EFFECT OF A CONSORTIUM OF PATAGONIC PROBIOTIC BACTERIA ON THE CULTIVABLE INTESTINAL MICROBIOTA OF TILAPIA (Oreochromis niloticus)

DEL FRESNO, PAMELA S.; SARRÁ, NICOLÁS.; MORIS, MARIANO.; PALACIOS, MARÍA GABRIELA.; SUEIRO, MARIA CRUZ,; SEQUEIROS, CYNTHIA.

Puerto Madryn, Chubut.

Congreso; XX Congreso de la Sociedad Argentina de Microbiología General 21 años explorando lo invisible, acercando el futuro; 2025

CENPAT-CONICET

Tilapia is one of the main freshwater farmed fish worldwide. Its production has quadrupled in the last decade, which has driven intensive farming and, consequently, recurrent bacterial diseases. In the aquaculture sector, the use of probiotics as a natural and environmentally compatible tool has become a common practice. With the aim of evaluating the probiotic effect of native bacteria from Patagonia on a commercially valuable fish, the cultivable intestinal microbiota of tilapia fed with and without probiotics was assessed. The probiotics used were: Carnobacterium sp. T4 and Lactiplantibacillus pentosus H16. The trials included two independent aquaculture recirculation systems, one for the probiotic treatment (commercial feed inoculated with 1x10^7 CFU/g of feed) and the other for the control (commercial feed inoculated with PBS buffer only). Each system was composed of 3 glass aquariums, a mechanical filter, a six bucket settling train, a biological filter, a submersible pump, aerators, and a water heater. The fish were fed for a week. The counts of total heterotrophic bacteria, lactic acid bacteria (LAB), enterobacteria, and vibrios were quantified on plates to evaluate the cultivable intestinal microbiota at the end of the experiment. The abundance of probiotic strains was indirectly monitored using the double-layer technique due to their antimicrobial activity against opportunistic pathogens. A significant decrease in the total heterotrophic bacteria count was detected in the intestines of tilapia fed with the probiotic consortium (1.79 x105 CFU/g of intestine, p