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The paper aimed to evaluate the effects of dietary inclusion of green tea powder (GTP) on laying performance, egg quality, and blood biochemical parameters of laying hens. A total of 240 Jingfen No. 6 laying hens (age, 24 wk) were randomly allocated into 4 groups: control group (CON , basal diet), GTP0.5, GTP0.75, and GTP1.0 (basal diet included 0.5, 0.75, and 1.0% GTP, respectively). Each group has 5 replicates with 12 birds each. The feeding trial lasted 8 wk. The results showed that the hen-day egg production rate in GTP0.5 and GTP 0.75 group was higher than that of GTP1.0 group (P < 0.05), hen-day egg production rate in the GTP1.0 group was lower compared to the CON group (P > 0.05), the feed conversion ratio (FCR) in the GTP0.75 group was lower than that in CON and GTP 1.0 group (P < 0.05) during the entire experimental period. Albumen height and Haugh unit were higher in the GTP0.75 and GTP1.0 group compared to the CON group at d 56 (P < 0.05). At the end of experiment, plasma TG content in the GTP0.75 and GTP1.0 group was lower than that in the CON group (P < 0.05), the T-CH concentration in the GTP0.5 and GTP0.75 group was lower compared to the CON group (P < 0.05), plasma LDL-C and CORT concentrations were decreased by dietary GTP supplementation (P < 0.05), the HDL-C and BUN concentrations in the GTP0.75 and GTP1.0 group were higher than that in the CON group (P < 0.05). The antibody titers of H5N1 in the GTP0.75 and GTP1.0 group, and H7N9 in the GTP1.0 group were lower than that in the CON group (P < 0.05). In conclusion, dietary GTP inclusion could affect laying performance, regulate lipid metabolism, and have no favorable influence on antibody titers of H5N1 and H7N9, herein, dietary 0.5% GTP inclusion is suggested for Jingfen No. 6 laying hens during the peak laying period. [ABSTRACT FROM AUTHOR]

The fishy odor of duck eggs has restricted their consumption and industrial development, a problem that producers need to address. We estimated the effects of cage, floor, and pond rearing systems on duck egg flavor, egg quality, and microbial diversity by evaluating yolk trimethylamine (TMA) content, egg quality, and the differences between duck cecum (cage cecum, CC ; floor cecum, FC ; pond cecum, PC) and the environment (cage environment, CE ; floor environment, FE ; pond environment, PE). The results show that the yolk TMA content of the floor-rearing and pond-rearing systems was significantly higher than that of the cage-rearing system (P < 0.001), with no difference between the floor and pond-rearing systems. No significant differences were detected in egg quality among the rearing systems. Firmicutes, Actinobacteria, and Bacteroidetes were the dominant phyla in the cecum, and in the rearing environment, Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria were the dominant phyla. The results of α and β diversity analyses show that changes in the rearing system affected the composition and diversity of duck cecal microbes. In addition, we screened several genera that may be related to the production of TMA in duck cecum under different rearing systems using LEfSe analysis; for example, Subdoligranulum in the CC group; Romboutsia in the FC group; and Lactobacillus, Clostridium , and Streptococcus in the PC group. In conclusion, the rearing system affects the cecal microbes of ducks, which in turn affect the deposition of TMA in duck eggs but have no adverse effect on egg quality. This study provides a basis for the development of rearing strategies to reduce the fishy odor of egg yolk in the duck industry. [ABSTRACT FROM AUTHOR]