Carcass and meat characteristics of sheep with an additional growth hormone gene
N. R. Adams A C , J. R. Briegel A , D. W. Pethick B and M. A. Cake BA CSIRO Livestock Industries, Floreat Park, WA 6014, Australia.
B School of Veterinary and Biomedical Sciences, Murdoch University, Perth, WA 6150, Australia.
C Corresponding author. Email: Norm.Adams@csiro.au
Australian Journal of Agricultural Research 57(12) 1321-1325 https://doi.org/10.1071/AR06064
Submitted: 1 March 2006 Accepted: 21 August 2006 Published: 21 November 2006
Abstract
Effects of high growth hormone (GH) activity on body composition and some aspects of meat quality were examined in sheep transgenic for an additional copy of the ovine GH gene, as a tool to explore the biological importance of the GH axis in sheep selected commercially for meat production. Carcasses of 16 GH and 25 control mixed-sex sheep aged 45 months, and 6 GH and 6 control ewes aged 20 months, were measured. The dressing percentage was lower in the GH sheep (P < 0.001). The GH sheep had similar muscle mass to controls, but the weight of their fat depots was reduced (P < 0.001) to approximately 40% of controls, whereas limb-bone mass was 43% greater (P < 0.001) than controls. Fore and hind limbs were equally affected. Skin and most internal organs were heavier, particularly the pancreas, kidney, alimentary canal, and the liver. The concentration of intramuscular fat in the GH sheep was only 27% that of controls (P < 0.001), whereas the average pH of muscle 24 h after slaughter and the melting point of subcutaneous fat were both increased (P < 0.05). Similar changes in organ weights and body composition have been observed in sheep selectively bred to enhance lamb growth rate or to decrease fatness, suggesting that relative GH activity contributed to the outcomes of those experiments. This study indicates the importance of a multi-trait breeding objective to ensure that mechanisms associated with GH do not impair meat quality.
Additional keywords: meat quality, fat, lean growth.
Acknowledgments
We thank P. Bullock, M. Carthew, G. Clune, J. Moore, D. Newman, A. Murray, T. Smith, L. Store, A. Williams, P. Young, M. Boyce, R. Jacobs, B. Waldoch, and J. White for assistance with the slaughter process, S. Stockwell for the DNA analyses, and P. Young and S. Kitessa for measuring intra-muscular fat.
Abdullah AY,
Purchas RW, Davies AS
(1998) Patterns of change with growth for muscularity and other composition characteristics of Southdown rams selected for high and low backfat depth. New Zealand Journal of Agricultural Research 41, 367–376.
Adams NR, Briegel JR
(2005) Multiple effects of an additional growth hormone gene in adult sheep. Journal of Animal Science 83, 1868–1874.
| PubMed |
Adams NR,
Briegel JR, Ward KA
(2002) The impact of a transgene for ovine growth hormone on the performance of two breeds of sheep. Journal of Animal Science 80, 2325–2333.
| PubMed |
Adams NR,
Sanders MR,
Briegel JR,
Peter DW, Rigby RDG
(1996) Responses of sheep to annual cycles in nutrition. 2. Effects of diet and endogenous growth hormone during replenishment. Animal Science 62, 287–292.
Barber MC,
Ward RJ,
Richards SE,
Salter AM,
Buttery PJ,
Vernon RG, Travers MT
(2000) Ovine adipose tissue monounsaturated fat content is correlated to depot-specific expression of the stearoyl-CoA desaturase gene. Journal of Animal Science 78, 62–68.
| PubMed |
Briegel JR, Adams NR
(2002) Long-term variations in growth hormone levels in sheep expressing an inserted gene for growth hormone. Animal Production in Australia 24, 33–36.
Cake MA,
Gardner GE,
Boyce MD,
Loader D, Pethick DW
(2006) Forelimb bone growth and mineral maturation as potential indices of skeletal maturity in sheep. Australian Journal of Agricultural Research 57, 699–706.
| Crossref | GoogleScholarGoogle Scholar |
Daniel ZCTR,
Richards SE,
Salter AM, Buttery PJ
(2004) Insulin and dexamethasone regulate stearoyl-CoA desaturase mRNA levels and fatty acid synthesis in ovine adipose tissue explants. Journal of Animal Science 82, 231–237.
| PubMed |
Francis SM,
Jopson NB,
Littlejohn RP,
Stuart SK,
Veenvliet BA,
Young MJ, Suttie JM
(1998b) Effects of growth hormone administration on the body composition and hormone levels of genetically fat sheep. Animal Science 67, 549–558.
Francis SM,
Veenvliet BA,
Littlejohn RP,
Stuart SK, Suttie JM
(1995) Growth hormone (GH) secretory patterns in genetically lean and fat sheep. Proceedings of the New Zealand Society of Animal Production 55, 272–274.
