The effect of different levels of fennel essential oil nanoemulsion on energy and protein efficiency ratio, litter and excreta quality and welfare related parameters of broiler chickens reared under heat stress

The present experiment was carried out to evaluate the effect of different levels of fennel essential oil nanoemulsion (FEON) on energy and protein efficiency ratio, litter and excreta quality and welfare related parameters of broiler chickens reared under heat stress. A total of 200 day-old Ross 308 broiler chicks were assigned in a completely randomized design with 5 treatments and 4 replicates. The experimental treatments were control (basal diet with no additive), basal diet and 200 mg/kg fennel essential oil (FEO) and basal diet with 50, 100 and 200 mg/kg of FEON. The results of this experiment showed that trans-anethole, fenchone and limonene with the values of 81.49, 7.16 and 4.98 percent, respectively were the main compounds of fennel essential oil. The protein and energy efficiency ratios were not affected by different experimental treatments. The excreta pH of chicks fed diet containing 200 mg/kg FEON was significantly (P≤0.05) less than those of fed diets containing 50 and 100 mg/kg of FEON and the control group. The litter moisture was decreased significantly (P≤0.05) by supplementation of diet with 50 mg/kg FEON when compared with control group. The hock burn and abdominal plumage scores were decreased significantly (P≤0.05) in chicks fed diet containing 50 mg/kg FEON when compared with other groups. According to the results of this experiment, it seems that the utilization of FEON in heat stress condition can improve broiler welfare related parameters via decreasing the litter moisture.