Effect of dietary energy on lipogenesis in turkey hens prior to and after sexual maturity.

An experiment was conducted with 208 Diamond Hybrid Small White turkey hens to determine the role of dietary energy on in vitro lipid metabolism. Young turkey hens were fed diets containing either a high (3100 kcal metabolizable energy) or low (2400 kcal metabolizable energy) energy level from 12 to 30 weeks of age. Both diets contained 12% protein and were fed on an ad libitum basis. Hens were then maintained under a constant (21 degrees C) or cyclic (12 to 27 degrees C) daily temperature regime and fed either a high (47% of the total energy) or low (8% of the total energy) fat diet for a 100-day egg collection period. Hens were killed at the end of the growing phase, after 1 week of receiving the breeder diets and after 2 weeks of stimulatory light (14 hr/day). Hens were also killed following a 100-day egg collection period. In vitro lipid metabolism and enzyme activities were determined at these periods. In vitro fatty acid synthesis was greater (P less than .05) in hens fed the high-energy prebreeder diet although total energy intakes for both groups of birds were similar. Transferring both groups of hens to individual cages in the breeder house decreased (P less than .05) fatty acid synthesis; however, lipogenic rates were higher (P less than .05) after 2 and 18 weeks of stimulatory light. The high-fat diet decreased (P less than .05) in vitro lipogenesis, fatty acid synthesis, malic enzyme and esterification of palmitate. Acetate utilization in the presence of pyruvate was one-half the rate in the absence. Diets fed prior to sexual maturity did not affect egg production or in vitro lipogenesis of mature hens.