Characterisation of the insulin status of lambs and consequences
for carcass composition
J.A. Willis; R. Bickerstaffe; J.M. Munro; D. O'Connell
Department of Biochemistry and Microbiology, Lincoln University,
Canterbury
Proceedings of the New Zealand Society of Animal Production. 1990,
50: 97-100
The nutritional treatment of lambs influences the extent of carcass
fat deposition. Suckled lambs deposit more fat than weaned lambs with
associated increases in plasma glucose and insulin levels. To
investigate the mechanisms involved, groups of lambs with different
insulin profiles were created, either nutritionally or by infusing
insulin, and the effect on carcass composition determined. Border
Leicester x Dorset lambs were either weaned at 5 weeks of age or
remained suckling with access to grass. Twenty four lambs were
slaughtered at 12 weeks of age, the remaining lambs were slaughtered at
23 weeks of age. A subset of both weaned and suckled lambs were treated
with exogenous insulin from 5 weeks until slaughter. Insulin status was
assessed by the glucose tolerance test and by the response of plasma
glucose to injected insulin. The prolonged suckling of lambs increased
carcass fatness and decreased carcass protein compared to early weaned
lambs. Infusing insulin decreased carcass fatness and increased carcass
protein. The alterations in carcass composition were associated with
changes in the sensitivity of peripheral tissues to insulin.
Keywords: NZSAPAB;
Lamb; glucose tolerance; insulin sensitivity; fat; protein; body
composition.
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Last Updated 25-01-1997
