P-138: The Effects of Omega-3, 6, 9 Fatty Acids on The Quality of Bovine Chilled Semen

Background: Many studies are being conducted to improve the quality of bull sperm in storage conditions. It seems that increasing sperm membrane unsaturated fatty acids can enhance sperm quality. This study was aimed to investigate the effects of combination of omega- 3, 6, 9 fatty acids on characteristics of bovine chilled semen. Materials and Methods: Different levels of oil containing omega- 3,6,9 fatty acids was added to semen extender. Five proven bulls were randomly selected and their ejaculates were collected by artificial vagina. Fresh semen was analyzed in terms of several parameters including volume, concentration, motility, viability and morphology. To emulsify the oil in semen extender, polyethylene glycol (PEG) was added as a more suitable solvent and solution was finally sonicated. Experimental groups included: control and treatments 1, 2, 3 and 4 as sham, levels 1, 2.5 and 5% of omega-3, 6, 9 fatty acids, respectively. In treatment 1, PEG was added alone to the diluents and in treatments 2, 3 and 4 different concentration of omega-3,6,9 fatty acids in combination with PEG were added to extender based Tris- citrate buffer, egg yolk and glycerol. After dilution, semen samples were packed into 0.5 ml straws and then cooling process was performed. Samples were evaluated in terms of motility, viability and morphology after 24 and 48 hours of storage in refrigerator (5°C). Motility and other dynamic parameters were analyzed by computer aided sperm analyzer (CASA) and viability and morphology were measured using phase contrast microscope after staining. The results were evaluated by repeated measure ANOVA using SPSS and p<0.05 was considered significant. Results: Immobility increased and all other parameters (including motility, progressive sperm, viability, morphology…) significantly decreased in all groups including control compared with fresh samples. Moreover, some parameters including motility and progressive sperm were significant different between groups (p<0.05). Our result showed that PEG has significant detrimental effects on motility (p<0.05) while its effects was not significant on the viability and morphology (p> 0.05). Combination of omega-3, 6, 9 fatty acids could not attenuate harmful effects of PEG significantly. Moreover, they could not improve sperm motility, viability and morphology of bovine sperm in chilled storage condition. Conclusion: Our result showed that this fatty acid combination does not appear to be a proper candidate for improving bovine sperm quality in cold conditions.