This study compared the effects of dietary Lactobacillus plantarum (Lpl) and selenium-enriched L. plantarum (Lplₛe) on the growth, hepatic antioxidant capacity, and intestinal microbiota of juvenile largemouth bass (initial weight 12. 50 ± 0. 81 g). Following a 58-day trial in an indoor rearing system, data were analyzed using one-way ANOVA followed by Tukey’s HSD test. Results showed that both Lpl and Lplₛe significantly improved growth versus the control (Weight Gain Rate: 379. 82% and 387. 18% vs. 326. 56%; p < 0. 05). Both supplements significantly elevated hepatic antioxidant enzymes (SOD, CAT, GSH) and reduced malondialdehyde (MDA) levels (p < 0. 05). Notably, these macroscopic parameters showed no statistical differences between the two probiotic treatments. However, 16S rRNA sequencing revealed distinct metabolic strategies. While both treatments enriched intestinal Lactobacillus, Lplₛe uniquely upregulated energy-harvesting and synthetic pathways (glycolysis and lysine biosynthesis), corroborated by increased intestinal glycogen synthase activity. In conclusion, while selenium enrichment did not further improve macroscopic growth statistically, it differentially modulated the intestinal functional profile towards enhanced carbohydrate and amino acid metabolism, presenting an alternative host nutrient assimilation strategy.
Ruan et al. (Sat,) studied this question.