Lactic acid bacteria with probiotic potential from Nellore calves raised in semiarid

Résumé

Colibacilosis is one of the major diseases of calves, causing huge losses. The aim in this study was to characterize and select lactic bacteria with probiotic potential from Nellore calves raised in northern Minas Gerais. Stool samples from six healthy calves were collected, with three days old and again at three months of age. After isolation, bacteria were enumerated and submitted to morphological and biochemical characterization with API 50 CH test, pH and acid resistance to bile salts and antagonist activity in vitro for three strains of Escherichia coli. The population of lactic acid bacteria was greater (p < 0.05) in feces of the calves at colostrum phase. For resistance to chloric acid, 92.3% of isolates from newborn calves resisted pH 4.0, presenting higher resistance than the isolates from calves at three months of age. In the antagonism test, the isolates Be4 1m, Be1 2b and Be6 2a were presumptively identified as Lactobacillus salivarius, L. crispatus and L. pentosus, respectively, and produced average inhibition zones greater than 10 mm of diameter and showed resistance acid pH and bile salts, indicating potential probiotics.