The probiotic effects of host-associated Bacillus velezensis in diets for hybrid yellow catfish (Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂)

Zhehui Ji; Xing Lu; Mingyang Xue; Yuding Fan; Juan Tian; Lixue Dong; Chuanzhong Zhu; Hua Wen; Ming Jiang

doi:10.1016/j.aninu.2023.08.004

The probiotic effects of host-associated Bacillus velezensis in diets for hybrid yellow catfish (Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂)

Anim Nutr. 2023 Aug 22:15:114-125. doi: 10.1016/j.aninu.2023.08.004. eCollection 2023 Dec.

Authors

Zhehui Ji^{1

2}, Xing Lu², Mingyang Xue², Yuding Fan², Juan Tian², Lixue Dong², Chuanzhong Zhu³, Hua Wen², Ming Jiang²

Affiliations

¹ College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China.
² Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, China.
³ Fujian Key Laboratory of Functional Aquafeed and Culture Environment Control, Fujian DBN-HY Aquatic Science and Technology Group Co., Ltd, Zhao'an, China.

Abstract

This study was to evaluate the potential of a host-associated Bacillus velezensis as a probiotic for hybrid yellow catfish (Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂). Diets (B0 to B5) containing 0, 0.90 × 10⁸, 0.80 × 10⁹, 0.85 × 10¹⁰, 0.90 × 10¹¹, 0.83 × 10¹² CFU/kg B. velezensis YFI-E109 were fed to the fish with initial weight (3.07 ± 0.08 g) in a recirculating aquaculture system for six weeks with three replicates, respectively. Probiotic effects were analyzed based on growth, body composition, liver and gut morphology, gut microbiome, and liver metabolome. Analysis of the bacterial genome has shown that the most abundant genes in B. velezensis YFI-E109 were distributed in carbohydrate and amino acid metabolism. Fish in groups B3 and B4 had better growth performance, and higher intestinal amylase (AMS) and lipase (LPS) activities compared with other groups (P < 0.05). Fish in groups B0 and B5 showed significant liver damage, while this status improved in group B3. The liver malondialdehyde (MDA) content in group B3 was lower than that in other groups (P < 0.05). The abundance of Mycoplasma, Ralstonia and Acinetobacter was significantly reduced in B3 and B5 compared to B0. The amino acid and carbohydrate metabolism pathways were enriched in group B3 compared with group B0. In conclusion, dietary B. velezensis YFI-E109 supplementation has the potential to improve growth, liver metabolism, and liver and gut health, and reshape the gut microbiome of hybrid yellow catfish. Excessive B. velezensis YFI-E109 reduced the prebiotic effects. The recommended dietary supplementation of B. velezensis YFI-E109 is 0.31 × 10¹⁰ to 0.77 × 10¹¹ CFU/kg for hybrid yellow catfish according to the quadratic regression method by plotting specific growth rate (SGR), feed conversion ratio (FCR), MDA and activities of AMS against dietary B. velezensis YFI-E109 levels.

Keywords: Bacillus velezensis; Hybrid yellow catfish; Intestinal health; Liver metabolome; Probiotics.