Effects Of Tea Polyphenols On Laying Performance,Egg Quality And Health Of Laying Hens

The objective of this study is to choose the optimal TP level for laying hens and to set foundamental basis for TP utilization in egg industry.Two experiments were conducted to determine the effects of tea polyphenols(TP)on production performance,egg quality,antioxidation status,lipid metabolism,and intestinal health of laying hens.Experiment 1:Effects of different tea polyphenols purity products on production performance,egg quality and lipid metabolism of laying hensA total of 1200 Lohman layers(67-week-old)were randomly allotted into 10 diets with 8 replicates of 15 hens each.The treatments were 1 control plus a 3×3 factorial completely randomized arrangement.The 3 tea polyphenols products are 3 tea polyphenols[20%(TP20),30%(TP30),and 60%(TP30)]contents with 3 tea polyphenol supplementation levels at 666,1333 and 2666mg/kg.At the experiment 1-9 weeks,the addition of TP30 at 1333mg/kg,TP30 at 2666mg/kg,and TP60 at 2666mg/kg significantly decreased the egg production compared with control(P<0.05).The egg production of TP20 was significantly higher than TP30,TP60(P<0.05)and the egg production of TP60 was significantly higher than TP30(P<0.05).The egg production of 2666mg/kg was significantly lower than 666,1333mg/kg in spite of the TP sources.The addition of TP30 at 1333 and 2666mg/kg,TP60 at 1333 and 2666mg/kg decreased the ADFI compared with the control treatment(P<0.05).TP30 and TP60 decreased the ADFI significantly with regard to the no TP and TP20 addition treatment(P<0.05),while the TP30 at 2666 mg/kg group were observe to have the lowest ADFI(P<0.05).The addition of TP30 at 1333mg/kg,TP30 at 2666mg/kg,TP60 at 1333mg/kg and TP60 at 2666mg/kg significantly decreased the average egg weight compared with the control group(P<0.05).The average egg weight in TP30 was significantly lower than that in TP20 and TP60.The addition of TP30 at 2666mg/kg and TP60 at 2666mg/kg significantly increased the feed to egg ratio compared with control(P<0.05).The feed to egg ratio of 2666mg/kg was significantly higher than the 666,1333mg/kg.At the second week,the addition of TP30 at 2666mg/kg and TP60 at 2666mg/kg significantly increased Haugh compare with control(P<0.05).At the fourth week,the addition of TP30 at 666mg/kg,TP30 at 2666mg/kg,and TP60 at 1333mg/kg significantly increased Haugh compared with the control(P<0.05).At the ninth week,the addition of TP60 at 2666mg/kg significantly increased Haugh compared with control(P<0.05).At the second week,the Haugh unit of TP20 were significantly lower than TP30,TP60(P<0.05).The Haugh unit of 2666mg/kg were significantly higher than 666,1333mg/kg(P<0.05).At the second week,the eggshell percentage of TP20 was significantly higher than TP30,TP60(P<0.05)and the eggshell percentage of 2666mg/kg was significantly lower than the 666,1333mg/kg(P<0.05).TP can decreased significantly the egg yolk cholesterol at the 666,1333,2666mg/kg of TP60(P<0.05).The addition of TP20,TP30,TP60 decreased the serum total cholesterol,triglyceride(TG),LDL-C,and increased the HDL-C significantly at the sixth weeks(P<0.05).The serum TG,TC,and HDL-C of TP20 were significantly higher than TP30、TP60(P<0.05).The serum LDL-C at the 2666mg/kg was significantly higher than the 666 and 1333mg/kg(P<0.05).Addtion of TP60 significantly increased the liver gene expression of AMPK(P<0.05).These results suggested that TP can increase egg Haugh unit and decrease yolk cholesterol,but TP decreased the production performance of laying hens.TP can regulate lipid metabolism in laying hens.Experiment 2:Effects of different tea polyphenols levels on production performance,egg quality,lipid metabolism,antioxidation,and intestinal health of laying hens.A total of 720 Lohmann laying hens(35-wk-old)were randomly allotted into 5 groups with 6 replicates of 24 hens each.Five diets(control、TP200、TP400、TP600、TP800)containing TP 0,200,400.600,800mg/kg were used in a 8-wk study.At eighth week,the Haugh unit and albumen height of TP400 were higher than the control,TP200(P<0.05),and the addition of 800m/kg TP significantly increased the Haugh unit compared with the control(P<0.05).There was an effect on eggshell colour when hens were fed TP diet.At the second week,the L*of TP600 was significantly lower than the control,TP800(P<0.05),while the b*of TP800 was significantly lower than thecontrol,TP200,TP600(P<0,05).At eighth week,TP400 decreased the serum TC、LDL-C significantly and increased the serum HDL-C significantly(P<0.05).Compared to the control hens,TP inproved the serum,liver,uterus and egg antioxidation status.TP 600、TP800 significantly increased the serum activity of GSH-ST,and decreased the serum MDA level(P<0.05).TP400 significantly increased the activity of liver T-SOD and uterus GSH-PX(P<0.05).TP significantly decreased the SCFA contents of caecum chime(P<0.05).Supplementation TP400 can significantly increase the acetic acid and butyric acid level compared to the control、TP200(P<0.05).Compared to the control,the addition of TP800 significantly increased the acetic and butyric acid(P<0.05)TP diet can increase the propionic acid of caecum chime(P=0.058).Supplementation TP could increase the lactobacillus content of caecum chime.The addtion of TP significantly increased the expression of liver gene LDLR(P<0.05).And the addition of TP significantly increased the expression of uterus gene FECH.These results suggested that supplementation TP could increase egg quality,antioxidation of laying hens and improve intestinal health.Moreover,the TP could regulate liver and body lipid metabolism of laying hens through regulating the concentration of cecum SCFA and lipid metabolism relatedgenes expression.In conclusion,the addition of four kinds of TP products(20%,30%,60%and 98%)chould improve the egg Haugh unit.The optimum addition level of was 666mg/kg for TP 20,TP30,or TP 60,and 400 mg/kg for TP 98 based on the cost and benefit,or 2666mg/kg for all TP products based on the improvement of egg quality.TP could improve the health of layer body and gut by improving the layer antioxidation status of body and uterus,the expression of LDLR gene in liver,the increase of beneficial bacteriumm in gut,but decreasing the serum cholesterol and triglyceride.