In vitro screening of lactic acid bacteria isolated from gastrointestinal tract of Atlantic salmon (Salmo salar) as probiont candidates

A total of 20 lactic acid bacteria (LAB) were isolated from the gastrointestinal tracts of Atlantic salmon (Salmo salar) and screened for antimicrobial activity against six fish pathogens using either a microtiter plate assay or a well diffusion assay. The results indicated that three LAB exhibited antimicrobial activity against at least two pathogens. Based on their partial 16S ribosomal deoxyribonucleic acid (16S rDNA) sequences, these isolates were identified as Lactobacillus farraginis, Pediococcus acidilactici, and P. pentosaceus. In addition, these LAB were able to tolerate the simulated gastrointestinal tract conditions (stomach and intestine), had a good adhesion capacity to intestinal mucus as well as were able to grow in intestinal mucus of Atlantic salmon. These results suggest that these LAB are potential probionts in aquaculture. However, further studies are required to evaluate probiotic properties in aquatic animals.