No abstract

SUMMARYIn two experiments a total of twelve male rats were reared from weaning for up to 63 weeks on an essential fatty acid (EFA)-deficient diet alone (2 x two animals) or supplemented with the methyl esters of linoleic acid (18: 2w6) (2 x two animals) or linolenic acid (18: 3w3) (2 x two animals). Testicular development was normal in rats given 18:2w6, but in rats fed the EFAdeficient diet alone, and in those supplemented with 18:3w3 the testes were reduced in size. Histologically, a degeneration of the seminiferous tubules was noted, with progressive loss of the germinal cells, and with an absence of spermatozoa in the lumina of the seminiferous tubules and epididymides. Leydig cells appeared unaffected, and were prominent. The six rats in Experiment 1 were capable of mating with females reared on commercial diets, but only the two 18: 20)6 supplemented animals were fertile. There was a marked reduction in the percentage of arachidonic acid (20:4wj6) and docosapentaenoic acid (22: 516) in the total fatty acids of the atrophic testes. There was no compensatory increase in long-chain derivatives of 18: 3w3 in the 18: 3w3 fed rats and it is concluded that linolenic acid cannot replace linoleic acid in the development of the rat testis.

Rats were reared into a third generation on diets deficient in essential fatty acids supplemented with linoleic acid (18:2 n-6) or linolenic acid (18:3 n-3) with the object of depleting the retina of n-6 or n-3 fatty acids. In the rats fed 18:2 n-6 the percentage by weight of 22:6 n-3 in retinal fatty acids fell from 22.5 to 8.5% in first-generation animals but then remained unchanged in second and third generations. There was no difference in b-wave amplitudes of the electroretinogram between the rats fed 18:2 n-6 and those fed 18:3 n-3. In guinea-pigs fed purified diets low in 18:3 n-3 the percentage by weight of 22:6 n-3 in retinas fell from 8 to < 0.5% by the third generation. However, there were no statistical differences in the b-wave amplitudes between these animals and those reared on a commercial diet. It is concluded that if n-3 fatty acids are involved in retinal function their role is too subtle to be detected by standard electroretinographic techniques.