| This experiment was conducted to investigate the effects of dietary different NCG levels on growth performance?intestinal health and cecal flora in weaned rabbits under normal or LPS induced stress condition.The main research content is divided into the following two research sections:Test 1: In this experiment,a total of 288 IRA 35-d weaned rabbits were randomly divided into 4 groups,and each group had 6 replicates with 12 rabbits per replicate.During the experimental period,the rabbits in 4 groups were fed a basal diet(control group),the basal diet with 0.1% NCG(group 1),the basal diet with 0.2% NCG(group 2),the basal diet with 0.3% NCG(group 3).The experiment was included 7 d pre-trial period and 28 d test period.The results showed that:(1)Compared with the control group,the ADG of group 3 increased significantly,increasing by 11.31%(P<0.05);The FCR of the test group 3 was significantly reduced,reducing by 4.97%(P<0.05);There was no significant change in the ADFI of each experimental group(P>0.05).2)Serum ALB levels reduced significantly in group 3(P<0.05);Serum TC and triglyceride levels reduced significantly in group 2?3(P<0.05);Serum BUN and LDL levels reduced significantly in group 1?2?3(P<0.05)?Serum IL-2 levels are significantly increased in group 3(P<0.05)?(3)The villus height of the test group 3 was significantly higher than that of the control group(P<0.05),and the crypt depth was significantly lower than that of the control group(P<0.05);The villus height/crypt depth values in group 2 and 3 were significantly improved(P<0.05).(4)Compared with the control group,the expression levels of Occludin and ZO-1 proteins in empty and ileum were significantly improved in group 2 and 3(P<0.05)?(5)Compared with the control group,the expression level of jejunal IL-2 gene was significantly increased in group 1?2?3(P<0.05),and the expression level of ileal IL-2 gene is significantly increased in group 3(P<0.05)?(6)(1)According to the analysis of Alpha diversity,the number of OUT of microorganisms observed in the cecal were increased.(2)At the phylum level,the dominant bacterial community of cecal contents were mainly consisted of Firmicutes,Bacteroidetes and Verrucomicrobia in weaned rabitts,as well as Proteobacteria,Tenericutes and Chloroflexi.Increasing dietary NCG level,the relative abdundance of Firmicutes was increased,and the relative abdundance of Bacteroidetes and Verrucomicrobia were decreased.(3)At the family level,there were 28 families with the abdundance of more than 0.1%,among them,Unclassified Clostridiales,Ruminococcaceae,Bacteroidales s24-7,verrucomicrobiaceae,etc.have relatively high density.Increasing dietary NCG level,the relative abdundance of unclassified clostridiales was increased,and the relative abdundance of Ruminococcaceae and Bacteroidales s24-7 were decreased?Test 2: The second experiment was conducted to evaluate the effect of dietary N-carbamylglutamate on growth performance and intestinal health with weaned rabbits under LPS stress.A total of 60 IRA 35-d weaned rabbits were randomly divided into 5 groups,and each group has 3 repliccates with 4 rabbits per replicate.During the experimental period,the rabbits in 5 groups were fed the basal diet(control group),the basal diet(group LPS),the basal diet+0.1% NCG(group A),the basal diet+0.2% NCG(group B),the basal diet+0.3% NCG(group C).The experiment was included 3 d pretrial period and 18 d test period.On the 16 th day of the experiment,rabbits in the group LPS,group A,group B and group C were intraperitoneally injected with 100 ?g/kg lipopolysaccharide(dissolve in a concentration of 1.0 mg/ml with 8.6 g/L sterile saline before injection.),and the control group was injected with the corresponding dose of sterile saline.The results showed that:(1)Compared with the control group,the ADG and ADFI of the meat rabbits were significantly lower(P<0.05),and the FCR was significantly increased in group LPS(P<0.05);Compared with the group LPS,the ADG of the group C was significantly increased(P<0.05),the FCR was significantly reduced(P<0.05),and the ADFI was not significantly differen(P>0.05)t;Compared with the control group,the ADG,ADFI and FCR of the group C were not significantly different(P>0.05).(2)In the duodenum,jejunum and ileum,the height of the villus were significantly reduced,the depth of the crypt were significantly increased(P<0.05),and the height of the villus/the depth of the crypt were significantly reduced in group LPS(P<0.05).Compared with the group LPS,the height of the villus were significantly increased(P<0.05),the depth of the crypt were significantly reduced(P<0.05),and the height of the villus/the depth of the crypt were significantly increased in group C(P<0.05);Compared with the control group,the difference in villus height,crypt depth,villus height/crypt depth is not significant in group 3(P>0.05).(3)Compared with the control group,the protein content,DNA content,RNA/DNA and Protein/DNA of jejunal were significantly reduced(P<0.05),and the protein content,DNA content and RNA/DNA of ileal were significantly reduced(P<0.05).Compared with the group LPS,the protein conten,DNA content and RNA/DNA of empty and ileal were significantly increased in group C(P<0.05),and the protein/DNA of jejunum in group C was significantly increased(P<0.05).Compared with the control group,the protein conten,DNA content,RNA content and RNA/DNA,protein/DNA of empty and ileal in group C were not significantly different(P>0.05).In summary,N-carbamoyl was contributed to improve the growth and development pf weaned rabbits,promote the development and repair of intestinal mucosa,increase the expression of tight junction protein and IL-2 in intestinal mucosa,and improve the florstic structure of cecal flora.N-carbamoyl can effectively alleviate the slow growth and intestinal damage caused by disease stress in rabbits. |
PDF Full Text Request