Evaluation of Three Formulations of Essential Oils in Broiler Chickens under Cyclic Heat Stress

SIMPLE SUMMARY: The use of essential oils in animal feeding has been practiced for their role as antibacterial, antiviral, antifungal, antioxidant, digestive stimulants, immunomodulators, hypolipidemic agents, and heat stress alleviators. The objective of the present research was to assess dietary supplementation of three formulations of essential oils on performance, bone mineralization, carcass component weights, intestinal permeability, anti-inflammatory, and antioxidant biomarkers in broiler chickens under cyclic heat stress. Heat stress reduced the body weight, feed intake, and bone strength through bone mineralization, while increasing feed conversion, gut permeability, IFN-γ and IgA levels in serum when compared with thermoneutral control broilers. Interestingly, in the present study, all three essential oils treatments partially mitigated these harmful effects at statistically significant levels compared with heat stress control chickens. These results suggest that the strategic use of some essential oils formulations during periods of stress, such as cyclic heat stress, could ameliorate adverse effects. ABSTRACT: The objective of the present research was to assess the dietary supplementation of three formulations of essential oils (EO) in chickens under heat stress (HS). Day-of-hatch Cobb 500 chicks (n = 500) were randomly distributed into four groups: 1. HS control + control diets; 2. HS + control diets supplemented with 37 ppm EO of Lippia origanoides (LO); 3. HS + control diets supplemented with 45 ppm LO + 45 ppm EO of Rosmarinus officinalis (RO) + 300 ppm red beetroot; 4. HS + 45 ppm LO + 45 ppm RO + 300 ppm natural betaine. Chickens that received the EO showed significant (p < 0.05) improvement on BW, BWG, FI, and FCR compared to control HS chickens. Average body core temperature in group 3 and group 4 was significantly (p < 0.05) reduced compared with the HS control group and group 2. Experimental groups showed a significant reduction in FITC-d at 42 days, a significant increase in SOD at both days but a significant reduction of IFN-γ and IgA compared with HS control (p < 0.05). Bone mineralization was significantly improved by EO treatments (p < 0.05). Together these data suggest that supplemental dietary EO may reduce the harmful effects of HS.