RESUMEN
Pharmacological levels of zinc oxide can promote growth and health of weaning piglets, but the underlying molecular mechanisms are yet not fully understood. The aim of this study was to determine changes in the global hepatic protein expression in response to dietary zinc oxide in weaned piglets. Nine half-sib piglets were allocated to three dietary zinc treatment groups (50, 150, 2500 mg/kg dry matter). After 14 d, pigs were euthanized and liver samples taken. The increase in hepatic zinc concentration following dietary supplementation of zinc was accompanied by up-regulation of metallothionein mRNA and protein expression. Global hepatic protein profiles were obtained by two-dimensional difference gel electrophoresis following matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. A total of 15 proteins were differentially (P<0.05) expressed between groups receiving control (150 mg/kg) or pharmacological levels of zinc (2500 mg/kg) with 7 down- (e.g. arginase1, thiosulfate sulfurtransferase, HSP70) and 8 up-regulated (e.g. apolipoprotein AI, transferrin, C1-tetrahydrofolate synthase) proteins. Additionally, three proteins were differentially expressed with low zinc supply (50 mg/kg Zn) in comparison to the control diet. The identified proteins were mainly associated with functions related to cellular stress, transport, metabolism, and signal transduction. The differential regulation was evaluated at the mRNA level and a subset of three proteins of different functional groups was selected for confirmation by western blotting. The results of this proteomic study suggest that zinc affects important liver functions such as blood protein secretion, protein metabolism, detoxification and redox homeostasis, thus supporting the hypothesis of intermediary effects of pharmacological levels of zinc oxide fed to pigs.
Asunto(s)
Hígado/efectos de los fármacos , Proteoma , Óxido de Zinc/administración & dosificación , Animales , Secuencia de Bases , Cartilla de ADN , Suplementos Dietéticos , Electroforesis en Gel Bidimensional , Hígado/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Porcinos , Destete , Óxido de Zinc/farmacologíaRESUMEN
Ruminal epithelium adapts to dietary change with well-coordinated alterations in metabolism, proliferation, and permeability. To further understand the molecular events controlling diet effects, the aim of this study was to evaluate protein expression patterns of ruminal epithelium in response to various feeding regimes. Sheep were fed with a concentrate-supplemented diet for up to 6 wk. The control group received hay only. Proteome analysis with differential in gel electrophoresis technology revealed that, after 2 days, 60 proteins were significantly modulated in ruminal epithelium in a comparison between hay-fed and concentrate-fed sheep (P < 0.05). Forty proteins were upregulated and 20 proteins were downregulated in response to concentrate diet. After 6 wk of this diet, only 14 proteins were differentially expressed. Among these, 11 proteins were upregulated and 3 downregulated. To identify proteins that were modulated by dietary change, two-dimensional electrophoresis was coupled with liquid chromatography electrospray ionization mass spectrometry. The differential expression of selected proteins, such as esterase D, annexin 5, peroxiredoxin 6, carbonic anhydrase I, and actin-related protein 3, was verified by immunoblotting and/or mRNA analysis. The identified proteins were mainly associated with functions related to cellular stress, metabolism, and differentiation. These results suggest new candidate proteins that may contribute to a better understanding of the signaling pathways and mechanisms that mediate rumen epithelial adaptation to high-concentrate diet.