Bactérias láticas com potencial probiótico provenientes de bezerrosnelore criados no norte de Minas Gerais

Abstract

Colibacillosis is one of the main causes of neonatal diarrhea in calves. The administration of probiotics represents a promising alternative to the treatment with anti-bacterial medication that can compromise the calves digestive tract. The objective of this research was to characterize and select strains of lactic bacteria with probiotic potential from Nellore calves in Northern Minas Gerais. Fecal samples were collected from six healthy suckling subjects, aged three to ten days and from those same subjects at three months. After isolation and quantification of the bacteria, a morphological and biochemical characterization was done using the API 50 CH test, resistance to acid pH and bile salts and in vitro antagonistic ability to three strains of Escherichia coli. A significantly higher (p< 0,05) population of lactic bacteria was verified in the calves feces in the colostral phase. Regarding resistance to hydrochloric acid, 92.3% of neonatal calves isolates resisted to pH 4.0. That is a significantly higher rate than the one observed on three-month-old calves. In the maximum bile salts concentration of 1%, 92.3 and 84.6% of new-born and three-month-old calves respectively, resisted and presented growth. On the test for antagonism to Escherichia coli strains, the isolates Be4 1m, Be1 2b and Be6 2a respectively identified as Lactobacillus salivarius, L. crispatus and L. pentosus produced an inhibition halo. Specifically, the L. salivarius isolate presented an inhibition halo of 20mm in diameter against the Escherichia coli from the small intestine of a two-month male calf with diarrhea. The same Lactobacillus spp. isolates presented better resistance to acid pH and bile salts, indicating potential for being rated as probiotics.