COMPARISON OF ANTIBODY TITRES OF NEWCASTLE DISEASE VIRUS IN RANDOMLY COLLECTED SERA AND EGG YOLK OF LAYERS Nidhin Raj 1 , Praseena Poulose 1 , Surya P. S. 1 , Chintu Ravishankar 2 and Mathew Sebastian 3 Department of Veterinary Microbiology College of Veterinary and Animal Sciences Pookode, Wayanad, Kerala - 673 576 Abstract A study was conducted to compare the Newcastle Disease (ND) virus antibody titre in randomly collected sera and egg yolk of layers using haemagglutination inhibition (HI) test. The mean log 2 HI titre values detected in sera and egg yolk were 4.50 and 5.68 respectively. Statistically there was significant difference between the two means (p < 0.03). Egg yolk samples may be used as a test material for detection of titre of ND virus antibodies in layers. But when egg yolk is the test material, the HI titre detected tends to be significantly higher. Key words Newcastle Disease, haemag- glutination inhibition test, serum, egg yolk. Newcastle disease (ND) is a viral disease of birds caused by ND virus (NDV) of Genus Avulavirus of Family Paramyxoviridae. Antibody titre against this virus is commonly assessed in bird sera by haemagglutination inhibition (HI) test. Though studies to compare the HI titres of NDV antibodies in birds and their corresponding eggs have been conducted, those on randomly collected bird sera and eggs are scarce. If the levels of the antibodies in randomly collected sera and eggs are comparable, then eggs can be preferred over sera for assessment of the antibody titre especially in farms. Hence a study was conducted to compare the NDV antibody titres in sera and egg yolk of layers collected at random from an organised farm. 1. Veterinary Graduates 2. Assistant Professor( On study leave) 3. Associate Professor (Statistics), College of Fisheries, KUFOS, Panangad P.O., Kochi- 682 506 Materials and Methods A total of 24 blood samples and 29 egg samples were collected at random from birds maintained at the University Poultry Farm, College of Veterinary and Animal Sciences, Pookode. All the birds had been vaccinated against ND using a commercial vaccine five months back. Blood was collected aseptically from the wing vein using sterile technique, allowed to clot and serum separated by centrifugation and stored at -20°C until tested. Eggs were collected on the same day and stored at room temperature. The eggs were broken and the contents gently transferred to separate filter papers. One ml of the yolk was collected and diluted in nine ml of sterile normal saline (1:10 dilution), mixed well and centrifuged at 2000 x g for 20 min. From the supernatant, 0.2 ml was collected and used in the HI test. Sera (0.2 ml) were used without any dilution. A field isolate of NDV obtained from the Department of Veterinary Microbiology, College of Veterinary and Animal Sciences, Mannuthy was used in the study. The isolate was passaged in 9 to 11 day old embryonated chicken eggs by the allantoic route of inoculation. The allantoic fluid was collected from the inoculated eggs and used as source of virus in the HI test. The HI test (â method) was performed as described by Allan and Gough (1974). Briefly the HI test was conducted as follows. Initially a haemagglutination (HA) test was performed by making serial two fold dilutions of the virus J. Vet. Anim.Sci. 2009. 40 : 20-21 RESEARCH ARTICLE 20 Antibody Titres of Newcastle Disease Virus...