Epsilon Open Archive

Abstract

The aim of this thesis was to investigate importance of dietary fatty acids (FA) and animal age and sex on FA metabolism. In addition relation between FA and antioxidants on the consequent nutritional and technological quality of reindeer and red deer meat were addressed. A diet rich in polyunsaturated FA (PUFA) especially long chained n-3 FA (≥C20) has beneficial effects on human health, e.g. in prevention of arteriosclerosis. Game meat is a potential food source that is both lean and rich in n-3 PUFA, however different animal production systems can affect its natural FA composition. In the present studies on reindeer and red deer, that were either grazing or fed with pellets, meat from grazing animals had higher amounts of n-3 PUFA and lower n-6/n-3 ratio. Our results from feeding studies indicate that reindeer are unable to sufficiently elongate and desaturate towards 22:5n-3 and 22:6n-3, and indicate that dietary intake of C 22 PUFA is necessary for reindeer. The differences in FA composition between grazing reindeer of different sex and age were ascribed mainly to fatness. FA composition of the meat influences not only its nutritional quality but also other quality aspects such as shelf life and processing stability. The higher degree of unsaturation of FA is, the more prone to oxidation they are. Therefore the antioxidant status in the animals is important for the protection of the meat against oxidation. The studies on processed and stored meat showed that changes in FA composition and antioxidant content influenced its processing stability and shelf life. α-Tocopherol status had a greater impact on lipid oxidation and colour stability than did changes in FA composition. In contrast to lipid oxidation, decreasing colour stability and increasing amounts of free FA were found to be the first indicators of quality deterioration. The knowledge from the present thesis adds valuable information on lipid metabolism of ruminants, demonstrated in reindeer.