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Heat stress (HS) and secondary restricted blood flow to the intestines cause dysfunction of the intestinal epithelial barrier. Tight junctions (TJs) are essential to maintain intestinal integrity. l-Arginine has beneficial effects on gut functions. However, the underlying mechanisms remain largely unknown. This study tested the hypothesis that l-arginine regulates the TJ network by activating AMP-activated protein kinase (AMPK) signaling, which in turn improves intestinal barrier functions under HS. IEC-6 cells and rat small intestines were used as experiment models of heat stress. AICAR and dorsomorphin were used to activate and inhibit the AMPK pathway, respectively. Cell proliferation, apoptosis, differential gene expression and KEGG pathway analysis, intestinal paracellular permeability, intestinal morphology, and expression of HSP and TJ proteins, and p-AMPK were determined. l-Arginine promoted cell proliferation and reduced apoptosis after heat exposure at an optimal concentration of 5 mmol. Transcriptome sequencing analysis revealed that differentially expressed genes associated with the HSP family and TJs were elevated by l-arginine. According to KEGG pathway analysis, l-arginine activated the AMPK signaling pathway. In vivo, intestinal damage resulted in obvious morphological changes as well as apoptosis with TUNEL and caspase-3 staining under HS and dorsomorphin treatments. Furthermore, HS and dorsomorphin increased the serum D-lactate concentration, diamine oxidase activity, and mRNA expression level of MLCK (P l-arginine and AICAR treatments reduced intestinal injury, maintained intestinal permeability, and increased the villus/crypt ratio under hyperthermia. l-Arginine had the same effect as AICAR both in vitro and in vivo, namely increasing p-AMPK protein expression. l-Arginine and AICAR also upregulated the mRNA expression level of HSP70 and HSP90, and downregulated mRNA expression of MLCK (P l-arginine and AICAR. Our findings indicate that activation of AMPK signaling by l-arginine is associated with improved intestinal mucosal barrier functions by enhancing the expression of TJs in rat small intestines and IEC-6 cells during HS.

Force-feeding was considered as a traditional high-efficiency approach to improve growth performance and accelerate fat deposition of Pekin ducks. However, force-feeding is a serious violation of international advocacy on animal welfare, because it can induce serious injuries to animals, such as damages to the digestive tract, effects on immunity and even severe oxidative stress. Therefore, it is urgent to stop force-feeding. The aim of this study was to determine the effects of force feeding on immune function, digestive function and oxidative stress in the mucosa of duodenum and jejunum of Pekin ducks. A total of 500 ducks were randomly divided into two groups. The control group was allowed to feed freely on a basal diet. The experimental group was force-fed by inserting a plastic feeding tube 8 to 10 inches long down the esophagus for 6 days. Compared with the control group, there was a significant (P

Light colors may affect poultry behaviors, well-being and performance. However, preferences of layer pullets for light colors are not fully understood. This study was conducted to investigate the pullet preferences for four light-emitting diode colors, including white, red, green and blue, in a lighting preference test system. The system contained four identical compartments each provided with a respective light color. The pullets were able to move freely between the adjacent compartments. A total of three groups of 20 Chinese domestic Jingfen layer pullets (54 to 82 days of age) were used for the test. Pullet behaviors were continuously recorded and summarized for each light color/compartment into daily time spent (DTS), daily percentage of time spent (DPTS), daily times of visit (DTV), duration per visit, daily feed intake (DFI), daily feeding time (DFT), feeding rate (FR), distribution of pullet occupancy and hourly time spent. The results showed that the DTS (h/pullet·per day) were 3.9±0.4 under white, 1.4±0.3 under red, 2.2±0.3 under green and 4.5±0.4 under blue light, respectively. The DTS corresponded to 11.7% to 37.6% DPTS in 12-h lighting periods. The DTV (times/pullet·per day) were 84±5 under white, 48±10 under red, 88±10 under green and 94±8 under blue light. Each visit lasted 1.5 to 3.2 min. The DFI (g/pullet·per day) were 27.6±1.7 under white, 7.1±1.6 under red, 15.1±1.1 under green and 23.1±2.0 under blue light. The DFT was 0.18 to 0.65 h/pullet·per day and the FR was 0.57 to 0.75 g/min. For most of the time during the lighting periods, six to 10 birds stayed under white, and one to five birds stayed under red, green and blue light. Pullets preferred to stay under blue light when the light was on and under white light 4 h before the light off. Overall, pullets preferred blue light the most and red light the least. These findings substantiate the preferences of layer pullets for light colors, providing insights for use in the management of light-emitting diode colors to meet pullet needs.

