Crecimiento de lactobacilos

medigraphic
Revista Latinoamericana de

Artemisa en línea

MICROBIOLOGÍA

ORIGINAL ARTICLE

Vol. 49, Nos. 3-4 July - September. 2007 October - December. 2007 pp. 46 - 54

Evaluation of probiotic properties in Lactobacillus isolated from small intestine of piglets
Iñiguez-Palomares C,* Pérez-Morales R,* Acedo-Félix E*

ABSTRACT. Lactobacillus has been associated with beneficialeffects in human and animal health. Oral administration of probiotic bacteria must resist gastrointestinal transit, in order to colonize the intestinal mucus and offer an antagonistic effect against pathogenic microorganisms. The aim of this work was to select Lactobacillus strains isolated from small intestine of piglets based on the characteristics of resistance to low pH and bile salts, surfaceproperties and antagonistic effect against Escherichia coli K88. To identify Lactobacillus species, a fragment of 16S rRNA gene of the strains was sequenced. Low pH, bile salts resistance and antagonistic activity were quantified by viable count in plates. Surface properties were measured using a spectrophotometer at 600 nm. Sixty-two Lactobacillus strains were isolated from small intestine ofpiglets. Species Lactobacillus salivarius, Lactobacillus reuteri and Lactobacillus mucosae were identified. We found that 20 Lactobacillus strains resisted low pH and bile salt, 8 of them were adherents and they inhibited in vitro the growth of E. coli K88. In conclusion, our results showed that 8 strains have potential probiotic value, according resistance to gastrointestinal tract, surface propertiesand antagonistic characteristics. Lb. salivarius was the species that fulfilled the criterion to be identified as a possible probiotic microorganism. Key words: Piglets, Lactobacillus, probiotic characteristics, antagonism.

RESUMEN. Con frecuencia los lactobacilos se han relacionado con diversos efectos benéficos en la salud humana y animal. En la administración oral de bacterias benéficas,éstas deben resistir el tránsito gastrointestinal para que colonicen la mucosa y ejerzan un efecto antagónico contra diversas bacterias patógenas. Por lo anterior el objetivo de este trabajo fue seleccionar cepas de Lactobacillus aisladas del intestino delgado de lechones de acuerdo a sus características de resistencia al pH bajo y sales biliares, propiedades de superficie y efecto antagónico en contrade Escherichia coli K88 para utilizarlas a futuro como probióticos. Se aislaron sesenta y dos cepas de Lactobacillus del intestino delgado de seis lechones. Se identificaron las especies Lactobacillus salivarius, Lactobacillus reuteri y Lactobacillus mucosae. Encontramos que 20 cepas de Lactobacillus resistieron la presencia de pH bajo y sales biliares, 8 de ellas fueron adherentes e inhibieronin vitro el crecimiento de E. coli K88. En conclusión, nuestros resultados mostraron que 8 cepas tienen valor probiótico potencial de acuerdo a la resistencia al tránsito gastrointestinal, propiedades de superficie y efecto antagónico. Lb. salivarius fue la especie que cumple con los criterios para ser identificada como un probiótico potencial para aplicarse en cerdos recién destetados. Palabrasclave: Lechones, Lactobacillus, características probióticas, antagonismo.

INTRODUCTION Pig breeding is a profitable activity in many countries. Sometimes, the economy of this activity is affected by infectious diarrhea in neonatal pigs (Gusils et al., 2002). Escherichia coli K88 has been identified as one of the main causal agents of this illness. Those bacteria invade mucosal cells and produceenterotoxins that cause diarrhoea and death of infected pigs (Meng et al., 1998). Commonly antibiotics are used to prevent and/or eliminate these infections, unfortunately low control or antibiotic misuse are frequent practices. The worst disadvantage of these practices

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* Laboratorio de Microbiología Molecular. Coordinación de Ciencia de los Alimentos. CIAD., AC....