| In order to study the anti-heat stress effect of curcumin,different concentrations of curcumin were added to the diet of laying hens,and the Hailan laying hens were fed under high temperature conditions in summer.The effects on the performance,serum biochemical parameters,intestinal,antioxidant and immune function of laying hens were tested.A total of 240 Hailan laying hens with the same body condition at 280 days of age were randomly divided into 4 groups,with 4 replicates in each group and 15 chickens per replicate.The egg production rate was similar between the groups.The control group was fed with basal diets.The experimental group was fed with test diets supplemented with 100mg/kg,150 mg/kg,and 200mg/kg curcumin in the basal diet.The experimental period was 42 day,and the average daily temperature was 28.7℃～34.4℃.The results are as follows:Experiment 1 Effect of curcumin on production performance,egg quality and reproductive regulation of heat-stressed laying hensCompared with the control group,1)different levels of curcumin in the diet had no significant effect on the average egg weight and death rate(P>0.05);At 3 weeks after the experiment,the egg production rate of the 150mg/kg curcumin group was significantly increased(P<0.05),and increased by 11.24%;the egg ratio of the 100mg/kg and 150mg/kg curcumin group was significantly decreased(P<0.05),and reduced by 7.63%and 9.75%,respectively.2)Different levels of curcumin in the diet had no significant effect on egg shape index,protein height,egg yolk color,egg yolk weight and Haugh unit(P>0.05);at the end of 6th week,the eggshell strength and eggshell thickness of the 150mg/kg and 200mg/kg curcumin group were significantly increased(P<0.05),the eggshell strength was increased by 16.06%and 18.07%,respectively,and the eggshell thickness was increased by 5.88%,respectively.3)At the end of 3th week,the addition of different levels of curcumin in the diet had no significant effect on serum CORT concentration(P>0.05),and the concentrations of FSH and LH in the 100mg/kg curcumin group were extremely significant increased(P<0.01).The concentrations of FSH,LH and E2 in the 150mg/kg and 200mg/kg curcumin groups were extremely significant increased(P<0.01).At the end of the 6th week,different levels of curcumin in the diet had no significant effect on serum LH concentration(P>0.05),the serum FSH concentration of 150mg/kg curcumin group was extremely significant increased(P<0.01);the serum E2 concentration of 150mg/kg and 200mg/kg curcumin group was significantly increased(P<0.05),and the concentration of CORT was extremely significant decreased(P<0.01).4)There was no significant effect of different levels of curcumin in the diet on the expression of ovarian Bax gene(P>0.05).The expression of Bcl-2 gene in the ovary was significantly increased in the 150mg/kg curcumin group(P<0.05),the expression of caspase-3 gene was significantly decreased(P<0.05),and the expression of p53 gene was significantly decreased at the end of the sixth week(P<0.05),and there was no significant difference at the third weekend(P>0.05).Experiment 2 Effect of curcumin on serum biochemical parameters and antioxidant function of heat-stressed laying hensCompared with the control group,1)different levels of curcumin in the diet had no significant effect on serum TP,TG,UA,ALP(P>0.05);At the end of the 6th week,the concentration of GLU was extremely significant increased in the 100mg/kg,150mg/kg and 200mg/kg curcumin group(P<0.01),and increased by 36.10%,52.48%5,3.53%,respectively,and the CHO concentration was significantly decreased(P<0.05),and decreased by 27.59%,33.45%,27.59%,respectively;the CREA concentration of serum in the 150mg/kg and 200mg/kg curcumin groups was extremely significant decreased(P<0.01),and the LDL-C concentration was significantly decreased(P<0.05);Serum ALT activity was significantly lower in the 150mg/kg and 200mg/kg curcumin group(P<0.05).The serum ALB and HDL-C concentrations in the 150mg/kg curcumin group were significantly increased(P<0.05),and the AST activity was significantly