الفهرس 
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Abstract
This study aimed to investigate the efficacy of dietary SP powder supplementation on some avian viral disease challenge. In order to achieve this aim, 322 one-day-old cobb chicks were used with the vaccination program against NDV, AI-H5N1, IBDV and IBV and the experimental design was performed into three experiments as follows:
Experiment I
Evaluation of SP efficacy on growth performance, immune response, and gene expression in commercial broilers chickens
Ninety-six chicks were divided randomly into five groups designated as:
1- Non-vaccinated non-supplemented group (G1): 12 chicks in three replicates; 4 chicks each.
2- The vaccinated non-supplemented group (G2): 21 chicks in three replicates; 7 chicks each.
3- The vaccinated 0.1% SP-supplemented group (G3): 21 chicks in three replicates (7 chicks each). The chicks were fed 1 gm SP powder mixed with one Kg ration.
4- The vaccinated 0.3% SP-supplemented group (G4): 21 chicks in three replicates (7 chicks each). The chicks were fed 3 gm SP powder mixed with one Kg ration.
5- The vaccinated 0.5% SP-supplemented group (G5): 21 chicks in three replicates (7 chicks each). The chicks were fed 5 gm SP powder mixed with one Kg ration
The chicks in all experimental groups were vaccinated according the designed vaccination program in this study except for G1.
Experiment II
Effect of SP supplementation on NDV challenge in commercial broiler chickens
One hundred eight chicks were divided randomly into six groups designated as:
1- Non-vaccinated non-supplemented group (G1): 12 chicks in three replicates.
2- Non-vaccinated non-supplemented group (G2): 12 chicks in three replicates.
3- The vaccinated non-supplemented group (G3): 21 chicks in three replicates.
4- The vaccinated 0.1% SP-supplemented group (G4): 21 chicks in three replicates.
5- The vaccinated 0.3% SP-supplemented group (G5): 21 chicks in three replicates.
6- The vaccinated 0.5% SP-supplemented group (G6): 21 chicks in three replicates.
At 29-day-old age, the chicks in all experimental groups except G1 were challenged with local NDV genotype VII with 0.01ml of EID50 via intramuscular route. All groups were kept under daily observation for 10 days post experimental infection and clinical signs, mortality rate, and pm lesion.
Experiment III
Effect of SP supplementation on IBDV challenge in commercial broiler chickens
One hundred eight chicks were divided randomly into six groups designated as:
1. Non-vaccinated non-supplemented group (G1): 12 chicks in three replicates.
2. Non-vaccinated non-supplemented group (G2): 12 chicks in three replicates.
3. The vaccinated non-supplemented group (G3): 21 chicks in three replicates.
4. The vaccinated 0.1% SP-supplemented group (G4): 21 chicks in three replicates.
5. The vaccinated 0.3% SP-supplemented group (G5): 21 chicks in three replicates.
6. The vaccinated 0.5% SP-supplemented group (G6): 21 chicks in three replicates.
At 26-day-old age, the chicks in all experimental groups except G1 were challenged with field isolate of IBDV at dose 0.1ml of EID50 via nasal-ocular route. All groups were kept under daily observation for 10 days post experimental infection and clinical signs, mortality rate, pm lesion and body and bursal weights were recorded.
The obtained results revealed that:
1- SP supplementation at higher concentration (0.5%) improved the final body weight gain and the feed conversion rate in normal unchallenged broilers and during the challenge period with both NDV and IBDV.
2- Dietary supplementation with SP enhanced the antibody titer against NDV and AI specially at dose 0.1 and 0.3% with no significant change on the Ab titre against IBDV and IBV in normal unchallenged broilers at 30th day.
3- Dietary inclusion of SP significantly up-regulated the mRNA expression of INF-γ and IL-18 in spleen tissue of normal unchallenged chicks alongside with down-regulation of IL-10 mRNA transcriptome.
4- SP significantly reduced the mortality rate, clinical signs (dullness, depression, conjunctivitis, ruffling feathers, edematous swollen head, anorexia, gasping and watery greenish diarrhea), and post mortem lesions (congestion of tracheal mucosa, proventriculus hemorrhage, congested pectoral muscles, mottled enlarged spleen, and intestinal and ileocecal tonsil hemorrhage) induced by NDV challenge compared to the vaccinated untreated chicks.
5- The Ab titre against NDV was non-statistically decreased in SP-treated groups at 10 dpc in dose dependent manner compared to the vaccinated untreated group indicating the antiviral efficacy of SP.
6- The NDV quantity titre in oropharyngeal swabs was significantly decreased in the groups treated with SP at 3, 5 and 7th dpc when compared with the nontreated group with the lowest viral titre was observed in the 0.5%-SP treated group.
7- SP improved the histopathological picture in the lung, trachea, and spleen during NDV challenge as the severe hemorrhage of the lung, necrosis of tracheal epithelium and depletion of spleen white pulp were minimized in the SP-treated groups.
8- The Ab titre against IBDV was significantly higher in the SP-treated groups compared to that in the nonvaccinated untreated group at 10 dpc but still lower than that in the vaccinated untreated group suggesting the antiviral efficacy of SP.
9- The IBDV quantity titre in cloacal swabs was significantly decreased in the groups treated with SP at 3, 5 and 7th dpc when compared with the nontreated group with the lowest viral titre was observed in the 0.5%-SP treated group.
10- The bursal weight index was significantly improved with dietary supplementation with SP during the IBDV challenge. The improvement was dose dependent.
11- The severe lymphocyte depletion of bursa and thymus induced by IBDV was improved upon treatment with SP. Also, the interstitial nephritis and severe depletion of white pulp of spleen was minimized to the lowest degree upon treatment with SP when compared to the vaccinated untreated groups.