Jane M. Morrell

By Jane M. Morrell

Part of the book: Artificial Insemination in Farm Animals

By Jane Morrell

Colloids have been used for several decades to prepare spermatozoa for assisted reproduction, initially for in vitro fertilization but, with the development of scaled‐up techniques, increasingly for artificial insemination and cryopreservation as well. The colloids usually consist of coated silica particles. Using colloid centrifugation, it is possible to select sperm subpopulations consisting of motile spermatozoa with intact membranes, stable DNA and normal morphology and to separate them from the rest of the ejaculate. This review explains why different protocols for colloid centrifugation are needed for different species, as well as species‐specific colloid formulations, to match the physical characteristics of the semen. The advantages and disadvantages of sperm preparation by this technique will be outlined. An emerging area of interest is the ability to separate spermatozoa from the bacteria that contaminate semen during collection. Thus, colloid centrifugation represents an alternative to using antibiotics in semen extenders. Since there is a worldwide movement to restrict the use of antibiotics, the possibility of physically removing the bacteria is of considerable interest. Moreover, it may be possible to use colloids to reduce viruses in semen. Transmission of viruses through semen is an emerging problem as more and more viruses are being identified that can potentially be spread in this manner.

Part of the book: Advances in Colloid Science

By Jane M. Morrell, Pongpreecha Malaluang, Aleksandar Cojkic and Ingrid Hansson

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.

Part of the book: The Global Antimicrobial Resistance Epidemic