Effect of dietary honeysuckle (Lonicera caerulea L.) supplementation on lipid metabolism, immunity and intestinal microbiota in grass carp (Ctenopharyngodon idellus)

To assess the role of honeysuckle in teleost, this study evaluated the effects of dietary honeysuckle extract on grass carp (Ctenopharyngodon idella). The results indicated that dietary HE supplementation: (1) increased the microvillus length and muscular thickness of the intestinal epithelium; (2) enhanced the mRNA expression of claudin-c and occludin; (3) downregulated expression of ACC1, FAS, SREBP-1 and upregulated expression of CPT1, ATGL, HSL, LPL, PPAR-alpha, FXR in the intestinal tissue; (4) downregulated the mRNA level of NF-kappa B p65, TNF-alpha, IL1 beta and IL-8 and upregulated the mRNA level of I kappa B-alpha, IL-10; (5) increased the activities of AKP, ACP, T-AOC and trypsin and lipase in the intestine but decreased the MDA content; (6) significantly increased the abundances of Firmicutes at the phylum level and Lactobacillus and Fructobacillus at the genus level, but decreased the abundances of Bacteroidetes at the phylum level and Cetobacterium and Aeromonas at genus level; (7) increased the levels of SCFAs. In conclusion, the results of this study indicated that dietary supplementation with HE at an appropriate dose could strengthen the intestinal mucosal barrier, improve lipid metabolism and immunity, and reshape the intestinal microbiota of grass carp.