Effect of the addition of sodium caseinate on the viability of cryopreserved buffalo semen

Abstract

The use of cooled semen in artificial insemination operations results in higher pregnancy rates than the use of frozen semen. This result seems to be related to the more severe damage triggered by the freezing process than that observed during refrigeration. Due to its ability to bind to sperm-binding proteins and calcium ions, sodium caseinate has been studied as a substance capable of preventing early sperm capacitation, a significant cause of the decreased pregnancy rate resulting from the use of frozen semen. The first objective of this study was to evaluate whether a commercial egg yolk diluent developed for frozen bovine semen could be used for buffalo semen cryopreservation; the second objective was to investigate the effect of this diluent in combination with sodium caseinate during the procedures of buffalo sperm cryopreservation using flow cytometry and computer-assisted sperm analysis. In the first part of the study, comparing the results of spermatic kinetics and plasma and acrosomal membrane integrity, it was observed that the freezing process resulted in more cell damage than the cooling process. In the second part of the study, no effects of the addition of sodium caseinate to the egg yolk diluent were observed. From the results of the present study, it was possible to conclude that the egg yolk-based diluent was suitable for buffalo semen cryopreservation and that the addition of sodium caseinate did not decrease the harmful effects related to seminal cryopreservation.

Chemically defined diluent based on Tris-casein in freezing goat semen

“…In order to solve the obstacles described above and allow a more adequate and safe processing of semen, some alternatives for the substitution of skimmed milk and egg yolk have been reported, among which soy lecithin can be highlighted (Alcay et al, 2017;Mehdipour et al, 2017;Najafi et al, 2017;Araújo Silva et al, 2019), caseinate (Da silva et al, 2020) and low-density lipoproteins (Luna-Orozco et al, 2019). Diluent based on these components have demonstrated a protective effect on sperm cells, a fact that makes them important alternatives for the formulation of seminal extenders (Alcay et al, 2017;Araújo Silva et al, 2019;Da silva et al, 2020).…”

“…In addition, casein micelles have the property of interacting with calcium ions. These ions are responsible for inducing tyrosine phosphorylation to initiate the capacitation process, as well as improving the rate of sperm binding to the zona pellucida of oocytes, with a consequent increase in in vitro embryo production (Da silva et al, 2020;Diniz et al, 2020). Thus, casein has been responsible for the protection of sperm, even at low concentrations in chilled (0.6%) or frozen (1.35%) semen (Lagares et al, 2012).…”