Chapter 9 - Intermittent feeding responses in genetically fat and lean chickens

Abstract

This chapter presents an experiment to determine intermittent feeding responses in genetically fat and lean chickens. A total of 300 unsexed chicks of the fat line (FL) and lean line (LL) were reared from 0 to 4 weeks of age in electrically heated battery brooders, with feed and water provided ad libitum. The intermittent feeding treatments were applied from 4 until 8 weeks of age and were as follows: (1) fed ad libitum; (2) fed 15 min of each 2 h; (3) fed 15 min of each 3 h; and (4) fed 15 min of each 4h. At 8 weeks of age, samples of four males and four females per pen were taken to collect blood and were then weighed and slaughtered to measure abdominal fat. Plasma samples were frozen for later analysis for levels of glucose, triglyceride, and free fatty acids (FFA). Proportion of abdominal fat varied among genetic lines within feeding intervals, FL birds having significantly more abdominal fat than LL birds in all intervals. Significant trends in both lines between restriction intervals for the blood parameters indicate that, starting around 3h post-feeding, the birds were withdrawing lipids from their tissues. Of particular interest is the significant increase in plasma FFA in the LL but not in the FL, supporting evidence that the LL birds have a greater propensity to utilize adipose stores.