O-7: Detrimental Effects of Dietary Fish Oil without Vitamin E Supplementation on Cryopreserved Sperm of Iranian Mehraban Rams
Although several studies confirmed positive effects of fish oil on semen quality, the antioxidant status in omega-3 supplemented diets of several studies is a fuzzy point. The aim of this study was to investigate the effect of dietary fish oil and (or) vitamin E supplementation on cryopreserved sperm in Mehraban rams.
Materials and methods
Sixteen fertile rams were randomly allotted to four groups and fed either of four diets during 13 weeks: І. control diet without fish oil and vitamin E supplementation (CON), ΙΙ. diet containing 200 IU/day/ram vitamin E (VE), ΙΙΙ. diet containing 2.5% (dry matter basis) fish oil (FO), and ΙV. diet containing 2.5% fish oil and 200 IU/day/ram vitamin E (OVE). Semen was collected at 14-d intervals during the breeding season. Semen samples were frozen in a Tris-based diluent, cooled to 4°C, frozen in liquid nitrogen vapor, and stored in liquid nitrogen. Finally, straws were thawed in a water bath (37°C) for 30 sec and evaluated by the CASA system. Data were analyzed using the MIXED procedure of SAS Institute (2003) with a repeated measurement analysis.
Sperm motility, viability, progressive motility, type A (rapid progressive) as well as type B (medium progressive) sperm were higher in frozen-thawed semen of rams fed fish oil and vitamin E (P<0.05). Hyperactive cells percent were lower in the FO group. Progressive motility was decreased by feeding dietary fish oil alone, but feeding of fish oil and vitamin E supplementation obliterated the detrimental effect of fish oil on progressive motility. The CASA parameters, (VCL, VSL, VAP, ALH, LIN, STR, WOB, and BCF) were not affected by the dietary treatment.
This study elucidates the importance of vitamin E supplementation once fish oil is to be consumed, especially for frozen-thawed semen.