Effect of long-term supplementation with arachidonic or docosahexaenoic acids on sperm production in the broiler chicken

The possibility was investigated that dietary supplementation of the male c hicken with long-chain polyunsaturated fatty acids of the n-6 and n-3 serie s may prevent the decrease in sperm output that normally occurs by 60 weeks of age. From 26 weeks of age, birds were raised on wheat-based diets suppl emented with either maize oil (rich in linoleic acid, 18:2n-6), arasco oil (rich in arachidonic acid, 20:4n-6) or tuna orbital oil (rich in docosahexa enoic acid, 22:6n-3). The effects of the last two oils were investigated at two levels of vitamin E supplementation (40 and 200 mg kg(-1) feed). By 60 weeks of age, there was a small increase in the proportion of the main pol yunsaturate of chicken sperm phospholipid, docosatetraenoic acid 22:4n-6, i n chickens fed arasco oil diet compared with chickens given the maize oil d iet, an effect that was potentiated at the higher dietary intake of vitamin E. Supplementation with tuna orbital oil significantly reduced the proport ions of 20:4n-6 and 22:4n-6 in the sperm phospholipid and increased the pro portion of 22:6n-3. The diet supplemented with tuna orbital oil and the low er level of vitamin E markedly depleted vitamin E from the tissues of the b irds and decreased the concentration of vitamin E in the semen; these effec ts were largely prevented by the higher level of vitamin E in the diet. The susceptibility of semen to lipid peroxidation in vitro was increased in ch ickens fed arasco and tuna orbital oils with 40 mg vitamin E kg(-1) feed, b ut was reduced when 200 mg vitamin E kg(-1) feed was provided in the diet. The number of spermatozoa per ejaculate decreased by 50% between 26 weeks a nd 60 weeks of age in the birds fed the maize oil diet. This age-related de crease in the number of spermatozoa was almost completely prevented by feed ing the birds with the oils enriched in either 20:4n-6 or 22:6n-3. Testis m ass at 60 weeks of age was approximately 1.5 times greater in birds given o f the arasco and tuna orbital oil diets compared with those given the maize oil diet.