Effects Of Three Probiotics On The Growth,Small Intestine Development And Cecum Microorganism Of Chicks

The aim of this experiment was to investigate on the growth,small intestine development and cecum microorganism of layer chicks.A total of 432 healthy one-day-old Roman male chicks with similar body weight were selected and randomly divided into four groups(A,B,C,D)with 6 replicates per group(18 chicks per replicate).Group A was the control group fed with basal diet;group B,C,and D were the test groups respectively fed with Enterococcus faecalis,Lactobacillus acidophilus,or bifidobacterium lactis supplement-ed into the basal diet(adding amount each group:1×107 CFU/g).The test lasted for 42d.The results were shown as follows:(1)The effects of probiotics on growth performance of chicks:At 0-21d,the average body weight of chicks in the test groups was lower than the control group.At 28?42d,the weight of chicks in the test groups was higher than the control group.At 35d and 42d,Compared with the group A,the body weight of chicks in group B,C,and D increased by 3.6%,4.4%,4.3%and 6.9%,7.9%,6.3%significantly(P<0.05).At 35d and 42d,compared with group A,the ADFI in group B,C,and D increased by 8.6%,10%,7.4%and 9.2%,13.5%,10%very significantly(P<0.01).At 42d,compared with group A,the ADG in group B,C,and D increased by 17.2%,18.7%,12.2%significantly(P<0.05).There was no significantly different in F/G among groups(P>0.05).(2)The effects of probiotics on blood biochemical and immune indexes of chicks:Compared with group A,the content of urea nitrogen(BUN)in group D decreased significantly(P<0.05).Compared with group A,the content of immunoglobulin A(IgA)in group B,C,and D increased very significantly by 24.4%,32%,and 28.5%(P<0.01).(3)The effects of probiotics on the visceral organ indexs of chicks:Compared with group A,the muscle index of B,C,and D increased by 6.8%,14%,and 22.3%respectively(P<0.05).(4)The effects of probiotics on the length and weight of small intestine of chicks:The different probiotics had no significantly effects on the length and weight of the small intestine of chicks(P>0.05).(5)The effects of probiotics on the morphology of small intestine of chicks:Compared with group A,the crypt depth of duodenum in group B,C,and D was very significantly decreased by 17.5%,16%,and 15,1%(P<0.01),and the villus height/crypt depth(V/C)of duodenum increased very significantly by 20.6%,25.3%,and 16.23%(P<0.01).Compared with group A,the villus height in group D increased significantly by 16.5%(P<0.05).(6)The effects of probiotics on the expression of MUC2 mRNA in chicks small intestinal:All probiotics promoted the secretion of MUC2 in different intestinal segments.Compared with group A,the expression of duodenal MUC2 mRNA in group C and D increased very significantly(P<0.01).Compared with group A,the expression of jejunal MUC2 mRNA in group B,C,and D increased(P=0.06).Compared with the group A,the expression of ileal MUC2 mRNA in group C and D increased very significantly(P<0.01).The group D was the best.(7)The influence of probiotics on the chicks Cecum microorganism:a)At 42d,there were Bacteroidetes,Firmicutes and Proteobacteriaon mainly in phylum.The contents of Bacteroidetes in group B,C,and D were significantly lower than group A by 38.3%,36.5%,and 35.4%(P<0.05),and Firmicutes was significantly higher than group A by 62.4%,52.6%,and 45.7%(P<0.05).B)In genus,there are mainly Alistipes,Barnesiella,Faecalibac-terium,Bacteroides and Ruminococcus2.Compared with group A,the Barnesiella in group B and D increased significantly(P<0.05).Compared with group A,the Clostridium sensu stricto in group B,C,and D decreased significantly(P<0.05),and the Escherichia/Shigella decreased by 87.5%,100%,and 75%in group B,C,and D very significantly(P<0.01).C)Compared with group A,the Shannon index in group D was higher than control A significantly(P<0.05).By PCA analysis,the distribution area of sample points of group A were different with group B,C,and D,indicateing that there were different in microorganism community structure among treatments.In conclusion,different probiotics can improve chick growth performance,promoteintestinal development and change cecum microorganism.The addition of bifidobacterium lactis was the best.