Marine Mammals: Animal Models for Studying the Digestion and Transport of Dietary Fats Enriched in w-3 Fatty Acids. Positional Analyses of Milk Fat Triacylglycerol Molecules

Abstract

In the depot fat of both marine and terrestrial animals, the relative percent distribution of the major fatty acids at the three positions of the glycerol backbone are not the same. Interestingly, studies have revealed that the polyenoic omega-3 fatty acids in marine mammalian blubber and fish oils are distributed differently. In marine mammalian blubber, the polyenoic omega-3 fatty acids are located on the outer positions of the molecule, i.e. the 1- and 3-positions. In fish oils, the polyenoic omega-3 fatty acids are located almost exclusively in the 2-position.

Because most marine mammals eat either fish or plankton (killer whales, polar bears and leopard seals being exceptions), we were interested in determining if the fat of marine mammalian milk contained triacylglycerol molecules (TG) with the polyenoic fatty acids distributed as in fish oil or as in the blubber of the lactating female. In our studies, we have obtained data on the milk fat of two species of pinnipeds, the northern elephant seal (Mirounga angustirostris) and the antartic fur seal (Artocephalus gazelle). These data demonstrate that the polyenoic omega-3 fatty acids together with the long chain monoenoic fatty acids are located on the 1- and 3-positions.