Introduction: Bacteria can deteriorate spermatozoal quality during semen cryopreservation, compromising artificial insemination (AI) success. Antibiotics are included in extenders to reduce the harmful effects of bacterial contamination. To the best of our knowledge, this is the first study to evaluate antibiotics in ring-necked pheasant semen cryopreservation. Objectives: This study was designed to assess the efficiency of antibiotics (gentamicin, streptomycin, penicillin) on sperm quality and total aerobic bacterial count (TABC) of cryopreserved ring-necked pheasant ( Phasianus colchicus ) semen. Methods: Semen from eight males (40 ejaculates) was pooled, diluted with Red Fowl Extender, and divided into five treatments including a control; experiments were repeated five times. Samples were cryopreserved using 10% glycerol and stored at −196°C. Sperm quality was assessed at multiple stages postdilution, postcooling, postequilibration, and post-thaw, along with fertility outcomes via AI. TABC was determined by culturing thawed samples at 37°C. Results: All antibiotic treatments significantly improved semen quality compared with the control, with the streptomycin–penicillin (SP) combination yielding the best results across all stages. The SP group exhibited higher acrosome integrity and sperm livability ( p < 0.01). Fertility trials showed higher fertilization and hatch rates in the postdilution group compared with the post-thaw group. TABC was below the detectable limits (<1.0 × 10 4 colony-forming units CFU/mL) in all the antibiotic-treated extenders compared with 1.1 × 10 4 CFU/mL in the control. Conclusion: This study supports the use of antibiotic-enriched extenders to reduce bacterial contamination and enhance reproductive outcomes in avian AI programs, with potential benefits for conservation. Further work is recommended to elucidate mechanisms and optimize antibiotic concentration for long-term storage.
Iqbal et al. (Sat,) studied this question.