Resveratrol and antifreeze protein type I show no synergistic benefits in cryopreserved ram sperm.

This study investigated the effect of resveratrol (RV) after thawing of ram sperm cryopreserved with or without the addition of antifreeze protein I (AFPI) on sperm quality during the 3 h incubation period. Each ram ejaculate was split into two aliquots, diluted in a TRIS egg yolk (TEY) extender supplemented with 0 (control) or 0.1 µg/mL AFPI, and then cooled and frozen. Thawed samples of both treatments were subdivided and incubated in Talp-Hepes medium with 0 (TEY and AFPI group) or 50 µM of RV (TEY + RV group and AFPI + RV group) for 3 h at 38 ºC. The sperm kinetics, capacitation status, plasma membrane integrity, mitochondrial activity, sperm-egg binding assay, and TBARS concentrations were evaluated at different intervals. Data were analyzed by mixed model, including the incubation time, AFP treatment, RV treatment, and their interactions as main effects, and the day of semen collection and the ram as random effects (P < 0.05; LS mean ± pooled SEM). The AFPI, RV treatments, and their interaction did not affect the average total motility (~ 17.1 ± 2.4%), progressive motility (~ 5.6 ± 1.4%), mitochondrial activity (~ 35.5 ± 2.3 arbitrary unit), plasma membrane integrity (~ 18.2 ± 2.4%), sperm binding capacity (~ 2.2 ± 0.1 sperm per mm²), TBARS concentrations (~ 1488.7 ± 27.4 ng/mL) and rates of capacitated (~ 27.5 ± 1.6%), non-capacitated (~ 20.9 ± 1.6%) and acrosome-reacted (~ 56.5 ± 4.1%) sperm. It was concluded that adding 0.1 µg/mL AFPI to the extender used for ram semen cryopreservation and/or further in vitro culture exposure to 50 µM RV did not improve in vitro sperm quality.