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The antiviral and immunostimulant effect of dietary supplementation of Spirulina platensis (SP) against Infectious bursal disease (IBD) was assessed as follows; 126 one- day-old cobb broiler chicks were randomly distributed into six groups (21 birds/group with three replicates, 7 birds each): G1 (non-vaccinated, and non-challenged ; NC), G2 (non-vaccinated, and challenged; PC), vaccinated challenged G3 (vaccinated, and challenged; VC), Spirulina 0.1% (vaccinated, 0.1% SP- supplemented, and challenged; G4), Spirulina 0.3% (vaccinated, 0.3% SP-supplemented, and challenged; G5), and Spirulina 0.5% (vaccinated, 0.5% SP-supplemented, and challenged; G6). The chicks in NC, PC, and VC groups were not supplemented with SP. All vaccinated groups, regardless SP supplementation, showed significant improvement of body weight gain (19% in 0.3% SP) and FCR during IBDv challenge (10 dpc) (P˂0.05). On the 10th dpc, IBD ELISA titer in SP-supplemented groups were decreased (P>0.05) than that of G3, suggesting an antiviral efficacy of SP. This antiviral activity was evident by the viral RNA load in the cloacal swabs as well. The viral shedding peak was on the 5th day pc which was significantly decreased on G4-6 (P˂0.05) in comparison to G2 and G3. Also, the bursal ratio was improved in SP supplemented groups. comparable to G3. Moreover, in unchallenged broilers, the gene expression of INF-γ and IL-18 were upregulated while that of IL-10 was downregulated in spleen of SP- supplemented chicks. Finally, severe histopathological lesions of kidneys, bursa, thymus, and spleen were observed in G2 which moderately minimized in G3 and were more alleviated in SP-supplemented groups. Collectively, SP supplementation improved body weight gain and decreased viral shedding with antiviral activity. The mechanisms of SP against IBDV challenge may include cell-mediated immunity promoting effect, antiviral activity, and/or anti-inflammatory effect that should be further studied. [ABSTRACT FROM AUTHOR]

In the present study, fifty chickens flocks (47 broiler and 3 native Saso) suspected to be infected with Newcastle disease virus (NDV) in 5 northern Egyptian provinces: El Beheira (n: 21), Kafr El Sheikh (n: 8), El Gharbia (n: 7), Alexandaria (n: 7) and Marsa Matrouh (n: 7) during the period (from September 2015 to February 2017), were investigated for clinical and postmortem examination as well as virus isolation and molecular identification. The results of virus isolation on SPF embryonated chicken eggs (ECE) revealed that 16/50 samples were haemagglutinatig agents by slide haemagglutination test. These haemagglutinating agents were confirmed as NDV by real time polymerase chain reaction rRT-PCR .The deduced amino acid sequences of the fusion protein of selected 8 positive isolates revealed that (7/8) isolates possessed the motif 112 RRQKRF 117at the cleavage site, indicating that these isolates are velogenic, whereas the other (1/8) isolates carries the motif 112 GRQGRL 117indicating a lentogenic strain. Phylogenetic analysis demonstrated that the 7 strains belong to the velogenic NDV (vNDV) genotype VIId and the other strain was of genotype II. These velogenic isolates were detected even in vaccinated flocks indicating the wide spreading of vNDV outbreaks in Egypt. [ABSTRACT FROM AUTHOR]

The present study aimed to specify the most important respiratory viral diseases affecting broiler chickens under Egyptian conditions. Forty four broiler chicken flocks were investigated in three governorates (Alexandria, El-Behera and Kafr El-sheikh) that showed high mortality rate with respiratory manifestations and/or diarrhea. The collected samples (trachea and lungs homogenates) were examined for Avian Influenza viruses (AIv) (H5&H9), Newcastle Disease virus (NDv) and Infectious Bronchitis virus (IBv) through isolation in specific pathogen free (SPF) eggs and identification by slide hemagglutination test and Real time reverse transcriptase polymerase chain reaction (RRT-PCR). The results revealed that the highest detection rate was NDv (20/44) with positivity percent (45.46%), 7 flocks out of 44 were positive for AI H9 (15.90%), while 3 flocks (3/44) were positive for AI H5 (6.82%), on the other hand 4 flocks (4/44) were positive for IBv (9.10%). Sequencing and phylogenetic analysis of F gene of selected 8 NDv isolates, they were related to genotype VII, also sequencing for haemagglutinin (HA) gene of AIv isolates showed that two isolates belonged to H5N8 highly pathogenic avian influenza (HPAI) (clade 2.3.4.4.b) and one isolate belonged to H5N1 HPAI clade 2.2.1.2, while two selected H9 isolates were related to H9N2 low pathogenic avian influenza (LPAI) group B. On the other hand, sequencing of S1 gene for one selected IBv isolate was related to EGY variant II. So, continuous surveillance of different respiratory diseases that represent a large economic threat for poultry industry should be maintained to facilitate the possible protocols to prevent and control these diseases. [ABSTRACT FROM AUTHOR]

