The optimum concentration of soya-lecithin for replacing egg yolk in INRA-82-modified semen extenders improved the cryopreserved semen quality and DNA integrity of Arabian stallions

Abstract

The cryopreservation of stallion spermatozoa varies greatly between animals. Different equine semen extender supplements were invented to maximize the post-thaw semen quality. Soy lecithin is one of those additives that contain plant origin phospholipids used to replace egg yolk to minimize disease transmission. This study aimed to determine which concentrations of soy lecithin can replace egg-yolk in modified INRA-82 semen extenders for the cryopreservation of horse semen. Semen was collected from six Arabian stallions and extended with modified INRA-82 semen extender supplemented with 0.0, 1.25, 2.50, and 5.0% soya lecithin. Frozen-thawed sperm motility was measured at 0, 1, 2, and 3 h. Viability index, sperm plasma membrane integrity (SPMI), and acrosome integrity in addition to the comet assay non-fragmented DNA, head DNA, tail DNA, tail length, and tail moment were statistically analyzed. The addition of 2.5% soya lecithin had the highest post-thaw sperm motility at 0, 1, 2 h (P < 0.001) and 3 h (P < 0.0001), the optimum viability index (P < 0.0001), SPMI (P < 0.05), acrosome integrity (P < 0.0001), non-fragmented DNA (P < 0.01), DNA in the comet head (P < 0.05), minimum DNA in the comet tail (P < 0.05), shortest comet tail length (P < 0.0001), and lowest comet tail moment (P < 0.01). Soy lecithin at concentrations other than 2.5% deteriorated all post-thaw semen parameters. Soy lecithin (2.5%) can replace egg yolk in the modified INRA-82 semen extender for the cryopreservation of good-quality stallion semen.