The aim of this study was to investigate the effects of Clostridium butyricum (C. butyricum) on the performance, serum lipid metabolism, muscle morphology, meat quality, and fatty acid profiles of Peking ducks. A total of 1,500 Peking ducks were randomly divided into five groups with five replicates and were fed a non-antibiotic basal diet (Control) or a basal diet supplemented with either 200, 400, or 600 mg/kg of C. butyricum (2.0 × 109 CFU/g) or 150 mg of aureomycin/kg for 42 d. Compared with the control group, supplementation with C. butyricum increased the average daily weight gain but reduced the feed/gain ratio from 1 to 42 d of age. Similarly, dietary C. butyricum increased the activities of antioxidant enzymes but decreased the malondialdehyde (MDA) and lipid metabolites concentration. C. butyricum supplementation increased the muscle pH value at 45 min postmortem, the redness of the meat, and the contents of inosine acid (IMP) and intramuscular fat (IMF) in Peking ducks. By contrast, C. butyricum supplementation lowered the lightness, drip loss, and the shear force of breast meat. Supplementation with C. butyricum increased the concentrations of essential amino acids and flavor amino acids, as well as arachidonic acid (AA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and total polyunsaturated fatty acids (PUFA) in breast muscle. Dietary C. butyricum could positively improve performance, lipid metabolism, meat quality, and the amino acid and fatty acid composition in a dose-dependent manner. Therefore, C. butyricum is proposed as a feasible alternative feed additive for the production of healthier Peking duck meat with favorable properties.

Background Aujeszky’s disease virus (ADV) can cause neurologic disease in young pigs, respiratory disease in older pigs and abortion or birth of mummified fetuses or stillborn neonates. The re-emergence of Aujeszky’s disease (AD) in pig farms vaccinated with live vaccine (Bartha-K61) caused substantial economic losses to Chinese pig industry since late 2011. A field ADV, named Qihe547, was isolated from pigs that exhibited suspected AD clinical symptoms. To better understand the genetic characteristics and mutations of Qihe547 ADV, the whole genome was sequenced and analyzed. Results The genomic length of Qihe547 ADV was 143,404 bp, with 73.59% G + C contents. Phylogenetic analysis based on the whole genome of ADV strains revealed that Chinese ADV strains were located to one group with three subgroups. Qihe547 ADV was closely related to these novel ADV strains isolated in China since 2012. Qihe547 presented numerous hypervariable regions compared with oversea ADV strains. In 34 genes of Qihe547 ADV, amino acid (AA) insertion or deletion were observed. In addition, numerous AA mutations were found in the main protective antigen genes (gB, gC and gD genes). The differences of potential antigenic peptides in the main protective antigens between Qihe547 ADV and ADV Bartha were discovered in the dominant antigenic regions of gB (AA59-AA126, AA507-AA734),the extracellular region of gC and gD. Conclusion High diversity was observed between Qihe547 and foreign ADV isolates. The AA variations and the differences of potential antigenic peptides in the important functional regions of the main protective antigen (gB, gC and gD) of ADV Qihe547 may contribute to immune evasion of the virus and may be partial reason that the virus escapes from the vaccination of Bartha-K61 vaccine. In a word, the effect of the variations obviously requires further research.

