Comparing effects of Ferulago angulate extract with antibiotic, probiotic, and vitamin-mineral complex on growth performance and immune response of broiler chickens exposed to heat stress

This study was conducted to investigate the effects of hydro alcoholic extract of Ferulago angulata, antibiotic, probiotic, and vitamin-selenium mixture on growth performance and immune responses of broiler chickens under heat-stress conditions. A total of 350 day-old male broiler chickens (Ross 308) were used in a completely randomized design with 7 dietary treatments and 5 replicates (10 chicks/replicate). Experimental treatments were as follow: no heat stress, without any additive in the diet (negative control; NC); challenged with heat stress, without any additive in the diet (positive control; PC); PC + antibiotic; PC + probiotic; PC + vitamin and selenium mixture; and PC + 200 or 400 mg/kg of Ferulago angulata extract. The results showed that all dietary supplements decreased the negative effects of heat stress on growth performance (P<0.05). All experimental diets(except diet containing antibiotic ) increased the lymphocyte counts, but decreased hetrophil counts and heterophil: lymphocyte ratio compared with the PC group (P<0.05). Secondary total titer and IgG titer against SRBC were higher in broilers receiving dietary supplements under heat stress conditions (P<0.05). The 400 mg/kg of Ferulago angulata extract increased the cell-mediated immune response after an intradermal injection with phytohaemagglutinin-P in the toe web (P<0.05). According to the results of this experiment, the use of 400 mg/kg of Ferulago angulata extract in broiler diets improves growth performance and immune response under heat stress conditions, and can be used as a suitable alternative to antibiotics and common supplements under the heat stress conditions.