Egg yolk enriched with polyunsaturated fatty acids (PUFAs) improves the shelf life of ram semen in liquid storage

The aim of the current study was to assess the ability of semen extenders using egg yolk enriched with different sources of PUFAs to increase the shelf life of the ram semen in liquid storage. Four sources of PUFAs: conjugated linoleic acid (CLA), olive oil, flaxseed oil and fish oil were included in a basal diet (50 g/kg) and were fed to thirty laying hens. Semen samples were collected twice a week from six sexually mature Afshari rams. Semen samples were pooled and extended with five Tris-based extenders containing egg yolk from a normal diet, or egg yolk from the four enriched diets. Diluted semen samples were cooled to 4 °C and stored for 120 h (h). Sperm parameters were assessed at 0, 96 and 120 h of liquid storage. Proportions of motile and viable sperm were highest in flaxseed oil and fish oil extenders at 0 (P < 0.05), 96 and 120 h post storage (P < 0.01) whereas sperm plasma membrane functionality was highest in flaxseed oil and fish oil extenders compared to that of the other extenders for all times (P < 0.05). Percent of spermatozoa bearing head abnormalities were lower (P < 0.05) in omega-3 based extenders (flaxseed oil, fish oil and CLA), while the mid piece and tail abnormalities were lower (P < 0.01) in flaxseed oil, fish oil and olive oil extenders. In conclusion, enrichment of egg yolk with polyunsaturated fatty acids can improve the shelf life of ram semen during liquid storage.