Prevalence of Senecavirus A in pigs from 2014 to 2020: a global systematic review and meta-analysis.

BACKGROUND: Senecavirus A (SVA), a member of the family Picornaviridae, is newly discovered, which causes vesicular lesions, lameness in swine, and even death in neonatal piglets. SVA has rapidly spread worldwide in recent years, especially in Asia. OBJECTIVES: We conducted a global meta-analysis and systematic review to determine the status of SVA infection in pigs. METHODS: Through PubMed, VIP Chinese Journals Database, China National Knowledge Infrastructure, and Wanfang Data search data from 2014 to July 26, 2020, a total of 34 articles were included in this analysis based on our inclusion criteria. We estimated the pooled prevalence of SVA in pigs by the random effects model. A risk of bias assessment of the studies and subgroup analysis to explain heterogeneity was undertaken. RESULTS: We estimated the SVA prevalence to be 15.90% (1,564/9,839; 95% confidence interval [CI], 44.75-65.89) globally. The prevalence decreased to 11.06% (945/8,542; 95% CI, 28.25-50.64) after 2016. The highest SVA prevalence with the VP1-based RT-PCR and immunohistochemistry assay was 58.52% (594/1,015; 95% CI, 59.90-83.96) and 85.54% (71/83; 95% CI, 76.68-100.00), respectively. Besides, the SVA prevalence in piglet herds was the highest at 71.69% (119/166; 95% CI, 68.61-98.43) (p < 0.05). Moreover, our analysis confirmed that the subgroups, including country, sampling year, sampling position, detected gene, detection method, season, age, and climate, could be the heterogeneous factors associated with SVA prevalence. CONCLUSIONS: The results indicated that SVA widely exists in various countries currently. Therefore, more prevention and control policies should be proposed to enhance the management of pig farms and improve breeding conditions and the environment to reduce the spread of SVA.

Combined Toxicity Evaluation of Ochratoxin A and Aflatoxin B1 on Kidney and Liver Injury, Immune Inflammation, and Gut Microbiota Alteration Through Pair-Feeding Pullet Model.

Ochratoxin A (OTA) and aflatoxin B1 (AFB1) are often co-contaminated, but their synergistic toxicity in poultry is limitedly described. Furthermore, the traditional ad libitum feeding model may fail to distinguish the specific impact of mycotoxins on the biomarkers and the indirect effect of mildew on the palatability of feed. A pair-feeding model was introduced to investigate the specific effect and the indirect effect of the combined toxicity of OTA and AFB1, which were independent and dependent on feed intake, respectively. A total of 180 one-day-old pullets were randomly divided into 3 groups with 6 replicates, and each replicate contained 10 chicks. The control group (Group A) and the pair-feeding group (Group B) received the basal diet without mycotoxin contamination. Group C was administrated with OTA- and AFB1-contaminated feed (101.41 µg/kg of OTA + 20.10 µg/kg of AFB1). The scale of feeding in Group B matched with the feed intake of Group C. The trial lasted 42 days. Compared with the control group, co-contamination of OTA and AFB1 in feed could adversely affect the growth performance (average daily feed intake (ADFI), body weight (BW), average daily weight gain (ADG), feed conversion ratio (FCR), and shank length (SL)), decrease the relative weight of the spleen (p < 0.01), and increase the relative weight of the kidney (p < 0.01). Moreover, the reduction of feed intake could also adversely affect the growth performance (BW, ADG, and SL), but not as severely as mycotoxins do. Apart from that, OTA and AFB1 also activated the antioxidative and inflammation reactions of chicks, increasing the level of catalase (CAT), reactive oxygen species (ROS), and interleukin-8 (IL-8) while decreasing the level of IL-10 (p < 0.01), which was weakly influenced by the feed intake reduction. In addition, OTA and AFB1 induced histopathological changes and apoptosis in the kidney and liver as well as stimulated the growth of pernicious bacteria to cause toxic effects. There were no histopathological changes and apoptosis in the kidney and liver of the pair-feeding group. The combined toxicity of OTA and AFB1 had more severe effects on pullets than merely reducing feed supply. However, the proper reduction of the feed intake could improve pullets' physical health by enriching the bacteria Lactobacillus, Phascolarctobacterium, Bacteroides, Parabacteroides, and Barnesiella.

