Impact of lauric acid supplementation on bovine oocyte maturation, IVF embryo development, and stress protection during IVM.

This study investigated the effects of lauric acid (LA) supplementation during in vitro maturation (IVM) of bovine oocytes on nuclear maturation and subsequent embryonic development. Cumulus-oocyte complexes (COCs) were matured in medium containing LA at concentrations of 50, 100, 150, 200, or 300 µM, or without LA (control). Embryo development following in vitro fertilization (IVF) and culture (IVC) was assessed. Based on optimal outcomes in the first experiment (A total of 1,558 oocytes were used across 6 - 8 replicates per treatment group),200 µM LA was selected to evaluate its protective role under cellular stress. Oocytes (n = 1,255; five replicates) were matured with or without 200 µM LA and exposed to heat stress (41 °C) or oxidative stress (1 mM H2O2). LA supplementation significantly improved blastocyst rates, with 100 - 200 µM groups showing higher formation rates (≥ 37.1%) compared to control (21.3%) (p < 0.05). Blastocyst quality, based on A-B grade embryos, was also enhanced in the 200 µM (51.1%) and 300 µM (56.5%) groups versus control (19.2%) and 50 µM (16.9%) (p < 0.05). Stress exposure reduced maturation and blastocyst rates. Oxidative stress significantly decreased maturation (OS: 44.9%) and blastocyst development (18.6%) compared to control (72.3% and 28.4%, respectively), while LA treatment improved these outcomes (OS-LA: 51.5% and 31.5%) (p < 0.05). Under heat stress, LA showed a non-significant trend toward higher blastocyst rates (24.8%) compared to stress alone (16.2%). Under normal conditions, 200 µM LA significantly enhanced blastocyst yield (44.2%) versus control (28.4%) (p < 0.05). Data were analyzed using ANOVA with post-hoc tests, and differences were considered significant at p < 0.05. These results indicate that LA supplementation during IVM enhances bovine embryo developmental competence and partially mitigates oxidative stress-induced impairment.