Growth performance, ascites sensitivity, and ileal microbiota as affected by licorice essential oil in broiler chicken diets

Abstract

Listen

Translate article

This experiment was conducted to evaluate the effect of licorice (Glycyrrhiza glabra) essential oil (LEO) as an alternative to antibiotic growth promoter on growth performance, ileal microbial population, blood biochemical traits, and ascites sensitivity in broiler chickens. A total of 625 one-day-old broiler chickens were assigned to 5 dietary treatments, including control(un-supplemented basal diet), antibiotic (basal diet + 150 mg avilamycin/kg), probiotic (basal diet + 100 mg probiotic/kg), basal diet + 200 mg LEO/kg, and basal diet + 400 mg LEO/kg, in a completely randomized design, with 5 replicates of 25 broiler chickens per pen. Dietary inclusion of 200 mg LEO/kg increased feed intake compared to control and 400 mg LEO/kg treatments (P < 0.05). Broiler chickens fed the diet containing 200 mg LEO/kg showed greater weight gain and better feed conversion ratio (P < 0.05) compared to diets containing 400 mg LEO/kg. No differences were observed in feed intake and weight gain among diets containing 200 mg LEO/kg, antibiotic, probiotic, or control treatment. No differences in blood lipids, Alkaline phosphatase, and albumin were observed among all the treatments. The concentrations of total protein and globulin in serum of broiler chickens fed control diet were greater than broiler chickens that received antibiotic, probiotic, or 400 mg LEO/kg (P < 0.05). Diet containing 200 mg LEO/kg caused the greatest serum concentration of T3 or T4 (P < 0.05). The T4/T3 ratio in broiler chickens fed the diet containing 400 mg LEO/kg was greater than those fed the antibiotic or control diets (P < 0.05). Also, broiler chickens fed 400 mg LEO/kg diet had lower right ventricle /total ventricles ratio (RV/TV) than those fed the control, antibiotic, or 200 mg LEO/kg diets (P < 0.05). The ileal population of Escherichia coli in broiler chickens fed diets containing 200 or 400 mg LEO/kg was lower than those fed the control diet (P < 0.05). The result indicates that LEO can improve thyroid hormones and reduce the population of some potential pathogenic bacteria in broiler chickens' gut, resulting in better growth performance. Therefore, LEO can be recommended as much as 200 mg/kg of diet as an alternative to antibiotics in promoting the growth performance of broiler chickens.