Alternatives to Antibiotics in Semen Extenders Used in Artificial Insemination

Abstract

Antimicrobial resistance is a serious global threat requiring a widespread response. Both veterinarians and medical doctors should restrict antibiotic usage to therapeutic use only, after determining the sensitivity of the causal organism. However, the addition of antibiotics to semen extenders for animal artificial insemination represents a hidden, non-therapeutic use of antimicrobial substances. Artificial insemination for livestock breeding is a huge global enterprise with hundreds of million sperm doses prepared annually. However, reporting of antimicrobial resistance in semen is increasing. This review discusses the consequences of bacteria in semen samples, as well as the effect of antimicrobial substances in semen extenders on bacteria in the environment and even on personnel. Alternatives to antibiotics have been reported in the scientific literature and are reviewed here. The most promising of these, removal of the majority of bacteria by colloid centrifugation, is considered in detail, especially results from an artificial insemination study in pigs. In conclusion, colloid centrifugation is a practical method of physically removing bacteria from semen, which does not induce antibiotic resistance. Sperm quality in stored semen samples may be improved at the same time.

Antimicrobial resistance of the microbiota in the reproductive tract of horses in conjunction with assisted reproduction

“…It was possible to retrieve approximately 85% of the original load of boar spermatozoa using this method, and sperm quality was not adversely affected by the lack of selection for robustness . Preliminary results from an AI trial indicated that fertility was similar in control and treated samples (Morrell et al, 2022). These results suggest that a similar approach for stallion semen might be possible.…”

Freezing Stallion Semen—What Do We Need to Focus on for the Future?

“…Moreover, bacteria may develop resistance [ 88 ]. It is questionable whether this nontherapeutic use of antibiotics fits with current recommendations for prudent use of antimicrobial substances [ 89 ]. Most of the liquid portion of the inseminate is expelled from the uterus via backflow; thus, the bacteria in the vagina and in the environment are exposed to the antibiotics contained in the insemination dose.…”

“…In the latter case, a low-density colloid could be used instead of the high-density colloid needed for the selection of robust sperm. When this technique was used to prepare boar semen for AI, there was no detrimental effect on reproductive efficiency in the inseminated sows compared to controls [ 89 ].…”

187 Single-layer centrifugation as a method for bacterial reduction in bull semen for assisted reproduction

“…Alternatives for antibiotics in semen extender have been discussed previously (Morrell et al 2022;Morrell and Wallgren 2014). Plant-based substances with known antimicrobial properties on different isolated bacteria have been proposed as an alternative but until recently, their antimicrobial effect in bull sperm had not been tested.…”