Journal article
Whole body insulin responsiveness is higher in beef steers selected for increased muscling
Animal, Vol.5(10), pp.1579-1586
2011
Abstract
The aim of this experiment was to evaluate the impact of selection for greater muscling on whole body insulin responsiveness in cattle, as reflected by greater uptake of glucose in response to constant insulin infusion and greater glucose disappearance following an intravenous glucose tolerance test. This study used 18-month-old steers from an Angus herd visually assessed and selected for divergence in muscling over 15 years. Eleven high-muscled (High), 10 low-muscled (Low) and 3 high-muscled steers, which were heterozygous for a myostatin polymorphism (High(Het)), were infused with insulin using the hyperinsulineamic-euglyceamic clamp technique. Insulin was constantly infused at two levels, 0.6 mu IU/kg per min and 6.0 mu IU/kg per min. Glucose was concurrently infused to maintain euglyceamia and the steady state glucose infusion rate (SSGIR) indicated insulin responsiveness. An intravenous glucose tolerance test was also administered at 200 mg/kg live weight. Sixteen blood samples were collected from each animal between -30 and 130 min relative to the administration of intravenous glucose, plasma glucose and insulin concentration was determined in order to analyse insulin secretion and glucose disappearance. Insulin-like growth factor-1 (IGF-1) was also measured in basal plasma samples. At the low insulin infusion rate of 0.6 mU/kg per min, the SSGIR was 73% higher for the High muscling genotype animals when compared to the Low (P < 0.05). At the high insulin infusion rate of 6.0 mU/kg per min, these differences were proportionately less with the High and the High(Het) genotypes having only 27% and 34% higher SSGIR (P < 0.05) than the Low-muscled genotype. The High-muscled cattle also had 30% higher plasma IGF-1 concentrations compared to the Low-muscled cattle. There was no effect of muscling genotype on basal insulin or basal glucose concentrations, glucose disappearance or insulin secretion following an intravenous glucose tolerance test. The increased whole body insulin responsiveness in combination with higher IGF-1 concentrations in the High-muscled steers is likely to initiate a greater level of protein synthesis, which may partially explain the increased muscle accretion in these animals.
Details
- Title
- Whole body insulin responsiveness is higher in beef steers selected for increased muscling
- Authors/Creators
- P. McGilchrist (Author/Creator) - Cooperative Research Centre for Beef Genetic TechnologiesD.W. Pethick (Author/Creator) - Cooperative Research Centre for Beef Genetic TechnologiesS.P.F. Bonny (Author/Creator) - Murdoch UniversityP.L. Greenwood (Author/Creator) - Cooperative Research Centre for Beef Genetic TechnologiesG.E. Gardner (Author/Creator) - Cooperative Research Centre for Beef Genetic Technologies
- Publication Details
- Animal, Vol.5(10), pp.1579-1586
- Publisher
- Cambridge University Press
- Identifiers
- 991005541987107891
- Murdoch Affiliation
- School of Veterinary and Biomedical Sciences
- Language
- English
- Resource Type
- Journal article
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- Collaboration types
- Domestic collaboration
- Citation topics
- 1 Clinical & Life Sciences
- 1.26 Diabetes
- 1.26.1099 Insulin Signaling
- Web Of Science research areas
- Agriculture, Dairy & Animal Science
- Veterinary Sciences
- ESI research areas
- Plant & Animal Science