SEROLOGICAL STASUS OF NEWCASTLE DISEASES VIRUS (NDV) IN COMMERCIAL LAYER CHICKEN IN PABNA DISTRICT

Abstract

Bangladesh is an agro-based developing country. Poultry, the sub-sector of agriculture plays an important role in its economy. ND causes huge economic losses to the commercial poultry farmers around the world including Bangladesh. This research work was conducted to screen out the serological status, as well as immune status of commercial layer chicken against Newcastle Disease Virus (NDV) in selected area of Pabna District, Bangladesh. From 25 different commercial layer farms, a total of 200 serum samples were collected and divided into three age groups such as 20–35 weeks, 36–47 weeks and 48 to above weeks. Haemagglutination Inhibition (HI) test was performed and Geometric Mean Titers (GMT) were calculated for layer groups of 20–35 weeks, 36–47 weeks and 48 to above weeks of age. SPSS software and logarithm table was used to analyze the recorded data. It was observed that out of 200 samples, all were found positive for specific immunity to ND virus with overall positive percentage of 100. However, in terms of age of the layer chickens, there was no significant differences (P>0.05) in specific immunity. Antibody titer against ND was between Log25 to Log210 reveals layer chickens of Pabna district had protective level of antibody. It was also observed that Geometric Mean Titre (GMT) of antibody level of commercial layer birds of Pabna district was also significantly differed (P<0.05) among the different age groups and it was highest in the layer chickens of 48 to above weeks of age (8.81), than the layers of 36-48 weeks of age (8.08) and the layers of 20-35 weeks of age (7.58). This was may be due to the more time exposure to the vaccination and natural infection of the more aged layers. Though all chickens (100%) showed positive specific immunity, good mean titers that was protective to ND, still the chickens remained susceptible to ND due to stress and different immune suppressive diseases, as well as cross infection between different strains of NDV, which needs further study and vaccination should be intensified with multi strain vaccine by screening immune status of the flock against ND.