Effects of in ovo injection of nanocurcumin and vitamin E on antioxidant status, immune responses, intestinal morphology and growth performance of broiler chickens exposed to heat stress

The aim of this study was to investigate the effects of in ovo injection of nanocurcumin (NC) and vitamin E (VE) on antioxidant status, intestinal histomorphology and growth performance of the hatched chicks. Fertile eggs (n=352) were allocated to 8 treatments with 4 replicates of 11 eggs each. At d 17.5 of incubation, the eggs were injected with 0.01, 0.03 and 0.05 mL/egg of NC and 0.03, 0.06 and 0.09 mL/egg VE solution into the amniotic cavity, and the rest two groups were used as sham and un-injected controls. The hatchlings from each treatment were randomly assigned to 4 replicates of 10 birds and reared until d 24 of age under heat stress (8 h daily at 35oC). The experimental design used was a completely randomized one. Results showed that superoxide dismutase activity in liver was increased (P<0.01) by IOI of 0.05 mL/egg NC in compare with control and sham groups on d 10. Total antioxidant capacity was decreased (P<0.05) by IOI of 0.03 and 0.06 mL/egg VE in compare with the control group. Liver glutathione peroxidase and malondialdehyde activities, blood heterophil (H) and lymphocyte (L) counts and H/L ratio, serum total cholesterol, HDL, LDL and VLDL levels and also crypt depth (CD) were not significantly affected by treatments on d 10. Villous height (VH) in the birds hatched from 0.01 and 0.03 mL/egg NC treatments were shorter than control group. The VH to CD ratio in NC treatments and 0.03 and 0.06 mL/egg VE were lower than controls (P<0.01). In ovo administration of NC and VE had no significant effects on growth performance of broiler chickens during 1-10 days of age; but decreased (P<0.05) feed intake during 1-24 d without affecting body weight gain and feed conversion ratio. Hatchability in 0.03 and 0.05 mL/egg NC treatments were decreased (P<0.05) in compare with the control treatment. In general, in ovo administration of NC improved antioxidant status of the hatchlings. In ovo injection of NC and VE didn’t have a significant effect on posthatch growth performance of the broiler chickens.