Effects of proteinate complex zinc on growth performance, hepatic and splenic trace elements concentrations, antioxidative function and immune functions in weaned piglets

Objective: To assess the effects of proteinate complex zinc (PC-Zn) on growth performance, antioxidative function, trace element concentrations and immune function in weaned piglets. Methods: Three hundred newly weaned barrows (Duroc×Landrace×Yorkshire), 28 days of age, were randomly allotted to 3 dietary groups of 5 replicate pens per group for 4 weeks of feeding. Experimental diets were: i) zinc deficient diet (ZnD, 24 mg/kg Zn supplementation from ZnSO₄), ii) inorganic Zn diet supplemented with 120 mg/kg of Zn from Zn sulfate (ZnSO₄), and iii) organic Zn diet supplemented with 120 mg/kg of Zn from PC-Zn. The body weight of pigs were recorded at the beginning, at the middle and at the end of the experiment, and the amount of feed supplied each day was recorded. Five barrows from each dietary treatment group were selected to be anesthetized and euthanized at the end of the trial to determine the Zn, Cu, Fe, and Mn concentrations, the hepatic metallothionein content, the levels of methane dicarboxylic aldehyde (MDA), Mn, and Cu/Zn superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in the spleen, the levels of interleukin (IL)-2, IL-4, IL-10, interferon (IFN)-γ, CD3+, CD4⁺, and CD8⁺ T lymphocyte. Results: The accumulation of Zn in the spleen, levels of SOD, GSH-Px, IL-4, IL-10, the proportions of CD3+ and CD4⁺ T lymphocyte, and the ratio of CD4⁺/CD8⁺ T lymphocyte were increased by organic Zn supplementation compared to ZnD, while the levels of MDA, IFN-γ, and proportion of CD8⁺T lymphocyte were lowered. Conclusion: These findings indicate that Zn can improve the antioxidant potential and immune functions of weaned piglets.