Effects Of Dietary Clostridium Butyricum On Production Performance,Egg Quality And Intestinal Tract Of Hens During The Late Laying Period

This experiment was conducted to study the effects of dietary Clostridium butyricum(CB)on production performance,egg quality,intestinal morphology and cecal microflora of hens during the late laying period.Thus,the problems of egg weight reduction and laying rate reduction of hens during the late laying period can be effectively solved,which provides theoretical reference for the application of CB in hen production in the future.In the experiment,two hundred and seventy 70-week-old Hey-Line brown hens with similar laying rates were randomly divided into 3 groups with 6 replicates in each group and 15 laying hens in each replicate.The hens in the control group were fed a basal diet,in experimental groupⅠwere fed the basal diet supplemented with 2.5×10~8CFU/kg CB and in experimental groupⅡwere fed the basal diet supplemented with 5×10~8CFU/kg CB.The preliminary experiment lasted for 7 days and the formal experiment lasted for 45 days.1、Measurement indicators and methods(1)Production Performance:During the experiment,the number of laying eggs,eggs weight,the number of broken eggs and the number of dead chickens were recorded every day,and the feed intake was counted weekly.The laying rate,average daily egg weight,average daily feed intake,the ratio of feed to egg,broken eggs rate and mortality rate of hens were calculated.(2)Egg Quality:On the 45th day of the experiment,ten saleable eggs(no shell defects or cracks)were randomly selected from each replication and utilized to determine the egg quality indicators by an egg quality analyzer,including egg weight,egg shape index,egg albumen height,haugh units,eggshell thickness,eggshell breaking strength,yolk relative weight and eggshell relative weight.Yolk cholesterol content was assessed by the Total Cholesterol Assay Kit.(3)Intestinal Morphology:On the 45th day of the experiment,six experimental chickens were randomly selected from each replication for intestinal morphology study.After fasting for 12 hours,they were quickly slaughtered and the duodenum,jejunum and ileum segments of each chicken were intercepted two centimeters,and fixed in 4%paraformaldehyde,and hematoxylin-eosin(HE)staining was used to make paraffin section.Then the intestinal morphology was observed.(4)Caecal Microbes:Four experimental chickens were randomly selected from control group and groupⅡand sacrificed on day 45.Caecum samples were aseptically collected from each chicken and immediately stored at-80℃and promptly processed.16S rDNA high-throughput sequencing method was used to detect the microbial community structure in the caecum V3-V4 region.2、The results showed as followsThe effects of Clostridium butyricum on laying hens:(1)Production performance:the laying rate of experimental groupⅠwas 4.18%higher than that of the control group(P<0.05).The laying rate of experimental groupⅡwas 3.71%higher than that of the control group(P<0.05).There was no significant difference between the experimental group I and the experimental group Ⅱ in the laying rate of hens(P>0.05).There were no significant difference in average daily egg weight,average daily feed intake,the ratio of feed to egg,broken egg rate and Mortality rate of hens in each group(P>0.05).(2)Egg quality:Compared with the control group,experimental groupsⅠandⅡdid not significantly affect average egg weight,egg shape index,albumen height,Haugh unit,eggshell thickness,eggshell strength,relative weight of yolk,relative weight of eggshell and yolk cholesterol content(P>0.05)(3)Intestinal morphology:(1)The villous height(VH)of duodenum:the experimental groupⅠincreased by 4.29%compared with the control group(P<0.05),and there was no significant difference between the experimental groupⅡand the control group(P>0.05),and the experimental groupⅠincreased by 4.48%compared with the experimental groupⅡ(P<0.05).There was no significant difference in crypt depth(CD)and villous height/crypt depth(VH/CD)of duodenum in each group(P>0.05).The intestinal wall thickness of duodenum:compared with the control group,the experimental groupⅠandⅡincreased by 24.94%and 40.49%(P<0.05),and there was no significant difference between the experimental groupⅠandⅡ(P>0.05).(2)The VH of jejunum:compared with the control group,the experimental groupⅠandⅡincreased by 19.54%and 13.14%(P<0.05),and there was no significant difference between the experimental groupⅠandⅡ(P>0.05).There was no significant difference in CD,VH/CD and intestinal wall thickness of duodenum in each group(P>0.05).(3)The VH of ileum:the experimental groupⅠandⅡincreased by 27.00%and 40.30%compared with the control group(P<0.05),and the experimental groupⅡincreased by 10.47%compared with the experimental groupⅠ(P<0.05).There was no significant difference in CD of ileum in each group(P>0.05).The VH/CD of ileum:the experimental groupⅠandⅡincreased by27.66%and 38.10%compared with the control group(P<0.05),and the experimental groupⅡincreased by 8.18%compared with the experimental groupⅠ(P<0.05).The intestinal wall thickness of ileum:the experimental groupⅠandⅡincreased by22.31%and 18.90%compared with the control group(P<0.05),and there was no significant difference between the experimental groupⅠandⅡ(P>0.05).(4)The cecal microflora:The Alpha diversity of cecal microflora in group Ⅱ was significantly decreased and the cecal microbial community structure was significantly changed compared with the control group.On the phylum level,results showed that the cecal microflora in the samples of the experimental groupⅡand the control group were mainly composed of Firmicutes and Bacteroidetes.Compared with the control group,the relative abundance of Fusobacteria in cecal microflora of group Ⅱ was significantly increased(P<0.05),and the relative abundance of Bacteroidetes increased to a certain extent(P>0.05),but the relative abundance of Firmicutes decreased to a certain extent(P>0.05).On the genus level,the cecal microflora in the samples of the experimental groupⅡand the control group were mainly composed of Rikenellaceae RC9 gut group and Bacteroides.Compared with the control group,Christensenellaceae R-7 group,norank f Ruminococcaceae,unclassified f Ruminococcaceae and Ruminococcaceae UCG-005 in the cecal microflora of the experimental group Ⅱ were significantly decreased(P<0.05),and the relative abundance of Bacteroides was increased to a certain extent(P>0.05),and the relative abundance of Rikenellaceae RC9 gut group increased to a certain extent(P>0.05).In conclusion,dietary CB supplementation can improve production performance and intestinal morphology of hens during the late laying period,and have a certain degree of influence on the cecal microflora.