Resveratrol improves boar semen quality in summer months through modulation of the AGEs-RAGE signaling pathway in Leydig cells

Abstract

The high ambient temperature and relative humidity in summer months induce the reduction of boar semen quality, which generates adverse effects to the productivity and economic benefits of swine farms. It has been investigated that resveratrol (RSV), a naturally occurring polyphenol, can effectively improve oxidative damage, but its functional roles and underlying mechanisms in improving boar semen quality in summer months remain unclear. Herein, we mainly explored the regulatory and functional roles of RSV in boar semen quality in summer months. Analysis of average functional sperm numbers throughout the year confirmed reductions during summer (April–September) in all three genetic lines, with Duroc boars exhibiting the most severe decline (reaching a nadir of 0.60 × 10¹⁰/mL in July) and highest variability. Dietary supplementation of RSV demonstrated positive effects to improve sperm concentration, sperm motility, and semen metabolites in summer months through enhancing the antioxidant capacity of semen and serum. Additionally, heat stress induced the structure damage of porcine Leydig cells, a higher ROS, MDA, and AGEs levels, as well as a lower testosterone level. Pretreatment with RSV (200 nM/mL) attenuated the heat stress induced oxidative stress, reduced AGEs accumulation, and restored testosterone production. Mechanistically, RSV inhibited the heat stress-activated AGEs-RAGE signaling pathway, and subsequently reducing oxidative stress. These findings explored that boar semen quality declined during summer months, and that RSV improved the boar semen quality in summer months through modulation of the AGEs-RAGE signaling pathway in Leydig cells.