Abstract：Isobaric tags for relative and absolute quantitation (iTRAQ) combined with mass spectrum identification and bioinformatics were applied in this study to analyze the molecular mechanisms of weak embryos of duck (Anas platyrhynchos domestica), and select differentially expressed proteins that could be used in promoting hatchability. All 136 differentially expressed proteins were identified, and 76 proteins were significantly up-regulated and 60 proteins were significantly down-regulated in helped breaking eggs compared with that in normally hatching eggs. Gene Ontology (GO) and pathway enrichment analyses showed that the most of the differentially expressed proteins were related to glucose metabolism, oxygen transport, stress response, redox reaction and cytoskeleton. Four enzymes in glycolysis, three enzymes in cellular respiration pathways were significantly up-regulated (P＜0.05), and 7 proteins in actin filament dynamic process were up-regulated, whereas 3 hemoglobins in oxygen transport and 3 heat shock proteins in stress response were significantly down-regulated (P＜0.05) in helped breaking eggs compared with normally hatching eggs. The qRT-PCR was used for verifying the mRNA expression of cytoplasmic aconitate hydratase (ACO1), fructose-bisphosphate aldolase B (ALDOB), glyceraldehyde-3-phosphate dehydrogenase 1 (G3P1) and heat shock cognate 71 kD protein (HSPA8). Only the expression level of ACO1 were consistent in mRNA and protein. The results indicated that weak embryo might be related to glycometabolism, respiratory metabolism and some other biological processes, and there was lower energy metabolism in helped breaking eggs. This study provides theoretical basis of proteomics for molecular mechanism of weak embryos in duck.
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