Saturated, omega-6 and omega-3 dietary fatty acid effects on the characteristics of fresh, frozen-thawed semen and blood parameters in rams

The aim of this study was to investigate the effects of several dietary fatty acids (FAs) on semen quality and blood parameters in rams. We gave diet-supplemented treatments (35gday(-1)ram(-1)) by C16:0 (palm oil), C18:2 [sunflower oil (SO)] and an n-3 source [fish oil (FO)] to 12rams, who were fed for 15weeks during their breeding season. Semen was collected once per week. Semen samples were extended with Tris-based cryoprotective diluents, then cooled to 5 degrees C and stored in liquid nitrogen. Positive responses were seen with FO after 4weeks. The mean prefreezing semen characteristics improved with the intake of FO (P<0.05). Interestingly, maximum sperm output in FO was achieved 7.5x10(9) when compared to palm oil 5.3x10(9). Rams that received FO had the highest total testosterone concentrations (11.3ngml(-1) for FO, 10.8ngml(-1) for SO and 10.2ngml(-1) for palm oil) during the experiment (P<0.05). FO also improved the rams' sperm characteristics after thawing (P<0.05). Although C16:0 is a major saturated FA in ram sperm and all rams have been fed isoenergetic rations, the unique FAs of FO improved fresh semen quality and freezing ability compared to other oils.