Chen H, Wiegand R D, Anderson R E
Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030.
Exp Eye Res. 1992 Jun;54(6):885-92. doi: 10.1016/0014-4835(92)90152-i.
Whole retina, rod outer segments, and retinal pigment epithelium of frogs (Rana pipiens) fed crickets for more than 1 year had significantly lower levels of docosahexaenoic acid (22: 6n-3) than the same tissues of frogs fed crickets for less than 1 month. Decreases in 22:6n-3 levels in these tissues were compensated for by increases in the n-6 polyunsaturated fatty acids (PUFAs), primarily 22:5n-6. There were no changes in the levels of saturated, monoenoic, or dienoic acids. Analysis of diacyl phospholipid molecular species (PLMS) revealed decreases in both the 22:6(n-3)-containing dipolyenoic molecular species in phosphatidylethanolamine and phosphatidylserine, and the monopolyenoic molecular species in phosphatidylcholine. These PLMS were replaced by species containing 22:5n-6 or other n-6 PUFAs. Examination of fatty acid methyl esters of total lipids extracted from crickets revealed that less than 1 mol% fatty acids were of the n-3 family, while more than 30 mol% were of the n-6 family. Thus, frogs raised on an n-3-deficient diet have reduced levels of n-3 PUFA in their retinas, rod outer segments, and retinal pigment epithelium. Although such changes have been reported for mammals, this is the first report of the effects of n-3 deficiency on the lipids of amphibians.
