Study On The Effect Of Bacillus Subtilis On The Growth And Development Of Huangshan Black Chicken In Replacing Antibiotics

Healthy breeding of livestock and poultry without antibiotics is the future development trend of animal husbandry.In the case of reducing the use of antibiotics and replacing antibiotics,more and more attention has been paid to the application of probiotics.Bacillus subtilis is one of the research hotspots,and there have been many studies on its role in livestock and poultry breeding,but the research on the application effect of the local poultry breed Huangshan Black Chicken in Anhui Province is still blank.The purpose of this study was to add different concentrations of Bacillus subtilis powder to the brooding diet of Huangshan Black Chickens to study the effects on its growth performance,blood indicators,intestinal morphology and microflora,and reproductive organ morphology,and to evaluate its replacement of antibiotics.The results provide technical support for the large-scale healthy breeding of Huangshan Black Chickens.In this study,600 21-day-old Huangshan Black Chicken were randomly divided into 4 groups,with 3 replicates in each group,50 chickens in each replicate,half male and half female. The control group was feed basal diets,and the test groups I,II,and III were supplemented with Bacillus subtilis(10~8CFU/kg),Bacillus subtilis(10~9CFU/kg)and Flavomycin(5 mg/kg)respectively,The feeding period is from 4 weeks to 18 weeks of age.Bodyweight is measured every two weeks,blood is collected to determine serum biochemical indicators,the structure of intestines and reproductive organs are slaughtered,and the microbial flora is sequenced.The result is as follows:1)Growth performance:At 5-6 weeks of age,the ADFI of group I was 0.93%higher than that of the control group(P>0.05),and the ADFI of group II was significantly higher than that of the control group by 1.37%(P<0.05);at 7-8 weeks of age,the ADFI of group I was significantly higher than that The ADFI of the control group was 2.69%(P<0.01),the ADFI of group II was extremely significantly higher than that of the control group 2.40%(P<0.01),the ADG of the I group and the group II were extremely significantly higher than that of the control group by 12.77%(P<0.01),12.27%(P<0.01);The F/G of group I and group II were significantly lower than that of the control group by 9.03%(P<0.05);the body weight of group I and group II also increased to a certain extent throughout the test cycle;2)In terms of serum indexes:During the test period,the contents of TP and ALB in groups I and II were measured twice higher than those in the control group(P>0.05),and the GSH-Px contents in groups I and II were higher than those in group III(P>0.05);at 14weeks the Ig A content of group I was significantly higher than that of group III by 5.55%(P<0.05);3)Intestinal morphology:the height of jejunal villi in group I was significantly higher than that in the control group by 17.09%(P<0.05),the height of jejunal villi in group II was significantly higher than that in the control group by 17.09%(P<0.05);the depth of jejunal crypt in group I was significantly lower than that in the control group by 25.53%(P<0.01);the jejunal V/C of group I was significantly higher than that of control group by61.45%(P<0.01);the jejunal V/C of group II was significantly higher than that of control group by 41.74%(P<0.05);the ileal V/C of group I was significantly higher than control group by 33.38%(P<0.01),the ileal V/C of group I was significantly higher than group III by 32.78%(P<0.01);4)In the aspect of intestinal flora:the species diversity of group I was the most abundant;the proportion of dominant flora in group I was relatively high compared with other groups,and the distribution of intestinal flora in group I and group III was similar;5)In terms of reproductive organ development,the area of seminiferous tubules in the testes of the males in group I was significantly higher than that in control group by 41.03%(P<0.05),the area of seminiferous tubules in the testes of the males in group I was nsignificantly higher than that in group III by 34.15%(P<0.05),the area of seminiferous tubules in the testes of the males in group II was significantly higher than that in control group by 66.67%(P<0.01),the area of seminiferous tubules in the testes of the males in group II was significantly higher than that in group III by 58.54%(P<0.01);To sum up,adding Bacillus subtilis in diet can significantly improve growth performance of Huangshan Black Chicken diets;compared with antibiotics;Bacillus subtilis can improve the antioxidant capacity and immunity of the body’s serum to a certain extent;promote intestinal development,increase intestinal V/C,and improve the body’s ability to absorb and transform nutrients;improve the area of testicular seminiferous tubules,accelerate the development of reproductive organs of the rooster,improve reproductive capacity;when the concentration of Bacillus subtilis is 10~8CFU/kg,it can improve the intestinal flora,increase the proportion and relative abundance of beneficial flora,inhibit harmful bacteria and promote the growth of the body.Therefore,Bacillus subtilis can be used as a potential substitute for antibiotics in the healthy breeding of Huangshan Black Chickens without resistance.