The Manipulation of Body Fat in Broiler Chickens by Chemical Means and Their Effects on Energy Metabolism

Abstract

1. The differences between two genetically fat and lean lines of broiler chicken; in growth rate, fat content, heat production and energy and nitrogen balance were studied respectively in two growth trials and two calorimetry experiments using closed-circuit respiration chambers. ... 9. The results of the present study demonstrated that cimaterol is effective in reducing body fat in the chicken and shows the potential to improve lean body mass, but its effects on commercial broiler birds needs further trials to be clarified. Both theophylline and caffeine decrease fat content over that caused by a depression in feed intake and their dose-effect relationship makes it worthwhile to test lower levels to overcome the depression in growth. Iodinated casein can reduce fat content while maintaining growth and improving feed conversion at the two levels tested; its combination with theophylline has a synergistic effect on further reducing fat content and such a combination requires economic considerations.