| Egg was one of the main source of proteid and vitamin in people's meals,which riched in nutrition,but cholesterol contents were high(about 200-300mg in one egg). Consumption of some Occidental eggs appeared downtrend,from 303 to 235 eggs of one person in one year.High cholesterol contents in eggs were the main factors.Hygienical eggs production was the major target of this research.Dietary effects of green tea powder supplementation on performance and lipid metabolism were investigated in laying hens by putting different doses of tea polyphenols and green tea powders into basal diet of laying hens in order to find some order linesses which were useful for low cholesterol eggs research.270 311-day-old Lohamann laying hens were randomly divided into 9 treatments,each with 30 hens,which CK fed a basal diet,groups 1,2,3 and 4 fed a basal diet supplemented with 500mg/kg,1000mg/kg,2000mg/kg and 4000mg/kg green tea powders and groups 5,6,7 and 8 fed a basal diet supplemented with 100mg/kg, 200mg/kg,400mg/kg and 800mg/kg tea polyphenols for a period of 35 days.Dietary effects of green tea powders and tea polyphenols(TP)supplementation on performance, blood biochemical index and egg quality were investigated in laying hens.The results are as follow:(1).Effect of egg production:Compared with control group laying rate of laying hens was increased when fed a basal diet added with 500mg/kg,1000mg/kg green tea powders and 200mg/kg TP,while the other treatments were decreased;However the differences were not significant(p＞0.05).Average egg weight were increased 1.84%, 2.75%and 1.38%respectively,when fed a basal diet added 500mg/kg,1000mg/kg and 2000mg/kg green tea powders,and the differences were notable(p＜0.01);egg weights of group fed TR were increased to TP additive.The four group fed green tea powders,dairy feed intake were increased 3.77%,5.51%,4.06%and 3.48%,respectively,the differences were significant(p＜0.01);5,6 and 8 group fed TP,dairy feed intake were all decreased, the differences were significant(p＜0.01),while 7 group was not notable(p＞0.05).There is a trend that dairy feed intakes were improved with increasing levels of added TP.The feed egg rates of fed with TP were decreased,especially 6 and 8 group,the difference between they and control group were significant(p＜0.01).However,the feed egg ratios of fed with green tea powders were increased,especially 2,3 and 4 group,the difference were signicant(p＜0.01).(2).Effect of blood biochemical index:Compared with control group,Higher green tea powders and TP would decreased TG and TCH contents of serum,impact of fed 4000mg/kg green tea powders and 800mg/kg TP was prime,decreased 42.3%and 24.16%repectivrly,the difference were significant a(p＜0.01).ALP,HDL content as well as TPR content were improved,while UA was decreased,but the difference were either significant(p＞0.05).Serum P content has increasing trend while GLO decreased,but the difference were not significant also(p＞0.05);serum CA and ALB content were significant decreased(p＜0.01).(3).Effect of egg quality:Compared with control group,effect of egg water content after adding green tea powders and TP in basal diet was not significant(p＞0.05);egg fat content and TCH were decreased together,yolk colour was more dark than before,but all of the difference were not significant(p＞0.05).In all,there was no significant effect on performance proguce of laying hens after adding green tea powders and TP in basal diet,while feed conversion efficiency and immunity could be improved to some extent.Stand on the point of economy,green tea powders was better than TP because of more cheaper and easier to get.
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