvliet, B. A., Young, M. J. and Suttie, J. M. 1998. Effects of growth hormone administration on the body composition and hormone levels of genetically fat sheep. Animal Science 67: 549–558.Google Scholar
Francis, S. M., Veenvliet, B. A., Littlejohn, R. P., Stuart, S. K. and Suttie, J. M. 1995a. Growth hormone (GH) secretory patterns in genetically lean and fat sheep. Proceedings of the New Zealand Society of Animal Production 55: 272–274.Google Scholar
Francis, S. M., Veenvliet, B. A., Stuart, S. K., Littlejohn, R. P. and Suttie, J. M. 1995b. Insulin-like growth factor-I (IGF-I) mRNA and plasma concentrations in lean and fat genotypes of sheep. Proceedings of the Endocrine Society of Australia 38: 168.Google Scholar
Francis, S. M., Veenvliet, B. A., Stuart, S. K., Littlejohn, R. P. and Suttie, J. M. 1997. The effect of photoperiod on plasma hormone concentrations in wether lambs with genetic differences in body composition. Animal Science 65: 441–450.Google Scholar
Kenward, M. G. 1987. A method for comparing profiles of repeated measures. Statistics 36: 296–308.Google Scholar
Landefeld, T. D., Ebling, F. J. P., Suttie, J. M., Vannerson, L. A., Padmanabhan, V, Beitens, L. Z. and Foster, D. L. 1989. Metabolic interfaces between growth and reproduction. II. Characterization of changes in messenger ribonucleic acid concentrations of gonadotrophin subunits, growth hormone and prolactin in nutritionally growth limited lambs and the differential effects of increased nutrition. Endocrinology 125: 351–356.Google Scholar
Lord, E., Fennessy, P. and Littlejohn, R. 1988. Comparison of genotype and nutritional effects on body and carcass characteristics of lambs. New Zealand Journal of Agricultural Research 31: 13–19.Google Scholar
Merriam, G. and Wachter, K. 1982. Algorithms for the study of episodic hormone secretion. American Journal of Physiology 243: E310–E318.Google Scholar
Moore, L. G. and Mylek, M. E. 1993. A novel method for the extraction of sheep insulin-like growth factors-1 and -II from plasma prior to radioimmunoassay. Journal of Endocrinology 137: 239–245.Google Scholar
Morris, C. A., McEwan, J. C., Fennessy, P. F., Bain, W. E., Greer, G. J. and Hickey, S. M. 1997. Selection for high or low backfat depth in Coopworth sheep: juvenile traits. Animal Science 65: 93–103.Google Scholar
Olthoff, J. C., Dickerson, G. E. and Nienaber, J. A. 1989. Energy utilisation in mature ewes from seven breeds with diverse production potentials. Journal of Animal Science 67: 2550–2564.Google Scholar
Onischuk, L. A. and Kennedy, A. D. 1990. Growth hormone, insulin, prolactin and glucose levels in ewe and ram lambs during normal and compensatory growth. Domestic Animal Endocrinology 7: 365–381.Google Scholar
Pell, J. M., Saunders, J. C. and Gilmour, R. S. 1993. Differential regulation of transcription initiation from insulin-like growth factor-I (IGF-I) leader exons and of tissue IGF-I expression in response to changed growth hormone and nutritional status in sheep. Endocrinology 132: 1797–1807.Google Scholar
Rule, D., Beitz, D., Boer, G. de, Lyle, R., Trenkle, A. and Young, J. 1985. Changes in hormone and metabolite concentrations in plasma of steers during a prolonged fast. Journal of Animal Science 61: 868–875.Google Scholar
Suttie, J. M., Foster, D. L., Veenvliet, B. A., Manley, T. R. and Corson, I. D. 1991a. Influence of food intake but indépendance of body weight on puberty in female sheep. Journal of Reproduction and Fertility 92: 33–39.Google Scholar
Suttie, J. M., Lord, E. A., Gluckman, P. D., Fennessy, P. F. and Littlejohn, R. P. 1991b. Genetically lean and fat sheep differ in their growth hormone response to growth hormone-releasing factor. Domestic Animal Endocrinology 8: 323–329.CrossRefGoogle ScholarPubMed
Suttie, J. M., Veenvliet, B. A., Littlejohn, R. P., Gluckman, P. D., Corson, I. D. and Fennessy, P. F. 1993. Growth hormone pulsatility in ram lambs of genotypes selected for fatness or leanness. Animal Production 57: 119–125.Google Scholar
Taylor, St C. S., Murray, J. I. and Thonney, M. L. 1989. Breed and sex differences among equally mature sheep and goats. 4. Carcass muscle, fat and bone. Animal Production 49: 385–409.Google Scholar
Weiler, P. A., Dauncey, M. J., Bates, P. C, Brameld, J. M., Buttery, P. J. and Gilmour, R. S. 1994. Regulation of porcine insulin-like growth factor I and growth hormone receptor mRNA expression by energy status. American Journal of Physiology 266: E776–E785.Google Scholar
Wood, R. I., Ebling, F. J. P., ľAnson, H. and Foster, D. L. 1991. The timing of neuroendocrine sexual maturity in the male lamb by photoperiod. Biology of Reproduction 45: 82–88.Google Scholar