PATHOLOGICAL, HAEMATOLOGICAL AND BIOCHEMICAL CHANGES IN COCKERELS EXPERIMENTALLY INFECTED AND VACCINATED AGAINST INFECTIOUS BURSAL DISEASE VIRUS.

No Thumbnail Available
Date
2014-08
Authors
KASSIM, IBRAHIM.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
This study was conducted to determine pathological, haematological, and biochemical changes in cockerels experimentally challenged with very virulent infectious bursal disease virus (vvIBDV), and those vaccinated against Gumboro disease. Two hundred and fifty day-old cockerels (chicks) were randomly distributed into 5 groups (A, B, C, D and E) of 50 chicks per group. Group A chicks were vaccinated at 2 and 4 weeks of age with intermediate strain (Georgia) IBD vaccine orally at dose of 10 ml (equivalent of 103 plague-forming units) per bird. Each bird in groups B, C and D was inoculated with 0.4 ml of vvIBDV inoculum equivalent to 16 x10 4.6 ELD50 of undiluted viral suspension via conjunctival instillation at 4, 6 and 8 weeks, respectively. Group E served as the control group. Chicks in this group were neither vaccinated against nor challenged with vvIBDV. Blood samples were collected from birds in each group and analysed for haematological parameters. Serum samples obtained from the birds were used to determine biochemical parameters, and antibody titres to IBDV, using an enzyme linked immunosorbent assay (ELISA) kit. Blood samples were collected one week after each vaccination in group A, first and second week after challenge in groups B, C, and D, and weekly (week 1 – 10) in the control group (E). Clinical signs exhibited by birds in the challenged groups include whitish-yellowish mucoid diarrhoea, recumbency, prostration, drooped wings, and reluctance to move. One hundred per cent morbidity rate was recorded in all the challenged groups (B, C, and D), while mortality rates of 54%, 72% and 50% were observed in groups B, C and D, respectively. The haematological parameters of the challenged groups revealed significant decrease (p < 0.05) in packed cell volume (PCV), total red blood cell count (TRBC) and haemoglobin concentration (Hb); and significantdecrease (p < 0.05) in lymphocyte and white blood cell count (WBC) values. On the other hand, there was a significant increase (p < 0.05) in heterophil value. In the vaccinated group, the haemogramme revealed significant decrease (p < 0.05) in lymphocyte and heterophil values. There were significant decreases (p < 0.05) in total protein (TP) and total cholesterol; as well as significant increase in urea (p < 0.05) in the challenged groups. In the vaccinated group potassium and total protein were significantly decreased (p < 0.05). Gross lesions, like enlarged, congested, haemorhagic and turgid bursa of Fabricius; enlarged and congested kidneys; and haemorhages in mucosae of the proventriculus were observed in the challenged groups. In the vaccinated group, no clinical signs were exhibited, but mild gross lesions were seen. Histopathological changes in the challenged groups revealed haemorhages, congestion, and necrosis of bursa of Fabricius, liver, kidney, spleen and muscle. In conclusion, the study revealed some pathological, haematological and biochemical differences in cockerels challenged with vvIBDV, and those vaccinated against IBDV.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF DEGREE OF MASTER OF SCIENCE IN VETERINARY PATHOLOGY.
Keywords
PATHOLOGICAL,, HAEMATOLOGICAL,, BIOCHEMICAL CHANGES., COCKERELS EXPERIMENTALLY,, INFECTED AND VACCINATED,, AGAINST,, INFECTIOUS BURSAL,, DISEASE VIRUS.
Citation