Aplicación de bacterias con potencial probiótico aisladas de camarones silvestres litopenaeus vannamei como una medida profiláctica para controlar la vibriosis

Abstract

Shrimp farming has increased on a large scale in recent years. Due to intensification, farming systems have been affected by bacterial problems, causing economic losses. In order to counteract these problems, wrong measures have been taken using exaggerated amounts of antibiotics causing resistance in pathogenic bacteria. Due to all these problems, the use of probiotics is chosen as a prophylactic measure, thus achieving sustainable and sustainable aquaculture. These probiotics are live microbial supplements that benefit the host and the environment. The main pathogenic bacteria that cause great mortality in larvae culture and in fattening pools are Vibrios sp. These extracellular bacteria are distributed in the water and the pool mud has the peculiarity of spreading rapidly during the first six hours in the shrimp. In this disease known as vibriosis, the pathogen enters through the gills, orally, colonize the entire intestine, then infect the other organs and tissues causing damage to the hepatopancreas, antenal gland, lymphoid organ, hemolymph and muscle tissue . Due to this, bacterial attacks must be controlled and this is achieved thanks to the mechanisms of action that probiotic bacteria have. These can be by competitive exclusion either by adhesion sites or by nutrients. Another mechanism is to interrupt the Quorum sensing. In addition, certain probiotics have bactericidal and bacteriostatic effects, are capable of producing different inhibitor compounds, organic acids, hydrogen peroxide, and even form biofilms and release auto-inductors preventing pathogenic bacteria from adhering to the intestinal mucosa. Preferably it is much better to use mixtures of probiotic strains with amounts greater than 108, achieving multiple benefits, the immune system is increased, better growth and greater survival in culture organisms is achieved, and water quality is improved by reducing the levels of Ammonia and nitrite. This work demonstrates the multiple benefits that can be obtained through the use of native bacteria as a prophylactic measure in culture systems. These native bacteria were isolated from the hepatopancreas and the intestine of wild shrimp separately, managing to isolate 10 different strains. Also, they were differentiated by their color and size, subsequent inhibition tests were performed in vitro and in vivo against Vibrios sp. In the first test performed, the two strains showed a halo of inhibition and those strains were frozen at -80 ° C. After, another test performed viability tests of frozen strains, gram stain, and finally in vivo tests with Litopenaeus vannamei shrimp postlarvae, to evaluate the protective effect of probiotic bacteria. Here, a mixture of the two bacterias and supernatants was used. Before performing the tests in vivo, safety tests were performed using a concentration of 10˄7 of this bacterium. The test was performed with post larvae of 180 per gram, in a total of 50 in a liter of treated seawater. At the end of the challenge tests, the data obtained were taken to the Anova program showing that there is a significant statistical difference between the treatments based based on the survival of the shrimp larvae, which suggests that these strains together with the extracellular products could be used to control vibriosis.