Effect of early feed restriction in broilers. II. Lipid metabolism

Three experiments were conducted with broiler chicks to evaluate the effect of dietary energy restrictions on in vitro lipid metabolism. In Experiment 1, chicks were restricted from either 6 to 12 or 6 to 18 days of age and then fed ad libitum until day 27. In Experiment 2, both male and female chicks were restricted from 5 to 11 days of age and then were refed until 27 or 54 days of age. Glutamic:oxaloacetic aminotransferase (GOT), isocitrate dehydrogenase (ICD), malic enzyme (ME) and the fatty acid synthetase complex (FAS) were assayed at 27 days (Experiment 1) and at 27 and 54 days (Experiment 2). In Experiment 3, male chicks were restricted from days 6 to 12 and then were refed until day 27. In vitro lipogenesis and enzyme activities were determined during the 12 to 18-day period as the chicks were refed following the restriction. Both restriction regimes decreased (P less than .05) ME and FAS at the conclusion of the respective restriction intervals (Experiments 1 & 2). The 6 to 12-day restriction decreased (P less than .05) in vitro lipogenesis in the 12 day old chick when compared to controls. When restricted chicks were refed, in vitro lipogenesis exceeded that of the controls at both 14 and 16 days, but was less than that of the controls at 27 days.