Effects Of Bacillus Subtilis A7 Strain On Growth Performance,Digestive Function And Intestinal Flora Of Jian Carp(Cyprinus Carpio Var.Jian)

The experiment was conducted to study the effects of Bacillus subtilis A7 strain on growth performance,digestive function and intestinal flora of Jian Carp(Cyprinus carpio var.Jian).By using the single factor design,720 Jian carps with initial body weight 3.35±0.04g were randomly allocated to 1 control group and 5 test groups.The control group was fed with the basal diet and the test groups were fed with the basal diet containing Bacillus subtilis A7 strain 0.0002%,0.0020%,0.0200%,0.2000% and 2.0000% respectively. The experiment lasted for 90 days. On the 30th,60th and 90th day of the experiment, weight gain rate(WGR),food conversion ratio(FCR),protein efficiency ratio(PER),survival rate(SR),hepatopancreas weight,intestine weight,intestine length,the protease activity of hepatopancreas,the amylase activity of hepatopancreas,the protease activity of intestine,the amylase activity of intestine,the quantity of Lactobacillus and Colibacillus in intestine,the head kidney weight,the midkidney weight,the spleen weight and the concentration of IgM in serum were determined.The results showed that Bacillus subtilis A7 strain can influence the growth performance of Jian carp significantly.Compared with the control group, The WGR of Jian carp in every test group rose 6.91%～12.07%.Compared with the control group, The FCR of the 0.2000% test group had reduced 4.46%, and the PER and SR of the 0.2000% test group had increased 6.21% and 2.63% respectively.About the effects of Bacillus Subtilis A7 strain on digestive function of Jian carp, the hepatopancreas weight,the intestine weight,the intestine length,the amylase activity of hepatopancreas,the protease activity and amylase activity of intestine of the 0.0002%,0.2000% and 2.0000% test groups were significantly higher than the control group(P<0.05).The detection consequence of the quantity of bacterial in intestine showed that:the quantity of Lactobacilli in every test group were higher than the control group and the quantity of Colibacillus in every test group were lower than the control group. Compared with the control group, the quantity of Lactobacilli in the 0.2000% test group reduced5.81% (P <0.05) and the quantity of Colibacillus in the 0.2000% test group rose 6.01%(P <0.05).In addition,except the 0.0002% test group, the head kidney weigh,the midkidney weight and the spleen weight of the other test groups were significantly higher than the contrl group(P<0.05). The content of IgM in serum of the 0.2000% test group was higher than the control group,it rose 18.81%.Results of the experiment indicated:Bacillus subtilis A 7 strain can promote the growth of Jian carp,the development of digestive organs;can enhance the activity of digestive enzyme;can promote the growth of Lactobacilli and inhibite the breeding of Colibacillus. At the same time, the diets with the appropriate amount of Bacillus subtilis A7 strain can promote the growth of immune organs and raise the content of IgM in the blood. In this test, the optimum addition of Bacillus subtilis A7 strain is 0.2000%.