Chlorogenic Acid Protects Intestinal Barrier via Enhancing Antioxidative Capacity and Altering Intestinal Microbiota in Heat-Stressed Meat Rabbits

The effects of chlorogenic acid (CGA) on intestinal histomorphology, barrier integrity, antioxidant parameters, and gut microbiota in heat-stressed rabbits were assessed in this study. One hundred and twenty weaned New Zealand rabbits were assigned to three groups: control (CON) at 25 ± 1 °C, heat stress (HS) at 35 ± 1 °C, and HS with CGA supplementation (HS + CGA) at 35 ± 1 °C. Rabbits in the CON and HS groups were fed a basic diet, while those in the HS + CGA group receive the basic diet added with 800 mg/kg CGA. HS induced intestinal oxidative stress, impaired intestinal morphology and barrier function, and altered the gut microbiota. CGA supplementation mitigated HS-induced increases in serum diamine oxidase and D-lactate levels, and intestinal malondialdehyde content (p < 0.05), and countered HS-induced reductions in intestinal superoxide dismutase activity, villus height/crypt depth ratio, and claudin-1 and ZO-1 mRNA expressions (p < 0.05). In addition, HS decreased the abundances of Akkermansia and uncultured_bacterium_g__Akkermansia and increased the Firmicutes/Bacteroidota ratio and uncultured_bacterium_g__unclassified_o_Clostridia_UCG-014 abundance as well as the abundance of bacterial functions related to animal_parasites_or_symbionts and human_pathogens_all. HS-induced gut microbiota dysbiosis was significantly restored by CGA supplementation. The findings indicated that dietary 800 mg/kg CGA supplementation effectively safeguarded intestinal health in rabbits under high temperatures.