| The study was first conducted to evaluate the biological characteristics of three and thebacteriostatic activity of these three bacilli strains against Escherichia coli..Then obtains effectiveinhibitory concentration. Selected the optimum combination of the three bacilli by using the orthogonaldesign. The compound bacilli was mixed using the selected concentration and ratio, sprayed to thecommercial broiler farm, to discuss the compound bacillus’s ability of improve the broiler house’senvironment and the broiler’s immunity. There are three parts in this study.In the first part, the study was conducted to evaluate the biological characteristics of2strains ofBacillus amyloliquefaciens and1strain of Bacillus thuringiensis, and the bacteriostatic activity of thesethree bacillus strains against Escherichia coli. In this study, the colony morphology and the growthcurve of three bacilli were examined. And the growth of the three bacilli in the condition of hightemperature and salt was examed. All of three bacteria were examined for their antimicrobial activityagainst E.coli.(Escherichia coli., CVCC1570) by using the agar diffusion system. The optimumcombination level of the three bacteria in the mixed product was investigated by using the orthogonaldesign in three factors and three levels. The results showed that all strains appeared as Gram-positiveand aerobic bacillus and can cultivate in7%salt and50℃. Bacillus SKN01, Bacillus SKN02had thesimilar growth curve entering the logarithmic phase in the first two hours. Bacillus SKN03bacillusgrew slowly and spent long time to enter the logarithmic phase. The bacillus strain had antimicrobialactivity against E.coli.The most effective concentration of antimicrobial activity in the mixture of threebacillus strains was4×10~8CFU/mL,4×10~8CFU/mL and6×10~8CFU/mL.In the second part, after being sprayed the mixture of three bacillus suspension which selected inthe first part to the broiler house, we detected the number of E.coli and staphylococcus in the air inorder to evaluate the applying effect of bacillus for improving environment. Three houses that have thesame environmental conditions were selected, each was a treatment group, three groups in all.15003one-day old Ross308was randomly devided into three groups(three treatment groups),each have5001broilers. The mixed product of three bacillus were sprayed in the poultry house, one for blank control A,one for chemical disinfectant (Benzalkonium Chloride) as positive treatment B,and one for bacillustreatment C. Each treatment contained three replications. The raising experiment lasted about35days.1-21days spraying the bacillus suspension every two days,and22-35days spraying everyday. Thenumbers of E.coli and staphylococcus aureus in the air of the poultry house were detected every week.The result is:1. The concentration of E.coli in the brolier house air in different growth stage: In the firstgrowth stage(1-21days),there is no evident difference between the three groups(P＞0.05). In the latergrowth stage(22-35days), The concentration of E.coli in the brolier house air of the control A is higherthan treatment B and treatment C(P＜0.05), and treatment B is higher than treatment C(P＞0.05).2.The concentration of staphylococcus aureus in the brolier house air in different growth stage: In thegrowth stage of1-14days,there is no evident difference between the three groups(P＞0.05). In the21 days and28days, treatment B and treatment C is lower than control A (P＜0.05).In the35days, Theconcentration of staphylococcus aureus in the brolier house air of the control A is higher than treatmentB(P＜0.05), and cotrol(B) is higher than treatment C(P＜0.05).The result shows that spraying themixture of bacillus suspension in the broiler house could effectively reduce the number of E.coli andstaphylococcus aureus in the air especially at the later growth stage of chickens. The concentration ofaerobic bacteria keep on increasing. After21days the concentration of treament C is lower thantreatment B and control A.. Spraying the mixture of three bacillus suspension in the broiler house couldreduce the number of E.coli, staphylococcus aureus and aerobic bacteria in the air and could improvethe environment effectively.In the third part,the mixed product of three bacillus were sprayed in the poultry house to test theimmune function of the broiler. The experiment design is same with the second part. The Mortality ofbroiler and growth performance, slaughter rate, immune organ index, serum lysozyme activity, serumimmunoglobulins (IgA, IgG, IgM), tracheal fluid and intestinal fluid secretory IgA (SIgA) wasmeasured in21-day and35–day.The result are:(1). The growth performance and the slaughter rate: Themortality of the control A is9.08%,and the treatment B is3.80%, treatment C is3.52%. In the first stage(1-21d), The ADG and ADFI of the treatment C is higher than control A and treatment B(P＜0.05),the F/G of the treatment B and treatment C is higher than control A,but have no significant (P＞0.05).In the later stage (22-35d), The ADG and ADFI of the treatment C is higher than control A (P＜0.05),the F/G of the three treatments have no significant (P＞0.05). There is no evident difference on theslaughter rate,percentage of half-eviscerated yield,percentage of eviscerated yield between the threegroups(P＞0.05).(2). Immune organ indexes: On21days, the spleen indexes, the BF indexes and thespleen of the treatment B and treatment C is a little higher than control A,but have no significant(P＞0.05). On35days, the spleen indexes and the thymus indexes of the treatment B and treatment C is alittle higher than control A,but have no significant (P＞0.05).(3). Serum immune (LZM、IgA, IgG,IgM): On21days, the LZM of the serum of the treatment C is higher than control A and treatment B(P＞0.05), the IgA of the treatment C is lower than control A and treatment B, IgM and IgG oftreatment B is a little lower than control A and treatment C. On35days, the LZM of the serum of thetreatment C is higher than control A and treatment B (P＜0.05), the IgA and IgM of the treatment B andtreatment C is lower than control A, but have no significant(P＞0.05), IgG of treatment C is higherthan control A and treatment B, but have no significant(P＞0.05).(4). Tracheal fluid and intestinal fluidsecretory IgA (SIgA): On21days,The tracheal fluid SIgA of treatment C is higher than control A andtreatment B (P＜0.05). The intestinal fluid have same effect, but have no significant difference(P＞0.05). On35days,The tracheal and intestinal fluid fluid SIgA of treatment C is higher than control Aand treatment B (P＞0.05) but have no significant difference(P＞0.05). The results showed that the bacillus strain had antimicrobial activity against E.coli.. Spraying thecomposite Bacillus can reduce Mortality of broilers and improve the tracheal fluid SIgA, that means thesprayer have some improvement on the the chickens growth conditions and immune health. |
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