The Study On The Damage Of The Growth And Health Of Yellow Catfish(Pelteobagrus Fulvidraco)by The Content Of Soybean Meal In Diet And On The Repairing Effect Of Two Additives

This article takes yellow catfish(Pelteobagrus fulvidraco)as the research object,which were cultivated 70 days in outdoor pond cages,to research the damage of the growth and health of yellow catfish(Pelteobagrus fulvidraco)by the content of soybean meal in diet and on the repairing effect of two additives.The effects of two additives and different levels of soybean meal on the structure of intestinal flora of yellow catfish were explored by choosing the right group.The main contents and results of this study are as follows:Part one:The effects of different levels of soybean meal on the growth performance and physiological health of yellow catfishThe purpose of this research is to study the effects of different levels of soybean meal in feed on the growing,physiology and tissue structure of yellow catfish.The formula of the feed was designed with 4 different levels of soybean meal(20%,30%,40%,50%)(C2,C3,C4,C5),Therefore,the research was designed 4 treatments,and each treatment was designed 3 repetitions(net cages).The yellow catfish with an initial weight of(17.60 ± 0.12)g was cultured in pond cages for 70 d.The results showed that with the C2 group as the control,the survival rate(SR)in the C5 group was significantly reduced(P<0.05).The specific growth rates of female or male yellow catfish were both reduced(P>0.05).The ratio of male to female in each group was not significant,and had no significant effect on SGR(P>0.05).The SGR of male yellow catfish in each group was significantly greater than that of female yellow catfish(P<0.05).As the level of soybean meal increased,there was no significant difference in FCR(P>0.05).The C5 group had significantly lower crude fat than the C2 group(P<0.05).The crude protein had a downward trend,but the difference was not significant(P>0.05).There was no significant difference in moisture and ash between the groups(P>0.05).There was no significant difference in the physical indexes of male fish in each group,and the condition factor(CF)of female fish in C4 and C5 groups was significantly reduced(P<0.05).At the same time,the different genders affect the CF of yellow catfish significantly.The serum globulin content and triglyceride of group C3 were the minimum(P<0.05),others indicators were not significantly different.There were some differences in the oxidation index of each group,but they were not significant(P>0.05).The content of D-lactic acid and the activity of diamine oxidase both decreased first and then increased,and the C4 group was the minimum.The tissue sections results showed that the liver,intestine,and stomach tissues began to show mild inflammation or damage of the C4 group,while the tissues of the C5 group had severe damage.In summary,the high-level soybean meal group reduced the survival rate,growth performance significantly,and reduced the content of crude fat.At the same time,the structural integrity and permeability of the liver,intestine and stomach tissues of the yellow catfish were damaged severely.According to the growth rate of male fish,and combine with the regression equation between the level of soybean meal and SGR,it is recommended that the maximum amount of soybean meal in diet of yellow catfish is 22.33%.Part two:The effects of yeast culture on the growth,health and repairing the damage from soybean meal of yellow catfishThe purpose of this test was to investigate the effects of yeast culture on the growth,health and repairing the damage from soybean meal of yellow catfish.On the basis of experiment 1,feed formula was supplemented with 1%yeast culture(YC)(YC2,YC3,YC4,YC5)in each group,and yellow catfish with an initial weight of(17.6 ± 0.2)g were fed in pond cage for 70 d.The research was designed 4 treatments,and each treatment was designed 3 repetitions(net cages).The results showed that there was no significant difference in the survival rate of yellow catfish in each group(P>0.05),and there was no significant difference in SGR among male yellow catfish in each group(P>0.05),but the SGR of female yellow catfish in YC5 group was significantly lower than that in YC2 group(P<0.05).The ratio of male to female in each group was not significant,and had no significant effect on SGR(P>0.05).The SGR of male yellow catfish in each group was significantly greater than that of female yellow catfish(P<0.05).There was no significant difference in FCR between groups(P>0.05).There was no significant difference in body composition of yellow catfish in each group(P>0.05).The CF of male fish in YC3 group was significantly higher than that in other three groups(P<0.05),and the VSI of male fish increased first and then decreased,among which in YC5 group was significantly different(P<0.05).The VSI of female fish in each group decreased gradually,which in YC4 and YC5 groups decreased significantly(P<0.05).At the same time,the different genders affect the CF of yellow catfish significantly.The content of serum cholesterol increased significantly in the YC4 and YC5 groups(P<0.05),the content of triglyceride and HDL was highest in the YC5 group.Among the indicators of the oxidation system,the content of malondialdehyde and hydrogen peroxide in the high-level soybean meal group was still at a high level relatively.There was no significant difference in enzyme activity which related to the permeability of hypertension tissues in each group(P>0.05).The tissue sections results showed that the nuclei of liver cells in the YC5 group became larger,discovered gathering at the same time.The villi in the intestine became thinner and the lamina propria thickened,when the stomach structure was damaged slightly.In summary,the difference in survival rate of yellow catfish in each group was no longer significant after adding an appropriate amount of yeast culture,and the growth performance of yellow catfish was improved to some extent.The reduction of crude fat and crude protein of yellow