EFFECT OF SELENIUM ON IMMUNE RESPONSEAND SUSCEPTIBILITY OF VACCINATED COCKERELS TO INFECTIOUS BURSAL DISEASE
EFFECT OF SELENIUM ON IMMUNE RESPONSEAND SUSCEPTIBILITY OF VACCINATED COCKERELS TO INFECTIOUS BURSAL DISEASE
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Date
2012-08
Authors
SHEKARO, Audu
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Abstract
Selenium (Se) is a micronutrient that has been used to stimulate the immune system in animals.
Infectious bursal disease (IBD) outbreaks in spite of vaccination are a common occurrence in
poultry production in Nigeria. This study was conducted to determine the effect of Se
supplementation on immune response and resistance of cockerels to IBD. In the experiment, 300
Dominant black marshal cockerels (DBMC) were divided into 12 groups of 25 birds each and
fed graded levels of dietary Se. Groups A, B, C received 0.1 ppm, 0.5 ppm and 1.0 ppm of Se in
feed, respectively. They were vaccinated with IBD vaccine (M.B strain) at 1 and 3 weeks old and
challenged with IBD virus (IBDV) at 6 weeks old. Groups D, E, F received 0.1, 0.5 and 1.0 ppm
of Se in feed, respectively; they did not received IBD vaccine, but were challenged at 6 weeks
old with IBDV. Groups G, H, I received 0.1, 0.5 and 1.0 ppm of Se respectively, received IBD
vaccine at 1 and 3 weeks old, but were not challenged with IBDV. Group J was not
supplemented with Se but vaccinated with IBD vaccine at 1 and 3 weeks old but not challenged
with IBDV. Group K was not supplemented with Se, not vaccinated with IBD vaccine and not
challenged with IBDV. Group L did not receive Se supplementation, not vaccinated against IBD,
but challenged with IBDV at six weeks old. Selenium concentration in the feed and tissues
sample was determined using inductively coupled plasma optical spectroscopy. Antibody titre
was determined using a commercial ELISA kit. Mortality and Protective rates in the challenged
birds were calculated. Gross and microscopic lesions were scored. Haematological parameters
were determined using auto haematology analyzer. Biuret method was used to determine total
protein. After graded levels of Se supplementation for 10 weeks, there was no correlation
between the dose of Se in feed and its concentration in the liver, muscles, blood and serum, but
there was a positive correlation (r = 0.94) in the kidneys. Increase in dietary Se concentration led
to increase in antibody titres. There was a negative correlation (r = - 0.93) in the vaccinated and
(r = -0.95) in unvaccinated chicks between the concentration of Se in feed and mortality rate in
chicks challenged with IBDV. There was a positive correlation between Se concentration in feed
and haematological parameters. Lesions were severe in birds that received lower doses of Se
than those that received higher doses. It was concluded that Se supplementation in feed enhances
the immune response of DBMC to IBD and it also reduces the severity of the disease. Selenium
supplementation in poultry feed was therefore recommended for industrial trial.
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Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES
AHMADU BELLO UNIVERSITY,
IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF
MASTER OF SCIENCE IN VETERINARY PATHOLOGY
DEPARTMENT OF VETERINARY PATHOLOGY,
FACULTY OF VETERINARY MEDICINE,
AHMADU BELLO UNIVERSITY
ZARIA, NIGERIA
Keywords
EFFECT,, SELENIUM,, IMMUNE RESPONSEAND SUSCEPTIBILITY,, VACCINATED COCKERELS,, INFECTIOUS BURSAL DISEASE.