Comparative pathogenicity of Malaysian variant and very virulent infectious bursal disease viruses in chickens.

Variant infectious bursal disease virus (vaIBDV) has been identified in various countries with significant economic losses. Recently, the first identification of a variant strain in Malaysia was reported. The pathogenicities of the Malaysian variant, UPM1432/2019, and very virulent infectious bursal disease virus (vvIBDV), UPM1056/2018 strains were comparatively evaluated in specific-pathogen-free (SPF) chickens based on gross and histopathological examinations and viral load. Four-week-old SPF chickens were randomly divided into three groups; group 1 served as the control, while groups 2 and 3 birds were challenged with the vaIBDV and vvIBDV, respectively. Three birds from each group were weighed, euthanized and necropsied at 2, 3, 4, 5, 7 and 21 days post-challenge (dpc). Unlike UPM1056/2018 group, birds from UPM1432/2019 group did not show clinical signs or death. UPM1056/2018 strain caused 11% mortality rate in the infected chickens. The bursal body index (BBIX) for UPM1432/2019- and UPM1056/2018-infected groups was <0.7 from 2 dpc and continued to decrease to 0.49 and 0.45, respectively, at 21 dpc. UPM1432/2019 strain was more persistent in the bursa than UPM1056/2018 strain. Both strains induced similar pathological lesions in SPF chicks. These results indicate that the Malaysian vaIBDV severely damaged the immune organs of chickens and was more persistent in bursal tissue than vvIBDV. The study provides insight into the pathogenicity of the variant strain as further study may be required to evaluate the efficacy of the currently available IBD vaccines in Malaysia against the strain. RESEARCH HIGHLIGHTSEmerging Malaysian variant IBDV caused severe bursal damage without mortality.Atypical vvIBDV induced bursal atrophy with inflammatory response and caused low mortality.Malaysian variant IBDV was more persistent in bursal tissue than vvIBDV.

Edible Bird Nest Protects the Kidney From Gentamicin Induced Acute Tubular Necrosis.

Every year, there are about 13.3 million cases of acute kidney injury (AKI). Although AKI is a preventable and treatable disease, if left untreated, it has high risk of multiple organ failure and progression to end stage kidney disease. Acute tubular necrosis (ATN) has been recognised as one of the major causes of AKI. Till to date, there is no effective supplement or medication in treating or reversing AKI. Most of the treatment strategies involve preventative measure to minimise the occurrence of AKI or to reverse the cause of AKI. Hence one of the primary area of research interests is to explore the potential treatment for AKI. Edible bird nests (EBN) are edible food produce by the swiftlet's saliva, which is rich in sialic acids. Sialic acids are monosaccharides that play a vital role in maintaining the integrity and proper function of the human organs, including kidneys. EBN also contains epidermal growth factor, which is widely believed to have rejuvenation and tissue repairing properties. We initiate this study to study the potential reno-protective effect of edible bird's nests by studying the Wistar rat model of gentamicin-induced AKI. Besides renal profiles, renal histology was also semiquantitatively assessed. In our study, pre-treatment with EBN prevented and ameliorated the gentamicin-induced AKI. To a lesser extent, post-treatment with EBN also protected the kidney from the toxic effect of gentamicin. Our findings are highly indicative that EBN possesses reno-protective properties.

Isolation, identification and molecular characterization of Newcastle disease viruses in vaccinated chickens from commercial farms in the Sultanate of Oman.

Newcastle disease (ND) remains an important enzootic disease in chickens in several parts of the world. With the increasing reports of virulence and genetic diversity of the causative agent; Newcastle disease virus (NDV), there is a need to identify the circulating NDV in specific regions. In Oman, to this moment, such information is still lacking. The aim of this study was to isolate and characterize the NDV from ND outbreaks from commercial farms in Oman. Following suspected outbreaks of ND in three commercial farms in 2017, a total of 30 carcasses (10 from each flock) of adult chickens were subjected to necropsy for gross and histopathological examination, virus isolation and molecular methods. Specifically, haemagglutination inhibition (HI) test and reverse transcription-polymerase chain reaction (RT-PCR) assay were used for the virus detection and confirmation, respectively. Lesions were suggestive of viscerotropic velogenic form of ND based on gross and histopathological examinations. Isolation of NDV was present in 4 cases and further confirmed by RT-PCR following the target of the partial fusion protein gene of the viral genome. The sequence of the partial fusion gene was determined and phylogenetic tree was constructed based on the partial length F gene of 4 Omani isolates and 65 previously published NDVs. The findings predicted that the Omani isolates had high homology (99%) with the isolate from Pakistan belonging to genotype VII. Subsequently, the isolated pathotype was identified as the virulent NDV. This study serves as a basic work for further research on the analysis and phenotyping of NDV in the Sultanate of Oman. Improved monitoring and surveillance of the disease is important for proper preventive measures.

Effect of Edible Bird's Nest Extract on Lipopolysaccharide-Induced Impairment of Learning and Memory in Wistar Rats.

