Slow recovery of the fatty acid composition of sciatic nerve in rats fed a diet initially low in n-3 fatty acids.

The sciatic nerve of rats fed sunflower oil (6 mg 18:3-n-3/100 g of diet) presented dramatic alterations in the long chain polyunsaturated fatty acids in comparison with those fed soy oil (130 mg 18:3n-3/100 g of diet). In both 15-day-old and 60-day-old animals fed sunflower oil, 22:6n-3 (cervonic acid) was four-fold less, 22:5n-6 was 10-fold greater; adrenic acid (22:4n-6) was slightly greater and arachidonic acid (20:4n-6) was close to that in rats fed soy oil. The percentage distribution of total polyunsaturated fatty acids as well as the individual saturated and monounsaturated fatty acids were the same in both groups. When the sunflower oil-fed animals were switched to a soy oil-containing diet for either 15 or 60 days, the percentage distribution of 22:6n-3 increased slowly to reach the control value 2.5 months later. Conversely 22:5n-6 decreased slowly. The decay of 22:5n-6 was more rapid than the increase of 22:6n-3.