AIM: In the current study, for further validation, we initiated a comprehensive epidemiological study to identify the dominant NDV genotype(s) circulating within the country. Collection of samples was executed between October 2017 and February 2018 from 108 commercial broiler farms which reported clinical signs of respiratory disease in their broilers.
RESULT: We report that 38 of the farms (> 35%) tested positive for NDV. The complete F gene sequences of seven of the isolates are shown as representative sequences in this study. According to the phylogenetic tree constructed, the recent broiler farm isolates clustered into the newly designated cluster VII(L) together with the older Iranian backyard poultry isolates in our previous work. All the sequences shared the same virulence-associated F cleavage site of 112RRQKR↓F117.
CONCLUSION: Our phylogenetic analysis suggested that the NDV subgenotype VII(L) may have been derived from subgenotype VIId, and contrary to popular belief, subgenotype VIId may not be the dominant subgenotype in Iran. Tracking of the subgenotype on BLAST suggested that the NDV subgenotype VII(L), although previously unidentified, may have been circulating in this region as an endemic virus for at least a decade. Other NDV genotypes, however, have also been reported in Iran in recent years. Hence, ongoing study is aimed at determining the exact dominant NDV genotypes and subgenotypes in the country. This will be crucial in effective mitigation of outbreaks in Iranian broiler farms.
RESULTS: The PFGE data was input into FPQuest software, and the dendrogram generated was studied for possible genetic relatedness among the isolates. All the isolates were found to belong to the Salmonella Enteritidis serotype with notable resistance to tetracycline, gentamycin, streptomycin, and sulfadimidine. The S. Enteritidis isolates tested predominantly subtyped into the ST11 and ST1925, which was found to be a single cell variant of ST11. The STs were found to occur in chicken meats, foods, and live chicken cloacal swabs, which may indicate the persistence of the bacteria in multiple foci.
CONCLUSION: The data demonstrate the presence of S. Enteritidis among chickens, indicating its preference and reservoir status for enteric Salmonella pathogens.
OBJECTIVES: To characterize FAdV isolates based on phylogenetic analysis, and to study the pathogenicity of FAdV-8b in specific-pathogen-free (SPF) chickens following virus inoculation via oral and intramuscular (IM) routes.
METHODS: Suspected organ samples were subjected to virus isolation and polymerase chain reaction (PCR) for FAdV detection. Hexon gene sequencing and phylogenetic analysis were performed on FAdV-positive samples for serotype identification. One FAdV-8b isolate, UPM/FAdV/420/2017, was selected for fiber gene characterization and pathogenicity study and was inoculated in SPF chickens via oral and IM routes.
RESULTS: The hexon gene phylogenetic analysis revealed that all isolates belonged to FAdV-8b. The fiber gene-based phylogenetic analysis of isolate UPM/FAdV/420/2017 supported the grouping of that isolate into FAdV species E. Pathogenicity study revealed that, chickens infected with UPM/FAdV/420/2017 via the IM route had higher clinical score values, higher percent mortality, higher degree of the liver lesions, higher antibody response (p < 0.05), and higher virus shedding amounts (p < 0.05) than those infected via the oral route. The highest virus copy numbers were detected in liver and gizzard.
CONCLUSIONS: FAdV-8b is the dominant FAdV serotype in Malaysia, and pathogenicity study of the FAdV-8b isolate UPM/FAdV/420/2017 indicated its ability to induce IBH in young SPF chickens when infected via oral or IM routes.
RESULTS: Present results showed that, Se and Vit E synergistic effect was clear in plasma IgM level at day 42 and in splenic cytokines expression (TNF-α, IFN-γ, IL-2, IL-10). The combination of 0.3 mg/kg ADS18-Se with 100 mg/kg Vit E showed the highest IgM level compared to Vit E- SS complex. The combination of either SS or ADS18-Se with Vit E had no significant effect on IFN- γ and IL-10 compared to Vit E alone, while Vit E alone showed the significantly lowest TNF-α compared to the Se combinations. Supplementation of 100 mg/kg Vit E had no effect on microbial population except a slight reduction in Salmonella spp. The main effect of Se sources was that both sources increased the day 42 IgA and IgG level compared to NS group. ADS18-Se modulate the caecum microbial population via enhancing beneficial bacteria and suppressing the E-coli and Salmonella spp. while both Se and Vit E factors had no effect on lymphoid organ weights.
CONCLUSIONS: The inclusion of 100 mg/kg Vit E with 0.3 mg/kg ADS18-Se, effectively could support the immune system through regulation of some cytokines expression and immunoglobulin levels more than using ADS18-Se alone, while no difference was observed between using SS alone or combined with Vit E.
RESULTS: The lysis buffer 2 (LB2) has been shown to be the best lysis buffer for DNA extraction from both raw and processed meat samples comparing to other lysis buffers tested. Hence, the LB2 has been found to be ideal to detect meat and porcine DNAs by real-time PCR using pairs of porcine specific primers and universal primers which amplified at 119 bp fragment and 93 bp fragment, respectively. This assay allows detection as low as 0.0001 ng of DNA. Higher efficiency and sensitivity of real-time PCR via a simplified DNA extraction method using LB2 have been observed, as well as a reproducible and high correlation coefficient (R2 = 0.9979) based on the regression analysis of the standard curve have been obtained.
CONCLUSION: This study has established a fast, simple, inexpensive and efficient DNA extraction method that is feasible for raw and processed meat products. This extraction technique allows an accurate DNA detection by real-time PCR and can also be implemented to assist the halal authentication of various meat-based products available in the market. © 2019 Society of Chemical Industry.