Characterization of Lactic Acid Bacteria Isolated from the Gastrointestinal Tract of Sea Bream (Sparus aurata) from Tunisia Aquaculture

Lactic acid bacteria are known mainly for their many metabolites still poorly explored, especially in Tunisian. The main aim of this study was to study the bioactive potential of lactic acid bacteria in the marine environment, especially for farmed sea bream (Sparus aurata) having undergone a diet enriched in lipids. Context/Purpose: Lactic bacteria are known mainly for their many metabolites still poorly explored, especially in Tunisian. Thus, in this study, we aimed to characterize the bioactive products of this bacterial group isolated from farmed fish, which is sea bream (S. aurata) having undergone different diets to characterize their bioactive potential and their future recovery. Methods: Twenty-six lactic acid bacteria were tested for their bioactive potential by morphological tests, biochemical tests (respiratory appearance, metabolic aspect, enzymatic appearance), and physiological tests. Antimicrobial susceptibility was performed by disk diffusion, and the identification was performed by sequencing of 16S rDNA. Results: The isolates were identified as Lactiplantibacillus plantarum, levilactobacillus brevis, Lactiplantibacillus pentosus, Lactococcus lactis, and Pediococcus spp. whereas 92% were multidrug-resistant. Interpretation: Levilactobacillus brevis, Lactiplantibacillus pentosus, and Pediococcus spp. presented a high potential for antagonistic activity, and no enzyme activity was observed among the isolates. Conclusion:Dietary lipid supplementation increases the antagonistic activity and favored the growth of the microflora.