الفهرس 
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Abstract
SUMMARY
The present study was carried out at Animal Experimental Station at
Nuclear Reseanch Centre, Enshas .
Radioimmunological and biochemical assays were performed in
Laboratories of Radioimmunology and Biochemistry unite of Atomic Energy
Autority .
It was planned investigate the effect of using different dietary protein
levels on the antibody formation oin female and male Hubbard chicks.
The study was also aimed to point out the effect of both dietary protein
levels and thyroglobulin immunization on growth measurments and some
metabolic blood parameters in relation to induced thyroid immunity to provide
some insights on the autoimmune diseases in fowl.
Atotal of 300 one - dau old Hubbard chicks ( 150 females and 150 males)
were used. Birds were reared on starter diet during the first two weeks of age
then randomly classified into 3 groups of 50 of each sex, representing three
nutrional diets applied up to the end of the experimental period that lasted
weeks. Low ( 14.44 % ) , medium ( 18.41 % ) and high ( 22.11 % ) levels of
protein in diet were fed to female and male chicks of the first , second and
third group, respectively.
All diets were formulated to be of equal energy and to cover the
nutritional requirements recommended by NRC, (1984) .
Thyroglobulin immunization treatment was carried out after 3 weeks of
applying the experimental diet ( at the 5th week of age) . Chicks of each sex
and dietary protein level were subdivided into three subgroups ( each of 15
chicks) . Birds of the first subgroup was injected with 0.5 mL saline solulion
and considered to be control, while birds of the second and third subgroup
were injected with 0.5 mL Complete Freund’s Adjuvant ( CFA ) or
thyroglobulin. respectively. Repeated injections were carried out a week later
(at the 6th week of age) to induce secondary immune response for chemical
and immunological assays. Blood samples were collected prior to and at the
2nd, 4th • 6th and 8th week after active thyroid immunization.
Immunoresponse was evaluated by estimating antibody strength (%T4_125I
bound to gamma globulin) using ammonium sulphate method, qualitative and
relative concentration of gamma globulin and fractions of sennn protein using
cellulose acetate electrophoresis and by estimating thyroid hormones thyroxine
(T4) and triiodothyronine (T3 ) levels in blood serum .
Total protein, albumin • globulin and A/G ratio ; total lipids , cholesterol
and serum transaminases activities ( SGOt and SGpt ) were estimated as
prameters related to both dietary protein and thyroglobulin immunization .
Body weight • weight gain , feed consumption and efficiency were
recorded weekly and considered to be growth performance measunnents .
Obtained results could be summerized as follows:
I - Effect of dietary protein level on immune response .
1- Percentage of T4_125I bound to gamma globulin . As a result of
thyroglobulin immunization antibody formation could be detected in all
groups of chicks at the second week after immunization , reaching its
peak values at the 4th week for the group of chicks fed low protein diet
and at the 6th and 8th week for those group fed medium and high
protein levels. respectively.
- Antibodies formed against thyroglobulin immunization were found to
be significantly affected by sex • dietary protein level . immunization
and time intervals .
- Females attained higher antibody titres than males in most groups .
- Birds of higher protein level group had the highest % of T4_1251
bound to gamma blobulin than those of medium or low level.
- Antibody production was found to be increased in all groups with the
progess of time
2 - Electrophoretic fractionation of serum proteins .
- Qualitative and relative concentration of gamma globulin showed
similar results to that obtained by ammonium sulphate method .
- Dietary protein level. immunization and time intervals significantly
affected gamma globulin concentration in serum .
- Serum albumin and alpha and beta globulin levels were not found to
be affected by thyroglobulin immunization . However • albumin and
alpha - globulin were significantly affected by dietary protein levels
and time intervals.
- Serum Beta globulin content was not significantly affected by any of
the studied factors .
3 - Serum Thyroid hormones levels .
Chick’s sex was found to be of no significant effect on both T4 or T3
levels in serum . Increased level of T4 was observed in the group of
birds fed medium or high levels of protein while those birds fed lower
dietary protein levels had lower T4 levels in serum .
- T4 increased at the time of antibody formation and decreased with the
progress of time .
- T3 was significanthy affected by the level of protein in diet and time
intervals.
II Effect of dietary protein levels and thyroglobulin immunization
on blood parameters
1 - Total proteins:
- Serum total proteins . albumin and globulin were found to be
significantly affected by dietary protein level and time intervals
(increased values in all the last mentioned parameters were associated
with the increasing percentages of protein in diet and with the progress
of time).
- Serum total proteins and globulins were found to be significantly ( P
< 0.05 ) affected by immunization. while sex showed a highly
significant effect ( P < 0.001 ) on serum globulins .
2 - Total lipids and total cholesterol.
Total lipids were significantly affected by dietary protein (decreased
with increasing levels of protein in diet ) and time intervals (increased
with the progress of time) . While cholesterol decreased in
concentration with the progress of time. No significant effect due to
immunization was found on either total lipids or cholesterol .
3 - Serum Transaminase activities (GOT and GPT)
Increasing levels of both GOT and GPT in serum were found in the
group of birds fed lower levels of protein in diet than those fed medium
or higher levels. Thyroglobulin immunized groups showed higher
levels of both enzymes than the control . They were increased with the
progress of time .
- Protein level in diet, immunization and time intervals significantly
affected both Got and Opt in serum .
III Effect of dietary protein and thyroglobulin immunization on
growth measurments •
- Body weight and feed efficiency were found to be significantly affected
by sex , dietary protein level and time intervals .
- Females had lighter body weights and lower feed efficiency than males.
- Lighter body weights and lower feed efficiency were associated with
feeding the birds lower dietary protein levels, while the heaviour
weights and higher feed efficiency were associated with feeding higher
dietary protein levels .
- Significant effect due to immunization was found to affect body weight,
while immunization had no effect on either feed consumption or feed
efficiency .