Dietary resveratrol supplementation alleviates cold exposure-induced pyroptosis and inflammation in broiler heart by modulating oxidative stress and endoplasmic reticulum stress

To explore the potential protective effect of resveratrol (RES) on cold-exposed broilers, 360 21-day-old broilers were equally divided into 5 groups with 6 replicates. A control (CON) group was reared at the normal feeding temperature and received a basal diet, and 4 cold exposure (8 ± 1°C for 10 h/d from d 29 to 42) groups were fed the basal diet with 0 (CE), 250 (CE + RES250), 500 (CE + RES500), and 750 (CE + RES750) mg/kg RES from d 22 to 42. Broilers were slaughtered on d 42 and heart tissues were collected to measure the relevant indexes. The results showed that heart tissues of all CE-broilers had inflammatory cell infiltrations, and dietary RES supplementation reduced this phenomenon. Compared to CON group, the concentrations of MDA and H₂O₂ were increased and activities of SOD and CAT were decreased in all CE-broilers (P < 0.05). mRNA expression of genes related to endoplasmic reticulum (ER) stress (GRP78, IRE1, PERK, EIF-2α, ATF4, ATF6, and CHOP), pyroptosis (NLRP3, ASC, Caspase1, GSDME, IL-18, and IL-1β), and proinflammation (TNF-α, IFN-γ, IL-2, and IL-6) was upregulated and that of ant-inflammatory cytokines (IL-4 and IL-10) was downregulated in CE and all CE + RES groups compared to CON group (P < 0.05). Compared to CE group, the activities of SOD and CAT and mRNA expression of anti-inflammatory genes were increased (P < 0.05), and concentrations of MDA and H₂O₂ and mRNA expression of ER stress, pyroptosis and proinflammatory genes were reduced (P < 0.05) in 3 CE + RES groups. Additionally, protein levels of PERK, ATF4, CHOP, NLRP3, Caspase1, GSDMD, IL-18, IL-1β, TNF-α, and IL-10 were similar in their mRNA expression. Overall, cold exposure caused oxidative stress and ER stress, and induced pyroptosis and inflammatory response, resulting in heart injury in broilers, and dietary RES addition reduced heart damage by enhancing antioxidant defense function. This study indicates that RES can be a feed additive to alleviate cold exposure-induced heart injury in broilers, and a 500 mg RES/kg diet is the optimal supplemental level.