catfish inYC4 and YC5group were improved.However,the indexes of yellow catfish in YC5 group had not been improved.According to the regression equation of level soybean meal and SGR,the optimal addition amount of soybean meal in yellow catfish diet can reach 27.5%,after adding yeast culture.There is an increase of 5.17 percentage points compared to Part 1.Part three:The effects of natural plant complex on the growth,health and repairing the damage from soybean meal of yellow catfishThe purpose of this test was to investigate the effects of natural plant complex on the growth,health and repairing the damage from soybean meal of yellow catfish.On the basis of experiment 1,feed formula was supplemented with 60 mg/kg natural plant complex(RC2,RC3,RC4,RC5)in each group,and yellow catfish with an initial weight of(17.58±0.17)g were fed in pond cage for 70 d.The research was designed 4 treatments,and each treatment was designed 3 repetitions(net cages).The results showed that there was no significant difference in survival rates of the yellow catfish in each group(P>0.05),the SGR of female and male yellow catfish was highest in the RC4 group,but there was no significant difference between the groups(P>0.05).The male-female ratio of the RC3 group was significantly higher than that of the other groups(P<0.05),but the effect of the difference of male-female ratio in each group on the SGR of yellow catfish had no significant effect(P>0.05).The SGR of male was significantly higher than that of female(P<0.05).There was no significant difference in body composition of the yellow catfish in each group(P>0.05),and the HIS of the male fish in the RC5 group was lower than that in the RC2 group significantly(P<0.05).Compared with the RC2 group,the content of total protein and triglyceride of the RC4 group were at a lower level(P<0.05).There were some changes in the oxidation index of each group.There was no significant difference in diamine oxidase between groups(P>0.05).Compared with the RC2 group,the content of D-lactic acid in RC3,RC4,and RC5 groups were reduced,the difference of which in RC3 and RC4 groups was significant(P<0.05).The tissue sections results showed thatthe liver cells appeared vacuoles and the cell nuclei were aggregated in the RC5 group.Voids appeared in the front end of the intestinal folds,and columnar epithelial cells in the stomach were orderless.To sum up,the addition of natural plant complex compound improved the survival rate and growth performance of yellow catfish in the high soybean meal group,the reduction of crude fat and crude protein of yellow catfish in RC4 and RC5 group were improved.The oxidative stress caused by the high soybean meal was relieved.And the liver and gastrointestinal tissue structure were improved.But inflammation presented yet in RC5 group.According to the regression equation between the level of soybean meal and SGR,it is recommended that the maximum amount of soybean meal in diet of yellow catfish is 42.25%,there is an increase of 17.92 percentage points compared to Part 1.Part four:The effects of different levels of soybean meal and two additives on gut microbes of yellow catfishBased on the preliminary conclusions of Experiments ?,? and ?,this experiment selected four groups:C2,C5,YC5 and RC5,to study on the effect of different levels of soybean meal and two additives on the structure of intestinal flora of yellow catfish.The results showed that the diversity index and richness index of the intestinal flora structure of yellow catfish in the high soybean meal group(C5)were higher than those in the low soybean meal group(C2),and after adding the yeast culture or the Chinese herbal compound(YC5,RC5)to the feed,he diversity index and richness index of the intestinal flora structure of yellow catfish were higher than those of high soybean meal group.The dominant flora in groups C2 and C5 are Proteobacteria,Fusobacteria and Firmicutes.The dominant flora in YC5 are Proteobacteria,Fusobacteria,Firmicutes and Cyanobacteria.The dominant flora in RC5 are Proteobacteria,Firmicutes,Cyanobacteria,Acidobacteria.Compared with the C2 group,the proportion of Proteobacteria in the C5 group increased by 35.67%,the proportion of Clostridium was reduced by 37.86%,the proportion of the Cetobacterium was reduced by 37.86%,and the proportion of the Plesiomonas was increased by 26.87%.Compared with the results of the C5 group,the proportion of Proteobacteria in the YC5 group increased by 26.05%,the proportion of Fusobacterium decreased by 33.36%,the proportion of Cetobacterium decreased by 33.36%,and the proportion of Pleuromonas decreased by 22.37%.Similarly,the proportion of Proteobacteria in the RC5 group increased by 33.85%,the proportion of Clostridium was reduced by 48.44%,the proportion of Cetobacterium was reduced by 48.44%,and the proportion of Pleuromonas was reduced by 28.65%.Significant differences between groups based on genus level analysis results showed,compared with the C2 group,there were 6 species of bacteria in the C5 group with significant differences.Among them,Clostridium was down-regulated,and Orthomonas was up-regulated(P<0.05).Compared with the C5 group,there were 16 species of bacteria in the YC5 group with significant differences,the Bacillus significantly increased(P<0.05).Compared with C5 group,there were 56 species of genus in RC5 group with significant difference,among which the Orthomonas genus is significantly down-regulated(P<0.05).The result shows that the structure of intestinal flora of yellow catfish in soybean meal group was relatively simple,the predominant flora was Proteobacteria,Fusobacterium,and Paenibacillus.Increasing the content of dietary soybean meal increases the number of Proteobacteria and decreases the number of Fusobacterium.Two kinds of additives have effectively improved the simplification of intestinal flora of yellow catfish,both promote the reproduction of beneficial bacteria of yellow catfish,and inhibit the number of harmful bacteria,had a positive effect on maintaining the dynamic balance of intestinal flora...