The effect of increasing dietary fat levels on hepatic lipogenesis in growing chicks was investigated. Increasing the level of dietary fat resulted in a linear depression of both acetate-1-14C and glucose-U-14C incorporation into fatty acids and glyceride-glycerol. Increasing the dietary fat level increased the activity of NADP-isocitrate d ehydrogenase. Chicks fed fat-free diet had lower (P<0.05) activity of NAD-malic dehydrogenase than those fed diets containing 5%, 10% and 15% fat. Activity

more »

... f glucose-6-phosphate dehydrogenase was higher (P<0.05) in chicks fed fat-free diet. The increase of the level of dietary fat resulted in a linear increase in non-esterified fatty acids in serum. The inverse relationship between the rate of fatty acid synthesis and the level of non-esterified fatty acids in serum suggested a role for non-esterified fatty acids in the control of fatty acid synthesis.