Effect of DHA and vitamin E enriched diets on the fatty acid content and quality of rabbit semen

The effect of supplementing the feed with Docosahexaenoic acid (DHA, 22:6n-3) and/or vitamin E to bucks was studied on semen quality and biochemical parameters. 52 rabbits were allocated to 4 groups fed diets as follows: A: control; B: A+200mg/kg Vit.E; C: A+1.5% fish oil (FO); D: A+1.5% FO+200mg/kg Vit.E. Semen was analysed at various time-points: volume, concentration, motility, viability were recorded. The spermatozoa lipids were separated in their various classes: phospholipids (PL), free cholesterol (Chol), free fatty acids and triacylglycerols; the fatty acid profile of these classes was determined. PL was the main lipid class present in spermatozoa, followed by Chol. PL displayed a high content of 22:5n-6 (~30% of total fatty acids) and low content of 22:6n-3 (~1%) in the control. At the end of the experiment, the proportion of DHA in groups C and D increased by 10-fold (8% against 0.8 % in the control). This was followed by a slight decrease of 22:5n-6, suggesting an increase of unsaturation of PL for animals receiving FO. Ejaculate volume was reduced when extra vitamin E was present in the feed. More work is required to understand the role of specific long chain polyunsaturated fatty acids on sperm functions.