Effect of food intake on energy and protein metabolism in the skin of Romney sheep.
Sheep fed on either a low (500 g lucern (Medicago sativa) chaff/d; L) or high (1100 g lucerne chaff/d; H) intake had measurements made, using arterio-venous techniques, of blood flow and energy metabolite and cysteine utilization in the skin. Sheep on the H intake had significantly increased skin blood flow (P = 0.014) and oxygen uptake (P = 0.05). Although the H sheep had higher skin blood flow they showed no difference in skin uptake of either glucose or acetate compared with the L sheep, but the H sheep had a significantly lower output of lactate (P = 0.014). Animals in each group had either [14C]glucose or [14C]acetate infused into the skin which showed that acetate was the predominant precursor of skin sterol and fatty acid synthesis in the H sheep while L sheep skin used both glucose and acetate. The H sheep showed an increase in the net uptake of cysteine by the skin (P = 0.053), and in the uptake of cysteine for protein synthesis (P = 0.078), relative to the L sheep and this increase was of a comparable magnitude to the increase in blood flow to the skin. Although blood flow, protein synthesis and energy supply increased in the skin of the H sheep by 200-300%, wool production would only have increased by 10-20%, suggesting that nutrient flux changes are not the sole level of regulation of wool production.
Harris
P M
PM
Ag Research, Grasslands Research Centre, Palmerston North, New Zealand.
Lee
J
J
Sinclair
B R
BR
Treloar
B P
BP
Gurnsey
M P
MP
D000085:Acetates / Q000378:metabolism; D000818:Animals; D001158:Arteries; D003545:Cysteine / Q000378:metabolism*; D004032:Diet; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005947:Glucose / Q000378:metabolism; D012039:Regional Blood Flow / Q000502:physiology; D012756:Sheep / Q000378:metabolism*; D012867:Skin / Q000098:blood supply / Q000378:metabolism*; D014935:Wool / Q000378:metabolism
D000085:Acetates; D005947:Glucose; D003545:Cysteine