ISOLATION AND SELECTION OF POTENTIALLY PROBIOTIC STRAINS FROM CHICKEN INTESTINAL CONTENT

BABOT J.D.; ARGAÑARAZ MARTÍNEZ E.; PEREZ CHAIA A.; APELLA M. C.

San Miguel de Tucumán

Congreso; VII CONGRESO ARGENTINO DE MICROBIOLOGÍA GENERAL SAMIGE DEL BICENTENARIO; 2011

Sección 3 - Fisiología y Metabolismo de Microorganismos Resumen 3.3 (ORAL) There is a worldwide attempt to reduce antibiotic use in animal production because increased microbial resistance to antibiotics and residues in animal products can be harmful to consumers. Therefore, feed companies and researchers are looking for alternative products and strategies that can help to maintain animal gut health in order to prevent or reduce the prevalence of pathogens in the food chain. An alternative and effective approach to antibiotic administration is the use of probiotics, which can help to improve gut microbial balance and therefore the natural defence of the animal against pathogenic bacteria. In the poultry industry, probiotic supplementation has been shown to improve daily weight gain, feed conversion ratio and mortality rate in broiler chickens. Probiotics used in broilers include Lactobacillus, Bifidobacterium and Enterococcus among other lactic acid and related microorganims. The aim of this paper was to isolate and select lactic acid bacteria (LAB) strains from chicken intestinal content, with potential use as chicken probiotics. The media used were HHD, LBS and KF, selective for Bifidobacterium, Lactobacillus and Enterococcus respectively. The LAB strains were isolated from chicken gastrointestinal tract; same niche previously isolated Propionibacterium strains were also studied. In order to analyse their capacity to grow at 42 °C, growth kinetics of the strains isolated in HHD, LBS and KF media were studied in LAPTg + 1% lactose, MRS and LAPTg broths, respectively. Then, the strains were subjected to a simulated gastrointestinal digestion, performed at 42 °C. Finally, their capacity to grow in co-culture was studied towards the selection of a combination of 3 strains. Out of 104 isolated strains 81 were considered as possible LAB (Gram and catalase negative). Fifty eight of these strains grew at 42 °C; the viable cells of the 14 possible LAB strains and 4 of the 9 propionibacteria strains previously isolated decreased less than a unit log after the simulated gastrointestinal digestion. Finally, all strain combinations grew in co-culture and showed a lower biomass than the addition of those of the corresponding mono-cultures. Thus, the combination that showed the least biomass decrease was selected for further studies as a potential probiotic supplement for chickens. In conclusion out of 104 strains isolated from chicken intestinal content, 13 were Gram and catalase negative, grew at 42 °C and survived a simulated gastrointestinal digestion. A combination of 3 strains showed compatibility and thus was selected as a potential probiotic supplement for chickens. Supported by CONICET PIP 0996, ANPCyT PICT 2168 and CIUNT