Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: May 31, 2004
Publication Date: June 1, 2004
Citation: Rosebrough, R.W., Russell, B.A., Poch, S.M., Richards, M.P. 2004. Dietary protein regulates short-term adaptations in lipogenic gene expression [abstract]. Poultry Science. v83(Suppl. 1):114 Technical Abstract: The purpose of these experiments was to determine possible relationships between certain indices of lipid metabolism and specific gene expression in chickens fed graded levels of dietary crude protein. Male, broiler chickens growing from 7 to 28 days of age were fed diets containing 12 or 30% protein ad libitum. Both groups were then switched to the diets containing the opposite level of protein. In Experiment 1, birds were killed on days 28 (basal values prior to the switch), 29, 30 and 31. Measurements taken included in vitro lipogenesis, malic enzyme activity the expression of the genes for malic enzyme, fatty acid synthase and acetyl coenzyme carboxylase. In Experiment 2, birds were sampled again prior to the switch and at 3, 6, 9 and 24 hr. following the switch in protein levels. Measurements taken were confined to malic enzyme activity and the expression of the genes for malic enzyme, fatty acid synthase and acetyl coenzyme carboxylase. In vitro lipogenesis and malic enzyme activity were inversely related to dietary protein levels (12 to 30%) and to acute changes from 12 to 30%. In contrast, expression of malic enzyme, fatty acid synthase and acetyl CoA carboxylase genes were constant over a dietary protein range of 12 to 21%, but decreased by feeding a 30% protein diet (acute or chronic feeding). Results of the present study demonstrate a continued role for protein in the regulation of broiler metabolism. It should be pointed out; however, that metabolic regulation at the gene level only occurs when feeding very high levels of dietary protein.