SIGNIFICANCE OF SEROLOGICAL MONITORING FOR POULTRY ORNITOBACTERIOSIS THERAPY

Abstract

One of the main problems of poultry diseases is respiratory diseases. Among them a special place is occupied by ornithobacteriosis (ORT). Losses from ORT consist of: direct losses as a result of the disease - death of chickens, increased culling due to lameness, low live weight gain (up to 40%), reduction of carcass categories, reduction of egg production by 6-20%; indirect losses associated with the immune-suppressive effect of ornithobacteria, which increase the risk of other infections and prevent the formation of post-vaccination immunity. The diagnosis is established on the basis of epizootological data, clinical signs, pathological and anatomical changes, bacteriological and serological tests, positive bioassay. In most cases, infections caused by ornithobacteria are not diagnosed in time, the pathogen is difficult to isolate due to complications of other pathogens, or because experts are currently insufficiently aware of the ability of ORT to cause disease. ORT can be isolated by bacteriological method only at an early stage of the disease. The most relevant method of diagnosis is PCR. The advantage of the method is not only the isolation of DNA of individual cells of the pathogen in the sample, but also the ability to detect all serotypes. In addition, PCR is a successful diagnosis in the detection of ORT nucleic acid not only in tissue samples, but also in feces, eggs, dust, which is important for timely diagnosis. Enzyme-linked immunosorbent assay (ELISA) is used to control the presence of ornithobacteriosis in bird. The presence of antibodies to this pathogen in poultry of many species indicates its wide circulation.
 Thus, when conducting serological monitoring of blood serum from different age groups of broilers aged 1-44 days, the percentage of positive samples ranged from 40 to 100, which indicates the circulation of the field strain of the pathogen ornithobacteriosis. The percentage of positive serum from broilers to ORT was: from 1 to 5 days - from 88 to 50, from 6 to 10 days serum were negative, while at 17, 21 days and from 32 days to the end of cultivation (44 days) – 100 %. The percentage of positive batches at the end of fattening ranged from 42-53 days in the range from 75 to 100%, indicating the circulation of the field strain of the ornithobacteriosis pathogen antibiotic therapy against this disease.