Effects of dietary fat on feed efficiency, reproductive performance, and in vitro lipogenesis by the turkey hen.

Two 16-week feeding trials were conducted with Large White turkey hens to determine the effect of graded energy levels (as fat-6, 18, 30, and 42% substituted isocalorically for corn meal) on energy efficiency, reproductive performance, lipogenic enzyme activity, and in vitro lipogenesis. A constant calorie: gram-protein ratio (17:1) was maintained for all dietary treatments. Also, other components of the diets were adjusted to maintain constant energy-to-nutrient ratios. Additional fat increased (P less than .05) energy utilization but had no effect on reproductive performance. Additional fat calories decreased (P less than .05) malic enzyme, isocitrate dehydrogenase, and fatty acid synthetase activities; however, fatty acid synthetase activity was the most responsive of the three enzymes to 42% metabolizable energy as fat. Liver lipid content was also decreased (P less than .05) by additional fat calories. In vitro lipogenesis (fatty synthesis from 10 mM (1-14C) sodium acetate) was also decreased (P less than .01) by additional dietary fat.