Background Bovine viral diarrhoea virus (BVDV) is the member of the genus Pestivirus within the Flaviviridae family and responsible for severe economic losses in the cattle industry. BVDV can employ ‘infect-and-persist’ strategy and ‘hit-and-run’ strategy to remain associated with hosts and thus contributes to BVDV circulation in cattle herds. BVDV have also evolved various strategies to evade the innate immunity of host. To further understand the mechanisms by which BVDV overcomes the host cell innate immune response and provide more clues for further understanding the BVDV-host interaction, in this descriptive study, we conducted a investigation of differentially expressed genes (DEGs) of the host during BVDV infection by RNA-Seq analysis. Results Our analysis identified 1297, 1732, 3072, and 1877 DEGs in the comparison groups mock vs. MDBK cells infected with BVDV post 2 h (MBV2h), mock vs. MBV6h, mock vs. MBV12h, and mock vs. MBV24h, respectively. The reproducibility and repeatability of the results were validated by RT-qPCR. Enrichment analyses of GO annotations and KEGG pathways revealed the host DEGs that are potentially induced by BVDV infection and may participate in BVDV-host interactions. Protein-protein interaction (PPI) network analyses identified the potential interactions among the DEGs. Our findings suggested that BVDV infection induced the upregulation of genes involved in lipid metabolism. The expression of genes that have antiviral roles, including ISG15, Mx1, OSA1Y, were found to be downregulated and are thus potentially associated with the inhibition of host innate immune system during BVDV infection. The expression levels of F3, C1R, KNG1, CLU, C3, FB, SERPINA5, SERPINE1, C1S, F2RL2, and C2, which belong to the complement and coagulation signalling cascades, were downregulated during BVDV infection, which suggested that the complement system might play a crucial role during BVDV infection. Conclusion In this descriptive study, our findings revealed the changes in the host transcriptome expression profile during BVDV infection and suggested that BVDV-infection induced altering the host’s metabolic network, the inhibition of the expression of antiviral proteins and genes within the complement system might be contributed to BVDV proliferation. The above findings provided unique insights for further studies on the mechanisms underlying BVDV-host interactions.

Heat stress (HS) and the associated restricted blood flow to the intestine have been proven to destroy intestinal integrity. Considering the beneficial properties of L-arginine on gut function, we investigated the protective effects of L-arginine on the intestine under HS conditions. In vivo, the serum cortisol level and the rectal temperature increased in response to HS. Under HS, the intestinal damage showed obvious morphological changes. Furthermore, HS decreased the mRNA and protein expression levels of Nurr1, ZO-1, occludin, claudin-6 and E-cadherin, increased the mRNA expression of NF-κB and IL-1β, and increased the protein expression of cleaved caspase-3. In contrast, L-arginine supplementation maintained intestinal integrity and increased the villus/crypt ratio. L-arginine also suppressed the expression of inflammation-related genes and the protein expression of cleaved caspase-3, whereas it upregulated the mRNA and protein expression of tight junction proteins and LC3B protein expression. In vitro, L-arginine attenuated HS-induced apoptosis as demonstrated by flow cytometry and decreased cleaved caspase-3 protein expression. L-arginine induced autophagy, which was demonstrated by decreased expression of p62 and p-mTOR/mTOR, and increased expression of LC3B. The protein expression levels of TJ proteins also enhanced by L-arginine in IEC-6 cells. Taken together, these results suggest that L-arginine can alleviate intestinal damage and protect the intestinal integrity by suppressing local inflammation response, promoting the production of TJs and facilitating autophagy under HS conditions.

