Effects of supplemental vitamin C and chromium on metabolic and hormonal responses, antioxidant status, and tonic immobility reactions of transported broiler chickens.

Three hundred female broilers were assigned to five groups with six replicates and were fed with either a basal diet (two control groups) or the basal diet supplemented with 800-mg vitamin C/kg (Vit C group), 1,200-μg Cr(+3) from chromium (Cr) chloride/kg (Cr group) or 800-mg Vit C and 1,200-μg Cr(+3) from Cr chloride/kg (Vit C + Cr group) from 42 to 49 days of age. Treatments did not affect performance. Transport decreased insulin level in the control and Cr groups and increased glucose/insulin (G/I) ratio in the groups. The level of insulin was higher in the Vit C + Cr group than those in the control and Cr groups after the transport. The G/I ratio was lowest in the Vit C + Cr group after the transport. The transport significantly decreased triiodothyronine (T3) concentration in the groups except the Vit C + Cr group and only increased thyroxin (T4) concentration in the Vit C + Cr group. The T3/T4 ratio was significantly decreased in the groups except the Cr group by transport. The T3/T4 ratio was greatest in the Vit C + Cr group before the transport. Alkaline phosphatase activity was decreased in the Vit C + Cr group due to transport. Transport decreased triglyceride levels in the groups and also decreased low-density lipoprotein cholesterol levels in the Vit-C-supplemented groups. Transport increased malondialdehyde concentration in the control and Vit C groups and also increased glutathione peroxidase (GPx) activity in the Cr-fed groups. The GPx activity was higher in the Vit C + Cr group than those in the control and Cr groups after the transport. Ferric reducing/antioxidant power (FRAP) value was decreased in the Vit C and Cr groups by transport. Either alone or in combination, Cr increased the FRAP value before the transport. Neither transport nor treatments had significant effects on the duration of tonic immobility (TI) and number of inductions to induce TI.