We have surveyed avian influenza virus (AIV) genomes from live poultry markets within China since 2014. Here we present a total of 16,091 samples that were collected from May 2016 to February 2019 in 23 provinces and municipalities in China. We identify 2048 AIV-positive samples and perform next generation sequencing. AIV-positive rates (12.73%) from samples had decreased substantially since 2016, compared to that during 2014–2016 (26.90%). Additionally, H9N2 has replaced H5N6 and H7N9 as the dominant AIV subtype in both chickens and ducks. Notably, novel reassortants and variants continually emerged and disseminated in avian populations, including H7N3, H9N9, H9N6 and H5N6 variants. Importantly, almost all of the H9 AIVs and many H7N9 and H6N2 strains prefer human-type receptors, posing an increased risk for human infections. In summary, our nation-wide surveillance highlights substantial changes in the circulation of AIVs since 2016, which greatly impacts the prevention and control of AIVs in China and worldwide.

BackgroundTibial dyschondroplasia (TD) is a common skeletal disorder in broiler chickens. It is characterized by the presence of a non-vascularized and unmineralized cartilage in the growth plate. Previous studies have investigated differential expression of genes related to cartilage development during latter stages of TD. The aim of our study was to identify differentially expressed genes (DEGs) in the growth plate of broiler chickens, which were associated with early stage TD. We induced TD using tetramethylthiuram disulfide (thiram) for 1, 2, and 6 days and determined DEGs with chicken Affymetrix GeneChip assays. The identified DEGs were verified by quantitative polymerase chain reaction (qPCR) assays.ResultsWe identified 1630 DEGs, with 82, 1385, and 429 exhibiting at least 2.0-fold changes (P < 0.05) at days 1, 2, and 6, respectively. These DEGs participate in a variety of biological processes, including cytokine production, oxidation reduction, and cell surface receptor linked signal transduction on day 1; lipid biosynthesis, regulation of growth, cell cycle, positive and negative gene regulation, transcription and transcription regulation, and anti-apoptosis on day 2; and regulation of cell proliferation, transcription, dephosphorylation, catabolism, proteolysis, and immune responses on day 6. The identified DEGs were associated with the following pathways: neuroactive ligand-receptor interaction on day 1; synthesis and degradation of ketone bodies, terpenoid backbone biosynthesis, ether lipid metabolism, JAK-STAT, GnRH signaling pathway, ubiquitin mediated proteolysis, TGF-β signaling, focal adhesion, and Wnt signaling on day 2; and arachidonic acid metabolism, mitogen-activated protein kinase (MAPK) signaling, JAK-STAT, insulin signaling, and glycolysis on day 6. We validated seven DEGs by qPCR.ConclusionsOur findings demonstrate previously unrecognized changes in gene transcription associated with early stage TD. The DEGs we identified by microarray analysis will be used in future studies to clarify the molecular pathogenic mechanisms of TD. From these findings, potential pathways involved in early stage TD warrant further investigation.

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A 3×2 factorial experiment was conducted to determine the effects of rearing system and stocking density on the growth performance, intestinal morphology and fermentation status of broilers. Broilers were kept on three rearing systems: floor litter rearing (FRS), plastic net rearing (NRS) and multilayer cage rearing system (CRS), each with two stocking densities (normal and high stocking densities). Results showed that on 7 to 28 days of age, body weight gain appeared as FRS > NRS > CRS. Whereas, CRS significantly enhanced the weight gain of broilers compared with the other systems subsequently. Broilers on FRS had higher counts of cecum Bifidobacteria and Lactobacilli at 28 days of age but had more Escherichia coli and less Bifidobacteria than CRS at 42 days of age. The FRS also decreased volatile fatty acid (VFA) concentration and jejunal villus height-to-crypt depth ratio at all ages. In conclusion, FRS appeared to benefit gut microorganisms during the early growing period along with high body weight gain of broilers, whereas this system might have a harmful effect on subsequent intestinal growth, as indicated by high E. coli, low Bifidobacteria count, low VFA concentration and villus height-to-crypt depth ratio along with low weight gain of broilers.

Live attenuated virus vaccines have been generated by several strategies, including cold-adapted live attenuated influenza vaccines (CAIVs), codon-deoptimized virus, premature termination codon-harboring virus, hyper-interferon-sensitive virus and viral-protein-altered virus 1-12 . However, current attenuation strategies are often accompanied by decrease or loss of safety, efficacy or productivity 1,[13][14][15][16] . In addition, immune escape due to rapid viral evolution poses a further challenge for traditional influenza vaccines 1,13 . Thus, there is an urgent need for new vaccine approaches that could enable the generation of safer and more effective live vaccines in a simpler way 2 .

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Twenty-six pluriparous Suffolk ewes were used to monitor the effects of four hormone treatments on the rate of uterine involution, which was assessed by means of radio-opaque markers and radiography. The close correlation between measurements of the genital tract in live sheep and after slaughter indicated that this method of monitoring uterine involution was acceptably accurate. Uterine involution was complete by about 29 days after lambing. None of the hormone treatments with progesterone, oestradiol-17 beta, prostaglandin F2 alpha or an oxytocin analogue, administered shortly after lambing, had any effects on the rate of uterine involution. There was no correlation between the duration of increased plasma concentrations of 13.14 dihydro-15-keto-prostaglandin F2 (PGFM) and the rate of uterine involution.

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