Utilización de cepas de Bacteroides spp. como probiótico en conejos

Abstract

The metaphylactic use of antimicrobials to maintain the health of animals in food production farms can be problematic in the near future, due to the high rate of resistances observed. This situation forces to looking for alternative measures, the most common based on the use of prebiotics, probiotics or a combination of both (symbiotic). _x000D_ The main objective of this work was to select strains of different species of the Bacteroides genus that could be used as probiotic in rabbits. _x000D_ Bacteroides genus is one of the main components of the mammalian intestinal microbiota (1011 CFU/g feces, in humans). These bacteria degrade complex molecules, especially carbohydrates, and play an important role in the control of the colonization of the digestive tract by pathogens; but, in some cases, they can act as opportunistic pathogens. Furthermore, they are involved in the maturation of the immune system associated with intestinal mucosa. _x000D_ The Bacteroides spp. could have probiotic activity in two different ways: producing inhibitory substances against other components of intestinal microbiota (bacteriocins, secondary metabolites…) or stimulating the immune system, increasing the nonspecific defenses of host (immune-modulators). _x000D_ Using the collection of Bacteroides spp. of CReSA, in this work different in vitro studies were conducted to select strains, looking for the absence of negative characteristics and the presence of positive characteristics, to be used for the in vivo studies on rabbits during the lactation period and to analyze their role as probiotic. _x000D_ The presence of resistances against antimicrobials, especially when transferable markers were present, was the most restrictive characteristic for the selection of the strains that were analyzed in vivo. _x000D_ After the selection of four strains, the in vivo study on a commercial farm was conducted, examining the effect on the intestinal microbiota and on different immune parameters. By the analysis of the obtained results can be inferred that some of the tested strains may be candidates for the development of probiotics for rabbit.

Date of Award	28 Oct 2014
Original language	Spanish
Supervisor	Ignacio Badiola Saiz (Director)