Safety of a bacterial mixture intended to be used into a probiotic product for poultry

BABOT, JD; ARGAÑARAZ MARTÍNEZ, E.; APELLA, MC; PEREZ CHAIA, A

San Miguel de Tucumán

Simposio; IV International Symposium on Lactic acid Bacteria: Food, Health and Applications; 2013

CERELA

Laying hen and broiler diet components have secondary products from plant metabolism like lectins that act as defence mechanisms in vegetables. Their presence may impair intestinal epithelia development and digestive enzyme activity in baby chicks, diminishing their growth. Bacteria may decrease lectin cytotoxic effects on intestine epithelial cells, capturing them by interactions with bacterial surface carbohydrates. Thus, the aim of this work was to assess the safety and compatibility of a mixture of five strains to be administered to BB chicks as a probiotic supplement. To this effect, P. acidipropionici LET103, L. salivarius LET201, L. reuteri LET210, E. faecium LET301 and B. infantis CRL1395, previously selected for their capacity to bind to deleterious dietary lectins were analyzed. Their compatibility was evaluated through three different approaches: growth in co-culture (with free and constant pH), well diffusion method and interaction of different strain colonies in agarized media. Their safety was analyzed through the study of their antibiotic sensibility pattern in LAPTg, LSM and MRS by the Kirby-Bauer method, the presence of virulence determinants and the vancomycin resistance by phenotypical tests and PCR using specific primers, respectively. None of the strains produced inhibitory substances against the others. LAB inhibited the development of P. acidipropionici LET103 and B. infantis CRL1395 in MRS agar, but not in LAPTg agar. All the strains grew well in the co-culture, except for P. acidipropionici LET103 because of the early decrease in pH. However, when the pH was fixed at 6.30, this bacterium could grow as expected. P. acidipropionici LET103 and B. infantis CRL1395 showed sensitivity to all the antibiotics tested in both media. E. faecium LET301 and L. reuteri LET210 presented resistance only to clindamycin and vancomycin, respectively, while L. salivarius LET201 was sensitive to all the antibiotics tested in both media with except for clindamycin in MRS. Virulence factors like gelatinase, hemolysin or hemagglutinin were absent in all strains. E. faecium LET301 presented three out of the ten virulence determinants studied (efaAfm, efaAfs and gelE) and it lacked the genes encoding vancomycin resistance. In conclusion, the five strains showed acceptable compatibility among them and proved to be highly safe for BB chicks, except for E. faecium LET301 whose resistance to clindamycin should be further studied. Nevertheless, in vivo trials should be performed in order to confirm the innocuous character of these strains.