Bioprospecting of bacteriocin-producing bacteria: from culture optimization to the application in animal production systems

Abstract

The use of probiotic microorganisms in the prevention and treatment of bacterial infections in animals intended for human consumption has been considered an efficient alternative to the use of antibiotics. In addition, recent studies have shown that certain substances produced by these microorganisms, such as bacteriocins, vitamins, fatty acids, exopolysaccharides, enzymes, among others, improve the immunity and development of their hosts. The most commonly used probiotic microorganisms in the food and pharmaceutical industries are those belonging to the lactic acid bacteria group (LAB), since they are considered safe by regulatory agencies in this area. However, it is known that the beneficial effects generated by probiotics are specific to each host and, frequently, the compounds of interest are synthesized in greater quantities by a given bacterial strain. The main objective of the present study is the isolation and identification of probiotic LAB present in the intestinal microbiota of poultry, swine and fish species. Strains with high capacity to produce bacteriocins will be selected. From this selection, compatibility tests will be carried out among the strains and, later, a mix of probiotics will be prepared. The strains that compose it will be individually micro-encapsulated and administered daily in the animals diet, through feed and water, in order to ascertain the probiotic effectiveness of the mixture. Synthetic bacteriocins will also be micro-encapsulated and administered to understand their individual effect on animals health. The results obtained with microcapsules will be compared with those obtained in the same biosystems in free form. In addition, we will carry out immunological studies, electron microscopy tests and analysis of the intestinal microbiota diversity of animals. (AU)