Antibacterial activity and stability of microencapsulated lemon grass essential oil in feeds for broiler chickens

SUMMARY The antibacterial effect of microencapsulated lemon grass (Cymbopogon citratus) essential oil on strains of Escherichia coli (ATCC8739), Staphylococcus aureus (ATCC 6538) and Salmonella enterica subsp. enterica (ATCC 6017), and the stability of this oil in feeds for broiler chickens were evaluated. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined by the macrodilution method, using the microencapsulated lemon grass essential oil at concentrations of 160 μL mL−1, 80 μL mL−1, 40 μL mL−1, 20 μL mL−1, and 10 μL mL−1. The oil concentration of 80 μL mL−1 presented the best results against the three bacteria evaluated. Samples of 200 g of feed mixed with 120 μL g−1 of the microencapsulated lemon grass essential oil was stored to evaluate the oil stability. Feed without microencapsulated lemon grass essential oil was prepared as control. The oil remained active for seven days, with significant reduction of S. aureus (3.08 CFU), E. coli (3.01 CFU), and S. enterica (3.10 CFU). The microencapsulated lemon grass essential oil at concentration of 80 μL mL−1 had antibacterial effect against the E. coli, S. enterica and S. aureus, and maintained stability of the feed for seven days, even with presence of organic matter, which is source of nutrients for pathogens