effect of the three herbal extracts on growth performance, immune system, blood factors and intestinal selected bacterial population in broiler chickens

a research study was conducted to evaluate the effects of three herbal extracts and an antibiotic –virginiamycin- on growth performance, immune system, blood factors and selected intestinal bacterial populations in broiler chickens. a total of four hundred and eighty 1-day old male broiler chicks were assigned to the basal diet (control) , basal diet supplemented with 15 ppm of virginiamycin, basal diets with a 0.1% dose of either thyme (thymus vulgaris), coneflower (echinacea purpurea), garlic (allium sativum) or a blend of the three extracts in the drinking water. the highest and the lowest body weight and weight gain were related to virginiamycin and coneflower, (p< 0.05) respectively. the lowest and the highest feed conversion rates were respectively related to virginiamycin and coneflower (p< 0.05). relative weight of bursa fabricius in the garlic group showed a significantly more increase as compared with other groups, while the relative weight of spleen was unaffected by treatments. cutaneous basophils hypersensitivity response (to phytohemaglutinin injection) and antibody response to sheep red blood cells (srbc) was higher in coneflower group (p< 0.05). antibody responses to newcastle disease vaccine (lasota) was unaffected by treatments but coneflower improved antibody levels (p> 0.05). garlic (allium sativum) significantly reduced the serum levels of cholesterol, ldl, and triglyceride as well as significantly increasing the level of hdl. thyme (thymus vulgaris) improved hematocrit percentage and hemoglobin concentration, but not significantly. the colony forming units of escherichia coli in digesta of ileo-cecum in the blend group showed a significantly lower number compared with control. however, there was no difference observed in e. coli counts between blend group and others, except for control. the lactic acid bacteria counts in the thyme group increased as compared to other groups, except for coneflower (p< 0.05).