Genetic and nutritional factors affecting growth, nutrient utilization and body composition of broiler chickens

Two growth trials were designed to measure the effects of: (1) dietary Virginiamycin (0 or 16.5 mg/kg) and added fat (0 or 4%), and (2) Virginiamycin (0 or 16.5 mg/kg) and dietary lysine levels (low, NRC, high) individually, and in combination on broiler performance. A third trial investigated the relationship of plasma glucose, triglyceride and phospholipid concentrations with degree of fatness/leanness in genetically lean and fat broiler chickens. A combination of supplemental fat and Virginiamycin increased protein and decreased fat content of the dressed carcass. Virginiamycin supplementation overcame the growth depression of a low lysine diet by increasing feed intake. In the low lysine diet, Virginiamycin supplementation reduced abdominal fat deposition in females and increased carcass yield in males. Carcass protein content was increased by feeding the NRC-recommended level of lysine or by Virginiamycin supplementation. (Abstract shortened by UMI.