Effect of dietary fat on the fatty acid composition and fertilizing ability of fowl semen

Abstract

Broiler breeder roosters received two diets, containing either 5% salmon oil (SO) or 5% corn oil (CO). The diets differed essentially in their polyunsaturated fatty acid (PUFA) composition, with n-6:n-3 fatty acid ratios of 41.6 in SO and 1.5 in CO. The effects of these diets on the fatty acid composition of spermatozoa and seminal plasma, and on fertility evaluated after artificial insemination were observed. Whatever the diet, the fatty acid composition of spermatozoa showed notable amounts of 20:4n-6 (5-9%) and 22:4n-6 (15-21%). These essential fatty acids were not detected in the diets and were synthesized from 18:2n-6, which was abundant in the diet (15-16%) but low in spermatozoa (2-3%). Spermatozoa were also very rich in saturated fatty acids (39%). There was a clear influence of dietary lipids on the spermatozoa fatty acid profile: the proportion of n-3 fatty acids in spermatozoa from males fed SO compared to CO was higher (9.6% vs. 4.3%) and that of n-6 fatty acids was lower (22.4% vs. 33.3%). The fatty acid composition of seminal plasma included a higher proportion of saturated fatty acids (49%) than the proportion in spermatozoa, whereas minor fatty acids (14:0, 16:1n-7, 16:1n-9, 22:5n-3) were not detected. The influence of dietary lipids on the seminal plasma fatty acid profile was the same as for the spermatozoa, especially in the PUFA profile. In addition, the SO diet gave significantly higher fertility rates (96%) than the CO diet (91.6%). These results clearly show that the lipid composition of the diet may modify the fatty acid composition of the semen and its fertilizing ability.