Abstract

This research aims to study the effects of rare earth-chitosan chelates (RECC) on growth performance, immunity and antioxidant function in broilers. A total of 192 one-day-old mixed-sex Arbour Acres (AA) broilers were allotted into 4 treatment groups with 6 replicates per treatment and 8 broilers per pen. Broilers were fed the basal diet supplemented with, respectively, 0 (control group), 150, 200 and 250 mg/kg RECC for 42 d. The results showed that dietary RECC improved average daily gain and decreased feed/gain (p < .05). Broilers fed with appropriate dose of RECC increased total antioxidant capacity (T-AOC) in serum (d 42) and liver (d 21). And the activity of glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) were increased, whereas malonaldehyde (MDA) concentration was decreased on d 42 in liver of broilers (p < .05) by enhancing the related gene expression in nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In addition, supplementing appropriate dose of RECC in diet increased the concentrations of interleukin 2 (IL-2), IL-4 in serum and jejunum (d 42). And the concentrations of immunoglobulin M (IgM) (d 21), and secretory immunoglobulin A (sIgA), IgG (d 42) (p < .05) in jejunum were elevated by decreased the related gene expression in Toll-like receptor 4/nuclear factor kappa-B (TLR4/NF-κB) pathway. In conclusion, RECC could exert beneficial effects on growth performance, immune function and antioxidant capacity of broilers, and the optimal supplemental dose for broiler production is 175 − 200 mg/kg.HIGHLIGHTSThis paper was very important in revealing the action mechanism of rare earth-chitosan chelate on immune function and antioxidant capacity of animals.The results of this study will provide a theoretical basis for further developing rare earth-chitosan chelate as antibiotic alternatives.The optimal dose range of rare ea