| The purpose of the experiment was to investigate the effects of complex acidifiers on the performance and intestinal health of yellow-feathered broilers.One thousand six hundred one-day-old yellow-feathered broilers were randomly divided into four treatments(A,B,C and D)with 5 replicates of 80 chickens per replicate in the experiment,the group A was fed basal diet,the group B was fed basal diet + acidifiers,the group C was fed low-protein diet,and the group D was fed low-protein diet + acidifiers.The whole experiment lasted 63 days.The feeding test was 63 days,and the performance of each treatment group was determined on the 21 st,42nd,and 63 th days respectively.On the64 th day,2 chickens were randomly selected from each replicate for slaughter and the relative organ weight and intestinal pH were measured.At the same time,jejunal mucosal samples and ileal food samples were collected to determine the ileal microorganisms,jejunum morphology and jejunum-related gene expression.The results were as follows:(1)Growth performance: During the 1-21 days,compared with the group A(positive control),ADFI in the group B and C increased significantly(P<0.05),and feed gain ratio(F/G)in the group C increased significantly(P<0.05).Compared with the group C(negative control),ADFI in the group D decreased significantly(P<0.05),During the 22-42 days,there was no significant difference between each group(P>0.05),During the 43-63 days,compared with the A group,both ADG and ADFI in the group B and C increased significantly(P<0.05),and F/G decreased significantly(P<0.05).Compared with the group C,both ADG and ADFI in the group D decreased significantly(P<0.05),and F/G increased significantly(P<0.05).During the 1-63 days,compared with the group A,both ADG and ADFI in the group B and C increased significantly(P<0.05).Compared with the group C,ADG and ADFI in the group D decreased significantly(P<0.05).(2)Slaughter performance: There was no significant difference in slaughter performance between the four groups(P>0.05).(3)Immune organ index: Compared with the group A,the bursal index in groups of B,C,D decreased significantly(P<0.05).And there was no significant difference in the spleen index among the four groups(P>0.05).(4)Gigestive tract pH: Compared with the group A,pH of proventriculus,jejunum,cecum increased significantly(P<0.01)in group C,and that in ileum increased significantly(P<0.05).The pH of duodenum in group B was significantly decreased(P<0.01).Compared with the group C,the group D was significantly increased(P<0.01).(5)Morphological indexes of jejunum mucosa: Villus length and V/C value of four groups have no difference(P>0.05).The crypts depth in group C increased significantly compared with that of the group B.(6)Variation of microbial flora in the ileal chime: Compared with the group A,the number of E.coli,salmonella,Lactobacillus and bifidobacteria in the group B decreased significantly(P<0.05),and that in the group C increased significantly(P<0.05),E.coli,salmonella in group D were the complete opposite(P<0.05);Compared with group C,the number of Lactobacillus and bifidobacteria in group D increased significantly(P<0.05),and the number of E.coli and Salmonella decreased significantly(P<0.05).(7)The abundance of ZO-1,Occludin and Claudin-1 mRNA genes in jejunum:Compared with the group A,the mRNA abundance of ZO-1 and Occludin in jejunum of the group B increased significantly(P<0.01),and that in the group C decreased significantly(P<0.01).Compared with the group A,the mRNA abundance of ZO-1,Occludin and Claudin-1 in jejunum of the group D increased significantly(P<0.05).In summary,both acidifiers addition with 1kg/t or feed protein level reduction of 17%in chick and chicken stage increased the ratio of F/G,while significantly improved the production performance of yellow-feathered broilers. |
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