Effect of Administration of β-carotene Enriched Yoghurt Using Lactobacillus bulgaricus and Streptococcus thermophilus on Gut Microflora Associated with E. coli Infection

Abstract

The study aimed to develop β-carotene-enriched yoghurt and to investigate its efficacy on gut microflora associated with E. coli infection. The study was conducted in the Department of Biotechnology, Assam Agricultural University, for product development, and the animal test was performed in the Department of Microbiology, College of Veterinary Science, Assam Agricultural University, Khanapara. Escherichia coli, a gram-negative coliform bacterium, has been considered as an agent which is responsible for diarrhoea in humans. The effect of Standard Probiotic Yoghurt (SPY) and β-carotene-enriched probiotic yoghurt (MBPY) on Escherichia coli infections was examined through an in vivo study using albino rats. Standard Probiotic Yoghurt (SPY) was developed using 100% cow’s milk and 7% skim milk powder, 1% Streptococcus thermophilus and Lactobacillus bulgaricus each. β-carotene enriched probiotic yoghurt (MBPY) was developed using 80% cow's milk, 7% skim milk powder, 2% fructooligosaccharide, 20% mango pulp, and 1% each of Streptococcus thermophilus and Lactobacillus bulgaricus. The antibacterial effects of lactic acid bacteria present in standard probiotic yoghurt (SPY) and β-carotene-enriched probiotic yoghurt (MBPY) were demonstrated in a dose-dependent manner. In this study, the animals used for this experiment were divided into three Experimental groups, namely Group A, Group B, and Group C, consisting of 4 animals in each group. All the animals of the group were fed intragastrically (i/g) with 24 hours growth of Escherichia coli. Two days after infection with Escherichia coli, Group B and Group C were given therapeutic treatment (10 g/day) of supplementation with standard probiotic yoghurt (SPY) and β-carotene-enriched probiotic yoghurt (MBPY), respectively, for 7 days. Faecal samples were collected continuously for 9 days, and cell density was measured using Mc. Farland Nephelometer Standards as well as the pour plate method for bacterial counts. We registered the effect of probiotics on Escherichia coli (E. coli) counts in albino rats. Results revealed that E. coli had inadequate survival ability in rats when fed with SPY and MBPY at a dose level of 10 g/day which shows an improvement in the gastrointestinal status of albino rats.