COMPARISON OF ACIDULATED RAPESEED-OIL SOAPSTOCK WITH ANIMAL TALLOW AS A SOURCE OF ENERGY IN BROILER DIETS

Two experiments were conducted to compare acidulated rapeseed-oil soapstock and animal tallow as sources of energy. Both experiments started with day-old, male, broiler-type chicks and lasted for 4 weeks. In the first experiment, the amount of protein was held constant and the calorie-to-protein ratio changed with the amount of supplementation of the two energy sources. The calorie-to-protein ratios used were 82, 97, 112, 127, and 142. In the second experiment, the protein-to-calorie ratio was held constant at 138. Each increase in the energy level of the diet up to 10% addition of each energy source resulted in improved weight gains and feed efficiency. Supplementation with either energy source over 10% did not improve growth over that obtained with 10%, but did improve feed efficiency. No differences in either growth or feed efficiency due to energy source were statistically significant. In both experiments, 10% tallow and 5% soapstock significantly reduced growth rate when compared with the 10% levels of supplementation, as did the 10% tallow and 10% soapstock in experiment 2. The results indicated that the energy value of the two supplements was approximately equal.