الفهرس 
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Abstract
·This study was carried out at the experimental animal house and
laboratories, belonging to Physiology and Biochemistry Unit, Nuclear
Research Center. Atomic Bnergy Authority. Inshas. Sharkia. Bgypt.
It was planned to find out the possibility to improve the productive
performance of the egg producer hybrid during the second year by
modifying the levels of thyroid and sexual hormones wbich are
considered the most important physiological factors affecting metabolism
rate and reproductive activities in laying hens.
The study was conducted onl40 laying hens of Shaver Starcross 288
hybrid aged 64 weeks of body weight ranged from 1730 tol868 gm, and
haVing an average egg production ranging from 260 to 285 eggs /hen/12
monthes during the first productive year.
Three experiments were carried out, the first on 42 hens to study the
effect of inducing mild hypo-and hyper-thyroidism. the second on 56
hens to find out the effect of modifying serum sexual hormones levels
and the third on 42 hens to inspect the possibility to improve the hen’s
productivity by adding LtJelo!JacilJus concentrate to laying ration.
In the first experiment . layers of the first, second, and the third
groups (each of 14 hens) were fed 5 mg Neo-mercazoletablets then /48
hrs for 6 weeks increased to 5 mg /hen/24 hrs for 3 weeks after one
week recovery period, 0.1 mg thyrOXinetablets/hen/24 hrs for 6 weeks
increased to 0.2 mg /hen /24 hrs for 3 weeks and yellow maize seed/
24 hrs, respectively.
Layers of the second experiment were .:fivided into four groups each
of 14 hens. Birds of the first, second and third groups were treated with
progesterone (I mg I henl 24 hrs), oestrogen (S mg I hen I 24 hrs) and
combined dose of progesterone and oestrogen ( 0.2’5 mg + 5 mg
respectively) those of the fourth group are considered as control.
/ actaL /aell./us concentrate was added to laying hens of the third
experiment at a level of 0.5 gm or of 2 gm per kg ration for birds of
the first and the second groups, respectively (each of 14 hens).
RadioimmunologicaIassays were carried out for the determination of
serum levels of thyroxine, triiodothyronine, oestrogen, progesterone and
testosterone.
Biochemical determination for total proteins, albumen, icalcium
inorganic phosphorus, total lipids. cholesterol, transaminases (GOT and
GpT) and alkaline phosphatase were also carried out.
In addition body weight, feed consumption, egg weight and egg
number were individually and daily recorded ,then data were presented
as weekly average.
The obtained findings are summarized in the followings:
I. The first eIperiDlent.
1. Treating laying hens with L-thyroxine. significantly increased serum
level of T3 and To( (P<O.I) as well as the ratio between them
(p<O.OS)Nhile Neo-mercazoltreatment decreased these levels.
2. While thyroid treatment was found to have no significant effect on
serum level of testosterone or progesterone, serum level of
oestrogen showed significant response (p<O.([) to this treatment. It
was decreased in case offeeding hens L-thyroxine while it increased
in applying goitrogenic material (NeO-mereazole)
3. Serum levels of total proteins, albumen and globulin were found to
be significantly affected by the thyroid treatment. While Albumen /
globulin ratio showed insignificant response to treatment applied.
Inhibiting thyroid activity decreased serum levels of the previously
mentioned parameters ,while feeding layers Lrthyroxine tablets
relatively increased them .
.of Serum total lipids as well as cholesterol significantly decreased as a
result of treating layers with t-tnvronne ,while their levels showed a
significant (P<O.(]») increase in case of applying the goitrogenic
material (Neo-mercazole) .
5. Opposite results were found In studying the effect of thyroid
treatment oncatcium and inorganic phosphorus levels in the blood
serum of the laying hens. They showed a significant Increase as a
result of feeding birds L-thyroline tablets ,while a pronounced
decrease was found in applying goitrogenic material (Neo-mercazole).
6. Enzymatic levels showed significant (p<O.O) variation due to thyroid
treatment. A significant decrease was observed in the level of serum
alkaline phosphatase and transaminases (OaT and OPT) when
feeding layers Neo- mercazol.Opposite results were obtained in case
of feeding birds L-thyroline tablets.
7. Egg weight. feed consumption and body weight were significantly
decreased by feeding layers L-thyroline tablets and increased by
applying Neo-mercazole ,While egg number increased by treating
layers with L-thyroline and decreased by administration with
Neo- mercazoJ e .
8. Estimating intervals as well as their interactions with treatments
applied showed significant effect on serum levels of 13’ total
protiens ,albumen, egg number and egg weight. Feed consumption
and body weight were also affected by treatments applied.
II _The second eIperiment
1. Sexual hormonal treatment applied showed pronounced and
significant effects (p<O.([) on all parameters estimated.
2. Higherlevels of13 ,T.qjtestosterone and progesterone were found in
the blood serum of experimental layers treated with progesterone
hormone, while those injected with oestrogen showed the lowest
averages ( except the oestrogen level ).
3. On the other hand birds treated with progesterone hormone had the
lowest averages of serum total lipids, cholesterol, calcium.
inorganic phosphorus . alkaline phosphatase and transaminases
(GOTGPT).The highest average of serum total lipids. cholesterol
and transaminases (GOT;md GPT)were observed in the group of
birds treatad with combined dose of progesterone and oestrogen.
of. Laying birds treated with progesterone showed the lowest averages
of egg number and feed consumption. while they had the highest
average of egg weight.
5. On the other hand, layers treated with oestrogen showed the
highest averages of egg number. feed consumption, and body weight
and the lowest average of egg weight when compared with those
treated with progesterone
progesterone.
or a combined dose from oestrogen+
III _ The third eIperiment
1. Feeding laying birds with LQc10/JaCWus concentrate significantly
affected serum total proteins, globulin (P<O.(])) and A/O ratio (P<O.05).
In addition birds age showed significant effect (P<O.(])) on
the previously mentioned parameters. They all were relatively
increased as the amount of LBCconcentrate added increased.
2. LQclofJgciUus concentrate showed significant effect (P<O.05) on
serum cholesterol level ,while variations III serum total lipids .
calcium, inorganic phosphorus and the ratio between them were of
no significant value.
3. Serum level of alkaline phoSPhatase was significantly (P<O.05)
increased as the amount of IaC/o/.[gciUus concentrate added Was
increased. While increasing the amount of Lac/o/JgciUus concentrate
significantly (p<O.05) decreased serum level of the transaminases
(OOTand OPT) studied.
-t. Egg number and egg weight showed a significant (P<O.Ollresponse.
while feed consumption and body weight showed a significant
response at (p<O.05). with adding LacLO/JaCWus concentrate to laying
ration. The amount of egg weight. feed consumed and body weight
increased as the amount of LBC added increased. while increasing it
resulted in decreasing either egg number and egg mass averages.