Lactic acid bacteria isolation from chicken intestinal content and selection of strains with capacity to capture toxic dietary lectins.

JAIME DANIEL BABOT; ELOY ARGAÑARAZ MARTÍNEZ; MARÍA CRISTINA APELLA; ADRIANA PEREZ CHAIA

Simposio; 10th Symposium on Lactic Acid Bacteria; 2011

The diet components of laying hens and broilers contain secondary products of plant metabolism, lectins among them, which act as a defence mechanism in vegetables. The presence of dietary lectins may impair intestinal epithelia development and enzyme digestive activity in baby chicks with the consequent growth depression. Lactic acid bacteria (LAB) may decrease the cytotoxic effects of lectins on intestine epithelial cells capturing these glycoproteins by interaction with bacterial surface carbohydrates. Hence, the aim of this work was to isolate, identify and select LAB strains with capacity to survive the gastrointestinal transit and capture toxic dietary lectins. In addition, 9 Propionibacterium strains previously isolated from the same niche were assayed. LAB strains were isolated from chicken gastrointestinal tract using HHD, LBS and KF agar media and identified by 16S rDNA gene sequencing. In order to analyze their ability to grow at 42 °C, growth kinetics of all strains were studied in LAPTg + 1% lactose, MRS or LAPTg broth depending on the isolation media. Then, the strains were subjected to an in vitro simulated gastrointestinal digestion, performed at 42 °C. Finally, their ability to capture lectins (DBA, ConA, PHA-P, PNA, UEA-I and WGA) was studied fluorometrically. Eighty one LAB strains were isolated from gastrointestinal content of laying hens; 58 of these strains grew at 42 °C. Viable counts of 14 LAB and 4 propionibacteria strains decreased less than a log unit after the simulated gastrointestinal digestion. Thirteen strains bound at least one lectin, being WGA and ConA caught by most of the strains. These strains may be used as probiotic in order to protect baby chicks intestinal epithelium in diets with high content of lectins.