RESUMO
This study was conducted to evaluate the effect of amino acid addition to semen on post-thaw quality of donkey spermatozoa. Eighteen ejaculates were pooled and divided into aliquots which were cryopreserved in Gent A® containing 1% ethylene glycol (Gent-EG) and supplemented with 0 (as control), 20, 40, or 60â¯mM of glutamine, proline, or taurine. The greatest concentration (60â¯mM) of glutamine and taurine resulted in greater (Pâ¯<â¯0.001) post-thaw sperm motility. Amino acid supplementation did not improve (Pâ¯>â¯0.05) sperm morphology and membrane plasma integrity compared with the control samples. Whereas, improvement (Pâ¯<â¯0.05) of acrosome integrity was observed with use of 60â¯mM glutamine. After thawing, there were no differences (Pâ¯>â¯0.05) in the sperm DNA fragmentation index (sDFI) among treatments. The 60â¯mM glutamine and 40â¯mM taurine treatments, however, resulted in a reduction (Pâ¯<â¯0.05) in sDFI values in the first 6â¯h of semen incubation, compared with the control samples. At 24â¯h, the sDFI values were less (Pâ¯<â¯0.05) in all supplemented as compared with control samples, except for the 20â¯mM proline treatment group. In conclusion, supplementation of the Gent-EG extender with glutamine or taurine at 60â¯mM improved post-thaw donkey sperm quality. The addition of proline to the freezing extender, however, did not provide any significant enhancement in sperm quality, compared with the control group.