title: The effects of antibiotic additions to extenders on fresh and frozen-thawed bull semen.
abstract: Reproduction in dairy cows is based around the use of cryopreserved semen. Antibiotics are utilized to control bacterial contamination and growth in cryopreserved bull semen. The antibiotic resistance of some bacteria required the evaluation of new antibiotic combinations with a high level of antibacterial effectiveness and a negligible effect on spermatozoa. In this research, we studied the effect of the fluorinate carboxyquinolone ofloxacin and the combination of ceftiofur/tylosin on bull spermatozoa and in-field bacterial growth. In Experiment 1, the toxicity of different levels of ofloxacin and ceftiofur/tylosin was tested by the incubation of bull spermatozoa and the evaluation of sperm kinetic parameters, membranes and acrosome integrity after dilution, and at 60 and 120 min after incubation. The data reported in this study reveals that both antibiotic combinations, at all concentrations, seem to have a negligible effect on spermatozoa with respect to all of the parameters examined (p>0.05). Furthermore, progressive motility was significantly higher for sperm diluted with both antibiotic combinations compared with samples without antibiotics (p<0.01). In Experiment 2, the ability of ofloxacin or ceftiofur/tylosin to control bacterial growth during bovine semen cryopreservation was compared with the combination of gentamicin/tylosin/spectinomycin/lincomycin. A significant reduction in progressive motility was found in cooled semen with respect to all of the antibiotic treatments (p<0.05). However, the membrane integrity was found to significantly rise in frozen samples with, compared to samples without, antibiotics (p<0.05). In a bull, gentamicin, tylosin, spectinomycin, and lincomycin failed to control bacterial growth in the cryopreserved sample, while no such growth was found in samples extended with ceftiofur/tylosin or ofloxacin. In conclusion, both ceftiofur/tylosin and ofloxacin can be safely added to bull seminal extenders, and both can protect insemination doses from bacteria that are resistant to other antibiotic combinations.
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Viale Crispi 212, 64100 Teramo, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Gloria
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Viale Crispi 212, 64100 Teramo, Italy. Electronic address: acontri@unite.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Contri
authors.affiliation: Provincial Breeders Federation of Trento, Via delle Bettine 40, 38121 Trento, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Wegher
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Viale Crispi 212, 64100 Teramo, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Vignola
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie SCT 5 Trento, Via Lavisotto 129, 38121 Trento, Italy.
authors.forename: Debora
authors.initials: D
authors.lastname: Dellamaria
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Viale Crispi 212, 64100 Teramo, Italy.
authors.forename: Augusto
authors.initials: A
authors.lastname: Carluccio
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle / Q000502:physiology*; D015925:Cryopreservation / Q000662:veterinary*; D005615:Freezing; D008297:Male; D012661:Semen / Q000187:drug effects*; D012662:Semen Preservation / Q000662:veterinary*
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antibiotics; Bacterial contamination; Bull semen; Cryopreservation; Sperm parameters