The effect of age and sex on the rate of change of fatty acid composition of turkeys following a change of dietary fat source.

Small White turkeys were fed 10% dietary rapeseed oil or animal tallow to 6, 12 or 18 weeks of age. The dietary fat was then changed from rapeseed oil to tallow or from tallow to rapeseed or corn oil. Weekly core samples of skin and subcutaneous fat were taken for nine weeks after each change of dietary fat. The half-time (t 1/2) of the exponential rate of change of individual fatty acids was unrelated to either the fatty acid carbon chain length or the degree of unsaturation. The average t 1/2 of 2.4 weeks was influenced by sex, with more rapid change of fatty acid composition in females than males during the first but not later periods, and by age, with decreasing rate of change of fatty acids as the birds approached maturity. The extent of change of fatty acid composition in response to dietary fat decreased with age. The data presented will aid in predicting the carcass fatty acid composition of turkeys fed specific dietary fats and in estimating the effect of a change of dietary fat on carcass characteristics.