Effects of star anise (Illicium verum Hook. f) and its extractions on carcass traits, relative organ weight, intestinal development, and meat quality of broiler chickens

Star anise (Illicium verum Hook. f) has been used as spice and herbal medicine for many years with lacking researches on evaluating its application for improving relative organ weight, intestinal development, and quality of animal products. The experiment was conducted to investigate the effects of star anise, its essential oil and leavings on carcass traits, relative organ weight, intestinal development, and meat quality of broiler chickens. A total of 384 broilers were randomly assigned to 4 treatments with 8 replicates of 12 birds each. The 4 dietary treatments were basal diet (Control), basal diet supplemented with 5 g/kg star anise (Star anise), basal diet supplemented with 0.22 g/kg essential oil (Essential oil), and basal diet supplemented with 5 g/kg leavings (Leavings). The concentration of main active components in the experimental diets was 0.204 g trans-anethole/kg of diet. All birds were fed a starter diet (0–21 d) and a grower diet (22–42 d). Birds supplemented with star anise and essential oil had a greater (P 0.05) among all treatments. Birds supplemented with star anise and essential oil had higher (P = 0.010) relative weight of thymus than those in control and leavings groups. Essential oil supplemented groups appeared to contain the highest (P