Effects of herbal extract, organic acid and antibiotic on reducing colonization of Campylobacter jejuni in intestine of broiler chickens

This study was conducted to compare three herbal extracts (thyme, yarrow and garlic), antibiotic, and organic acids to reduce Campylobacter jejuni colonization in digestive tract of broiler chickens. A total of 336 one-day old male broilers (Cobb 500) were randomly allocated to 7 treatments, 4 replicates with 12 birds in each replicate with a completely randomized design. The experimental groups included negative control (basal diet without challenge), the positive control (basal diet with challenge), organic acids (1 mL per liter in drinking water for first 14 days of age, then 8 hours each day until end of the experiment), antibiotic (oxytetracycline 100 ppm in feed), yarrow extract (1 mL per liter in drinking water), thyme extract (1 mL per liter in drinking water), and garlic extract (1 mL per liter in drinking water) throughout the experiment. Except for the negative control group, all chickens were orally challenged with (109cfu/mL) C. jejuni suspension on day 21. The negative control group was inoculated with 1 mL of saline solution. Feed intake, weight gain, and feed conversion ratio were measured weekly. At end of the experiment (day 42), the blood samples were taken from the wing vein to determine serum biochemical parameters. The effect of treatments on the morphology of the small intestine, lymphatic organs weight, and colonization of C. jejuni were measured. The results of statistical analysis showed that treatments had significant effect (P>0.05) on Campylobacter jejuni colonization,so that, the highest and lowest levels of the bacterial colony were observed in positive control and antibiotic treatment. The negative control and yarrow treatments had a significant difference (P0.05). According to the results of this experiment, the use of above mentioned treatments had positive effects on decreasing serum cholesterol and triglyceride, as well as reducing the colonization of Campylobacter jejuni in digestive tract of broiler chickens.