Activity and Anti-Aflatoxigenic Effect of Indigenously Characterized Probiotic Lactobacilli against Aspergillus flavus-A Common Poultry Feed Contaminant

Aflatoxin contamination in human food and animal feed is a threat to public safety. Aflatoxin B1 (AFB1) can be especially damaging to poultry production and consequently economic development of Pakistan. The present study assessed the in vitro binding of AFB1 by indigenously characterized probiotic lactobacilli. Six isolates (Lactobacillus gallinarum PDP 10, Lactobacillus reuetri FYP 38, Lactobacillus fermentum PDP 24, Lactobacillus gallinarum PL 53, Lactobacillus paracasei PL 120, and Lactobacillus gallinarum PL 149) were tested for activity against toxigenic Aspergillus flavus W-7.1 (AFB1 producer) by well diffusion assay. Only three isolates (PL 53, PL 120, and PL 149) had activity against A. flavus W-7.1. The ameliorative effect of these probiotic isolates on AFB1 production was determined by co-culturing fungus with lactobacilli for 12 days, followed by aflatoxin quantification by high-performance liquid chromatography. In vitro AFB1 binding capacities of lactobacilli were determined by their incubation with a standard amount of AFB1 in phosphate buffer saline at 37 °C for 2 h. AFB1 binding capacities of isolates ranged from 28-65%. Four isolates (PDP 10, PDP 24, PL 120, and PL 149) also ceased aflatoxin production completely, whereas PL 53 showed 55% reduction in AFB1 production as compared to control. The present study demonstrated Lactobacillus gallinarum PL 149 to be an effective candidate AFB1 binding agent against Aspergillus flavus. These findings further support the binding ability of lactic acid bacteria for dietary contaminants.