| The experiment was designed to investigate the effect of adding Bacillus amyloliquefaciens in the diet of broilers on their growth performance, nutrient apparent metabolic rate, duodenal digestive enzymes, gut microbes, immunity and anti-oxidation function.The study includes three parts. 720 one-day old healthy Ross broilers were randomly divided into 6 groups. Every group has 6 replications, each replication including 20 birds. Using corn-soybean meal as the basal diet in the study, negative control group feed the basal diet while positive control group feed the basal diet added 1×107 CFU/g Bacillus subtilis.Group Ⅰ,Group Ⅱ,Group Ⅲ,Group Ⅳ were added 1×106 CFU/g, 1 ×107 CFU/g, 1× 108 CFU/g, 1 × 109 CFU/g of Bacillus amyloliquefaciens in the basic diet respectively. The experiment period was 42 days. At 35 days of feeding trials, each repeat choose 1 bird, a total of 36 experimental chickens were selected to carry out muck metabolic experiment.(1)Feeding and metabolic trials results showed that compared with negative control group, Group Ⅰ,Group Ⅱ and Group Ⅲ could increase daily gain, crude protein and calcium apparent metabolic rate significantly(P<0.05) while no significant difference were found between groups and Daily intake(P>0.05); GroupⅠ,GroupⅡincreased feed conversion rate and phosphorus apparent metabolic rate significantly(P<0.05); Compared with positive control group, the differences of the chicken daily gain and feed intake between four groups were not significant(P>0.05);Group Ⅰ and Group Ⅱ increased feed conversion rate significantly(P<0.05);Crude protein, calcium and phosphorus apparent metabolic rate were significantly increased in groupⅠ(P<0.05), the other groups have no significant differences(P>0.05). Between the experimental groups, compared with the GroupⅣ, GroupⅠ,GroupⅡand GroupⅢ increased daily gain significantly(P<0.05); GroupⅠincreased daily feed intake significantly(P<0.05), but GroupⅡand GroupⅢ have no significant differences(P>0.05);Experimental groups have no significant differences on feed conversion rate(P>0.05);Group Ⅰ, Group Ⅱ,Group Ⅲ increased Crude protein and calcium apparent metabolic rate significantly(P<0.05);Group Ⅰ and GroupⅡincreased phosphorus apparent metabolic rate significantly(P<0.05), Group Ⅲ has no significant difference(P>0.05).(2)According to the results of duodenal digestive enzyme activity, compared with negative control group, trypsin in GroupⅠincreased significantly(P<0.05) but decreased significantly in Group Ⅳ(P<0.05);Group Ⅰ,Group Ⅱ and Group Ⅲ increased amylase significantly(P<0.05);Group Ⅰand GroupⅡ increased lipase significantly(P<0.05). Compared with positive control group, trypsin in GroupⅠincreased significantly(P<0.05) but decreased significantly in Group Ⅳ(P<0.05); GroupⅠincreased amylase significantly(P<0.05), but GroupⅡ,Group Ⅲ and Group Ⅳhave no significant differences(P>0.05); Group Ⅰand GroupⅡ increased lipase significantly(P<0.05). Between the experimental groups, trypsin in GroupⅠ,Group Ⅱ,Group Ⅲincreased significantly than Group Ⅳ(P<0.05), GroupⅠincreased significantly than Group Ⅲ(P<0.05);Amylase in GroupⅠincreased significantly than Group Ⅱ, Group Ⅳ(P<0.05);Lipase in GroupⅠ, Group Ⅱincreased significantly than Group Ⅲ and Group Ⅳ(P<0.05),and GroupⅠincreased significantly than Group Ⅱ(P<0.05). Through the analysis of chicken intestinal microflora, we found that the microbial stability of duodenum,jejunum,ileum and appendix was decreased with the increase of the dosage of Bacillus amyloliquefaciens,the best stability was 1×106 cfu/g. Intestinal flora mainly means lactic acid bacteria genera, fusobacterium.(3) According to the results of the immune organ index, compared with negative control group, the spleen index, no significant difference were found between groups(P>0.05); Bursa of fabricius index was significantly increased in Group Ⅰ, Group Ⅱ, Group Ⅲ(P<0.05);Thymus index was significantly increased in Group Ⅰ(P<0.05); Each groups has no significant difference in serum SA(P>0.05);T-SOD was significantly increased in Group Ⅰ, Group Ⅲ(P<0.05);MDA was significantly decreased in groups(P<0.05);GSH-Px was significantly increased in Group Ⅰ(P<0.05). Compared with positive control group, the spleen index, bursa of fabricius index, thymus index,SA,T-SOD,MDA has no significant difference between groups(P>0.05); GSH-Px was significantly increased in Group Ⅰ(P<0.05), the other groups have no significant differences(P>0.05); Between the experimental groups, the spleen index has no significant difference(P>0.05); Bursa of fabricius index in Group Ⅰ,Group Ⅱ,Group Ⅲincreased significantly than Group Ⅳ(P<0.05); Thymus index in Group Ⅰ increased significantly than Group Ⅳ(P<0.05); SA has no significant difference(P>0.05);T-SOD in Group Ⅰ,Group Ⅲincreased significantly than Group Ⅳ(P<0.05);MDA, GSH-Px has no significant difference between groups(P>0.05).The above results show that the broilers growth performance, nutrients metabolism, digestive enzyme activity, immune and antioxidant function increased in the presence of Bacillus amyloliquefaciens added 1 x 106CFU/g ~ 1 x 108 CFU/g.The effect was better than that of Bacillus subtilis in the dosage of 1 x 106CFU/g,the similarity coefficient of the intestine was the highest and the stability was best. |
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