Rapid detoxification of Jatropha curcas cake by fermentation with a combination of three microbial strains and characterization of their metabolic profiles.

AIM: Our previous study reported a strain that can detoxify Jatropha curcas L. cake (JCC), but the detoxification duration is long. This study intends to explore the efficient detoxification of JCC through multi-strain collaborative fermentation to accelerate the detoxification process. METHODS AND RESULTS: Mucor circinelloides SCYA25 strain that we previously reported can effectively degrade the toxicity of JCC, and the newly screened Bacillus megaterium SCYA10 and Geotrichum candidum SCYA23 strains were used to detoxify JCC. Different solid-state-fermentation (SSF) parameters were optimized by single-factor tests and response surface methodology. A detoxification rate established by zebrafish toxicity of JCC at 96% was achieved under the following optimized conditions: the combination ratio of B. megaterium SCYA10, G. candidum SCYA23 and M. circinelloides SCYA25 at 2:3:1, a total injection amount of 15.25%, a feed to water ratio of 1:0.68, a fermentation temperature of 30.3°C and fermentation duration of 21.5 days. The protein content of fermented JCC (FJCC) increased, while the concentrations of ether extract, crude fibre and toxins were all degraded considerably. Metabolomics analysis revealed that the fermentation increased the contents of neurotransmitter receptor modulator, emulsifier, aromatic substances and insecticidal compounds, as well as decreasing the contents of oxidative stress and neurotoxic substances. A rat feeding trial showed that the growth performance of the rats provided with the FJCC diet was similar to that of the corn-soybean meal group, and no lesions in the liver and kidney were observed. CONCLUSION: The co-bio-fermentation process can effectively detoxify JCC and improve its nutritional value, which means it could be served as a protein feed in animal husbandry. SIGNIFICANCE: The combination of three microbial strains can detoxify JCC in a safe and effective manner to provide a great potential alternative to soybean meal. The research also suggests that metabonomics and bioinformatics are useful tools for revealing the bio-detoxification mechanism.

Vector competence is strongly affected by a small deletion or point mutations in bluetongue virus.

BACKGROUND: Transmission of vector-borne virus by insects is a complex mechanism consisting of many different processes; viremia in the host, uptake, infection and dissemination in the vector, and delivery of virus during blood-feeding leading to infection of the susceptible host. Bluetongue virus (BTV) is the prototype vector-borne orbivirus (family Reoviridae). BTV serotypes 1-24 (typical BTVs) are transmitted by competent biting Culicoides midges and replicate in mammalian (BSR) and midge (KC) cells. Previously, we showed that genome segment 10 (S10) encoding NS3/NS3a protein is required for virus propagation in midges. BTV serotypes 25-27 (atypical BTVs) do not replicate in KC cells. Several distinct BTV26 genome segments cause this so-called 'differential virus replication' in vitro. METHODS: Virus strains were generated using reverse genetics and their growth was examined in vitro. The midge feeding model has been developed to study infection, replication and disseminations of virus in vivo. A laboratory colony of C. sonorensis, a known competent BTV vector, was fed or injected with BTV variants and propagation in the midge was examined using PCR testing. Crossing of the midgut infection barrier was examined by separate testing of midge heads and bodies. RESULTS: A 100 nl blood meal containing ±105.3 TCID50/ml of BTV11 which corresponds to ±20 TCID50 infected 50% of fully engorged midges, and is named one Midge Alimentary Infective Dose (MAID50). BTV11 with a small in-frame deletion in S10 infected blood-fed midge midguts but virus release from the midgut into the haemolymph was blocked. BTV11 with S1[VP1] of BTV26 could be adapted to virus growth in KC cells, and contained mutations subdivided into 'corrections' of the chimeric genome constellation and mutations associated with adaptation to KC cells. In particular one amino acid mutation in outer shell protein VP2 overcomes differential virus replication in vitro and in vivo. CONCLUSION: Small changes in NS3/NS3a or in the outer shell protein VP2 strongly affect virus propagation in midges and thus vector competence. Therefore, spread of disease by competent Culicoides midges can strongly differ for very closely related viruses.

