الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The present study was carried out in Poultry Nutrition Farm,
Poultry Production Department, Faculty of Agriculture, Ain Shams
University, Shoubra El-kheima, Egypt. The objective was to evaluate the
effect of supplementing different levels of threonine and tryptophan on
growth performance, carcass traits and some plasma parameters of broiler
chicks under Egyptian summer conditions. All farm work during the
experimental period from August to September 2017.
A total of 360, Ross 308, one-day-old broiler chicks were randomly
allocated into 9 treatments with 8 replicates of 5 chicks each. Three levels
of threonine (100, 150 or 200 %) and three levels of tryptophan (100, 150
or 200%) according to dietary requirements for Ross 308 chick’s guidebook
were used in a factorial design arrangement to obtain nine experimental
treatments. Two periodical diets (A corn-soybean basal diets) were used
(starter phase 1-21 days of age and grower phase 22-35 days of age).
Growth performance traits including live body weight (LBW),
Body weight gain (BWG), feed consumption (FC) and feed conversion
ratio (FCR) were recorded at the end of each week. Carcasses were
manually eviscerated and weighed. Components of total protein, albumin,
cholesterol, and triglycerides were analyzed by using commercial kits.
The main results could be summarized as follows:
1- Chicks fed diet supplementing 200 % threonine had an
improvement in live body weight and body weight gain with
different levels of tryptophan compared to other treatments.
2- The highest LBW was recorded by chicks fed diet supplemented
with 150 % of chicks’ requirements of both types’ amino acids and
the lowest was recorded by chicks fed diet supplemented with 200%
of the tryptophan requirement with 150% threonine (1593.91 vs
1504.75g).3- Birds fed diet supplemented with 150% tryptophan gave the highest
daily body gain compared with other groups fed diets supplemented
with tryptophan. (44.13 g/d).
4- Concerning relative weight of carcass and edible parts, there were
significantly reduced with increasing threonine level in the broiler
diets, but tryptophan amino acid had not any significant effect on
the above-mentioned traits.
5- Percentages of giblets differed significantly related to tryptophan
amino acids effect, where giblets weight percentage increases with
increasing tryptophan, so the interaction between types and levels
was affected. But threonine amino acid had not any significant
effect on the percentage of giblets.
6- Liver weight percentage differed significantly related to tryptophan
amino acids effect, where it increased with increasing tryptophan
levels in broiler diets, but threonine amino acid and the interaction
between types and levels were not affected on the percentage of
liver.
7- The percentage of gizzard weight affected significantly decreased
with increasing of both types of amino acids, but the interaction
between types and levels was not affected.
8- Percentage of heart differed significantly related to tryptophan
amino acids effect, where this percentage increased with increasing
tryptophan, but threonine levels and the interaction between types
and levels were not affected.
9- Spleen percentage reduced significantly with increasing threonine
amino acid but adding tryptophan in the diets significantly
increased this percentage, but the interaction between types and
levels was not affected. Bursa percentage was affected significantly
by threonine level in diets where chicks fed 100% recorded highest bursa percentage (0.17%), so the interaction was affected, but
chicks fed diets with tryptophan had not affected.
10- There were no significant (P>0.05) differences of different types
and levels of amino acid on percentages of breast, thigh, drumstick,
wing, and nick.
11- Birds fed diets with 150% tryptophan were recorded higher
percentages of breast, drumstick, and nick (32.19, 11.18, 5.38%,
respectively) and birds received diets with 200% recorded higher
thigh percentage (21.24%) and higher wing percentage (7.99%) in
birds fed diets with tryptophan.
12- The differences between plasma concentration of total protein,
globulin, and A/G ratio were significant due to both tryptophan and
threonine supplementation of experimental diets.
13- Total cholesterol concentration increased significantly with the
different levels of threonine, and interaction between them.
Whereas, adding threonine has no effect on the concentrations of
triglyceride. Tryptophan supplementation had no impact on the
blood plasma concentrations of total cholesterol and triglyceride.
In this study, it concluded that supplementation of threonine and
tryptophan improves productive performance and health status of broiler
chicks without imposing any toxicity as all blood components were in
normal range.