Evaluation of quality and sex ratio of sperm in post-thaw sexed Brahman semen using magnetic-activated cell sorting conjugated with Y-scFv antibodies (M-Zlex)

Abstract

Brahman cattle (Bos indicus) are the breed suitable for beef production in tropical climate rearing conditions, where the use of sexed semen helps to pass on the good genetics of the superior sire and expand the herd rapidly and efficiently. This research evaluated the motility, kinematic variables, and sex ratio of sperm in post-thaw sexed Brahman semen using magnetic-activated cell sorting conjugated with Y-scFv antibodies (M-Zlex) by computer-assisted sperm analysis (CASA) and imaging flow cytometry. Fresh semen samples from a total of 26 ejaculates were collected one per week from eight Brahman bulls (2-4 ejaculates/bull) and divided into two parts to produce conventional (CONV) semen and M-Zlex semen. CASA was used to evaluate sperm motility and kinematic variables, and imaging flow cytometry was used to assess the X-/Y-chromosome bearing sperm ratio. The results found that sperm motility and all kinematic variables of M-Zlex semen did not differ from those of CONV semen. A significant difference was observed between M-Zlex and CONV in the proportion of X-sperm (p < 0.05) in eight bulls. 76.10%–78.78% X-sperm was present in M-Zlex, while the range of CONV was between 50.60% and 51.35%. Therefore, M-Zlex sexing method is another alternative for producing sexed Brahman bull sperm, which has the same sperm quality as CONV but increases the number of X-chromosome-bearing sperm that tend to produce female calves.