Molecular microbial analysis of Lactobacillus strains isolated from the gut of calves for potential probiotic use

SOTO, L.P.; FRIZZO, L.S.; BERTOZZI, E.; AVATANEO, E.; SEQUEIRA, G.J.; ROSMINI, M.R.

VETERINARY MEDICINE INTERNATIONAL

SAGE-Hindawi

Año: 2009 p. 1 - 7

2042-0048

The intestinal microbiota has an influence on the growth and health status of the hosts, generating non-specific resistance against infectious diseases. This is of particular interest in animals reared using intensive farming practices. Hence, it is necessary to know more about the complexity of the beneficial intestinal microbiota and develop tools that enable the distinction between the different relevant autochthonous bacteria and the members of the probiotic inoculum. The use of molecular methods has revolutionised microbial identification by improving its quality and effectiveness. This study is part of a work that seeks to identify native strains with probiotic properties to form inocula for young calves. The specific aim of the study was to analyze the predominant species of Lactobacillus in the intestinal microbial ecosystem of young calves. Forty-two lactic acid bacteria (LAB) isolated from the intestinal tract of young calves were characterised by: Amplified Ribosomal DNA Restriction Analysis (ARDRA), by using Hae III, Msp I, and Hinf I restriction enzymes, and 16S rDNA gene sequencing. ARDRA screening revealed nine unique patterns among 42 isolates, with the same pattern for 29 of the isolates. Gene fragments of 16S rDNA of 19 strains representing different patterns were sequenced to confirm the identification of these species. The data obtained from this technique confirmed that ARDRA is a good tool for identification and discrimination of bacterial species isolated from a complex ecosystem and between closely related groups. This paper provides information about the LAB species predominant in the intestinal tract of young calves that could provide beneficial effects when administered as part of a probiotic inoculum.