Effect of oleic-linoleic acid and ?-sitosterol to freezing extender of bulls and stallions semen

Abstract

Addition of polyunsaturated fatty acids and/or cholesterol to a freezing diluent can modify the sperm plasma membrane composition, influencing its behavior during cryopreservation, thus, favoring seminal cryoresistance. The present study aimed to evaluate the effects of the addition of oleiclinoleic acid, (OLA); β-sitosterol (β-sit), a plant analog of cholesterol; and OLA + β-sit in combination to a freezing diluent, on the cryopreservation bull and stallion semen. The following variables were analyzed: motility/vigor, plasma and acrosomal membrane integrity (by Trypan Blue/Giemsa staining), mitochondrial activity (by DAB staining), and lipid peroxidation (by a TBARS assays). The lipids were added according to experimental treatments: C -control group, A1 and A2 -OLA at concentrations of 37 μM and 74 μM, B1 and B2 -β-sit at concentrations of 1 µg mL -1 and 2 µg mL -1 ; AB1 and AB2 -OLA 37 μM + β-sit 1 µg mL -1 and OLA 74 μM + β-sit 2 µg mL -1 , respectively. The study was divided into three experiments; in Experiment 1, the concentrations of the groups A1, B1, and AB1 were evaluated, whereas in Experiment 2 the concentrations of the groups A2, B2, and AB2 were analyzed, both experiments were performed with bull semen. We conducted Experiment 3 using equine semen with the addition of lipids at all of the concentrations described. Data were subjected to analysis of variance, using the GLM procedure of SAS, with treatment means compared by Duncan test considering 5% significance. These variables differed significantly after thawing the semen post-collection. However, there was no significant difference between treatments when variables were compared within the same time point, except for Experiment 2, where there was a decrease in motility and vigor decrease postthaw in the groups following β-sit addition (C -51.0 ± 13.7%/2.9 ± 0.4; B2 -35.8 ± 15.8%/2.3 ± 0.6; AB2 -38.5 ± 16.6%/2.5 ± 0.5, respectively; p < 0.05). In conclusion, the tested concentrations of these lipids did not confer greater cryoresistance to the spermatozoa, and were not effective in preserving the structural integrity of plasma and acrosomal membranes after thawing. Furthermore, there was no change in the mitochondrial activity and lipid peroxidation due to lipids addition. Key words: Cholesterol, cryopreservation, PUFAs, spermatozoa ResumoA adição de ácidos graxos poli-insaturados e/ou colesterol ao diluidor pode modificar a composição da membrana plasmática do espermatozoide, influenciando seu comportamento frente à criopreservação e favorecendo, assim, a crioresistência seminal. O presente trabalho teve como objetivo avaliar o efeito da adição do ácido oleico-linoleico (AOL), β-sitosterol (β-sit), um análogo vegetal do colesterol, e da associação AOL + β-sit, ao diluente de congelação de sêmen bovino e equino. As variáveis analisadas foram motilidade/ vigor, integridade das membranas plasmática e acrossomais (Trypan Blue/Giemsa), atividade mitocondrial (DAB) e nível de peroxidação lipídica (TBARS). Os lipídios foram adicionados de acor...

Effect of sheep diets with macadamia by-product and protected fat on the quality of fresh and frozen semen

“…This process generates reactive oxygen species that can have pathological effect on the sperms if in excess, or if the balance with available antioxidant defences compromised, resulting in a decrease In viability, motility and increases in DNA damage, morphology defects as well as lipid peroxidation (AMARAL et al, 2013). According to Sampaio et al (2015), there were no differences between treatments in which different concentrations of lipids (oleic-linoleic acid and beta-sitosterol) were used in the freezing dilution of semen from bulls and stallions in terms of mitochondrial activity. Studies of the role of vitamin E in the dilution of epididymis semen have shown that the addition of docosahexaenoic acid (DHA), a component of the omega-3 family associated with vitamin E, causes a decrease in mitochondrial activity, showing the combined activity of vitamin E with polyunsaturated fatty acids.…”