Effects of dietary oregano essential oil supplementation on the stress response, antioxidative capacity, and HSPs mRNA expression of transported pigs

Abstract Transportation stress affects carcass quality, metabolism and immune function. The utilization of feed additives is a possible strategy of mitigating physical and psychological stresses after animal transportation. Oregano essential oil (OEO) is an aromatic plant extract that mainly contains carvacrol and thymol. However, the effects of dietary supplementation with OEO for the welfare of transported pigs are limited. This study aimed to investigate the effect of OEO on alleviating stress and increasing antioxidative capacity after the transportation of finishing pigs. 180 crossbred pigs were randomly allocated to 1 of 3 diets: the basal diets, 200 mg kg −1 vitamin E (VE), or 25 mg kg −1 OEO. Each group was divided into two subgroups: no stress (NS) or transportation stress (TS) after 28 days. Here we report that serum cortisol and norepinephrine concentrations of transported pigs were significantly reduced ( P P P P =0.01) in dietary treatment. Liver SOD was dramatically raised no matter transportation ( P P =0.01). Liver heat shock protein (HSP) 27 and HSP90 were significantly increased ( P