Cognitive disability is a common feature associated with a variety of neurological conditions including Alzheimer's Disease (AD), Parkinson's Disease (PD), brain injury, and stroke. Emerging evidence has demonstrated that neuroinflammation plays an important role in the development of cognitive impairment. Current available therapies are relatively ineffective in treating or preventing cognitive disabilities, thus representing an important, unfulfilled medical need. Hence, developing potential treatment is one of the major areas of research interest. Edible bird's nests (EBN) are nests formed by swiftlet's saliva containing sialic acid, which is believed to improve brain function. This present study was embarked upon to evaluate the learning and memory enhancing potential effect of EBN by using Morris water maze test in a Wistar rat model of LPS-induced neuroinflammation. LPS elicited cognitive impairment in the rats by significantly increasing the escape latency while decreasing the number of entries in the probe trial, which are coupled with increased production of proinflammatory cytokines (TNF-α, IL-1ß, and IL-6) and oxidative markers (ROS and TBARS) in the hippocampus. Treatment with EBN (125 mg/kg, 250 mg/kg, and 500 mg/kg; p.o.) effectively reversed the effect of LPS on escape latency and probe trial and, in addition, inhibited the LPS-induced upregulation of proinflammatory cytokines and oxidative markers. These findings are suggestive that there is existence of neuroprotective effect contained inside the edible bird's nest.

The effects of different velogenic NDV infections on the chicken bursa of Fabricius.

BACKGROUND: Virulent Newcastle disease virus (NDV) was reported to cause rapid depletion of chicken bursa of Fabricius. Severe pathological condition of the organ is commonly associated with high levels of virus replication, intense inflammatory response and also the degree of apoptosis. In this study, the responses of chicken bursa of Fabricius infected with two different strains of velogenic NDV, namely AF2240 and IBS002, were investigated by observing cell population changes, oxidative stress, viral replication and cytokine expression in the organ. Subsequently, apoptosis of enriched bursal IgM+ cells was determined to help us elucidate possible host pathogen relationships between the chicken bursa of Fabricius and NDV infection. RESULTS: The depletion of IgM+ cells and infiltration of macrophages were observed to be higher in bursa infected with AF2240 as compared to IBS002. In line with the increment of the macrophage population, higher nitric oxide (NO) and malondialdehyde (MDA) contents which indicated higher oxidative stress were also detected in bursa infected with NDV AF2240. In addition, higher pro-inflammatory cytokines and chemokine gene expression such as chicken CXCLi2, IL-18 and IFN-γ were observed in AF2240 infected bursa. Depletion of IgM+ cells was further confirmed with increased cell death and apoptosis of the cells in AF2240 infected bursa as compared to IBS002. However, it was found that the viral load for NDV strain IBS002 was comparatively higher than AF2240 although the magnitude of the pro- inflammatory cytokines expression and cell apoptosis was lower than AF2240. CONCLUSION: The results of our study demonstrated that infection of NDV strains AF2240 and IBS002 caused apoptosis in bursa IgM+ cells and its severity was associated with increased expression of pro-inflammatory cytokines/chemokine, macrophage infiltration and oxidative stress as the infection duration was prolonged. However, of the two viruses, we observed that NDV AF2240 induced a greater magnitude of apoptosis in chicken bursa IgM+ cells in comparison to IBS002. This might be due to the high level of oxidative stress and inflammatory cytokines/chemokine as well as lower IL10 expression which subsequently led to a high rate of apoptosis in the chicken bursa of Fabricius although the detected viral load of AF2240 was lower than IBS002.

Nutrition and immunity: the effects of the combination of arginine and tryptophan on growth performance, serum parameters and immune response in broiler chickens challenged with infectious bursal disease vaccine.

To explore the effects of the combination of tryptophan (Trp) and arginine (Arg) on growth performance, serum parameters and immune response of broiler chickens challenged with intermediate plus strain of infectious bursal disease virus vaccine, an in vivo experiment was conducted. A corn-soybean meal-based diet containing different levels of Arg and Trp was used. Cobb500 male broiler chickens from 0 to 49 days of age were subjected to a diet supplemented with the combination of Trp and Arg. Growth performance parameters and serum parameters were measured at 27 and 49 days of age. To evaluate the immunomodulatory effects of the combination of Trp and Arg on the challenged chickens, we measured the serum levels of interferon-α, interferon-γ and immunoglobulin G at 27, 35, 42, and 49 days of age. The results showed that the three evaluated immune system parameters including interferon-α, interferon-γ and immunoglobulin G were significantly enhanced after treatment. This enhancement resulted in the recovery of infectious bursal disease virus-infected chickens compared with controls as confirmed by histopathological examinations. Moreover, serum parameters such as albumin and total protein increased, whereas the treatment decreased (P<0.05) the feed:gain ratio, aspartate amino-transferase, alkaline phosphatase, lactic dehydrogenase, triglyceride and cholesterol. These findings suggest that the combination of Arg and Trp has a regulatory effect on growth performance. Moreover, it modulates the systemic immune response against infectious bursal disease.

Survey of campylobacter, salmonella and mycoplasmas in house crows (Corvus splendens) in Malaysia.

