Extra Virgin Coconut Oil as a Cryoprotector for Cryopreservation of Caprine Semen

Abstract

The study aimed to evaluate the effect of powdered coconut water-based diluent (ACP-101c) associated with extra virgin coconut oil (CO) as an external cryoprotectant in the conservation of cryopreserved buck sperm. For cryopreservation, the ejaculates from four bucks were pooled and divided into three aliquots and diluted at 37°C for treatments T1 (ACP-101c + 2.5% egg yolk +7% glycerol), T2 (ACP-101c + 2.5% CO +7% glycerol), and T3 (ACP-101c + 5% CO +7% glycerol). Then, the samples were packaged and cooled at a rate of 1.07°C/min decrease. Upon reaching 4°C, the samples were stored in a refrigerator at 4°C for 30 minutes for stabilization. After this period, the straws were frozen in nitrogen vapor for 15 minutes and then immersed and stored in liquid nitrogen at −196°C. After thawing, the samples were evaluated for sperm kinetics, plasma membrane integrity, acrosomal integrity, membrane functionality, mitochondrial activity (MA), and sperm morphology. In this study, no statistically significant differences were observed between the three treatments regarding the kinetic parameters (p > 0.05; Table 1). However, in relation to the velocities, a reduction was observed beyond the expected. There were no statistically significant differences between the diluents T1, T2, and T3 for the three velocities (curvilinear velocity [VCL], linear velocity [VSL], average path velocity [VAP]). Furthermore, no statistically significant differences were observed (p > 0.05) among treatments regarding the evaluation of membrane integrity, the functional membrane, MA, and sperm morphology after thawing. In conclusion, the use of CO in concentrations of 2.5% and 5.0% is effective in maintaining goat sperm quality, presenting itself as an alternative diluent for international programs of artificial insemination and embryo transfers.

Table 1.

Kinetic Parameters (Mean ± SEM) of Post-Thaw Buck Sperm Cryopreserved in Powdered Coconut Water Base Medium (ACP-101c)

Parameters/treatments	T1 (control)	T2	T3
MT (%)	35.20 ± 4.50a	36.87 ± 4.72a	42.13 ± 4.32a
VCL (μm/s)	43.59 ± 5.20a	40.58 ± 3.64a	50.17 ± 9.32a
VSL (μm/s)	24.72 ± 5.29a	18.98 ± 3.71a	26.48 ± 9.53a
VAP (μm/s)	32.98 ± 5.42a	26.52 ± 8.98a	35.80 ± 10.10a

Different superscript lowercase letters in the same row means that there was a statistical difference among treatment evaluations (p < 0.05).

T1 = ACP-101c + 2.5% EY +7% glycerol; T2 = ACP-101c + 2.5% CO +7% glycerol; T3 = ACP-101c + 5% CO +7% glycerol.

CO, coconut oil; EY, egg yolk; MT, total motility; SEM, standard error of mean; VAP, average path velocity; VCL, curvilinear velocity; VSL, linear velocity.