Pathomorphological Changes, Immunopathological Effects And Interaction With Newcastle Disease Virus In Low Grade Ochratoxicosis In Broiler Chicken

Title : PATHOMORPHOLOGICAL CHANGES, IMMUNOPATHOLOGICAL EFFECTS AND INTERACTION WITH NEWCASTLE DISEASE VIRUS IN LOW GRADE OCHRATOXICOSIS IN BROILER CHICKEN Name : NAKKA SAILAJA (DPV 07010) Degree for which Submitted : Ph.D. (Veterinary Pathology) Chairman : Dr. C. BALACHANDRAN, Ph.D. Registrar Tamilnadu Veterinary and animal Sciences University, Mahdavaram Milk Colony Chennai600 051 Then Professor and Head Department of Veterinary Pathology Madras Veterinary College, Chennai-600 007 University Tamilnadu Veterinary and Animal Sciences University Year : 2010 The effects of low levels of Ochratoxin-OA (30, 60 and 90 ppb) in broiler chicks were studied by feeding OA from 0 to 5 weeks of age. A significant (P<0.05) reduction in the body weight gain was observed from second and fourth week onwards in the 90 and 30 ppb groups respectively and only in the 4 week in the 60 ppb OA fed birds when compared to the control group. Significant decrease (P<0.05) in the feed consumption was found in OA fed birds. Leucocytosis was found in the 90 ppb OA fed group. Hypoproteinaemia, hypoalbuminaemia and hypoglobulinaemia were observed in the OA fed birds. Significant (P<0.05) increases were noticed for the serum AST in the 30 ppb and ALP and GGT in the 90 ppb OA treated birds. Significant (P<0.05) increase in the BUN in the 90 ppb and hyperuricaemia in all doses of OA were found. Hypocalcaemia and hyponatraemia were observed in all OA treated groups. OA significantly (P<0.05) increased the serum triglycerides and VLDL levels in the 30 ppb group and serum cholesterol and LDL levels in the 60 ppb group. The liver lipid peroxidation increased significantly (P<0.05) in a dose dependent manner in the OA fed groups. The liver antioxidant levels, GSH, GPx, GST, SOD and CAT decreased significantly (P<0.05) except GST, where the level was increased in OA fed birds. OA caused significant (P<0.05) decrease in the HI titres against NDV at 21 day in the high dose group and significant (P<0.05) decrease was noticed in the splenocyte indices in all doses of OA compared to the control. Grossly, the liver and kidneys showed paleness and enlargement in the 90 ppb OA fed birds in the 5 week. Microscopically, vacuolar degeneration and necrosis of hepatocytes, focal mononuclear cell (MNC) infiltration, microgranuloma, biliary epithelial hyperplasia, portal fibrosis and periductular MNC infiltration in the liver and tubular epithelial degeneration and necrosis, focal MNC infiltration and microgranuloma in the kidneys were observed in the OA fed birds. Crop mucosa showed hyperplasia and parakeratosis. Proventricular mucosa revealed MNC infiltration, fibrosis, hyperplasia and broadened villi. MNC infiltration, focal glandular necrosis, reduced secretion and dilatation of glands and defective kiolin layer formation in the gizzard mucosa, fusion of villi and mild MNC infiltration in the duodenal mucosa and focal MNC infiltration and microganuloma in the pancreas were observed in the OA fed birds. Bursa of Fabricius revealed mild to moderate lymphoid cell depletion, lack of corticomedullary differentiation and cystic follicles. Spleen showed mild lymphoid cells depletion, reticular cell hyperplasia and apoptosis. Lymphoid cell depletion and necrosis in the caecal tonsils and mild plasma cell depletion in the Harderian gland were noticed in the OA fed birds. Ultrastructurally, the proximal convoluted tubular epithelium of kidney showed swelling, loss of brush border, variable sized mitochondria with vacuolation and loss of cristae and chromatin margination and disintegration in the nuclei and disruption of nucleoli in OA treated birds. NDV-ochratoxin (80 ppb) interaction resulted in significant (P<0.05) decrease in the HI titres against NDV at 21 days of age in the unvaccinated birds and 33.33 per cent mortality in all but vaccinated control group. Conclusions: Ochratoxin (30 ppb) affected the performance, health, biochemical parameters and immune status of birds. Vaccinated OA birds succumbed to NDV.