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Background: Lipopolysaccharides (LPS) are the main pathogenic substances in Gram-negative bacteria. The aim of this study was to investigate the preventive effects of dietary curcumin (CUR) on LPS toxicity in the duck ileum. The duck diet was supplemented with CUR (0.5 g kg -1 ) for 28 days, while the birds were injected with LPS (0.5 mg kg -1 body weight per injection, administered as seven injections in the last week of the experimental period)., Results: LPS significantly decreased the ileal villus-to-crypt ratio in the non-supplemented CUR group. Dietary CUR alleviated LPS-induced morphological damage to the ileum. Moreover, dietary CUR alleviated oxidative stress by increasing the levels of total superoxide dismutase (T-SOD) (P < 0.05) and glutathione S-transferase (GST) (P < 0.05) and decreasing the production of malonic dialdehyde (MDA) (P < 0.05) in control ducks and LPS-challenged ducks. Dietary CUR significantly inhibited the LPS-induced massive production of inflammatory factors (IL-1β, IL-6, and TNF-α) (P < 0.05). CUR induced the inhibition of TLR4 and activation of Nrf2 to reduce the expression of inflammation-related genes (TLR4, NF-κB, IKK, TXNIP, NLRP3, caspase-1, IL-1β, IL-6, and TNF-α). Moreover, dietary CUR ameliorated the decrease in claudin-1 and occludin expression (P < 0.05) and improved ZO-1 expression in the duck ileum (P < 0.05)., Conclusion: In conclusion, dietary CUR has beneficial effects on LPS-induced ileal damage, oxidative damage, and inflammatory response by inhibiting the TLR/NF-κB and activating the Nrf2 signaling pathways in ducks. This study provides valuable information regarding the therapeutic uses of CUR in duck ileitis. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)

Gram-negative bacteria contamination of feed can occur at all the stage of feed production, storage, transportation and utilization. Lipopolysaccharide (LPS) is a major toxic metabolite of Gram-negative bacteria. The aim of this study was to explore the effect of dietary resveratrol on the duck ileitis caused by LPS and its optimum addition level in diet. The results showed that LPS-induced duck ileitis with the destruction of intestinal structure, oxidative stress, mitochondrial dysfunction, inflammatory response and permeability alteration. Dietary resveratrol alleviated LPS-induced intestinal dysfunction and the increase of intestinal permeability by linearly increasing mRNA levels of tight junction protein genes (Claudin-1, Occludin-1, ZO-1) (p < 0.05) and protein expression of Claudin-1 (p < 0.01). In addition, dietary resveratrol improved the antioxidant capacity of duck ileum by reducing the production of MDA and increasing the activity of T-SOD (p < 0.01) and CAT. Lipopolysaccharide increased Keap1 at mRNA and protein level (p < 0.01) and decreased the protein level of Nrf2 (p < 0.05). Dietary resveratrol significantly downregulated expression of Keap1 and upregulated expression of Nrf2 in duck (p < 0.05). Dietary resveratrol suppressed the TLR4/NF-κB signalling pathway and the expression of its downstream genes including IKK, TXNIP, NLRP3, Caspase-1, IL-6 and IL-18. Meanwhile, the levels of inflammatory cytokines (IL-6, IL-18 and TNF-α) showed a linearly decrease (p < 0.01) with increasing dietary resveratrol level. These results demonstrated that resveratrol alleviated the LPS-induced acute ileitis of duck through Nrf2 and NF-κB signalling pathways, and the dietary resveratrol of 500 mg/kg is more efficiently., (© 2021 Wiley-VCH GmbH.)

Aflatoxin B1 (AFB1) is a stable toxic metabolite threatening health of human and animal and widely contaminated animal feed and human food. This present study aimed to investigate the effects of dietary curcumin on ileum injury in ducks induced by AFB1 administration and explore its underlying mechanisms. Ducks (N = 450, one-day-old male) with a similar weight were randomly assigned to 3 groups, containing the control group, AFB1 group (60 μg AFB1 kg−1 body weight) and curcumin (500 mg curcumin kg−1 diet) + AFB1 group. AFB1 administration markedly increased the ileum damage, AFB1-DNA adducts in the plasma and oxidation stress and inflammation. Adding curcumin into diet protected the ileum against morphology damage induced by AFB1 administration, decreased AFB1-DNA adducts in the plasma and eliminated oxidation stress and inflammation in the ileum of ducks. Anti-oxidation and anti-inflammatory effects of curcumin could protect the ileum against acute damage via activating Nrf2-ARE signaling pathway and inhibiting NF-κB signaling pathway. Conclusively, curcumin was a dietary anti-oxidation and anti-inflammation agent via activating Nrf2-ARE signaling pathway and inhibiting NF-κB signaling pathway to protect ileum against acute damage induced by AFB1 administration. [ABSTRACT FROM AUTHOR]