Selection of non-apoptotic sperm by magnetic activated cell sorting in Senegalese sole (Solea senegalensis)

Abstract

Senegalese sole (Solea senegalensis) is a promising species in aquaculture. However, due to decreased sperm quality in F1 generations and the absence of courtship in those individuals born in captivity, artificial fertilization is being used to generate new progenies. The objective of this study was to implement a sperm selection method for non-apoptotic sperm subpopulation recovery prior to sperm cryopreservation. In particular, magnetic activated cell sorting (MACS) is used to eliminate apoptotic spermatozoa. This study represents the proof-of-concept for MACS applicability in teleost species relevant in aquaculture. Apoptotic cell population was studied by flow cytometry using YO-PRO 1 and a caspase detection kit. Also, reactive oxygen species were measured in sperm samples. Our data demonstrated that caspase detection is more specific than YO-PRO 1 in the identification of apoptotic cells in S. senegalensis seminal samples. The results showed that the percentage of apoptotic cells (caspase positive) was significantly higher (p=0.04) in seminal samples from F1 than from wild individuals. MACS removed a significant number of apoptotic cells from the samples (54% and 75% in wild and F1 individuals, respectively), decreasing the level of cells positive for reactive oxygen species (p=0.17). In conclusion, this technique reduces the percentage of non-functional spermatozoa in a seminal sample prior to cryopreservation. This novel technique can be applied directly in the aquaculture industry.