Effect of different antibiotic combinations in extender on bacterial load and seminal characteristics of Murrah bulls

Abstract

In order to evaluate the effect of different antibiotics in extender a study was conducted on 36 ejaculates from six Murrah buffalo bulls maintained at Artificial Breeding Research Centre (ABRC), National Dairy Research Institute (NDRI), Karnal. Each ejaculate wassplit in to three parts and the each part was diluted in Tris egg yolk dilutor with separate combination of antibiotics [Conventionally used Benzyl penicillin (1000 IU/ ml) + Streptomycin (1000 ug/ml) (PS), Benzyl penicillin (500 IU/ml) + Streptomycin (1000 ug/ ml) + Gentamicin (500 ug/ml) (PSG) and Benzyl penicillin (500 IU/ml) + Streptomycin (1000 ug/ml) + Amikacin (1000 ug/ml) (PSA)]. The microbial load and sperm quality was evaluated in refrigerated (0, 24 and 48 h) and cryopreserved (at -196°C) semen. The results depicted that individual sperm motility, sperm abnormalities, percent intact acrosome, HOST was significantly higher and lowest bacterial load was observed in semen fortified with benzyl penicillin, streptomycin and amikacin combination at refrigerated temperature, but the differences in bacterial load between different treatment combinations were not significant. The results revealed that benzyl penicillin, streptomycin and amikacin combination had higher efficacy in maintaining the individual sperm motility, percent intact acrosome and HOST, but non-eosinophilic counts and sperm abnormalities were higher in semen treated with amikacin combination. No significant difference in bacterial load was observed in different antibiotic combination treatments in cryopreserved semen, but lowest values of bacterial load were observed in semen treated with benzyl penicillin, streptomycin and amikacin combination. Overall the results suggested that fortification of semen extender with benzyl penicillin, streptomycin and amikacin combination would have positive effect on preservability of semen.