EFFECT OF PROTEIN SOURCE AND PROBIOTIC ON THE INTESTINAL TRACT OF PACIFIC WHITE SHRIMP Litopenaeus vannamei

This study aimed to evaluate the viability of supplementing two diets for the shrimp Litopenaeus vannamei with Lactobacillus plantarum. One using fish meal as a protein source and another using soy protein concentrate, as well as the effect of these formulations on shrimp intestinal microbiota. To assay probiotic viability in the formulated diets, the number of CPU g(-1) was observed weekly over the course of four weeks. The viability of Lactobacillus plantarum in relation to the physical parameters of the diets, including stability, buoyancy, and expansion, was quantified. The effect of the diets on microbiota and intestinal tract morphology was determined by performing a 2x2 factorial experiment (two diets, with or without supplementation) in triplicate, totaling 12 experimental units, with five animals per unit, fed with 3.5% of biomass for 17 days. The concentration of lactic acid bacteria decreased over time, irrespective of protein source. The diet with fishmeal as a protein source, independent of probiotic supplementation, presented good stability and did not disintegrate after four hours. In contrast, the diet with soy protein concentrate, supplemented or not, disintegrated between 2.5 and 3 hours, presenting low stability. All diets presented 0% buoyancy. The expansion rate was higher in diets with soy protein concentrate, but without the influence probiotic supplementation or interaction between the factors. In the in vivo assay, both supplemented diets showed greater total heterotrophic bacteria count than without probiotic; however, no difference in count was noted in diets with different protein source. Lactic acid bacteria were only observed in the shrimp fed diets supplemented with probiotic. Histology of the intestinal tract showed that all intestines had intact, well-developed and well-organized cells, irrespective of diet. Thus, L. plantarum, when combined with different protein sources, produced similar effects on the structure and microbiota of the marine shrimp Litopenaeus vannamei.