Abstract

Escherichia coli and Salmonella spp are two bacterial infectious diseases responsible for heavy economic losses in the poultry industry. The emergence of antimicrobial resistance and its potential harmful threat to human health has led to a need to find safe alternatives for the control of these bacteria. To this end, the use of herbal remedies in poultry has been suggested. In this study, we have investigated the effect of essential oils extracted from five different herbal plants against Salmonella spp and Escherichia coli that have been isolated directly from infected broiler flocks. Standard Disk-diffusion method, Minimum Inhibition Concentration and minimum bactericidal concentration were used to determine the inhibitory effect of these essential oils. Also, tetracycline was used as a control group. Among the essential oils, Carum copticum had the highest antibacterial properties. The maximum inhibition zone in diameter against Salmonella and Escherichia coli were respectively 26.7 and 22.5 mm that concern about Carum copticum essential oils. According to the results of this study, it was found that some of the essential oils have a stronger antibacterial effect than tetracycline. So, after the complementary studies, some of these herbal plants can be suggested as alternatives to antibiotics for treating infections caused by these bacteria in poultry industry.