الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 152 |  |  |
| | | from | 152 | | |
Abstract
SUMMARY AND CONCLUSION The present study was carried out at the Poultry experimental Laboratory, Department of Poultry Production, Faculty of Agriculture, Ain Shams University and Animal Production Department, National Research Centre, Dokki- Giza- during the period from July, 2013 to March, 2014. Two experiments were conducted to investigate the effects of increasing dietary levels of chromium methionine, selenium methionine and Vitamin E either singly (Exp-1) or combination (Exp-2) and their iteraction with early heat conditioning on performance and some physiological responces in broiler chicks, reared under summer environment. - Experiment 1 A total of 120 one day old commercial broiler chicks (Cobb) were divided into four groups with six replications, each of five chicks. The first group was the control group, the second group was fed the basal diet supplemented with organic chromium (0.8 mg/kg diet), the third group was fed the basal diet supplemented with organic selenium (0.3 mg/kg diet) and the fourth group was fed the basal diet supplemented with vitamin E (200 IU/kg diet). At 42-d of age all groups were exposed to 41±1°C for 1h. Growth performance, hematological parameters, plasma biochemical constituents, immune responses and heat shock protein (HSP 70) were studied. Results obtained could be summarized as follows:
1. Live BW and BWG at 21 and 42 DOA were significantly increased (P<0.05) by dietary supplementation of vitamin E, organic selenium and organic chromium compared with the control.
SUMMARY AND CONCLUSION
Ahmed G. Abd-Allah., PhD., 2015
89
2. Feed intake was significantly (P<0.05) increased and feed conversion ratio significantly improved in vitamin E, organic selenium and organic chromium fedr chicks compared with control at periods from 1 to 21 DOA; 21 to 42 and 1 to 42 DOA.
3. Haematocrit value (Ht %); haemoglobin (Hb); red blood cell count (RBC´S), mean corpuscular hemoglobin (MCH); mean corpuscular hemoglobin concentration (MCHC); mean corpuscular volume (MCV) and heterophils to lymphocytes ratios (H/L ratio), were significantly (p<0.05) improvemed in birds fed the experimental treatments compared by control either at 21 or 42 DOA.
4. Plasma total protein and globulin levels were significantly increased, by dietary supplementaion with vitamin E, organic selenium and organic chromium, respectively compared with the control.
5. Albumin to globulin ratio was significantly (p<0.05) the lowest in the vitamin E treatment group than the other groups compared with control group either at 21 and 42 DOA.
6. Insulin-like Growth factor -1 (IGF-1) in blood plasma was significantly higher for the organic chromium supplemented group followed by vitamin E and then organic selenium fed groups compared by the control group.
7. Glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) enzymes activities were significantly higher for vitamin E, organic selenium and organic chromium treatments compared with the control group.
8. All dietary supplements have decreased significantly (p<0.05) malondialdehyde (MDA) level compared with control at 42 DOA.
SUMMARY AND CONCLUSION
Ahmed G. Abd-Allah., PhD., 2015
90
9. There were significant (p<0.05) increased in the antibody titer against NDV (as primary and secondry ersponses), with supplemental vitamin E; organic selenium or organic chromium compared with the control group.
10. Heat shock protein 70 (HSP 70) level was significantly (p<0.05) increased by dietary supplements, espcially Vit.E and Cr at 42 DOA.
11. Dressing carcass weight, breast, thigh, gizzard and heart as a percentage of live body weight were shown significantly (P≤0.05) increased by dietary supplemnts.
12. The relative weights of liver were significantly (P< 0.05) decreased for all treatment groups compared with control.
13. The relative weights of thymus, bursa and spleen did not significantly changed in all groups.
- Experiment 2 A total of 240 one day old commercial broiler chicks (Cobb) were divided into two groups of 120 birds each. The first group was the control (Non heat conditioning). The second one was exposed to 40±1°C for 24h at 5 DOA, (early age heat conditioning). Each group was further subdivided into 4 sub-groups of 30 birds each. The first sub-group was the control group, the second was fed the basal diet supplemented with 200 IU of vitamin E /kg diet and 0.8 mg/kg diet organic Cromium; the third was fed basal diet supplemented with 200 IU of vitamin E /kg diet and 0.3 mg/kg diet organic selenium and the fourth was fed basal diet supplemented with 200 IU of vitamin E /kg diet, 0.8 mg/kg diet organic Cromium and 0.3 mg/kg diet organic selenium). At 42 DOA all groups were exposed to 41±1°C for 1h. Results obtained could be summarized as follows
SUMMARY AND CONCLUSION
Ahmed G. Abd-Allah., PhD., 2015
91
1. Chicks exposed to early age heat conditioning recorded significantly higher (P< 0.05) BW, BWG compared with non heat conditioning chicks at 21and 42 DOA.
