Effect of dietary omega-6 to omega-3 fatty acids and herbal antioxidants on sperm quality and fatty acid profile in rams

An increased ratio of omega-6 to omega-3 fatty acids in spermatozoa has been associated with impaired sperm parameters and elevated sperm DNA damage in human and different animal species. The present study investigated the impact of dietary omega-6 to omega-3 fatty acid ratio on sperm quality, fatty acid profile, and DNA damage in rams. A total of 19 Shall rams were allocated to a 2 × 2 factorial arrangement design, receiving either a low or high ratio of omega-6 to omega-3 fatty acids (LR: low ratio [4:1] and HR: high ratio [10:1]), with or without the addition of a 1:1 blend of Rosemary (Salvia rosmarinus) and Pennyroyal (Mentha pulegium) for 10 weeks. The HR without herbal antioxidant considered as control group. Feeding LR diets (P < 0.05) improved sperm parameters including semen volume, sperm concentration, motility, and membrane integrity (40 %, 58 %, 41 %, and 15 %, respectively). Additionally, rams fed with LR diets had lower (P < 0.01) sperm DNA damage indexes, as indicated by aniline blue, chromomycin A3, and acridine orange (36 %, 90 %, and 68 %, respectively). The LR diets increased (P < 0.01) the concentration of docosahexaenoic acid, eicosapentaenoic acid, and omega-3 fatty acids in sperm, and reduced the ratio of omega-6 to omega-3 fatty acids in sperm (71 %, P < 0.001), seminal plasma (35 %, P < 0.01), and blood plasma (55 %, P < 0.001). Overall, our findings revealed that supplementation of a low ratio of omega-6 to omega-3 fatty acids in rams’ diet positively affected their semen quality by incorporating omega-3 fatty acids into the sperm structure and seminal plasma, resulting in improved sperm parameters and reduced DNA damage.