Francis SM,
Veenvliet BA,
Stuart SK,
Littlejohn RP, Suttie JM
(1998a) Growth hormone secretion and pituitary gland weight in suckling lambs from genetically lean and fat sheep. Archives of Animal Nutrition – Archiv fur Tierernahrung 41, 387–393.
Gardner GE,
Martin KM,
McGilchrist P, Thompson JM
(2005) The impact of selection for muscling on carbohydrate metabolism. Asia Pacific Journal of Clinical Nutrition Suppl. 14, S26.
Hopkins DL,
Hegarty RS, Farrell TC
(2005) Relationship between sire estimated breeding values and the meat and eating quality of meat from their progeny grown on two planes of nutrition. Australian Journal of Experimental Agriculture 45, 525–533.
| Crossref | GoogleScholarGoogle Scholar |
Johnsson ID,
Hart IC, Butler-Hogg BW
(1985) The effects of exogenous bovine growth hormone and bromocryptine on growth, body development, fleece weight and plasma concentrations of growth hormone, insulin and prolactin in female lambs. Animal Production 41, 207–217.
Kadim IT,
Purchas RW,
Rae AL, Barton RA
(1989) Carcass characteristics of Southdown rams from high and low backfat selection lines. New Zealand Journal of Agricultural Research 32, 181–191.
Kadokawa H,
Briegel JR,
Blackberry MA,
Blache D,
Martin GB, Adams NR
(2003) Relationships between plasma concentrations of leptin and other metabolic hormones in GH-transgenic sheep infused with glucose. Domestic Animal Endocrinology 24, 219–229.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Lewis RM,
Simm G,
Dingwall WS, Murphy SV
(1996) Selection for lean growth in terminal sire sheep to produce leaner crossbred progeny. Animal Science 63, 133–142.
Mezoszentgyorgyi D,
Husveth F,
Lengyel A,
Szegleti C, Komlosi I
(2001) Genotype-related variations in subcutaneous fat composition in sheep. Animal Science 72, 607–612.
Morris CA,
McEwan JC,
Fennessy PF,
Bain WE,
Greer GJ, Hickey SM
(1997) Selection for high or low backfat depth in Coopworth sheep: juvenile traits. Animal Science 65, 93–103.
Nsoso SJ,
Young MJ, Beatson PR
(2003) Correlated responses in tissue weights measured in vivo by computer tomography in Dorset Down sheep selected for lean tissue growth. South African Journal of Animal Science 33, 176–184.
Ortoft G, Oxlund H
(1996) Qualitative alterations of cortical bone in female rats after long-term administration of growth hormone and glucocorticoid. Bone 18, 581–590.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Perry D,
Shorthose WR,
Ferguson DM, Thompson JM
(2001) Methods used in the CRC program for the determination of carcass yield and beef quality. Australian Journal of Experimental Agriculture 41, 953–957.
| Crossref | GoogleScholarGoogle Scholar |
Pitchford WS,
Deland MPB,
Siebert BD,
Malau-Aduli AEO, Bottema CDK
(2002) Genetic variation in fatness and fatty acid composition of crossbred cattle. Journal of Animal Science 80, 2825–2832.
| PubMed |
Safari E,
Fogarty NM, Gilmour AR
(2005) A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep. Livestock Production Science 92, 271–289.
| Crossref | GoogleScholarGoogle Scholar |
Simm G, Murphy SV
(1996) The effects of selection for lean growth in Suffolk sires on the saleable meat yield of their crossbred progeny. Animal Science 62, 255–263.
Skarda J
(1998) Effects of bovine growth hormone on growth, organ weights, tissue composition and adipose tissue metabolism in young castrated male goats. Livestock Production Science 55, 215–225.
| Crossref | GoogleScholarGoogle Scholar |
Ward KA, Brown BW
(1998) The production of transgenic domestic livestock: successes, failures and the need for nuclear transfer. Reproduction, Fertility and Development 10, 659–665.
| Crossref | GoogleScholarGoogle Scholar |
Watt PW,
Finley E,
Cork S,
Clegg RA, Vernon RG
(1991) Chronic control of the beta-adrenergic and alpha-2-adrenergic systems of sheep adipose tissue by growth hormone and insulin. Biochemical Journal 273, 39–42.
| PubMed |
Wolf E,
Rapp K, Brem G
(1991) Expression of metallothionein-human growth hormone fusion genes in transgenic mice results in disproportionate skeletal gigantism. Growth, Development, and Aging 55, 117–127.
Young MJ, Sykes AR
(1987) Bone growth and muscularity. Proceedings of the New Zealand Society of Animal Production 47, 73–75.
