Improvements in semen quality, sperm fatty acids, and reproductive performance in aged Ross breeder roosters fed a diet supplemented with a moderate ratio of n-3: n-6 fatty acids

The purpose of this study was to evaluate the effects of dietary n-3: n-6 fatty acid (FA) ratios and vitamin E (vitE) on the semen quality, FA composition, hormonal responses, and reproductive performance of aged roosters. Thirty-six Ross broiler breeder roosters were assigned to a 3 x 2 factorial design with 3 n-3: n-6 FA ratios (0.09, 0.16, and 0.23) based on the inclusion of 3 oil sources (canola, canola/fish, and fish) and 2 vitE levels (0 and 200 mg/kg). During the 60 d of treatment, semen parameters, FAs composition of sperm, lipid peroxidation, and hormonal responses were monitored. Reproductive performance using artificial insemination was also evaluated at the end of experiment (on day 60). Results showed that the 0.16 and 0.23 dietary ratios increased docosahexaenoic acid and n-3 polyunsaturated FA and decreased docosatetraenoic acid and arachidonic acid in rooster sperm (P < 0.05). The 0.16 dietary ratio supplemented with 200 mg vitE improved total sperm motility (P < 0.05) than the 0.09 and 0.23 ratios, both with and without vitE. Progressive motility, membrane functionality, and viability were significantly (P < 0.05) improved in the 0.16 and 0.23 ratios supplemented with vitE. The highest concentration of testosterone was observed in the roosters fed a diet ratio of 0.16 (P < 0.05). Compared with no supplementation of vitE, 200 mg/kg vitE reduced the lipid peroxidation of rooster sperm (P < 0.05). In the artificial insemination, the higher significant percentage of fertility rate (P = 0.02) was observed in the 0.16 ratio group that was supplemented with vitE compared to other groups. It can be concluded that supplementation of aged roosters' diet with 0.16 ratio of n-3: n-6 can be a beneficial strategy for improvement of their fertility.