Turmeric powder mitigates oxidative stress in broilers dietary exposed to Aflatoxin B1 at EU maximum tolerated levels

Introduction: Aflatoxin B1 (AFB1) causes hepatotoxicity, immunotoxicity, and organ damage (e.g., heart and kidney), besides being a IARC group I carcinogen. The most frequent adverse effects in farm animals are decreased growth and productivity, leading to economic losses. In the EU maximum limits (MLs) of AFB1 in feed range from 0.005 to 0.02 mg/kg. Chicken is moderately sensitive to AFB1, which leads to low performance and reduced quality of both eggs and meat. Oxidative stress (OS) is a critical risk factor for AFB1 toxicity, and we demonstrated that it underpins renal damage in broilers (1). Our aim is to investigate: i. the AFB1-induced OS in broilers dietary exposed to concentrations approaching the MLs; ii. the ability of curcumin and curcuminoids, known antioxidant compounds, to mitigate such effects. Materials and Methods: Twenty-day-old broilers (n=8 for each experimental group) were treated for 10 days with AFB1 (0.02 mg/kg feed), alone or in combination with Turmeric Powder (TP, 400 mg/kg feed), containing 2.5% curcumin and its main metabolites. Blood samples were collected at T0 and T10 for the evaluation of the serum antioxidant capacity (SAC) by the OXY-Adsorbent test. Liver samples were tested for malondialdehyde (MDA) levels by TBARS assay, glutathione (GSH) content and glutathione peroxidase (GPx) and glutathione S-Transferase (GSTs) activities. Gene expression of antioxidant and biotransformation enzymes, and drug transporters was assessed in samples from liver and small intestine by qRT-PCR. Results: Animals exposed to AFB1 alone displayed significant (p<0.01) alterations of some OS parameters compared with controls: SAC was reduced by approximately 30%, while liver MDA levels were increased by about 9 folds. The concomitant administration of TP completely reverted such affects. Moreover, TP alone significantly upregulated the hepatic gene expression of catalase and superoxide dismutase, which further augmented in combination with AFB1. Conclusions: These results demonstrate that AFB1 causes OS in broilers at serum and liver levels, even following the exposure for a limited period of time (10 days) to concentrations approaching the EU limits in feed. Moreover, curcumin dietary supplementation (in the form of TP) can positively regulate the expression of certain hepatic antioxidant enzymes and ameliorate AFB1-mediated effects, resulting as an effective feeding strategy to prevent AFB1 toxicity in broilers. References: 1. Damiano et al. Front Vet Sci 2022; 8:822227