Propolis supplementation attenuates the negative effects of oxidative stress induced by paraquat injection on productive performance and immune function in turkey poults

Abstract

Paraquat (PQ) is used as an herbicide in agriculture and may cause oxidative and inflammatory damages to animals and humans. The current study was conducted to investigate the positive effects of dietary propolis (PR), as a potent naturally-produced antioxidant, on growth performance and immune function of turkey poults exposed to PQ injection. Native male turkey poults (n=120, 49-d-old) were randomly assigned into 4 groups: poults received a basal diet with a daily subcutaneous PQ injection of 5 mg/kg BW for 7 consecutive days (PQ group), an experimental diet containing 1 g/kg PR with a daily subcutaneous PQ injection for 7 days (PR+PQ group), or received the experimental PR diet with a daily subcutaneous injection of 0.5 ml sterile saline for 7 days (PR group); while the control poults received a basal diet with a daily subcutaneous saline injection for 7 consecutive days (C group). The productive performance in PQ group showed a significant (P<0.05) reduction in the weight gain (WG) and feed intake (FI), and impaired feed conversion ratio (FCR). Propolis supplementation in the PR+PQ group significantly (P<0.05) ameliorated the PQ effects on WG and FCR. Turkey poults of the PQ and PR+PQ groups had a significant (P<0.05) augmentation in the blood malondialdehyde (MDA), tumor necrosis factor-α (TNFα) and corticosterone levels, and in contrast, a significant reduction in the triiodothyronine (T3), when compared with poults of the C group. While propolis significantly (P<0.05) reduced the MDA and corticosterone, and increased the T3 levels in the PR+PQ group compared to the PQ group. Furthermore, the dietary PR supplementation significantly (P<0.05) limited the PQ-suppressive effects on cell- and humoral-mediated immunity and lymphocyte proliferation of turkey poults. In addition, propolis supplementation in the PR and PR+PQ groups markedly reversed the PQ-induced DNA degradation and Heat shock protein 70 (Hsp70) over-expression in blood cells. It can be concluded that PR could improve turkey immunity and performance, particularly under inflammation and oxidative stress induced by PQ exposure.