Faculty: Biosences
Department: Applied Microbiology And Brewing


Okafor, Chibuanuli .M
Archibong E.J.


Lactobacillus fermentum strains isolated from the following fermented foods: Gari FCM (fermenting cassava mash), Nunu and Akamu were evaluated in vitro and in vivo for probiotic potentials. Four L. fermentum strains which were acid and bile tolerant with other essential probiotic properties were selected for in vivo studies. These strains: L. fermentum strain MGB 32-1, L. fermentum F-6, L. fermentum CECT 5716 and L. fermentum cc IMAU:80780, were characterised based on 16SrDNA sequencing. For the in vivo assay, albino rats were orally administered skimmed milk fermented by the four strains of L. fermentum. Results of the 2 weeks feeding trial and 13 weeks sub-chronic oral toxicity studies showed that all treatment groups exhibited significantly higher (p<0.05) mean weight when compared to the control groups. Lactobacillus count was increased while enterobacteria count were reduced significantly in the treatment groups. No dose-related effects and no significant differences were observed in alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase levels at the end of the study when compared to the control groups. Investigation of the haematological parameters showed that the haemoglobin concentration, red blood cell count, packed cell volume and the red blood cell indices of all treatment groups were significantly higher in both male and female rats while the white blood cell count was significantly lower than the controls in the male rats. There were no significant changes (p>0.05) in the relative weights of the heart, liver, spleen, kidney and brain of all the treated rats in relation to control groups. Histopathological evaluation of the liver and kidney tissues showed no histological indication of inflammation. Results from this study showed that only L. fermentum CECT 5716 did not reduce serum cholesterol level significantly (p<0.05) when compared to the control after 2 weeks of consumption of 1ml of probiotic fermented milk. All the test strains displayed significant reduction in the serum cholesterol level of both male and female rats after 13 weeks consumption of 1ml of probiotic fermented milk. All probiotic fermented milk samples produced in this study were in the acidic range of pH scale. The 4 strains of L. fermentum showed desirable probiotic properties in terms of weight gain, safety of use and hypocholesterolemic effect. Strain L. fermentum F-6 was selected as the best because it resulted in a good health status in the rats based on haematology and weight gain. It also had the most hypocholesterolemic effect which was observed to be dose dependent. L. fermentum F6-probiotic fermented milk could therefore be considered a safe natural method for maintaining good cholesterol levels in humans, with no adverse effects occurring and could also be used to optimize nutrient absorption for proper growth and development.