Oral toxicity evaluation of probiotic strains isolated from Finger millet [Eleusine coracana (L.) Gaertn.] in Wistar rat models (in vivo)

Abstract

This study evaluates the oral toxicity of five probiotic strains recently isolated from fermented flour of finger-millet (Eleusine coracana) varieties of Sri Lanka. Probiotic strains; Lactobacillus plantarum MF405176, Lactobacillus fermentum MF033346, Lactococcus lactis subspecies lactis MF480428, Enterococcus faecium MF480431and Pediococcus acidilactici MF480434 were evaluated for acute and sub-chronic oral toxicity in Wistars.  Three individual doses (10⁸ CFU/g, 10¹⁰ CFU/g and 10¹² CFU/g) of each probiotic strain at single oral dose of 5000 mg/kg bw were orally administered to rats and observations were done till 14^th day. Since no animals demonstrated signs of toxicity as a result of the administrated probiotics strains, repeated dose sub-chronic oral toxicity study was conducted by oral administration of three doses (10⁸ CFU/g, 10¹⁰ CFU/g, 10¹² CFU/g) of each probiotic strain at 1000 mg/kg bw/day for consecutive 90 days. Administration of probiotic strains to rats did not caused mortality in any of the tested doses. No changes in animal behavior, feed or water intake and negative effects on body weight observed. Probiotic feeding did not cause changes in analyzed biochemical and hematological parameters attributed to toxicity. Bacteremia, bacterial translocation and histopathological changes in rat organs were not observed. No significant difference in liver enzymes observed in treatment groups compared to control. In conclusion, all tested probiotic strains are nonpathogenic therefore could be considered as safe for human consumption.