Beneficial properties of lactic acid bacteria isolated from young calves

NATALIA CECILIA MALDONADO; MARIA CLAUDIA OTERO; FERNANDO SESMA; MARIA ELENA NADER-MACIAS

Journal of Dairy Research

Cambridge

Lugar: Londres; Año: 2008

Lactic acid bacteria are the dominant microorganisms in different human and animal’s tracts. They protect the host from the income of pathogenic microorganisms by different mechanisms. They have been widely used as probiotics to restore the ecological balance of different ecosystems, and also to help in the physiological functions of the host. Newborn calves are very susceptible to diarrhoea, mainly because they do not receive antibodies from their mother during pregnancy. Then, the isolation of 96 strains of lactic acid bacteria from faeces, oral cavity and colostrum of newborn calves was performed in this work, studying some beneficial properties. Most of the strains were identified as bacilli, and a lower number as cocci, from all the areas of isolation. The surface properties of the isolated strain showed that they do not present hydrophobic characteristics, but some of them were able to autoagglutinate, which would help to form the protective biofilm. Small amount of strains produced H202, but some others were able to inhibit pathogens responsible of diarrhoea by organic acid production. Only one bacteriocin-producer strain was detected. The functional properties assayed showed that some strains were able to grow at very lows pH and high bile salts concentrations, which make these strains potentially useful to be used as probiotics for the prevention of diarrhoea, combined with those selected from the healthy vaginal tract of adult cows The strains sharing some beneficial properties were identified by genetic methodologies, to go further in the selection of a lower number of strains with probiotic characteristics, and later to test their efficacy through in vivo assays. The main objective of our research group is the design of a specie-specific product for newborn calves.