The Role Mechanism Of Bacillus Subtilis Supplemented In Feed On Gushi Chicks

The study was conducted with 234 7-week-old Gushi laying hens.There were three treatment groups:control,with no added B.subtilis and antibiotic supplementation,and 2treatment groups receiving feed supplemented with B.subtilis at 2.0�10~100 CFU/kg and flavomycin at 100g/kg,respectively.Experimental diets were fed in two phases:growth phase(w 7-20)and production phase(w 21-30).This study aimed to investigate the supplemental effects of Bacillus subtilis(B.subtilis)on growth,production performance and the expression of TLRs in intestinal of Gushi laying hens.Overall:(1)Supplementation with B.subtilis showed a higher improvement(P<0.05)in growth performance compared to birds fed control(0%B.subtilis)diets during all periods.The average daily weight gain and feed conversion rate of the B.subtilis group were increased by 3.3%and 6.7%,respectively,compared with the antibiotic group.There was no significant difference(P>0.05)between B.subtilis group and antibiotic group but pronounced trend was noticed in chicks fed B.subtilis compared to chicks fed antibiotic diets(P=0.078).(2)Compared with control and antibiotics groups,total cholesterol(TG),triglycerides(TC)and malondialdehyde(MDA)content in the serum of birds in B.subtilis group were reduced(P<0.01)and calcium(Ca)was improved(P<0.01)during growing period.(3)Birds supplemented with B.subtilis showed decrease in caecal Escherichia coli(E.coli)count(P<0.05)and increase in lactobacillus and bifidobacteria counts(P<0.01).(4)In comparison to control and antibiotic groups,the B.subtilis group had higher(P<0.05)activities of intestinal digestive enzyme.(5)The egg weight,the average egg weight and the feed egg ratio of the B.subtilis group were 3.5%,33.3%and 27.79%higher than those in the control group(P<0.05)and the total number of egg production increased by 28.96%(P<0.01).(6)In addition,the egg shell strength in the B.subtilis group significantly increased by(P<0.05)when compared to the control group.Meanwhile,egg shell thickness,egg yolk color,egg weight,egg yolk weight,protein height,Haugh unit in the B.subtilis group were increased compared to the control group(P=0.084).(7)Moreover,the results showed that B.subtilis could significantly increase the expression of TLR21 in ileum.Collectively,our results indicated that supplementation of the basal chicken diet with B.subtilis had apparent positive effects on production performance,blood parameters,serum antioxidant enzyme activities and beneficial microbiotia,and B.subtilis can stimulate the expression of intestinal TLRs mRNA,which is beneficial to the early formation of natural immunity.In conclusion,our study demonstrated that B.subtilis has the potential to become an alternative to antibiotic which are very important to the well being of man and poultry.