Mouse Models of Yersiniosis.

Yersiniosis is common foodborne gastrointestinal disease caused by the enteric pathogens Yersinia enterocolitica and Yersinia pseudotuberculosis. The mouse model of oral infection serves as a useful tool to study enteropathogenic Yersinia infection in mammals. The following protocol describes two distinct oral infection methods: the commonly used oral gavage method in which the bacterial inoculum is instilled directly into the mouse stomach using a feeding needle, and an alternative method in which mice are fed bread soaked with Yersinia culture.

Elevated oxysterol levels in human and mouse livers reflect nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH), a primary cause of liver disease, leads to complications such as fibrosis, cirrhosis, and carcinoma, but the pathophysiology of NASH is incompletely understood. Epstein-Barr virus-induced G protein-coupled receptor 2 (EBI2) and its oxysterol ligand 7α,25-dihydroxycholesterol (7α,25-diHC) are recently discovered immune regulators. Several lines of evidence suggest a role of oxysterols in NASH pathogenesis, but rigorous testing has not been performed. We measured oxysterol levels in the livers of NASH patients by LC-MS and tested the role of the EBI2-7α,25-diHC system in a murine feeding model of NASH. Free oxysterol profiling in livers from NASH patients revealed a pronounced increase in 24- and 7-hydroxylated oxysterols in NASH compared with controls. Levels of 24- and 7-hydroxylated oxysterols correlated with histological NASH activity. Histological analysis of murine liver samples demonstrated ballooning and liver inflammation. No significant genotype-related differences were observed in Ebi2-/- mice and mice with defects in the 7α,25-diHC synthesizing enzymes CH25H and CYP7B1 compared with wild-type littermate controls, arguing against an essential role of these genes in NASH pathogenesis. Elevated 24- and 7-hydroxylated oxysterol levels were confirmed in murine NASH liver samples. Our results suggest increased bile acid synthesis in NASH samples, as judged by the enhanced level of 7α-hydroxycholest-4-en-3-one and impaired 24S-hydroxycholesterol metabolism as characteristic biochemical changes in livers affected by NASH.

A feeding model of oyster larvae (Crassostrea angulata).

There is a need to develop more efficient rearing systems for the aquaculture of economically important bivalves, such as oysters. Here, we constructed a model that describes the feeding behavior of larval Crassostrea angulata oysters and tested it in an experimental setting. Larval ingestion rate is closely correlated with larval length. Based on our model, we showed that larval swimming speed, velum diameter and the filtration coefficient, which also determine the ingestion rate, are also correlated with larval length. Our model integrates morphological, locomotory and feeding behavior parameters to establish a relation between them and so provides a mathematical way to describe variation in the feeding behavior of bivalve larvae. The results of this study could facilitate the precise management of the aquaculture of bivalve larvae, in particular the optimum prey density and feeding rate of these important organisms.

Enhancement of cell biomass and cell activity of astaxanthin-rich Haematococcus pluvialis.

Fed-batch culture and the transformation conditions of Haematococcus pluvialis in a 5L photobioreactor were investigated. Methods of feeding model, low temperature at night and proper feeding time were used to increase both cell biomass and cell activity. Dry cell weight of 1.87 g/L which was 2.0-fold of batch culture and the specific growth rate of 0.43 d(-1) suggested the superduper results of these methods to increase the dry cell weight in the short cultivation time. Furthermore, mixed lights of blue and white (ratio of 3:1) at 7000 xl were used to expedite the morphologic changes of H. pluvialis from green cells to red cyst cells with the yield of 91.8±2.53 mg/L.