Nutritional and physiological influences of dietary supplementation of garlic oil on alleviating heat stress impact in broiler chickens

Abstract

 This study evaluated impact of dietary supplementation with garlic oil (GO) on growth performance and alleviation of heat stress (HS) impact in broiler chickens. A total of 240 one-day old Cobb broilers were randomly assigned to four treatments, each with six replicates of 10 birds. Treatment one (-Control) was offered a basal diet (BD) and raised under thermo-neutral temperature throughout the experiment (42 days), while Treatment 2 (+Cont) received BD throughout the experimental period, and raised under thermoneutral temperatures during the experiment weeks, but subjected to HS during the fifth week. Treatments 3 and 4 were exposed to the same HS during the fifth week and fed a BD supplemented with 5 g GO/kg, and 15g GO/kg throughout the experimental period. Compared to the thermoneutral control, the heat-stressed control displayed a lower growth performance, in terms of decreased feed intake, higher feed conversion ratio, higher mortality, altered serum metabolites, and lower antioxidative activity. Both GO treatments resulted in deteriorated growth performance compared to the thermoneutral control and relatively worse than the CHS control (P > 0.05). The GO treatments reduced serum triglycerides, cholesterol, and malondialdehyde concentrations, but enhanced glutathione peroxidase activity and total antioxidant capacity compared to HS control. The two GO treatments exhibited significantly higher villus length/crypt depth ratio than the thermoneutral control. In conclusion, GO treatments displayed poor growth performance results, but enhanced the serum antioxidant properties under the study conditions.