Probiotic supplementation is a promising strategy to enhance fish health and growth, but its application in aquaculture remains limited by viability challenges and short shelf life. In this study, carbohydrate ingredients [corn meal, corn germ, wheat midds, inulin, and yellow field peas (YFP)] with potential prebiotic-like properties were evaluated for their ability to support the growth of a host-associated probiotic strain, Lactococcus lactis MA5. The catfish pathogenic bacterium, Edwardsiella ictaluri S97-773, the causative agent of enteric septicemia of catfish, was treated in vitro with both MA5 cells and MA5 cultured supernatants fermented with prebiotic candidates. Results suggested that YFP and wheat midds best supported MA5 proliferation and fermentation in culture media. Moreover, MA5 metabolites fermented with YFP significantly downregulated the expression of E. ictaluri virulence-related genes (eihA, eihB, and luxS) after 3h incubation, suggesting attenuation of pathogenicity. A 21-day feeding trial was conducted to investigate synbiotic interaction between selected prebiotic-like ingredients and MA5. A total of 1,080 hybrid catfish juveniles were equally distributed in 36 tanks (30 fish/tank) operating as a flow-through system, supplied with pond water. Half of the tanks were offered MA5-coated control diets (wheat midds + MA5) for seven days prior to 14 days of potential prebiotic diets (wheat midds, corn, or YFP). Meanwhile, the other half were fed the control diet without MA5 during the same period, before 14 days of the potential prebiotic diets. Twenty hours after feeding the fish to apparent satiation, digesta samples were collected on days 0, 7, 14, and 21. The change in intestinal microbiota was assessed using AVITI sequencing, to target the V3-4 region of 16S DNA. Lactococcus spp. relative abundance was not significant in both interactions between time × probiotic and probiotic × prebiotics. Results suggested that MA5 may require a longer administration time and did not significantly increase the Lactococcus genus after offering the experimental diets. In conclusion, wheat midds and YFP increase MA5 proliferation in modified culture media, and the latter attenuated the virulence of E. ictaluri in vitro. Symbiotic effects of MA5 and these ingredients remain to be validated for hybrid catfish in feeding trials.