Rabbit viral haemorrhagic disease (RVHD) is a highly contagious, highly fatal, peracute and acute viral disease of both wild and domestic rabbits caused by rabbit haemorrhagic disease virus (RHDV). Testing for haemagglutination activity (HA) in processed liver samples is one of the cornerstones for rapid diagnosis of RHDV outbreaks in national rabbitries. However, RHDV isolates exhibiting no HA activity are increasingly being reported. The extent of deviation from classical HA activity patterns for RHDV strains in Egypt has not been investigated. This study compared the HA activity patterns of samples collected from 61 RHDV outbreaks that occurred between 1999 and 2005 to determine whether dependence on HA test (HAT) for diagnosis of RHDV outbreaks needs to be reviewed. All samples were confi rmed RHDV positive using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting. Using slide HAT, only 36.1% of samples were positive (22 samples). Plate HAT conducted at 4ºC detected an additional 16 positive samples bringing the total HA-positive samples to 38 (62.3%). Plate HAT conducted at 22ºC failed to detect additional positive samples. The majority of samples detected after plate HA testing (62.5%) had HA titres comparable to those obtained from slide-HA-positive samples, indicating that the difference in HA activity is dependent on the nature of the HA antigen rather than its presence. Direct detection of HA activity failed in 37.7% of samples despite the presence of classical signs, pathology, and being reverse transcription polymerase chain reaction (RT-PCR) positive for three different VP60 regions. Experimental infection of seronegative rabbits with 9 HA negative RHDV samples showed that 5 isolates were in-fact HA positive, while only 4 isolates remained HA negative. The increased detection of viruses lacking HA activity and the low HAT sensitivity mandates the use of molecular techniques for rapid confi rmation of RHDV diagnosis in the Egyptian environment.

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This study was carried out to investigate the prevalence, molecular characterization and pathogenicity of field infectious bursal disease virus (IBDV) isolates. Nine isolates of IBDV were isolated from 13 naturally infected broiler flocks. Detection of IBDV antigen was carried out by agar gel precipitation test (AGPT), followed by virus isolation in specific pathogen free (SPF) embryonated chicken eggs (ECE) and finally molecularly characterized and identified using reverse transcriptase polymerase chain reaction (RT-PCR). The obtained nine strains of IBDV by RT-PCR were further classified by using restriction fragment length polymorphism (RFLP) technique into (4) classical, (3) variant and (2) very virulent (vv) IBDV serotype (I). The pathogenicity of the isolated IBDV strains was detected by three passages in SPF ECEs and by experimental infection of one hundred 14 days old maternally immune layer chicks. The results showed that the mortality rate of the embryos was increased by increase the number of passages till the third passage where it reached 100% for all IBDV strains and the embryos showed typical lesions of IBDV. Chicks inoculated with variant IBDV strains showed morbidity rates of 60-80 %, without mortalities. Sacrificed birds showed atrophied bursae and thymus glands and enlarged thickened proventriculus. Groups infected with classical IBDV strains showed morbidity rates 40-60,% with mortality 0-20%. The detectable lesions were muscular hemorrhages with variable bursal lesions. Inoculated chicks with vvIBDV strains showed 50-70% morbidity and mortality of rate was 30% with lesions of muscular hemorrhages, severe nephrosis with ureates in the ureters, hemorrhagic bursitis and pin point hemorrhages on the proventricular glands. Control negative non-infected group showed neither clinical signs nor mortalities along the observation period. The histopathological effect (lesion score) of IBDV strains on the bursa, spleen and thymus glands confirmed the previously mentioned results and revealed that the highest severity (score) for these organs were induced by vv IBDV strains. ef Su -Beni Veterinary Medical ِ Journal

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This study was aimed at determining the effect of clove meal addition in diets on nutrient digestibility and metabolizable energy in broilers and whether it could be an alternative to antibiotics or not. In this experiment, twenty-four 35-day-old broilers of the chicken strain Lohman were used. A total of twenty broiler chickens were selected as representatives for determining the digestibility. The treatment diets were: T0 (basal diet), T1 (basal diet + 0.25% clove meal), T2 (basal diet + 0.5% clove meal), T3 (basal diet + 0.75% clove meal), and T4 (basal diet + 1% clove meal). The variables measured were dry matter digestibility, organic matter digestibility, apparent protein digestibility, true digestible protein (TDP),Apparent Metabolizable Energy (AME), True Metabolizable Energy (TME), Nitrogen Corrected Apparent Metabolizable Energy (AMEn) and Nitrogen Corrected True Metabolizable Energy (TMEn). A completely random design was used, with five treatments and four replications. The data were analyzed using analysis of variance (ANOVA), and differences among treatments were examined using Duncan’s multiple range test. The results show that the treatment influences significantly (P<0.05) of dry matter, organic matter, apparent protein digestibility, and TDP. In contrast, there wereno significant effects (p>0,05) of dietary treatment on AME, TME, AMEn, and TMEn. However, the addition of 0.75% clove meal indicated the best result in AME, TME, AMEn, and TMEn. It can be concluded that the experiment indicated that the addition of clovemeal (Syzygium aromaticum L.) in 0.75% on the diet of broiler chickens was effective in increasing the digestibility of dry matter, organic matter,crude protein, TDP, and metabolizable energy.