title: Short-Term Subclinical Zinc Deficiency in Weaned Piglets Affects Cardiac Redox Metabolism and Zinc Concentration.
abstract: Background:Subclinical zinc deficiency (SZD) represents the common zinc malnutrition phenotype. However, its association with oxidative stress is not well understood. The heart muscle may be a promising target for studying early changes in redox metabolism.Objective:We investigated the effects of short-term SZD on cardiac redox metabolism in weaned piglets.Methods:Forty-eight weaned German Large White × Landrace × Piétrain piglets (50% castrated males and 50% females; body weight of 8.5 kg) were fed diets with different zinc concentrations for 8 d. Measurements included cardiac parameters of antioxidative capacity, stress-associated gene expression, and tissue zinc status. Analyses comprised (linear, broken-line) regression models and Pearson correlation coefficients.Results:Glutathione and α-tocopherol concentrations as well as catalase, glutathione reductase, B-cell lymphoma 2-associated X protein, and caspase 9 gene expression plateaued in response to reduction in dietary zinc from 88.0 to 57.6, 36.0, 36.5, 41.3, 55.3, and 33.8 mg/kg, respectively (P< 0.0001). Further reduction in dietary zinc promoted a linear decrease of glutathione and α-tocopherol (30 and 0.6 nmol/mg dietary Zn, respectively;P< 0.05) and a linear increase of gene expression [0.02, 0.01, 0.003, and 0.02 Log10(2-ΔΔCt)/mg dietary Zn, respectively;P< 0.05)]. Tissue zinc declined linearly with reduction in dietary zinc (0.21 mg tissue Zn/mg dietary Zn;P= 0.004) from 88.0 to 42.7 mg/kg (P< 0.0001), below which it linearly increased inversely to further reduction in dietary zinc (0.57 mg tissue Zn/mg dietary Zn;P= 0.006). H2O2-detoxification activity and metallothionein 1A gene expression decreased linearly with reduction in dietary zinc from 88.0 to 28.1 mg/kg [0.02 mU and 0.008 Log10(2-ΔΔCt)/mg dietary Zn, respectively;P< 0.05]. Fas cell-surface death receptor, etoposide-induced 2.4 and cyclin-dependent kinase inhibitor 1A gene expression correlated positively to cardiac zinc in piglets fed ≤42.7 mg Zn/kg (r≥ 0.97;P< 0.05).Conclusions:Short-term SZD decreased cardiac antioxidative capacity of weaned piglets while simultaneously increasing stress-associated gene expression and zinc concentration. This is the first report to our knowledge on the effects of SZD on redox metabolism.
authors.affiliation: School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany daniel.brugger@wzw.tum.de.
authors.forename: Daniel
authors.identifier: 0000-0001-7267-0335
authors.initials: D
authors.lastname: Brugger
authors.affiliation: School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.
authors.forename: Wilhelm M
authors.identifier: 0000-0001-5714-2702
authors.initials: WM
authors.lastname: Windisch
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D003677:Deficiency Diseases / Q000378:metabolism / Q000662:veterinary*; D005260:Female; D005786:Gene Expression Regulation; D006321:Heart / Q000502:physiology*; D008297:Male; D010084:Oxidation-Reduction; D013552:Swine; D015032:Zinc / Q000737:chemistry / Q000172:deficiency*
chemical_list: D015032:Zinc
keywords: gene expression; heart muscle; oxidative stress; pig; zinc deficiency