Fishes, Vol. 9, Pages 157: Mechanism of Ligilactobacillus salivarius GX118 in Regulating the Growth of Rainbow Trout (Oncorhynchus mykiss) and Resistance to Aeromonas salmonicida Infection

Fishes, Vol. 9, Pages 157: Mechanism of Ligilactobacillus salivarius GX118 in Regulating the Growth of Rainbow Trout (Oncorhynchus mykiss) and Resistance to Aeromonas salmonicida Infection

Fishes doi: 10.3390/fishes9050157

Authors: Xiyu Cao Bowen Wang Wenhao Ren Jiang Wang Qi Liu Yichao Ren Xianliang Meng

Lactic acid bacteria Ligilactobacillus salivarius has been shown to be a substitute for antibiotics in the treatment of bacterial disease in high animals. However, its beneficial mechanism in fish farming is still unclear. This study evaluated the antagonistic effects of the Ligilactobacillus salivarius GX118 strain on Aeromonas salmonicida and its regulation of rainbow trout growth in vivo and in vitro. The results found that GX118 produces an antibacterial substance that can directly destroy the cell wall of A. salmonicida. Whole-genome sequencing of GX118 revealed that Enterolysin A is a type III bacteriocin with antibacterial properties. An in vivo experiment showed that the supplementation of GX118 in diet competitively inhibited the colonization of A. salmonicida in the intestine. In addition, it was able to improve the growth performance of rainbow trout within a 21-day feeding experiment. The supplementation of GX118 increased the diversity of gut microbiota, in which the abundance of Bacteroidota, Blautia, and Rhodobacteraceae increased. In addition, the use of GX118 activated the expression of IFN-γ and NF-κB genes and reduced the expression level of IL-6 and IL-8, thus exhibiting a certain effect on activating the immunity of rainbow trout. This study provides a scientific basis for the development of antibacterial probiotics in the healthy farming of rainbow trout.