SAGE-Hindawi Access to Research Veterinary Medicine International Volume 2010, Article ID 274987, 7 pages doi:10.4061/2010/274987 Research Article Molecular Microbial Analysis of Lactobacillus Strains Isolated from the Gut of Calves for Potential Probiotic Use Lorena P. Soto, Laureano S. Frizzo, Ezequiel Bertozzi, Elizabeth Avataneo, Gabriel J. Sequeira, and Marcelo R. Rosmini Departamento de Salud P´ ublica Veterinaria, Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, Kreder 2805 (S3080HOF) Esperanza, Santa Fe, Argentina Correspondence should be addressed to Marcelo R. Rosmini, mrosmini@unl.edu.ar Received 1 June 2009; Accepted 29 July 2009 Academic Editor: Alessandro Mannelli Copyright © 2010 Lorena P. Soto et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The intestinal microbiota has an influence on the growth and health status of the hosts. This is of particular interest in animals reared using intensive farming practices. Hence, it is necessary to know more about complexity of the beneficial intestinal microbiota. The use of molecular methods has revolutionized microbial identification by improving its quality and effectiveness. The specific aim of the study was to analyze predominant species of Lactobacillus in intestinal microbial ecosystem of young calves. Forty-two lactic acid bacteria (LAB) isolated from intestinal tract of young calves were characterized 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. These results confirmed that ARDRA is a good tool for identification and discrimination of bacterial species isolated from complex ecosystem and between closely related groups. This paper provides information about the LAB species predominant in intestinal tract of young calves that could provide beneficial effects when administered as probiotic. 1. Introduction The natural microbiota of the gastrointestinal tract has an influence on the biochemistry, immunology, physiology, and nonspecific host’s resistance against infectious diseases [1]. Therefore, the role of the intestinal microbiota is of vital importance in the nutritional status of the host, and particularly in farm animals that are reared in intensive systems [2]. Because of this it is necessary to determine the complexity of the intestinal flora and recognize the different microorganisms that compose it. This is particularly relevant in the probiotic therapy field where it is necessary to distin- guish between probiotics and autochthonous microbiota [3]. Lactobacilli are part of the normal human gastrointesti- nal microbiota and may also be found in other mammalian species [4–7] and birds [8]. It has been reported that some Lactobacillus species have probiotic properties and that they are “live micro-organisms which when administered in adequate amounts confer a health benefit on the host” [9]. The first step in the probiotic production is the isola- tion and identification of the normal components of the gut microbiota, because one of the desirable characteris- tics of strains used as probiotics is that they should be autochthonous to the ecosystem of which they will be part once ingested [2]. Then, we must assess the probiotic and technological properties of the strains [4] in order to select the best examples that will form the probiotic inoculum. The inocula can be either monostrain or multistrain [10]. The latter is more effective because it can use the complementary and synergistic effects of each microorganism [11]. To analyse and rapidly identify bacteria from microbial communities, classical physiological and biochemical tests are not adequate because the bacterial populations involved often have similar nutritional requirements and grow under similar environmental conditions. Currently, there is a wide variety of molecular strategies, such as PCR with specific primers, DGGE, RAPD, PFGE, FISH, RFLP, and PCR-ARDRA, among others [12], which are available to determine the species diversity of Lactobacillus [13].