the impact of reduced licorice levels on performance, carcass characteristics, blood constituents, immunity, intestinal microflora, intestinal morphology, and breast muscle fatty acid profile in broilers

Background: phytogenic feed additives derived from plants have gained special attention in poultry farming. this research was conducted to investigate the effects of low doses of licorice on broiler productivity.methods: this experiment was conducted using 120 commercially bred ross 308 broiler chickens at one day of age to investigate the effects of three different levels of licorice (0, 100, and 200 mg/kg) in their feed.results: the results showed that chickens fed with a diet supplemented with 200 mg/kg of licorice (glycyrrhizaglabra) had the highest feed intake (94.27 g/d) and weight gain (57.67 g/d), along with the most favorable feed conversion ratio (1.63 g/g). moreover, this treatment had the highest economic returns (34.99 $/m2) and demonstrated the best european production index (359.81) compared to other treatments. it also led to a significant increase in certain carcass characteristics compared to the control group (p < 0.05). the effect of two different levels of licorice on some blood parameters (ldl/hdl ratio, ldl, vldl, triglyceride, and glucose) was statistically significant (p < 0.05). the use of the licorice had no significant effect on the humoral immune system (p ≥ 0.05). also, the inclusion of 200 mg/kg of licorice resulted in the lowest population of escherichia coli (9.18 cfu/g) the highest bifidobacterium count (9.673 cfu/g), and the lowest ratio of saturated fatty acids to unsaturated fatty acids (1.27).conclusion: the use of 200 mg/kg of licorice (glycyrrhizaglabra) as a dietary additive is recommended for ross 308 broiler chickens. the use of licorice can improve feed intake, weight gain, feed conversion ratio, cost per kilogram of live chicken, and production index at the end of the period.