Effect of extender and amino acid supplementation on sperm quality of cooled-preserved Andalusian donkey (Equus asinus) spermatozoa

The main aim of this study was to evaluate the efficacy of two commercially available liquid stallion semen extenders for the preservation of Andalusian donkey semen at 5 °C for up to 72 h, and to evaluate the effect of amino acid addition on sperm quality of cooled donkey semen. In addition, this study investigated the effect of seasons on semen characteristics of Andalusian jackasses. Throughout a year, 50 ejaculates were collected from ten adult donkeys and a complete semen evaluation was performed immediately after collection. In Experiment 1, semen samples (n = 32) were pooled, divided into two aliquots, and cooled in either Gent® A or INRA 96®. In Experiment 2, pooled semen samples (n = 9) were cooled in Gent A® supplemented with 0 (as control), 20, 40, or 60 mM for each glutamine, proline, or taurine. Fresh semen and chilled samples were assessed for sperm motility, morphology, acrosome integrity, and plasma membrane integrity. Sperm motility variables were greater (P < 0.05) in Gent® A than in INRA 96®. The presence of glutamine, proline, or taurine in Gent® A improved (P < 0.001) the motility of Andalusian donkey spermatozoa. Differences (P < 0.05) in some sperm variables were observed among seasons. In conclusion, Gent® A maintained sperm motility characteristics after 72 h of cold storage to a greater extent than INRA 96®. Moreover, motility was greater when Gent® A supplemented at different concentrations of amino acids than Gent® A with no supplementation. An effect of seasons on the semen quality of the Andalusian donkey was demonstrated.