Drinking Warm Water Improves Growth Performance and Optimizes the Gut Microbiota in Early Postweaning Rabbits during Winter

SIMPLE SUMMARY: Epidemiological investigations have revealed that cold temperature can increase the risk of diarrhea in children, and similar observations have been made in early postweaning livestock. Recent studies have shown that cold temperature alters the gut microbiota, which may be associated with the pathogenesis of various intestinal diseases, such as inflammatory bowel diseases. However, few studies have focused on how to improve intestinal health from the perspective of the gut microbiota in early postweaning livestock during winter. In the present study, using early postweaning rabbits as a model, we analyzed the effects of drinking warm water (WW) on the growth performance and gut microbiota structure of postweaning rabbits during winter. Our results confirmed that drinking WW improved the growth performance and optimized gut microbiota in early postweaning rabbits during winter. Therefore, our results provide a new perspective for improving early postweaning rabbits welfare during winter. ABSTRACT: Accumulating evidence indicates that cold exposure changes the composition of the gut microbiota and reduces intestinal immunity in early postweaning livestock. However, little is known about the effects of drinking warm water (WW) on gut microbiota during winter. In this study, we investigated the effects of drinking WW in winter on the growth performance and gut microbiota structure of rabbits raised in poorly insulated housing from the early postweaning period (day 46) to the subadult period (day 82). The average daily gain and feed conversion ratio in rabbits drinking WW were significantly improved compared to those of the rabbits drinking cold water (CW) during 47–58 days. In addition, rabbits drinking WW had a significantly decreased the risk of diarrhea during 71–82 days. 16S rRNA sequence analysis revealed that the alpha diversity of the cecal microbiota was not significantly different between the WW and CW groups, but significantly increased with age. The relative abundance of cecal microorganisms, such as Coprococcus spp. was considerably increased at day 70 in the group drinking WW. Correlation analysis indicated that Coprococcus spp. was negatively associated with pro-inflammatory factors. In conclusion, our results suggest that drinking WW has a positive effect on growth performance and gut microbiota in rabbits during the early postweaning stage in winter.