Curcumin enhances developmental competence and ameliorates heat stress in in vitro buffalo (Bubalus bubalis) embryos

Abstract

Background and Aim: Buffalo is the principal dairy animal and plays a major role in the economic growth of the dairy industry, contributing nearly 50% of the country’s milk production. The Buffalo core body temperature is typically 38.5°C, but it can rise to 41.5°C in the summer, causing heat stress, which leads to the generation of reactive oxygen species or oxidative stress and affects the reproductive physiology of animals. Curcumin acts as an antioxidant, improves cellular development, and combats the effect of heat stress on in vitro-produced embryos. This study aimed to examine the impact of curcumin on developmental competence and the expression of important genes under normal and heat-stressed conditions during in vitro embryo production in buffalo. Materials and Methods: Group-1: All embryo production steps (i.e., in vitro maturation [IVM], in vitro fertilization [IVF], and in vitro culture [IVC]) were conducted at 38.5°C. The presumed zygotes were cultured in media supplemented with different concentrations of curcumin, that is, 0 μM, 5 μM, and 10 μM of curcumin. Group-2: All embryo production steps (i.e., IVM, IVF, and IVC) were carried out at 38.5°C. The presumed zygotes were cultured in media supplemented with different concentrations of curcumin, that is, 0 μM, 5 μM, and 10 μM of curcumin, but the early cleaved embryos were exposed to heat stress (39.5°C) for 2 h after 48 h of IVF and then cultured at 38.5°C for embryo production. Results: Blastocyst production was 16.63 ± 1.49%, 21.46 ± 0.67%, and 6.50 ± 1.17% at control, 5 μM and 10 μM of curcumin at 38.5°C, respectively, whereas at 39.5°C, it was 8.59 ± 1.20%, 15.21 ± 1.31%, and 3.03 ± 1.20% at control, 5 μM and 10 μM curcumin, respectively. The blastocyst rate was found to be significantly higher (p < 0.05) at 5 μM curcumin compared with the control or 10 μM at 38.5°C and 39.5°C. The antioxidant, antiapoptotic, and pluripotency-related genes exhibited higher (p < 0.05) expression in the presence of 5 μM curcumin compared to 10 μM or control at both temperatures. Conclusion: Curcumin supplementation in embryo culture media effectively enhances embryo production in vitro and mitigates the adverse effects of heat stress. Keywords: antioxidant, buffalo, curcumin, embryo, heat stress.