Epidemiological Investigation On Bacterial Diseases Of Large-scale Caged And Flat Duck Farms

In recent years,China’s waterfowl industry has developed rapidly,among which meat duck breeding plays an important role in the waterfowl industry.Duck meat ranks third in China’s meat consumption products.Therefore,the breeding of meat ducks is particularly important for the development of aquatic poultry industry.Meat duck breeding model plays an important role in the growth and development of meat ducks.A good breeding model can reduce the stress of meat ducks and make meat ducks obtain higher economic benefits.At present,the feeding amount of meat ducks in China is increasing year by year.It is difficult to manage meat ducks under the traditional flat breeding mode.In addition to viruses,bacterial infection has also become a major problem in meat duck breeding.The cage rearing mode of meat ducks reduces the environmental pollution,improves the utilization rate of the duck shed,realizes the automation of temperature,humidity and ventilation,and improves the feeding and management conditions.In order to further explore the differences between cage and flat duck breeding,this study carried out bacterial epidemiology investigation and production performance of research meat duck,so as to provide a theoretical basis for the prevention of bacterial diseases of meat duck and provide support for the popularization and application of cage breeding mode.Seven batches of experiments were carried out in this study.The recovery rate of seven batches of meat ducks in cage and flat feeding mode and the cost and economic benefits of meat ducks’ growth were investigated and analyzed.The results showed that the recovery rate of meat ducks in cage mode was 9.07% higher than that in flat feeding mode,the total cost was 5.53% lower,and the economic benefits produced by a single duck were 1.52 times higher,However,the meat ducks in cage and flat culture have no drug residues before and after slaughter,and the quality of meat ducks meets the national standards,shows that the breeding cost of meat duck in cage is lower and the economic benefit is better than that in flat culture.740 samples were collected in this experiment: 332 in cage and 408 in flat.The results of bacterial isolation showed that a total of 247 strains of bacteria were isolated.153（62%）strains of Escherichia coli,39（16%）strains of Staphylococcus and 55（22%）strains of Clostridium perfringens were detected.The detection rates of Escherichia coli,Staphylococcus and Clostridium perfringens in cage mode were 25%,3% and 8%respectively;The detection rates under flat culture mode were 37%,13% and 14% respectively.Therefore,the probability of infection of meat ducks in cage is lower than that in flat culture.According to the disk method recommended by the World Health Organization,the resistance of isolated bacteria to 10 antibiotics（florfenicol,enrofloxacin,neomycin,etc.）was tested.The results showed that 27 strains of bacteria were sensitive to polymyxin（50%）and kanamycin（56.25%）,and the resistance to florfenicol was the highest,up to 87.5%.Staphylococci were sensitive to polymyxin,gentamicin,spectinomycin and cefradine,but highly resistant to florfenicol and neomycin.Clostridium perfringens is sensitive to amoxicillin and ciprofloxacin,and has the highest resistance to neomycin,up to 100%.This study shows that quinolones can be selectively selected in the treatment and prevention of pathogenic bacterial infection of meat ducks in Shandong area,and it can also provide a theoretical basis for the prevention of certain bacterial diseases.The drug resistance genes of different types of antibiotics were amplified by PCR.The results showed that the positive rate of Escherichia coli carrying tet（M）drug resistance gene was the highest,while that of qnr S gene was the lowest,that of staphylococci carrying tet（M）was the highest,and that of CTX-M was the lowest,and that of Clostridium perfringens carrying tet A（P）,aad A and sull genes was the highest.The positive rate of CTX-M and cmy genes was the lowest.The classification showed that the positive rate of tetracycline resistance genes in Escherichia coli was high,the detection rate of quinolone resistance genes was the lowest,and the positive rate of tetracycline resistance genes in staphylococci was the highest.the detection rate of lactam and aminoglycoside resistance genes was low;the positive rate of sulfonamides and aminoglycosides resistance genes in Clostridium perfringens was the highest,and the detection rate of quinolones resistance genes was the lowest.This study shows that quinolone drugs can be selected to prevent bacterial diseases of meat ducks in this area,and develop scientific and effective drug regimen through drug sensitivity test.