The versatility of Bacillus tequilensis Bt-CO as an additive: Antagonizing pathogens, enhancing immunity, promoting intestinal health, and optimizing gut microbiota of tilapia

作者：Xiaoyuan Ge, Jintao Pan, Kunlian Mo, Hongsong Chen, Jingran Sun, Huiqin Huang, Yanjiao Zhang, Kangsen Mai, Hanjie Gu, Yonghua Hu · 发表于：Animal nutrition · 年份：2025 · DOI：10.1016/j.aninu.2025.07.001 · 被引用次数：8 · 研究领域：Aquaculture disease management and microbiota、Aquaculture Nutrition and Growth、Aquatic life and conservation

Probiotics are gaining increasing attention as potential alternatives to antibiotics for enhancing the health and welfare of aquatic organisms. However, identifying and developing highly effective probiotic strains with superior intestinal colonization and antagonistic properties remains a significant challenge. This study identified a strain of Bacillus tequilensis , designated as Bt-CO, from coral in a tropical marine environment. Following an in vitro assessment of its antimicrobial activity and colonization properties, the potential of Bt-CO as an antibiotic alternative was evaluated through in vivo trials. A total of 720 fish (initial body weight 2.06 ± 0.01 g) were randomly distributed across four dietary treatments in triplicates, consisting of a basal diet (CON group), and the diet supplemented with 1 × 10 7 (T1 group), 1 × 10 8 (T2 group), or 1 × 10 9 colony-forming unit (CFU)/g (T3 group) of Bt-CO. After a feeding period of 4 weeks, fish were sampled or challenged with Aeromonas hydrophila . For the challenge, 30 fish in each tank were intramuscularly injected with 50 μL of A. hydrophila at a concentration of 5 × 10 6 CFU/mL. Tilapia survival was monitored for 20 d post-infection. The results demonstrated that Bt-CO possessed pronounced antagonistic effects against several important pathogenic bacteria affecting tilapia, particularly A . hydrophila . Bt-CO also demonstrated excellent physiological characteristics, including auto-aggregation. adhesion, and biofilm fo...