The effect of dietary lipids on the trout erythrocyte membrane.

Rainbow trout were fed either a commercial diet or semi-purified diets containing 8% by weight of either cod liver oil, grape seed oil or hydrogenated coconut oil. Important changes in the fatty acid composition of erythrocyte membrane phospholipids were induced by these dietary fats. No changes were seen in the cholesterol/phospholipid ratio and in the cellular ATP level. Shape changes (crenation of cell margin and shrinkage) were only seen in trout fed hydrogenated coconut oil in connection with an accumulation of high amounts of (n-9) fatty acids including 20:3 (n-9) phospholipids. The compositional changes affect the stability of the erythrocyte membrane. An increased rate of osmotic hemolysis appeared to be associated with an increased unsaturated fatty acid content of the membranes.