Enrichment of semen extender with Syzygium aromaticum extract: it’s impact on bull sperm preservation as an alternative to antibiotics

The present study was carried out to investigate the antimicrobial activity of Syzygium aromaticum (clove bud) extract and its effects on semen quality parameters after cryopreservation of cattle bull spermatozoa. The basic extender was composed of Tris, citric acid, fructose, egg yolk, glycerol and antibiotics. The antibiotics were replaced with Syzygium aromaticum extract at concentrations of 0, 25, 50 and 75 μg/ml of the extender. The microbial load was evaluated in fresh semen and frozen thawed semen of all the groups. Results showed that clove bud extract at 50 and 75 μg/ml had a comparable antimicrobial activity as that of antibiotics. However, semen supplemented with 25 μg/ml of extract had a slightly higher microbial load. Motility parameters, as well as morphological parameters, were observed to be better (P<0.05)
in the semen diluted with medium containing clove bud extract at 25 and 50 μg/ml. Sperm livability and plasma membrane integrity were also higher (P<0.05) in the semen exposed to medium containing 25 and 50 μg of clove buds extract after cryopreservation. Higher levels of clove bud extract, however, had an adverse effect on all the sperm quality parameters and significantly reduced (P<0.05) the motility, movement parameters, and viability of the sperm. Thus it can be concluded that the clove bud extract possessed antimicrobial potential that makes it suitable for addition to semen extenders and the best results are obtained with a maximum clove bud extract of 50 μg/ml.