This study was conducted to investigate the effects of oridonin (ORI) on growth performance and antioxidant capacity in broiler chickens that were repeatedly challenged with lipopolysaccharide (LPS). A total of 384 one-day-old male Arbor Acre broiler chickens were randomly assigned to 8 treatments with 6 replicate cages per treatment and 8 birds per replicate. There were 4 dietary treatments: the control group (birds fed the basal diet), the ORI 50 group, the ORI 80 group, and the ORI 100 group (the basal diet supplemented with 50, 80, and 100 mg/kg oridonin, respectively). Broilers were intraperitoneally injected with either 250 μg/kg BW LPS or an equivalent amount of sterile saline at 16, 18, and 20 d of age. LPS decreased the average daily weight gain (ADG), the average daily feed intake (ADFI), and the feed conversion ratio (FCR) of broiler chickens (P < 0.05); oridonin supplementation had no effects on performance whether before or after LPS injection (P > 0.05). LPS stimulation increased the relative weight of the spleen and bursa (P < 0.05); oridonin inclusion markedly attenuated the increased spleen index (P < 0.05). Additionally, the LPS-induced increases in the concentrations of malondialdehyde (MDA) and decreases in activities of total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and catalase (CAT) were dramatically attenuated by oridonin in both the serum and liver (P < 0.05). Furthermore, LPS down-regulated the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), copper and zinc superoxide dismutase (Cu/Zn-SOD), manganese superoxide dismutase (Mn-SOD), glutathione peroxidase (GPx1), and CAT in the liver (P < 0.05), However, oridonin inclusion increased the liver mRNA expression levels of Nrf2, Cu/Zn-SOD, Mn-SOD, CAT, and GPx1 (P < 0.05). It was concluded that the dietary oridonin supplementation at an optimum dose of 100 mg/kg improves the antioxidant capacity in broilers, as evidenced by the decrease in MDA and the increase in total SOD activities and mRNA expression levels of the liver antioxidant genes, although the effects on growth performance was negligible.
Keywords: antioxidant capacity; broiler; growth performance; lipopolysaccharide; oridonin.
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