EFFECTS OF VARIATIONS IN THE PROPORTIONS OF SATURATED, MONOUNSATURATED AND POLYUNSATURATED FATTY-ACIDS IN THE RAT DIET ON SPLEEN LYMPHOCYTEFUNCTIONS

To obtain further information about the immunomodulatory effects of sp ecific dietary fatty acids, weanling male rats were fed for 6 weeks on high-fat (178 g/kg) diets which differed according to the principal f atty acids present, The nine diets used differed in their contents of palmitic, oleic, linoleic and cu-linolenic acids; as a result the tota l polyunsaturated fatty acid (PUFA) content and the PUFA:saturated fat ty acid ratio varied (from 178 to 58.5 g/100 g fatty acids tend from 0 .28 to 5.56 respectively), The n-6 PUFA: n-3 PUFA ratio was kept const ant in all diets at approximately 7.0. The fatty acid compositions of the serum and of spleen lymphocytes were significantly influenced by t hat of the diet fed, The ex vivo proliferation of spleen lymphocytes d ecreased as the level of oleic acid in the diet increased, Spleen natu ral killer cell activity decreased as the oleic acid content of the di et increased and increased as the palmitic acid content of the diet in creased, The extent of the effects of these fatty acids on lymphocyte functions was modified by the nature of the background fatty acid comp osition of the diet.