To obtain an effective vaccine candidate against duck Tembusu viral (DTMUV) disease which causes egg-drop and great economical loss in the Chinese duck industry, liposome vaccines containing recombinant E protein were prepared and assessed in this study. The recombinant plasmid (PET28a-E) was constructed and transformed into BL21 (DE3) cells to produce E proteins. The recombinant E proteins were purified and entrapped by liposomes through reverse-phase evaporation. Eighty-four cherry valley ducks were randomly divided into seven groups and inoculated intramuscularly at one- or seven-day-old with liposomes-E protein or Freund's adjuvant-E protein vaccine. Blood samples were collected from the first week to the tenth week for serum antibody, plasma for viremia, as well as oropharyngeal and cloacal swabs for virus shedding analyses after being challenged with a 10(2.4) 50% tissue culture infective dose (TCID50) of duck Tembusu virus. Results showed that serum antibody level of the liposomes vaccine was higher than the Freund's adjuvant vaccine, and inoculating twice was superior to once; furthermore, the viremia and virus shedding tests also proved that the liposomes vaccine can provide complete protection against DTMUV challenge. These results demonstrated that the liposomes-E protein vaccine could be used as a potential candidate vaccine to prevent DTMUV infection in ducks.

This experiment was conducted to investigate the oxidative stress in chickens exposed to different concentrations of chromium trichloride (CrCl3) in drinking water. Seventy-two Hylan Brown male chickens were randomly divided into four groups: three experimental groups and one control group. The experimental groups were exposed to three different doses (50 % LD50, 25 % LD50, and 12.5 % LD50) of CrCl3 mg/kg body weight for 42 days, while the control group was given the equivalent water. The activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and non-enzymatic index (glutathione, total antioxidant capacity, malondialdehyde, and hydrogen peroxide) were measured after obtaining the brain samples. Results suggested that 50 % LD50 chromium(III) significantly increased (P

Background Increased attention is being paid to breast muscle yield and meat quality in the duck breeding industry. Our previous report has demonstrated that dietary Clostridium butyricum (C. butyricum) can improve meat quality of Pekin ducks. However, the potential biological processes and molecular mechanisms that are modulated by dietary C. butyricum in the breast muscle of Pekin ducks remain unknown. Results Supplementation with C. butyricum increased growth performance and meat yield. Therefore, we utilized de novo assembly methods to analyze the RNA-Seq transcriptome profiles in breast muscle to explore the differentially expressed genes between C. butyricum-treated and control Pekin ducks. A total of 1119 differentially expressed candidate genes were found of which 403 genes were significantly up-regulated and 716 genes were significantly down-regulated significantly. qRT-PCR analysis was used to confirm the accuracy of the of RNA-Seq results. GO annotations revealed potential genes, processes and pathways that may participate in meat quality and muscle development. KEGG pathway analysis showed that the differentially expressed genes participated in numerous pathways related to muscle development, including ECM-receptor interaction, the MAPK signaling pathway and the TNF signaling pathway. Conclusions This study suggests that long-time dietary supplementation with C. butyricum can modulate muscle development and meat quality via altering the expression patterns of genes involved in crucial metabolic pathways. The findings presented here provide unique insights into the molecular mechanisms of muscle development in Pekin ducks in response to dietary C. butyricum. Electronic supplementary material The online version of this article (10.1186/s12864-018-5261-1) contains supplementary material, which is available to authorized users.

This study aimed to investigate the effects of oral administration of trivalent chromium on the contents of Ca, Mg, Mn, Fe, Cu, and Zn in the heart, liver, and kidney. Different levels of 1/8, 1/4, and 1/2 LD50 (LD50 = 5000 mg/kg body mass) CrCl3 milligrams per kilogram body mass daily were added into the water to establish the chronic poisoning model. Ca, Mg, Mn, Fe, Cu, and Zn were detected with the flame atomic absorption spectrometry in the organs exposed 14, 28, and 42 days to CrCl3, respectively. Results showed that Cr was accumulated in the heart, liver, and kidney significantly (P

