الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This experiment was conducted at the poultry farm belonging to the poultry nutrition department and in the laboratories of the Regional Center Food and Feed (RCFF), Agriculture Research Center.
Poultry is one of the major sources of protein in the entire world but there are some factors which threaten poultry industry such as infection with microorganisms. This leads to reduced immunity and reduced growth rate and increased mortality rate as well as high economic loss. So they resorted to the use of antibiotics as growth promoters but this leaded to antimicrobial resistance.
In this study we decided to use natural alternative growth promoter (Spirulina Platensis) and evaluate its effect on productive performance, carcass characteristics, blood parameters, mortality rate, bacteriological analysis of intestine and histopathological examination.
The main results can be summarized as follows:
1. The body weight of broiler chicks supplemented with Spirulina in their diets during the rearing period were significantly increased (p<0.001) in all treatments compared to control treatment.
2. The body weight gain also was significantly higher (p<0.001) for all supplemented groups when compared with the control group.
In this study the best result obtained at body weight was in treatment added 1gm Spirulina /kg diet.
3. The present result showed that the broiler chicks groups contained Spirulina in their diet were consumed less feed compared to control group so the feed intake were significantly decreased (p<0.001) in supplemented groups gradually reaching to marketing time.
Concerning feed conversion ratio, it could be observed that at 29-35 days chicks had better feed conversion ratio compared to other groups. It is increased significantly (p<0.01) at the finishing period of rearing.
4. Performance index (PI) and European production efficiency factor (EPEF) were increased significantly (p<0.001) with Spirulina inclusion in poultry diet.
5. It could be observed in this study that the Spirulina addition to poultry diets has good effect in increasing edible parts weight as it is significantly different according to control group. The highest percentage of carcass was obtained in group supplemented with 1gm/kg diet.The relative weight of gizzard, heart and giblets have high significant difference (p<0.001) and the relative weight of liver differs significantly (p<0.01) when compared with control.
Results of edible meat parts (Breast, Thigh and dram stick muscles) of broiler chicks which affected by Spirulina supplementation showed that the best weight of breast muscle was obtained when adding from 0.5gm to 1gm spirulina / kg diet and they are highly significantly different (p<0.001) as compared with control.
6. Abdominal fats weight was affected by Spirulina addition in diet especially T6 in which the lowest abdominal fat weight and percentage were obtained as compared with control.
7. The present results showed that the relative spleen and bursa weights and percentages were significantly increased (p<0.001) in groups supplemented with Spirulina compared to control group.
The highest weight of spleen was obtained from T6 (2.5gm) and the highest bursa weight was obtained at T5 (2gm/ kg)
8. Intestinal length also affected by inclusion of Spirulina especially at concentration 2.5gm/kg diet. The relative length of digestive tract was higher significance (p<0.001) in T6 than in other treatments.
9. It could be noticed that the chicks supplemented with Spirulina had significant decrease of AST (p<0.001) and ALT (p<0.05) than in control.
10. Kidney function was also improved in treatments supplemented with Spirulina. Urea and creatinine were significantly decreased (p<0.01) and (p<0.05) respectively.
11. The present results indicated that there is slight increase in serum total protein, Albumins and Globulins when compared with control group. The best result of total protein was in T6 and T7.
12. Administration of Spirulina platensis resulted in significant increase (p<0.01) in IgG and (p<0.001) in IgM as compared with control. The highest result obtained at concentration 1.5gm Spirulina/kg.
13. Conclusion of Spirulina in poultry diet reduces the total lipids, cholesterol and triglycerides level. HDL in our result had significant increase (p<0.001) especially in Treatment 3 (1gm) and Treatment 4 (1.5 gm). LDL decreased significantly (p<0.001) and the best concentration leads to decreasing LDL was 2.5g spirulina/kg diet.
14. Plasma thyroid hormones T3 and T4 were non-significantly affected by Spirulina addition in broiler feed.
15. The result shown indicated that the mortality rate reduced significantly (p<0.001) in groups supplemented with Spirulina compared with control treatment. The best results were obtained with concentrations from 0.5 to 1.5gm/kg diet. The control broiler chicks control had significantly highest mortality number compared to all treatments.
16. The color of breast muscle and the color of thigh muscle did not affected significantly with Spirulina addition. The meat texture (tenderness) of breast muscle was improved significantly (p<0.01) and taste has significant difference (p<0.05).
17. In the present study, feeding Spirulina in diet increased the Lactobacillus count and decreased E.coli count.
18. Microscopy of the intestine revealed increasing the villi length (p<0.001) in treatments supplemented with Spirulina compared with control treatment. The liver histopathology also revealed mild periportal leukocytes infiltration in control treatment but in treatments supplemented with Spirulina in diet showed normal histological structure.
19. The bursa, spleen, thymus and pancreas of chicken didn’t show any change in the supplemented treatments with Spirulina compared with control treatment.
20. The economic efficiency of birds fed dietary Spirulina Platensis was superior to that of the control group.