Astragalus polysaccharides mitigate heat stress and enhance rabbit does fertility and growth of kits via the gut–short chain fatty acids axis

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The aim of this study was to investigate the effects of dietary Astragalus polysaccharides (APS) on reproductive performance, gut microbiota, short-chain fatty acids (SCFAs) of reproducing does, and growth of sucking rabbits (kits) under heat stress conditions. A total of 460 Hyla rabbit does with similar body weight and parity were randomly assigned to five dietary treatments. Rabbits received a basal diet supplemented with 0 (Control group), 200 (APS200 group), 400 (APS400 group), 800 (APS800 group), and 1000 (APS1000 group) mg/kg APS, respectively. The temperature-humidity index (THI) was documented during the trial period. For this, reproductive performance, concentrations of hormones and cytokines in plasma, as well as gut microbiota and SCFAs in feces, were determined. Whereas growth performance was monitored for kits. Results showed that ratios of extreme heat stress, severe heat stress, and moderate heat stress were 50%, 26.67%, and 3.33%, respectively. Rabbits fed diets supplemented with 400 and 800 mg/kg APS had higher pregnancy rate, farrowing rate, and litter weight as well as average weight of kits at weaning, when compared with the control group ( P < 0.05). Moreover, the concentration of interleukin-6 (IL-6) was lower, and the concentration of interleukin-10 (IL-10) was higher in the APS400 group and the APS800 group when compared with the control group. Furthermore, concentrations of progestogens (P4) and estradiol (E2) in plasma were enhanced by 200 or 400 mg/kg APS supplementation ( P < 0.05). In addition, APS supplementation enhanced the relative abundance of Rikenellaceae_rc9_gut_group , Cyanobacteria, Candidatus_Saccharimonas , Alistipes , and Akkermansia , as well as production of caproate, heptanoate, caprate ( P < 0.05). Of note, correlation analysis indicated that Colidextribacter and Monoglobus displayed a strong positive correlation with acetate, butyrate, and propionate. In conclusion, dietary APS supplementation exerts beneficial effects on the growth of kits and the reproductive performance of rabbit does by modulating gut microbiota composition and SCFAs production.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.