Klebsiella pneumoniae, which exists in the intestinal and respiratory tracts of humans and animals, is an important conditional pathogen in many animals. The aim of the current study was to investigate the antimicrobial resistance profiles and genotypes of extended-spectrum β-lactamase (ESBL)- and AmpC β-lactamase-producing K. pneumoniae isolated from dogs.A total of 285 isolates, collected from faecal and urine samples of diseased dogs in a Veterinary Teaching Hospital in Beijing, were characterised by antimicrobial susceptibility testing and screened for ESBL and AmpC β-lactamase phenotypes. The relevant genes were identified by polymerase chain reaction and sequencing.All K. pneumoniae isolates were susceptible to meropenem, while the rates of resistance to the remaining 27 tested antimicrobials ranged from 24% to 97%. A total of 53% and 18% of K. pneumoniae isolates were positive for ESBL and AmpC β-lactamase production, respectively. ESBL/AmpC-producing strains were significantly resistant to more antimicrobial agents compared non-ESBL/AmpC-producing strains (P0.05). CTX-M groups 1 and 9, and DHA-1 were the predominant genotypes of the ESBL/AmpC-producing K. pneumoniae isolates.In conclusion, the high percentage of drug resistance among K. pneumoniae isolates suggests that routine detection of ESBL production by reliable laboratory methods is required in small animal clinical practice.

This study aimed to investigate the effects of chromic chloride (CrCl

This study aimed to evaluate the effects of adding chromic chloride (CrCl3) in the drinking water of chickens. Hyland brown male chickens were randomly divided into four groups. Three groups orally received 1/2 LD50, 1/4 LD50, and 1/8 LD50 CrCl3mgkg(-1) body weight daily for 42d. The fourth group was treated with water. The chickens were sacrificed at 14, 28, and 42d post-treatment. The renal injury was examined through histological analysis, and kidney mass was determined. The effects on growth performance were assessed by measuring the weight of the body, chest muscles, and leg muscles. Oxidative damage was evaluated by determining the antioxidant defense levels in kidney homogenates. The body weight and the weight of tissues gained time-dependently, but significantly decreased compared with those in the control group (P

Low molecular weight polypeptides 2 (LMP2) and low molecular weight polypeptides 7 (LMP7) are located within the major histocompatibility complex and have been associated with autoimmune disease. In this study, polymorphisms of porcine LMP2 and LMP7 genes were analyzed by PCR-SSCP and DNA sequencing methods. Four SNPs (DQ659151:g.2115T>C; DQ659151:g.4343A>G; DQ872631:g.1232C>G; DQ872631:g.2847C>T) were identified. Four SNPs of genes were analyzed for association with 22 haematological traits in Large White (n = 195), Landrace (n = 84) and Songliao Black (n = 86) pig population. Of all the 22 traits, seven were significant associated with the SNPs of LMP2/LMP7 gene (P < 0.05). They included white blood cell count (WBC) (P = 0.028), neutrophilic granulocyte count (GRAN) (P = 0.037), monocytes percentage (MO%) (P = 0.015), red blood cell (RBC) (P = 0.004), red blood cell volume distribution width (RDW) (P = 0.004), mean platelet volume (MPV) (P = 0.016) and CD4(+)CD8(+)% (P = 0.045). These results suggest LMP2/LMP7 gene should be regarded as molecular marker to estimate animal's immune status for their effects on hematological traits.

Interferon regulatory factor 1 (IRF1) is a member of IRF-family that was discovered to activate promoters in type I interferon (IFN) genes. It is shown to play functionally diverse role in the regulation of the immune system. In this report, the porcine IRF1 cDNA were cloned and a 7500 bp genomic DNA structure was identified. The putative IRF1 protein included 322 amino acids. Alignment and phylogenetic analysis of the predicted porcine IRF1 amino acids sequence with its homologies of other species show high identity (over 88%). Tissues expression of IRF1 mRNA was observed by RT-PCR, the results revealed IRF1 gene expressed widely in all analyzed tissues. Using the radiation hybrid panel, the porcine IRF1 gene was mapped to porcine chromosome 2 and closely linked to the locus IL4 (LOD = 7.09, 57cR). A SNP in exon2 of porcine IRF1 gene was demonstrated by sequencing and PCR–RFLP analysis. The further association analysis indicated that the SNP was significant associate with level of IFN-γ (day 20) in serum (P = 0.0001) and the ratio of IFN-γ to IL10 (day 20; day 35) in serum (P = 0.0165; P = 0.0095). The results suggested that the porcine IRF1 gene is strong candidate gene for these immune traits in pig.