A fluorescent amplified fragment length polymorphism study of Salmonella enterica serovar Sofia, the major Salmonella serovar isolated from chickens in Australia

Fluorescent amplified fragment length polymorphism (FAFLP) analysis was performed on 68 isolates of Salmonella enterica subsp. salamae serovar Sofia (S. Sofia). Fifty eight isolates were obtained over a period of approximately 15 years from a range of human, chicken industry and environmental sources throughout Australia. A further ten isolates were identified from human and poultry sources in Israel from 1972 to 1987. Analysis of FAFLP profiles for fragments between 50 to 500 base pairs in length indicated distinct clusters of isolates. All but seven isolates clustered into four groups of >90% similarity and all isolates displayed at least 70% similarity with each other. No cluster could be attributed to a particular geographical, temporal or source-of-isolation origin. It is concluded that S. Sofia is genetically variable with certain clones persisting over time but no group appears unique to Australia.     

Emergence of gyrovirus 3 in commercial broiler chickens with transmissible viral proventriculitis

Gyrovirus 3 (GyV3) has been identified in faeces from children with acute gastroenteritis. However, whether GyV3 is prevalent in poultry has not been determined to date. To the best of our knowledge, this study is the first to isolate GyV3 from commercial broiler chickens with transmissible viral proventriculitis (TVP ) in China. The complete genome of the virus shares 98.4% sequence identity with the FecGy strain that causes acute gastroenteritis in children. Epidemiological investigation from 2013 to 2017 revealed that the infection rate of GyV3 reached 12.5% (42/336) in commercial broiler chickens with TVP , indicating that the infection of GyV3 was ubiquitous in chickens. The emergence of GyV3 in commercial broiler chickens should be highly concerning for public health.     

Evaluation of different chemical adjuvants on an avian influenza H6 DNA vaccine in chickens

This study assessed the ability of three adjuvants (aluminium hydroxide, Essai (microparticle) and Phema (nanoparticle)) to enhance the immune response of chickens to an H6N2 avian influenza DNA vaccine. No haemagglutination inhibition antibody was detected following two intramuscular immunizations with the adjuvanted and non-adjuvanted pCAG-HAk vaccine, which has previously been shown to induce moderate H6 haemagglutinin antibody response in SPF chickens. Following virus challenge, neither the vaccinated group without adjuvant nor the Essai-adjuvanted group showed a statistically significant reduction in virus shedding in oropharyngeal and cloacal swabs compared with the naive control group. However, the aluminium hydroxide and Phema-adjuvanted groups significantly reduced the frequency of virus shedding in oropharyngeal swabs, indicating that these adjuvants appeared to further enhance the vaccine potency. Aluminium hydroxide holds promise as an adjuvant for enhancing DNA-induced immune response in chickens owing to its low price and safety record.     

Marek's disease viruses circulating in commercial poultry in Italy in the years 2015–2018 are closely related by their meq gene phylogeny

Marek's disease (MD) is a lymphoproliferative disease important to the poultry industry worldwide; it is caused by Gallid alphaherpesvirus 2 (GaHV‐2). The virulence of GaHV‐2 isolates has shifted over the years from mild to virulent, very virulent and very virulent +. Nowadays the disease is controlled by vaccination, but field strains of increased virulence are emerging worldwide. Economic losses due to MD are mostly associated with its acute form, characterized by visceral lymphomas. The present study aimed to molecularly classify a group of 13 GaHV‐2 strains detected in vaccinated Italian commercial chicken flocks during acute MD outbreaks, and to scrutinize the ability of predicting GaHV‐2 virulence, according to the meq gene sequence. The full‐length meq genes were amplified, and the obtained amino acid (aa) sequences were analysed, focusing mainly on the number of stretches of four proline molecules (PPPP) within the transactivation domain. Phylogenetic analysis was carried out with the Maximum Likelihood method using the obtained aa sequences, and the sequences of Italian strains detected in backyard flocks and of selected strains retrieved from GenBank. All the analysed strains showed 100% sequence identity in the meq gene, which encodes a Meq protein of 339 aa. The Meq protein includes four PPPP motifs in the transactivation domain and an interruption of a PPPP motif due to a proline‐to‐serine substitution at position 218. These features are typically encountered in highly virulent isolates. Phylogenetic analysis revealed that the analysed strains belonged to a cluster that includes high‐virulence GaHV‐2 strains detected in Italian backyard flocks and a hypervirulent Polish strain. Our results support the hypothesis that the virulence of field isolates can be suggested by meq aa sequence analysis.     

Chronic Exposure to Deoxynivalenol Has No Influence on the Oral Bioavailability of Fumonisin B1 in Broiler Chickens

Both deoxynivalenol (DON) and fumonisin B₁ (FB₁) are common contaminants of feed. Fumonisins (FBs) in general have a very limited oral bioavailability in healthy animals. Previous studies have demonstrated that chronic exposure to DON impairs the intestinal barrier function and integrity, by affecting the intestinal surface area and function of the tight junctions. This might influence the oral bioavailability of FB₁, and possibly lead to altered toxicity of this mycotoxin. A toxicokinetic study was performed with two groups of 6 broiler chickens, which were all administered an oral bolus of 2.5 mg FBs/kg BW after three-week exposure to either uncontaminated feed (group 1) or feed contaminated with 3.12 mg DON/kg feed (group 2). No significant differences in toxicokinetic parameters of FB₁ could be demonstrated between the groups. Also, no increased or decreased body exposure to FB₁ was observed, since the relative oral bioavailability of FB₁ after chronic DON exposure was 92.2%.     

