Effects of varying fat and protein in diets of growing large white turkeys. 1. Body weights and feed efficiencies.

Abstract An experiment was conducted to determine the effects of varying levels of dietary fat and protein in corn-soybean meal diets on body weight gain, feed consumption, and feed efficiency (gain:feed ratio) of Nicholas Large White male turkeys between 8 and 22 wk of age. Diets containing 0, 5, 10, or 15% added fat from one of three sources and 18, 21, or 24% protein were fed. At 12 and 16 wk of age, protein levels of all diets were decreased by 2%. A total of 917 turkeys in 36 pens was used. Additions of 5, 10, and 15% fat increased body weight gains 3.3, 7.5, and 6.0%, respectively. Feed consumption decreased 1.3% and feed efficiency increased 2.1% for each 1% fat added to the standard and high protein diets. The fat containing 15% free fatty acids and 1.5% moisture, impurities, and unsaponifiables (MIU) decreased feed consumption 1.5% and increased feed efficiency 2.3% for each 1% added fat, and the two fat sources containing 48% free fatty acids and 5% MIU decreased feed consumption 1.2 or 1.1% and increased feed efficiency 2.1 or 2.0% for each 1% added fat. The former fat source was estimated to contain 7.7% more metabolizable energy than the average of the latter two fat sources. Cumulative body weight gain, feed consumption, and feed efficiency decreased 13.2, 5.7, and 8.1%, respectively, from feeding low protein diets in comparison with results of feeding standard and high protein diets. Maximum increases in body weight gains were obtained with 10% added fat at all levels of protein. No interaction between fat and protein was observed, and added fat appeared to reduce the daily intake requirement for protein and lysine or some other amino acid.