2. There were significant (P<0.05) effects of dietary supplements on BW and BWG at 21 and 42 DOA. The best BW and BWG values were recorded for the (Vit.E + organic selenium) followed by (Vit.E + organic chromium) and (Vit.E + organic selenium+ organic chromium) compared with control.
3. Feed intake was significantly (P<0.05) increased in the early age heat conditioning groups than non-heat treated ones. Also feed conversion ratio was significantly (P< 0.05) improved for early age heat conditioning groups compared with non-heat treated
4. Feed intake and feed conversion ratio were significantly (P< 0.05) improved by dietary supplements and also by the interaction between early age heat conditioning and dietary supplements.
5. Early age heat conditioning had significant (P< 0.05) effect on Hb, HT, RBC´S, MCHC and MCV levels at 21 DOA, but MCH values was insignificantly influanced.
6. Significant (P< 0.05) effects of early age heat conditioning significant (P< 0.05) effects on Hb, HT, and RBC´S levels of broiler chicks at 42 DOA, however, MCH, MCHC and MCV levels were not affected.
7. Dietary supplements (regardles early age heat conditioning) significantly increased Hb, HT, RBC´S, MCH, MCHC and MCV levels at 21 DOA and at 42 DOA except MCH, MCHC and MCV which were not significant.
8. The interaction between early age heat conditioning and dietary supplements was significant for most of the hematological parameters studied either at 21 or 42 DOA.
SUMMARY AND CONCLUSION
Ahmed G. Abd-Allah., PhD., 2015
9. Early age heat conditioning had a significant (P< 0.05) effect on H/L ratio, but the effect of dietary supplements alone was not significant at 21 and 42 DOA.
10. Plasma total protein, albumin and globulin were significantly higher for chicks of the early age heat conditioning group compared with the non early age heat conditioning group at 21 and 42 DOA.
11. Dietary supplements (irrespective of HC treatment) had insignificant effect on plasma total protein at 21 and 42 DOA, but this effect on albumin at 42 DOA was significantly.
12. Broiler chicks subjected to early age heat conditioning recorded significantly higher (P< 0.05) values for IGF-1
13. All dietary supplements caused a significant (P< 0.05) increase in IGF-1 level at 42 DOA compared with the control group. This trend was also observed for the interaction between the early age heat conditioning and dietary supplements which were significant (P< 0.05).
14. Glutathione peroxidase (GPX); superoxide dismutase (SOD) and catalase (CAT) enzymes activites were significantly higher at 42 DOA as affected by early age heat conditioning and dietary supplements and their interaction.
15. Malondialdehyde (MDA) level was lower for treated groups than control (early age heat conditioning and dietary supplements). Also, the interaction between the early age heat conditioning and dietary supplements was significant (P<0.05).
16. Early age heat conditioning have significant effects, (p<0.05) on antibody production against NDV (Primary and secondary responses). The best value was recorded for early age heat conditioning group Also all dietary supplemented groups and their interaction with early age heat conditioning improved antibody production against NDV.
SUMMARY AND CONCLUSION
Ahmed G. Abd-Allah., PhD., 2015
17. Early age heat conditioning, dietary supplements and their interaction have insignificant effects on HSP 70 at 21 DOA.
18. There is insignificant increased in early age heat conditioning group, dietary supplements and their interaction on HSP 70 at 42 DOA.
19. Dietary supplements as well as early age heat conditioning treatment significantly (P<0.05) increased the relative weights of carcass, breast, thigh, gizzard and heart of broilers.
20. Ther was an insignificant increase in the relative weights of abdominal fat due to dietary supplements, but the effect of early age heat conditioning was significant.
21. The relative weight of liver was significantly (P<0.05) decreased for broilers exposed to early age heat conditioning or dietary supplements and their interaction.
22. The relative weights of lymphoid organs (thymus, bursa and spleen) of broilers at 42 DOA did not significantly affected by early age heat conditioning; dietary supplements and their interaction.
Based on the results of the the present study it is concluded that early age heat conditioning of broiler chicks and dietary supplements by Vit.E; organic chromium or organic selenium either singly (Exp. 1) or in compination (Exp. 2) could be recommended for alleviating the negative effects of heat stress during the summer season, on broiler chicks performanc