Page 186 - 《水产学报》2026年第2期

2 期 水 产 学 报 50 卷

Effects of selenium-enriched Enterococcus faecalis on growth performance,
gut microbiota homeostasis, and disease resistance in
largemouth bass (Micropterus salmoides)

1
1
2*
1
ZHANG Yun 1,2,3 , YU Penghui , SU Lei , SU Jianguo , GAO Yu , YUAN Gailing 1*
(1. College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China;
2. Faculty of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China;
3. Jiangxi Aquatic Biology Protection and Rescue Center, Nanchang 330029, China)

Abstract: To investigate the effects of selenium-enriched Enterococcus faecalis (EFSe) on growth performance, antioxidant
capacity and disease resistance in largemouth bass (Micropterus salmoides). E. faecalis MSEF22 was isolated from intestinal
tract of healthy largemouth bass and enriched with sodium selenite to obtain EFSe. Three groups were designed: control (basal
7
7
diet), EF (basal diet + 1×10 CFU/g E. faecalis MSEF22), and EFSe (basal diet + 1×10 CFU/g EFSe, 0.76 mg Se/kg). After 42-
day feeding, growth indices, hepatic antioxidant enzymes and intestinal microbiota were analyzed. Disease resistance was eval-
uated by 14-day challenge with Nocardia seriolae. EFSe group showed significantly higher WGR, hepatic SOD activity and
GSH content than control (P<0.05), while serum AST activity decreased markedly. Compared with EF group, EFSe signific-
antly increased gut microbial diversity and abundance of beneficial bacteria (e.g. Lactobacillus spp.). Post-challenge survival
rate in EFSe group (52.22%) was higher than EF (50.00%) and control groups (43.33%), with reduced hepatic nodules and
downregulated mRNA expression of pro-inflammatory cytokines IL-1β (-76%) and TNF-α (-23%) (P<0.05). Dietary supple-
mentation with EFSe enhances growth performance, antioxidant capacity, and disease resistance in largemouth bass, demon-
strating significant potential for eco-efficient and sustainable aquaculture.
Key words: Micropterus salmoides; Enterococcus faecalis; selenium-enriched; sarcoidosis; Nocardia seriolae

Corresponding authors: GAO Yu. E-mail: gaoyu@ynau.edu.cn;
YUAN Gailing. E-mail: yuangailing@mail.hzau.edu.cn
Funding projects: National Key Research and Development Program of China (2024YFE0112200); Young Talent Project of
the “Xing Dian Talent Support Program” of Yunnan Province in 2022

https://www.china-fishery.cn 中国水产学会主办 sponsored by China Society of Fisheries
14