Effect of docosahexanoic acid on quality of frozen–thawed bull semen in BioXcell extender

This study was conducted to investigate the effect of docosahexanoic acid (DHA) supplementation in BioXcell extender on the quality of frozen–thawed bull semen. Twenty-four ejaculates were collected from three bulls (eight from each bull). Ejaculates with motility =70% and normal morphology =80% were extended into BioXcell extender to which 0 (control), 3, 5, 10 or 15 ng mL–1 DHA was added. The supplemented semen samples were incubated at 37°C for 15 min for DHA uptake by spermatozoa. Later, samples were cooled for 2 h at 5°C and packaged into 0.25-mL straws, frozen in liquid nitrogen for 24 h and subsequently thawed for evaluation. Results are presented as percentages ± s.e.m. Supplementation with DHA at 3 ng mL–1 significantly improved sperm functional parameters including sperm motility, normal morphology, viability, acrosome integrity and membrane integrity when compared with other supplemented groups and the control. Lipid peroxidation increased as the incorporation of DHA supplementation increased. In conclusion, 3 ng mL–1 concentration of DHA resulted in superior quality of frozen–thawed bull spermatozoa and is suggested as the optimum level of DHA to be added into BioXcell extender.