The Effect of the Level and Source and of a Change of Source of Dietary Fat on the Fatty Acid Composition of the Depot Fat and the Thigh and Breast Meat of Turkeys as Related to Age

The fatty acids of abdominal depot fat and thigh and breast meat of turkeys fed 0, 2, and 11.4% palm oil or rapeseed oil from day-old to 24 weeks of age were strongly influenced by the level and source of dietary fat. Birds fed no added dietary fat deposited palmitic, palmitoleic, stearic and oleic acids in greater proportions than were provided in the diet. Increasing the level of fat in the diet resulted in the deposition of fat that resembled the dietary fat in composition, the greatest similarity occurring at the higher level of added fat. Increasing levels of palmitoleic, stearic and oleic acids with age indicated an increasing rate of fatty acid biosynthesis as the birds approached maturity. Thigh meat contained a higher level of stearic acid than depot fat, and breast meat contained higher levels of stearic and arachidonic acids and fatty aldehydes than thigh meat. These differences reflected the greater proportions of phospholipids in thigh and breast meat, which were reflected also in decreased sensitivity of the meat lipids to changes in fatty acid composition in response to dietary fat. The average rate of change of fatty acid levels following a change of dietary fat at 16 weeks was such that half the total change in level took place in 2.4 weeks. The previously reported effects of dietary fat on carcass composition and quality are substantiated by the fatty acid data presented here.