Effect of extender supplementation with various antimicrobial agents on viability of Brucella ovis and Actinobacillus seminis in cryopreserved ovine semen

Impact of antibiotics on spermatozoa quality and bacterial load of chilled-stored camels (Camelus dromedarius) semen

This experiment was conducted to assess the effect of different antibiotics in tris-fructose egg yolk-based diluent on bacterial load and sperm quality of dromedary camels during processing and cold storage. Ten semen ejaculates were collected from five male dromedary camels. Each sample was fractioned into four equally divided aliquots and diluted in one of four tris-fructose egg yolk. The first extender contained no antibiotic (NC). The second extender included streptomycin sulphate (1000 μg/ml) and benzyl penicillin (1000 IU/ml) (SP). The third extender was supplied with 250 μg/ml gentamicin sulphate (Gent). The fourth extender contained 500 μg/ml gentamicin sulphate,100 μg/ml tylosin tartrate, 300 μg/ml lincomycin hydrochloride and 600 μg/ml spectinomycin hydrochloride (GTLS). After dilution, the extended semen samples were cooled to 5 °C within 2 h and finally stored at 5 °C for 72 h. Microbial concentration, motility of spermatozoa, live spermatozoa, plasma membrane and acrosome integrity percentages were evaluated just after dilution at 35 °C, 0, 24, 48 and 72 h from the start of cooling to 5 °C. The results revealed that the diluent containing gentamicin had significantly (P<0.05) maximum motility percentage at the different examination intervals. The pattern of live spermatozoa percentage was varied between the different treatments at different examination intervals. The diluent supplied with Gent was distinguished with a significant peak percentage (P<0.05) of swelled spermatozoa among the other antibiotics supplied diluents. The number of colony-forming units isolated from the semen samples kept in diluent containing no antibiotics was significantly (P<0.05) higher than that isolated from the diluents supplemented with antibiotics. In conclusion, the semen diluents fortified with gentamicin generally keep the motility, acrosomal and plasma membrane integrity and live spermatozoa for 72-h preservation of dromedary semen.

Influence of antibiotics on bacterial load and sperm parameters during short-term preservation of collared peccary semen

Studies on semen and sperm cells are critical to develop assisted reproductive technologies for the conservation of the collared peccary. The objective of the study was to compare the effect of different antibiotics on the bacterial load and sperm quality during short-term storage of peccary semen. Fresh semen samples from 10 males were extended in Tris-egg yolk or Tris-Aloe vera supplemented with streptomycin-penicillin (SP; 1 mg/mL - 1000 IU/mL or 2 mg/mL - 2000 IU/mL) or gentamicin (30 µg/mL or 70 µg/mL) before storage at 5°C. Bacterial load and sperm motility, membrane integrity and function, mitochondrial activity, and morphology, were evaluated at different time points for 36 h. The SP and gentamicin treatments concentration inhibited (p < 0.05) bacterial growth for 36 h regardless of the extender. Compared to the other treatments, Tris-egg yolk plus 70 µg/mL gentamicin maintained the sperm parameters for longer, including total motility (41.9 ± 6.1%) at 24 h, and membrane integrity (58.3 ± 2.1%) at 36 h. In contrast, the highest SP concentration in both extenders impaired sperm membrane integrity at 36 h (p < 0.05). For the liquid storage of collared peccary semen, it therefore is recommended to use Tris extender supplemented with egg yolk and gentamicin (70 µg/mL).

Current and alternative trends in antibacterial agents used in mammalian semen technology

The use of antibacterial substances as additives in extenders for ensuring the sanitary quality of the semen employed in reproductive biotechniques and preserving it from bacterial deterioration has been reported since the mid-twentieth century. However, the deleterious effects of these drugs on the sperm quality as well as their effectiveness in controlling bacterial growth in the preserved semen have been questioned. The aim of this review was to report the antimicrobials primarily used in the extenders added to the semen of mammals, and to present alternatives to their use. Among the various mammalian species, there is a large variation regarding the antimicrobial types added to semen extenders as cephalosporins (ceftiofur, cefdinir, eg) and quinolones (ofloxacin, ciprofloxacin), alone or in combination with large action spectra substances as penicillin-streptomycin and gentamicin-tylosin-lincomycin-spectinomycin. To combat problems related to bacterial resistance to these drugs, the emergence of alternatives is increasingly evident. Among these alternatives, use of physical methods as centrifugation and filtration, as well as the use of antimicrobial peptides and other substances from different origins have been highlighted for presenting antimicrobial potential.

Bacteriospermia and Sperm Quality of Cryopreserved Bull Semen Used in Artificial Insemination of Cows in South Wollo Zone, Ethiopia

The objectives of this trial were to estimate prevalence of bacteriospermia, to determine the bacterial load, and to isolate the types of bacteria as well as to assess the association between bacterial load and sperm quality traits in cryopreserved bull semen in field conditions in the South Wollo Zone. A total of 309 cryopreserved straws of semen from the Holstein Friesian (HF)-cross bull (n = 180 straws) and pure Jersey bull (n = 129 straws) were investigated. Bacteriological assessments of the presence of aerobic bacteria, estimation of bacterial count and bacterial isolation, as well as semen quality were performed. Aerobic bacterial contamination was prevalent in 38.8% of the semen straws. No significant difference in the prevalence of bacteriospermia was observed among bulls although the HF-cross bull had a higher prevalence (40.0%). But, significant difference in prevalence of bacteriospermia was found among semen ejaculates of the same bull. The risk of bacteriospermia in the HF-cross bull was higher (Odds ratio = 1.86, 95% CI = 0.168–20.26) compared to Jersey although not significant. Overall average bacterial load of 50.38 ± 16.29 colony-forming units (CFU)/ml (from nil to 1318.20 CFU/ml) was found. No significant difference in bacterial count among bulls and their ejaculates was observed. Moreover, correlation analysis revealed that the proportions of motility, live, and normal morphology were negatively influenced by an increase in the bacterial contamination of semen. In this study, three isolates of coagualse-negative Staphylococcus species and one isolate of Corynebacterium species were found. Average percentages of sperm motility (48.35 ± 1.23), live (66.08 ± 1.0), and normal morphology (80.62 ± 1.24) were observed. It was concluded that cryopreservation does not guarantee the quality of semen from bacterial contamination. Hence, meticulous care should be adopted to prevent contamination of semen by bacteria during collection, transportation, processing, and storage times.