Dietary Saccharomyces cerevisiae improves intestinal flora structure and barrier function of Pekin ducks.

This study aimed at investigating the effects of dietary Saccharomyces cerevisiae (SC) on the intestinal flora structure and barrier function of Pekin duck. A total of 180 1-day-old Pekin ducks were randomly divided into 3 groups with 6 replicates in each group and 10 birds per replicate. The birds in the control group (CON) were fed the basal diet, and those in the experimental group were fed the basal diets supplemented with 600 mg/kg SC (LSC) and 1,200 mg/kg (HSC), respectively. The trial lasted for 42 d. Results showed that LSC and HSC treatments tended to improve the feed conversion efficiency during the trial. The ileum length of birds in the LSC and HSC groups was elevated. Additionally, with 600mg/kg SC supplemented, the mRNA levels of villin, claudin3, and MUC 2 in d21 were up-regulated, as well as the mRNA levels of villin, claudin3, occludin, i-FABP, ZO-1, and MUC 2 in d42. In addition, dietary SC supplementation improved the α-diversity of the bacteria in cecal chyme and tended to increase the abundance (RA) of Bacteroidetes (P = 0.071). Besides, the RA of Ruminococcaceae_UCG-014 was raised in the LSC group. Beyond that, the RA of Proteobacteria was descended with two levels of SC added. In conclusion, dietary Saccharomyces cerevisiae, particularly at 600 mg/kg level, improved the intestinal flora structure and barrier function of Pekin duck.

Dietary Lactobacillus plantarum improves the growth performance and intestinal health of Pekin ducks.

Lactobacillus plantarum (LP) contributes to the intestinal health, whereas the study about the effects of LP on Pekin ducks is lacking. This study aimed to investigate the effects of LP on growth performance and intestinal health of Pekin ducks. A total of 180 one-day-old birds were randomly allotted to 3 treatments, and ducks were fed with a basal diet (Control) or basal diet supplemented with 400 (LP1) and 800 (LP2) mg/kg LP (5 × 109 CFU/g). The animal trial lasted for 42 d. Results showed that the LP1 and LP2 treatments improved growth performance (feed conversion) of ducks during the period of 1 to 42 d. At the end of 21 d, the decreased serum levels of interleukin (IL)-1ß, interferon (IFN)-γ as well as downregulated ileal mRNA expression of IL-1ß were observed in 2 doses of LP group. Meanwhile, the ileal mRNA levels of major histocompatibility complex (MHC)-II, IL-4, Claudin, Occludin were upregulated with 2 doses of LP supplemented. In addition, both LP treatments increased the relative abundance of Firmicutes and decreased Bacteroidetes wherein the relative abundance of Bacteroides fragilis was dropped parallelly. It is worth mentioning that markedly increased secretory immunoglobulin A content in ileal mucosa was observed in the LP1 group at d 21. At the end of the trial, the levels of serum complement 3 and ß-defense were elevated with 2 doses of LP treated. Additionally, the ileal mRNA expressions of MHC-II, lysozyme were upregulated, and the diversity of the flora was also improved in the LP1 and LP2 groups. In conclusion, dietary LP improved the growth performance and intestinal health of Pekin ducks, and 400 mg/kg LP seemed to work better.

Protective effects of L-arginine on the intestinal epithelial barrier under heat stress conditions in rats and IEC-6 cell line.

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-1ß, 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.

H3N2 canine influenza virus and Enterococcus faecalis coinfection in dogs in China.

BACKGROUND: In May 2017, 17 dogs in a German Shepherd breeding kennel in northern China developed respiratory clinical signs. The owner treated the dogs with an intravenous injection of Shuang-Huang-lian, a traditional Chinese medicine, and azithromycin. The respiratory signs improved 3 days post-treatment, however, cysts were observed in the necks of eight dogs, and three of them died in the following 2 days. CASE PRESENTATION: Quantitative real-time PCR was used to detect canine influenza virus (CIV). All of the dogs in this kennel were positive and the remaining 14 dogs had seroconverted. Two of the dogs were taken to the China Agricultural University Veterinary Teaching Hospital for further examination. Two strains of influenza virus (A/canine/Beijing/0512-133/2017 and A/canine/Beijing/0512-137/2017) isolated from the nasal swabs of these dogs were sequenced and identified as avian-origin H3N2 CIV. For the two dogs admitted to the hospital, hematology showed mild inflammation and radiograph results indicated pneumonia. Cyst fluid was plated for bacterial culture and bacterial 16 s rRNA gene PCR was performed, followed by Sanger sequencing. The results indicated an Enterococcus faecalis infection. Antimicrobial susceptibility tests were performed and dogs were treated with enrofloxacin. All 14 remaining dogs recovered within 16 days. CONCLUSIONS: Coinfection of H3N2 CIV and Enterococcus faecalis was detected in dogs, which has not been reported previously. Our results highlight that CIV infection might promote the secondary infection of opportunistic bacteria and cause more severe and complicated clinical outcomes.

RNA-Seq transcriptome analysis of breast muscle in Pekin ducks supplemented with the dietary probiotic Clostridium butyricum.

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.

Dietary supplementation with Clostridium butyricum modulates serum lipid metabolism, meat quality, and the amino acid and fatty acid composition of Peking ducks.

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.

Jujuboside A attenuates norepinephrine-induced apoptosis of H9c2 cardiomyocytes by modulating MAPK and AKT signaling pathways.

Cardiomyocyte apoptosis is closely associated with the pathogenesis of heart failure. Jujuboside A (JUA) is a type of saponin isolated from the seeds of Zizyphus jujuba. In traditional Chinese medicine, it is believed that JUA possesses multiple biological effects, including antianxiety, antioxidant and anti­inflammatory activities. The present study aimed to evaluate the effects of JUA on norepinephrine (NE)­induced apoptosis of H9c2 cells and to investigate its underlying mechanisms. Rat H9c2 cardiomyocytes were pretreated with JUA and were then exposed to NE as an in vitro model of myocardial apoptosis. A cell viability assay, scanning electron microscopy, transmission electron microscopy, flow cytometry assay, acridine orange/ethidium bromide staining, reverse transcription­quantitative polymerase chain reaction and western blotting, all revealed that NE induced H9c2 cell apoptosis. The results demonstrated that NE inhibited cell viability, and enhanced cell damage and apoptosis of H9c2 cells. Conversely, pretreatment with JUA was able to reverse NE­induced decreased cell viability and increased apoptosis. Furthermore, JUA suppressed upregulation of the B­cell lymphoma 2 (Bcl­2)­associated X protein/Bcl­2 ratio, and inhibited the increased protein expression levels of cleaved caspase­3 and cleaved caspase­9 following NE exposure. However, the protein expression levels of cleaved caspase­12 and cleaved caspase­8 were not significantly altered following exposure to NE or JUA pretreatment. In addition, in JUA­pretreated cells, the protein expression levels of phosphorylated (p)­p38 and p­c­Jun N­terminal kinase were downregulated compared with in NE­treated cells. Furthermore, JUA regulated the activation of extracellular signal­regulated kinase (ERK) in NE­treated cells and significantly increased the expression levels of p­AKT. Taken together, these data suggested that JUA may protect against NE­induced apoptosis of cardiomyocytes via modulation of the mitogen­activated protein kinase and AKT signaling pathways. Therefore, JUA may be considered a potential therapeutic strategy for the treatment of heart disease.