Salmonella enterica Serovar Enteritidis,England and Wales, 1945–2011

In England and Wales, the emergence of Salmonella enterica serovar Enteritidis resulted in the largest and most persistent epidemic of foodborne infection attributable to a single subtype of any pathogen since systematic national microbiological surveillance was established. We reviewed 67 years of surveillance data to examine the features, underlying causes, and overall effects of S. enterica ser. Enteritidis. The epidemic was associated with the consumption of contaminated chicken meat and eggs, and a decline in the number of infections began after the adoption of vaccination and other measures in production and distribution of chicken meat and eggs. We estimate that >525,000 persons became ill during the course of the epidemic, which caused a total of 6,750,000 days of illness, 27,000 hospitalizations, and 2,000 deaths. Measures undertaken to control the epidemic have resulted in a major reduction in foodborne disease in England and Wales.     

Procedures for the study of behavior in avian embryos

New procedures and an automated technique are presented for the study of prenatal behavior in birds. Their application, functions, and construction are discussed in detail.     

Similar effects of a monoamine oxidase inhibitor and a sympathomimetic amine on memory formation

Amnesia resulting from inhibition of cerebral protein synthesis by cycloheximide can be prevented by subcutaneous injection of the monoamine oxidase inhibitor pargyline (25 mg/kg) or the sympathomimetic amine metaraminol (3.0 mg/kg) administered up to 30 min following learning of a single trial passive avoidance task in day-old chickens. The injection has to be made during the life time of labile memory for the prevention of cycloheximide-induced amnesia. On the other hand, amnesia induced by the Na/K ATP'ase inhibitor ouabain can only be prevented if these two agents are administered up to 5 min after learning, i.e. during the life time of short-term memory. In addition, both agents produce a retrieval deficit 90 min after the injection, but only when memory is in long-term storage. These results are compared to those obtained with administration of norepinephrine, d-amphetamine and diphenylhydantoin.     

Melatonin inhibits PHA-stimulated chicken lymphocyte proliferation in vitro

Many studies have shown that melatonin plays a fundamental role in neuroimmunomodulation. There are known differences between mammals and birds in immunomodulatory function of melatonin exerted in vivo. In present study the effect of exogenous melatonin on chicken lymphoid cell proliferation in vitro was examined. Melatonin alone (10(-10)M-10(-5)M) did not exert any effect on the proliferation of the chicken thymocytes, splenocytes and lymphocytes from the bursa of Fabricius. On the other hand, melatonin addition strongly inhibited the proliferation of PHA-activated thymocytes and splenocytes from young chickens. The effect of melatonin was hormone- and mitogen-(PHA) dose-dependent; the most pronounced effect was obtained at low PHA and melatonin concentrations i.e., 1.6-3.125 microg/100 microl of PHA and 10(-10) M-10(-7) M melatonin, respectively. Prior immunization of chickens with sheep red blood cells (SRBC) inhibited the proliferative response of splenocytes to the same dose of PHA and, consequently, the effect of melatonin addition was not observed. The results reported demonstrate a direct inhibitory effect of melatonin on in vitro activated chicken lymphocytes.     

Epigenetic‐Imprinting Changes Caused by Neonatal Fasting Stress Protect From Future Fasting Stress

Unfavourable nutritional conditions during the neonatal critical period can cause both acute metabolic disorders and severe metabolic syndromes in later life. These phenomena have been tightly related to the epigenetic modification controlling the balance between satiety and hunger in the hypothalamus. In the present study, we investigated epigenetic modification associated with both the fasting stress effects and the short‐term resilience to fasting stress in the hypothalamic paraventricular nucleus (PVN) of chicks. Fasting for 24 h at 3 days of age (D) (i.e. D3) significantly increased global methylation at lysine 27 of histone 3 (H3K27) and its specific histone methyltransferase (HMT) expression level in the PVN. Because global methylation could not fully reveal the changes at specific genes, the regulation of the gene for brain‐derived neurotrophic factor (Bdnf), which was recently also found to have an anorexigenic effect, was evaluated as a potential target. Chromatin immunoprecipitation assay analysis revealed that tri‐ (me3) and di‐methylated (me2) H3K27 exhibited an instant (on D4 only) and latent increase (on both D11 and D41), respectively, at the putative promoter of Bdnf after 24 h of fasting on D3. This indicated that fasting could regulate energy‐expenditure‐related genes via modifying methylation at H3K27, which we suspected might be a protective mechanism for keeping the inner environment homeostatic. To test this hypothesis, a short‐term repetitive fasting stress was applied to chickens, which were fasted for 24 h either on D10 only or on both D3 and D10. It was found that pre‐existing fasting on D3 could induce a short‐term fasting resilience, which rescued the reduction of Bdnf expression from future fasting on D10. We call this phenomenon the ‘molecular memory’, which was mainly conducted by HMTs and H3K27me2/me3 in the PVN. In conclusion, chicks respond to fasting with dynamic methylation at H3K27 in the PVN during the neonatal critical period. This allows the PVN to form a ‘molecular memory’, which keeps the individual inner environment homeostatic and resilient to future fasting over the short term.