Background: Microbial exopolysaccharides (EPSs) are effective prebiotics produced by microorganisms with diverse functional groups. These compounds are biodegradable, safe, and cost-effective, playing a significant role in enhancing host health and immune performance. Exopolysaccharides (EPSs) are secreted outside cell wall during bacterial growth and are composed of glycosidic linkages that form natural macromolecular polymers. Recent studies show that EPSs from LAB are effective stimulants for boosting fish development and defensive systems.
Objectives: This study aimed to evaluate the effects of exopolysaccharide derived from Lactobacillus plantarum (LP-EPS) on growth performance, immune parameters, antioxidant enzyme activities, gut microbiota composition, and short-chain fatty acid (SCFA) levels in Asian seabass (Lates calcarifer).
Methods: Fish were randomly divided into four groups: control (no EPS), treatment 1 (200 mg/kg EPS), treatment 2 (400 mg/kg EPS), and treatment 3 (800 mg/kg EPS). After 60 days of feeding, samples were collected to assess intestinal enzymatic activity, microbial composition, SCFAs content, immune indices, and antioxidant enzyme activities.
Results: The results showed that dietary LP-EPS supplementation significantly enhanced intestinal immune and antioxidant enzyme activities compared to the control group. In addition, the abundance of pathogenic bacteria in the gut was reduced, and the microbial composition was positively modulated. Five microbial Phylum were identified: Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Fusobacteriota, with Firmicutes being the most dominant.
Conclusions: The findings suggest that LP-EPS can serve as an effective dietary supplement to improve growth performance, enhance immune responses, and modulate intestinal health in Asian seabass. Therefore, LP-EPS has promising potential as a functional feed additive in aquaculture for promoting fish health and productivity.