Green tea powder inclusion promoted hatchability through increased yolk antioxidant activity

Dietary supplementation of green tea powder (GTP) changes egg quality of hens, however, whether these changes affect incubation is still unknown. This study was to compare the proteomic difference of incubated eggs from hens with GTP supplemented or not. Huainan partridge chickens (1,080) at 35 wk of age were allocated into 2 groups, one group fed basal diet (CG) and one group fed basal diet plus 1% GTP (EG). After 4 wk feeding, artificially fertilized eggs were collected for yolk cholesterol determination and incubation. During incubation, 6 embryos from each group were randomly selected in each day for yolk protein extraction and quantification. Yolk cholesterol content was significantly lower, while the hatchability was significantly higher in EG than that of the CG group (P < 0.05). Yolk protein concentration at embryonic days (ED) of 0, 2, 6, and 13 showed significant changes and were selected for proteomic analysis by 2-dimensional gel electrophoresis combined with liquid chromatography-tandem mass spectrometry. Fifty-one differentially expressed (DE) protein spots were identified among different incubation stages between CG and EG group which were mainly classified into vitellogenin, immunoglobulin, and ovoinhibitor, and occupied 45.1, 23.5, and 15.7%, respectively, to the total DE proteins. Ovotransferrin, participated in extracellular sequestering of iron ion process, was significantly lower in EG group than that of the CG group (P < 0.05). Ig light chain precursor (Immunoglobulin) exhibited higher expression at ED6 in EG group as compared with that of the CG group, and was participated in immune response related processes. Ovoinhibitor, mainly involved in protease binding activity, showed lower abundance at ED13 in EG group as compared with that of the CG group. Vitellogenin-3, showed lower expression in EG group as compared with that of the CG group, was mainly participated in lipid transportation and localization according to GO enrichment. Chickens fed diet with GTP provided eggs more antioxidant ability that increased hatchability, indicated that GTP could be considered as additive in breeding layer.