decreased(P<0.05).2)The addition of different levels of curcumin had no significant effect on liver GSH-Px activity(P>0.05).At the end of the 3th week,serum and liver SOD activities were significantly increased in the 100mg/kg,150mg/kg and 200mg/kg curcumin groups.The increase of serum and liver CAT activity in the 150mg/kg curcumin group was significantly increased(P<0.05),and the serum and liver MDA levels in the 100mg/kg and 150mg/kg curcumin group were significantly decreased(P<0.05).At the end of the 6th week,serum SOD,CAT and GSH-Px activities in the 150mg/kg curcumin group were significantly increased(P<0.05),liver MDA content was significantly decreased(P<0.05),the liver SOD of the 100mg/kg curcumin group was significantly increased(P<0.05),and the liver CAT activity of the 100mg/kg and 150mg/kg curcumin groups was significantly increased(P<0.05).3)Different levels of curcumin in the diet had no significant effect on SOD,CAT and MDA in the duodenum(P>0.05);the activity of GSH-Px in the duodenum was extremely significant increased in the 100mg/kg,150mg/kg and 200mg/kg curcumin group(P<0.01);the addition of different levels of curcumin had no significant effect on GSH-Px,SOD and CAT activities in the jejunum(P>0.05),and added 100mg/kg,150mg/kg and 200mg/kg curcumin group,the content of MDA was extremely significant reduced(P<0.01).Experiment 3 Effects of curcumin on intestinal morphology,caecal flora and immune function of heat-stressed laying hensCompared with the control group,1)different levels of curcumin in the diet had no significant effect on duodenum CD,the VH and VH/CD values of the duodenum in the 150mg/kg and 200mg/kg curcumin groups were significantly increased(P<0.01);different levels of curcumin in the diet had no significant effect on CD and VH/CD in jejunum(P>0.05),VH was significantly increased(P<0.05);There were no significant differences in the ileal VH,CD and VH/CD between the different levels of curcumin in the diet(P>0.05).2)At the classification level of the phylum,both the control group and the curcumin group were mainly Bacteroidetes and Firmicutes,followed by Proteobacteria.Bacteroides gate accounted for 43.02%in the control group,and 54.79%、51.98%、47.61%in the curcumin group,Firmicutes gate accounted for 46.23%in the control group,and 33.56%,36.44%,41.70%in the curcumin group,respectively,at the classification level of the genus,both the control group and the curcumin group were mainly Bacteroides and Rikenellaceae RC9 gut group;Bacteroides accounted for 17.47%in the control group,and 29.24%,21.30%,21.17%in the curcumin group,respectively;Rikenellaceae RC9 gut group accounted for 8.15%in the control group;11.49%,9.66%,8.68%in the curcumin group,respectively.3)The serum IgA and IgM levels in the 150mg/kg and 200mg/kg curcumin groups were extremely significant increased(P<0.01),C3 levels increased significantly(P<0.05),IL-6 levels extremely significant decreased(P<0.01),Serum IgG and C4 levels were significantly increased in the 150mg/kg curcumin group.At the end of the 6th week,the addition of different levels of curcumin had no significant effect on serum IL-6 levels(P>0.05),serum IgM and C3 levels in the 100mg/kg,150mg/kg and 200mg/kg curcumin groups were extremely significant increase(P<0.01);serum IgA levels were extremely significant increase in the 150mg/kg and 200mg/kg curcumin groups(P<0.01),serum IgG levels were significantly increased in the 150mg/kg curcumin group(P<0.05).and the serum C4 level in the 200mg/kg curcumin group was significantly increased(P<0.05).4)The addition of different levels of curcumin had no significant effect on the expression of IL-2 gene in spleen(P>0.05).The expression of IL-4 and INF-γ genes in spleen of 150mg/kg curcumin group was significantly increased(P<0.05).The results of this thesis indicate that the addition of curcumin to laying hens can improve production performance,egg quality,enhance antioxidant performance,improve intestinal morphology,and improve immune function.Therefore,curcumin can be used as an anti-heat stress agent in the laying hens. |
