الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
SUMMARY AND CONCLUSION
Experimental design: In one experiment with 300 Indian River (IR) unsexed chicks, one-day-old chicks were randomly distributed into five treatments with six replicates of 10 chicks in 6 treatments, which was used in this study to assess the effects of decreasing dietary CP with amino acid supplementation.
The data collected were: Body weight, body weight gain, feed consumption (FC), feed conversion ratio (FCR), mortality rate, performance index (PI), European Production Efficiency Factor (EPEF), protein conversion ratio (PCR), calories conversion ratio (CCR), economic efficiency, carcass characteristics, digestive track length, some blood parameters, some intestinal activity of enzymes, nutrients digestibility coefficients, intestine microbiology, and intestine histology.
The experimental groups were as follows:
Control: Chicks - fed the basal diet.
Treatment 1: (T1) Chicks - fed diets with 1% protein loss and 10% high amino acids.
Treatment 2: (T2) Chicks - fed diets with 2% protein loss and 20% high amino acids.
Treatment 3: (T3) Chicks - fed diets with 3% protein loss and 30% high amino acids.
Treatment 4: (T4) Chicks - fed diets with 4% protein loss and 40% high amino acids.
The main results obtained can be summarized as follows:
1. Chicks were fed diets containing 1% protein loss and 10% high amino acids (T1) to increase body weight (1889.87g) compared to the control (1862.83g) and increase body weight gain (1849.19g) compared to the control (1822.29g).
2. Chicks - fed diets with 1% protein loss and 10% high amino acids (T1) increased feed consumption (2903.54g) compared to control groups (2861.67g), while FCR was not affected between T1 and control groups (1.57), but other treatments were affected, which was poor.
3. The total mortality rate was 1.66% during the total experimental period (1–35 days).
4. Chicks fed diets with 1% protein loss and 10% high amino acids (T1) showed improvement in PI and PEEF compared to control groups. PI ranged between 60.46 and 120.48, while EPEF ranged between 164.12 and 344.25.
5. There was a significant effect on protein conversion ratio (PCR) and calorie conversion ratio (CCR) among all treatments. The best CCR was in the control and T1 groups (3.82). Also, the best PCR was in the T1 group (0.25).
6. Carcass% was not significantly affected by different dietary treatments.
7. Decreasing dietary CP with amino acid supplementation tended to increase the relative weight of the liver. Chicks fed control diets had the lowest percentage of liver (2.03%), and chicks fed T4 diets had the highest percentage of liver (2.82%).
8. Carcass had a significantly higher gizzard percentage. Chicks fed control diets had the lowest percentage of gizzard (1.08%), and chicks fed T4 diets had the highest percentage of gizzard (1.80%).
9. Heart percent between treatments had a significant effect. Chicks fed T4 diets had the highest percentage of heart (0.77%) compared with other dietary treatments (control, T1, T2, and T3), where the values were (0.56, 0.60, 0.55, and 0.75%, respectively).
10. Decreasing dietary CP with amino acid supplementation tended to decrease the relative weight of the spleen. Chicks fed control diets had the highest percentage of the spleen (0.16%), and chicks fed T3, and T4 diets had the lowest percentage of the spleen (0.10%).
11. Decreasing dietary CP with amino acid supplementation tended to increase the percentage of abdominal fat. Chicks fed control diets had the lowest percentage of abdominal fat (0.37%), and chicks fed T4 diets had the highest percentage of abdominal fat (1.20%) compared with other dietary treatments T1, T2, and T3, where the values were 0.44, 0.88, and 1.19.
12. There was a significant increase in the length of the total digestive tract and small intestinal tract in birds fed T1 diets compared to control groups.
13. The GPT, GOT, and blood total protein activity weren’t significantly affected by dietary treatments.
14. Globulin wasn’t significantly affected between dietary treatments, but albumin and the A/G ratio were significantly affected between dietary treatments, which by decreasing dietary CP with amino acid supplementation, tended to increase albumin and A/G.
15. Dietary treatments had no significant effect on cholesterol concentration. However, it had a significant effect on triglyceride; the highest value was obtained in the T4 diet (53.93 mg/dL), whereas the lowest value was obtained in broilers fed the control diets (12.44 mg/dL).
16. There was a significant effect on nutrients digestibility coefficients (%) among all treatments.
18. The activity of trypsin and chymotrypsin was affected by decreasing dietary CP with amino acid supplementation. while the activity of amylase and lipase was non-significant in birds compared to control groups.
19. Decreasing dietary CP with amino acid supplementation increased total counts and E. coli forms, but lactic acid bacteria increased in T1 groups compared to control groups.
20. There were significant differences in villi height and muscle thickness.
21. The dates for economic efficiency of feeding costs of broiler chicks as affected by diet during 0-35 days of age. Relative economic efficiency (REE) values were 101.41, 83.95, 39.33, and 6.23%, respectively, for the groups (T1-4) compared to 100% for the control groups. Therefore, the best REE was in T1 (101.41%).
Conclusion
It could increase amino acid levels in low protein diets in broilers, which was 1% protein loss and 10% high amino acids (T1), due to their positive effect on productive performance, gut health (digestive morphology and histology), and improved activity of intestinal enzymes and nutrients digestibility coefficients, without negative effects on chick viability. However, increasing amino acids to 30% and 40% levels in low-protein diets may have negative impacts on broiler performance.