The effect of wintertime undernutrition on the fatty acid composition of leg bone marrow fats in reindeer (Rangifer tarandus tarandus L.)

We studied the effects of wintertime undernutrition on the fatty acid composition of bone marrow triacylglycerols (TAGs) of legs in freely-ranging reindeer calves (< 1 year) and adult hinds by comparing reindeer in poor condition slaughtered in February with reindeer in good condition slaughtered in October. Significant reductions were found in the proportions of the major monounsaturated fatty acid, or oleic acid, and in linoleic and α-linolenic acids in the femur TAGs of the undernourished reindeer as compared with the reindeer in good condition. As a result of these changes, the unsaturation index (UI) of the femur TAGs was reduced by 11% both in the calves and hinds. Similarly, there were also significant reductions in the proportions of oleic and linoleic acid in the metatarsal TAGs in the undernourished hinds, but only in linoleic acid in the calves. The UI of the metatarsal TAGs of the hinds was reduced by 7%, but that of the calves remained unchanged. The results suggest selective mobilization of oleic acid and the principal C18-polyunsaturated fatty acids from bone marrow TAGs in the undernourished reindeer during winter. These changes decrease the unsaturation degree of bone marrow fats, and, if advanced, may impair their fluidity and the functioning of the legs in the cold.