Simple Summary: The current study was performed to study the efficacy of live Salmonella Enteritidis (SE) vaccine alone and with simultaneous administration of probiotic or prebiotic on broiler chickens. The using of probiotic or prebiotic products administered via drinking water enhanced the growth performance of broiler chickens experimentally challenged with SE at the 28th day of age. The use of probiotic or prebiotic simultaneously with the live Salmonella vaccine can diminish the negative effect of live vaccines in terms of the growth performance, mortality rate, fecal shedding and organ re-isolation of SE. It is therefore a good strategy to relieve the negative effect of the harmful bacterium and improve the growth performance of broilers. Salmonellosis is one of the most important bacterial diseases in poultry, causing heavy economic losses, increased mortality and reduced production. The aim of this study was the comparative efficacy of a commercial probiotic and/or prebiotic with a live attenuated Salmonella Enteritidis (SE) vaccine on the protection of broiler chickens from SE challenge. The efficacy of probiotic or prebiotic products, as well as a live Salmonella Enteritidis (SE) vaccine at the 7th day of age, administered via drinking water, were evaluated for clinical protection and effects on growth performance of broiler chickens experimentally challenged with SE at the 28th day of age. The use of probiotic or prebiotic simultaneously with the live Salmonella vaccine can diminish the negative effect of live vaccine growth performance, reducing mortality rate, fecal shedding, and re-isolation of SE from liver, spleen, heart and cecum. The use of probiotic or prebiotic simultaneously with the application of the live Salmonella vaccine is a good practice to diminish the negative effect of the harmful bacteria and improve the growth performance of broilers. Thus, further studies may be carried out with layers and breeders. [ABSTRACT FROM AUTHOR]

Simple Summary: Vaccination is the main method to control infectious bursal disease (IBD) in commercial broilers worldwide. The main obstacle to the vaccination process is maternally derived antibodies; thus, new generations of vaccines such as vector and immune complex vaccines have been developed. The efficacies of new and classical vaccines were compared to those of vvIBDV in the presence of high levels of maternally derived antibodies. The best results were obtained when using the vector IBD vaccine followed by the immune-complex vaccine, and the use of killed along with the live intermediate vaccine in terms of mortality, feed conversion ratio, bursal and spleen index, bursal lesion score, and serology. Infectious bursal disease (IBD) causes increased mortality and severe immunosuppression in commercial chickens. Currently, vaccination mainly used to control IBD. In this study, Group A (n = 30) received the HVT-IBD vector vaccine (Vaxxitek®) s/c and Group B (n = 30) received the immune complex vaccine (Bursa-Plex®) s/c at 1 day of age. Group C (n = 30) received a single dose of intermediate plus vaccine (228E) through the eye-drop route at 14 days of age. Group D (n = 30) was vaccinated twice with the intermediate vaccine (D78) at 12 and 22 days of age by eye-drop. Group E (n = 30) had the same treatment as group D along with the IBD killed vaccine (Nobilis G®) at 5 days of age. The PC (n = 20) and NC (n = 20) groups were non IBD vaccinated birds either challenged or not with vvIBDV, respectively; 20 chicks from each group were challenged with vvIBDV at 4 weeks of age. Based on clinical signs, postmortem gross lesions, histopathological changes, mortality rate, feed conversion rate, serology, bursal and spleen indices, the HVT-IBD vector vaccine administered was found to be safer and provided better protection against the vvIBDV challenge. The use of a killed IBD vaccine at an earlier age in broilers strengthened the protection induced by double doses of intermediate vaccines in broilers with high maternally derived antibodies against the vvIBDV challenge. [ABSTRACT FROM AUTHOR]