In vivo lipogenesis in genetically fat and lean chickens of various ages

Lipogenesis was studied in vivo in genetically fat and lean male chickens at 2, 5 and 15 weeks of age using tritiated water. At 2 and 5 weeks of age, the liver was the major site of de novo fatty acid synthesis rather than the carcass. Per 100 g of tissue lipogenesis was greater in the carcass at 15 weeks of age than at 2 or 5 weeks. Lipogenesis in the liver did not vary according to age. At 15 weeks of age there was no observable exaggeration in the degree of fattening (as in genetically obese rodents) of fat line chickens. The regulation of fattening in fat line chickens, at least at the onset of sexual maturity, appears to be different to that in genetically obese rodents.