Abstract

Probiotic-fermented Chinese herbal medicine has been shown to stimulate immunity and modulate gut microbiota. It has been considered to be an ideal alternative to antibiotics in a variety of species. In this study, Clostridium butyricum was used as a fermentation strain, while a mixture of licorice root, Astragalus membranaceus and Acanthopanax senticosus was used as a substrate for solid-state fermentation. The fermented product (F-CHM) was mixed with basic feed at levels of 0 (NC), 5% (S-5%), 10% (S-10%) and 20% (S-20%) to feed largemouth bass for 56-day. The results showed that no significant effect of F-CHM was observed on weight gain, but the resistance to A.hydrophila infection was improved. The activity of alkaline phosphatase and lysozyme in plasma was increased with F-CHM addition, and the content of malondialdehyde was significantly decreased. In the spleen, a higher expression of the inflammatory factor TGF-β and apoptosis related genes (Caspase-3 and p53) was detected after the addition of F-CHM. With the addition of F-CHM, the midgut villus height of largemouth bass was significantly increased, and the expression of the intestinal barrier related genes, ZO-1 and Claudin-4 was upregulated. Furthermore, the concentration of short-chain fatty acids was increased in the S-20% F-CHM addition group. Sequencing results showed that the intestinal flora abundance and diversity were dramatically increased in the S-10% group. In addition, the development of harmful bacteria was restrained, and the colonization of beneficial flora was increased. Collectively, dietary F-CHM can be applied as a largemouth bass feed supplement to enhance fish immunity, regulate the intestinal flora and improve the ability of the host to protect against pathogenic bacteria.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call