House crows (Corvus splendens) in Selangor, Malaysia were examined for the presence of Campylobacter species, Salmonella species, Mycoplasma gallisepticum and Mycoplasma synoviae by serology, culture and pcr. For the detection of Campylobacter and Salmonella species swabs were taken either from the intestine or cloaca. For the detection of mycoplasmas, swabs were taken either from the choanal cleft or trachea for culture and pcr and serum samples were tested by the rapid serum agglutination (rsa) and monoclonal antibody-blocking elisa (mbelisa) for antibodies to M gallisepticum and M synoviae. For campylobacter, 25.3 per cent of the crows were positive by culture, and the species identified were Campylobacter jejuni and Campylobacter coli. No Salmonella species were isolated. Four of 24 swabs were positive for M gallisepticum dna but none gave positive results for M synoviae dna. No M gallisepticum or M synoviae antibodies were detected by rsa but 60 per cent of the sera gave positive reactions for M gallisepticum and 13 per cent gave positive reactions for M synoviae by mbelisa.

Characterisation and molecular cloning of an erythromycin resistance plasmid of Lactococcus lactis isolated from chicken cecum.

An erythromycin resistance plasmid, pAJ01 was isolated from Loctococcus lactis isolate C5 that was isolated from a healthy two-week-old chicken cecum. A 4 kb plasmid was transformed into plasmidless L. lactis MG1363 before a restriction endonuclease map was constructed. It was then fused with pUC19 to form pAJ02, which can replicate in Escherichia coli XLI-Blue as well as L. lactis MG1363. The plasmid was stably maintained in Lactococcus for more than 100 generations.

The resistance of meat chickens vaccinated by aerosol with a live V4 Newcastle disease virus vaccine in the field to challenge with a velogenic Newcastle disease virus.

Meat chickens housed on a commercial broiler farm in Australia were vaccinated once at 10 to 11 days-of-age by aerosol with live V4 Newcastle disease virus (NDV) vaccine. Groups of vaccinated and unvaccinated birds were flown to Malaysia, where they were challenged with a virulent strain of NDV. Survival rates in vaccinated chickens challenged 7, 14, 21 or 31 d after vaccination were 0.47, 0.77, 0.97 and 0.92, respectively. All unvaccinated chickens died due to Newcastle disease (ND) following challenge. Chickens in Australia and Malaysia were bled and the serums tested for haemagglutination-inhibiting (HI) antibody to NDV. Many vaccinated birds with no detectable antibody, and all birds with a log2 titre of 2 or greater, survived challenge. The results showed that this V4 vaccine induced protective immunity in a significant proportion of chickens within 7 d of mass aerosol vaccination. This early immunity occurred in the absence of detectable circulating HI antibody. Non-HI antibody mediated immunity continued to provide protection up to 31 d after vaccination. Almost all vaccinated birds were protected within 3 w of vaccination. It is concluded that the V4 vaccine is efficacious and could be useful during an outbreak of virulent ND in Australia.

Vaccination of chickens against Newcastle disease with a food pellet vaccine.

The Australian, heat-resistant, a virulent V4 strain of Newcastle disease (ND) virus was selected for further heat resistance to give a variant designated V4-UPM. V4-UPM was sprayed on to food pellets which were fed to chickens in amounts calculated to give about 10(6) EID50 per chicken. Chickens vaccinated only once by feeding developed no haemagglutination-inhibition (HI) antibodies and were not protected against challenge with a viscerotropic velogenic strain of ND virus. Chickens given food pellet vaccine at 3 and 6 weeks of age developed HI antibodies and were substantially protected against parenteral and contact challenge with virulent ND virus. Similar protection was achieved when the V4-UPM vaccine was given intranasally on two occasions or when the vaccine virus was allowed to spread by contact from intranasally vaccinated chickens to nonvaccinated chickens. Heat resistant ND vaccine incorporated in food pellets may provide a method for protecting village chickens against ND in tropical countries.

Mycoplasma iowae infection in young turkeys.

A comparison was made of the effect of five different strains of M. iowae after inoculation of one-day-old poults via the thoracic air sac and foot pad. Three strains appeared to be more virulent and more invasive than the other two, causing stunting, poor feathering and leg abnormalities including chondrodystrophy. One of these three strains was used in a second experiment in which three routes of infection were compared. Infection in ovo caused a severe generalised disease in hatched poults with high mortality. The only two birds which survived into the third week developed chondrodystrophy. One group was infected orally at one day of age and some birds developed bone and joint abnormalities but another group, infected via both the thoracic air sac and the foot pad, also at one day of age, developed a higher incidence of these, abnormalities, which included chondrodystrophy, rotated tibia, deviated toes and, in a few cases, erosion of the articular cartilage of the hock joint. Some of the control uninfected birds developed leg abnormalities but never chondrodystrophy, rotated tibia or cartilage erosion. M. iowae was most widely disseminated in tissues following in ovo infection and least after oral infection. Isolations became less frequent with age and no organisms were recovered in birds sampled at 12 weeks. In neither experiment could antibodies to M. iowae be detected by rapid agglutination.