الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
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Abstract
Three hundred and sixty, 2 weeks old, Cobb 500 chicks were distributed to ten dietary treatments each composed of, 36 chicks in three equal replicate groups. All groups of chicks were fed their respective experimental diets from the second to the sixth week of age.
Ten experimental diets were formulated and used. A basal diet containing 19%CP was considered as a control. Another basal diet containing 17% CP was considered as a negative control diet. The remaining 8 experimental diets were compounded by adding two levels (0.1 or 0.2 %) of lysine or methionine in presence or absence of a probiotic to the 17% CP diet.
Results obtained could be summarized as follows:
1- At 5 and 6 weeks of age, broilers fed the experimental diet containing 17 % CP plus probiotic (T10) attained significantly higher body weight.
2- BWG during the growth period from 2-3 weeks of age was significantly increased for birds fed lysine or methionine supplemented diets with the probiotic addition.
3- During 3-4 weeks of age, the high methionine (0.2%) diet alone or combined with the probiotic achieved the best BWG comparable to that of the 19% CP control diet.
4- During the whole period (2-6 weeks), broilers that fed low-CP, lysine (0.2%) plus probiotic-supplemented diet, and those fed methionine diets (0.1 or 0.2%) alone or in combination with probiotic gained significantly more body weight than the other treatments.
5- The lowest feed intake was recorded for low-CP with lysine (0.1 and 0.2%) plus probiotic supplement diets.
6- The FCR was not significantly affected for the whole period; however, the best value was recorded with lysine plus probiotic-diets and for methionine supplemented diets with or without probiotic.
7- Blood Hemoglobin concentration was significantly higher in the 19%CP-control birds compared with other treatments.
8- Blood plasma ALT and AST activities were higher in the 19%CP-fed broiler chicks compared with the other treatments.
9- Plasma cholesterol levels were significantly decreased in broilers fed the low-CP lysine (0.2%), lysine + probiotic, and all methionine supplemented diets compared with the control group. The lowest values of blood plasma cholesterol were recorded for the methionine + probiotic treatment group.
10-The percentages of gizzard, liver and abdominal fat were significantly influenced by dietary supplementation with amino acids with or without probiotic.
11- Results showed also that abdominal fat percentage of broilers was significantly higher for the low-CP, lysine plus the probiotic treatments and for all methionine supplemented diets.
Conclusion: It is concluded from the present results that dietary supplementation with lysine and methionine alone or combined with a probiotic could improve the productive performance of broiler chicks without adverse effects on their blood parameters.