Bacterial contamination of poultry semen, its dilution and storage

SUMMARY Good quality of semen, its proper dilution with appropriate diluent and storage are the assurance for successful artificial insemination (AI) in poultry. Semen dilution is needed to extend a low volume of good quality poultry semen for economic poultry production through AI. Using diluent, poultry semen can be stored for short and long term. For short-term storage, various diluents have been developed in past and present which preserve high fertilising ability of chicken spermatozoa up to 24 h at low temperature. Research is required for further storage beyond 24 h in chicken and 6 h in turkey to ensure the transportation of the semen to distant places. Protocols for long-term storage of semen for various poultry species are available but its routine commercial application similar to the mammalian species is not economically viable and subjected to the future investigation. Insemination of contamination-free poultry semen into the hens seems to guarantee to get the healthy chicks. However, bacterial contamination is a common problem in poultry semen specially in turkey that deteriorates the semen quality and fertility. To eliminate it, supplementation of antibiotics in semen dilutors is the solution. However, its frequent use poses a threat of developing antibiotic-resistant bacterial strains at AI centres. To overcome these problems, antimicrobial peptides, nanoparticles and various natural bioactive compounds have been used. To detect the contamination, microbiological screening of semen samples is the need of the day. However, it seems impractical under the field condition and necessitates rapid reliable biomarker tests in this regard. Diluent composition along with suitable additives and discovery of proper cryoprotectant are the crucial factors for the effective storage of avian male gametes. Success in these aspects enables to develop cryobanks throughout the world.