Zinc glycine chelate ameliorates DSS-induced intestinal barrier dysfunction via attenuating TLR4/NF-κB pathway in meat ducks.

BACKGROUND: Zinc glycine chelate (Zn-Gly) has anti-inflammation and growth-promoting properties; however, the mechanism of Zn-Gly contribution to gut barrier function in Cherry Valley ducks during intestinal inflammation is unknown. Three-hundred 1-day-old ducks were divided into 5 groups (6 replicates and 10 ducks per replicate) in a completely randomized design: the control and dextran sulfate sodium (DSS) groups were fed a corn-soybean meal basal diet, and experimental groups received supplements of 70, 120 or 170 mg/kg Zn in form of Zn-Gly. The DSS and treatment groups were given 2 mL of 0.45 g/mL DSS daily during d 15-21, and the control group received normal saline. The experiment lasted 21 d. RESULTS: Compared with DSS group, 70, 120 and 170 mg/kg Zn significantly increased body weight (BW), villus height and the ratio of villus to crypt, and significantly decreased the crypt depth of jejunum at 21 d. The number of goblet cells in jejunal villi in the Zn-Gly group was significantly increased by periodic acid-Schiff staining. Compared with control, the content of intestinal permeability marker D-lactic acid (D-LA) and fluxes of fluorescein isothiocyanate (FITC-D) in plasma of DSS group significantly increased, and 170 mg/kg Zn supplementation significantly decreased the D-LA content and FITC-D fluxes. Compared with control, contents of plasma, jejunum endotoxin and jejunum pro-inflammatory factors IL-1ß, IL-6 and TNF-α were significantly increased in DSS group, and were significantly decreased by 170 mg/kg Zn supplementation. Dietary Zn significantly increased the contents of anti-inflammatory factors IL-10, IL-22 and sIgA and IgG in jejunum. Real-time PCR and Western blot results showed that 170 mg/kg Zn supplementation significantly increased mRNA expression levels of CLDN-1 and expression of OCLN protein in jejunum, and decreased gene and protein expression of CLDN-2 compared with DSS group. The 120 mg/kg Zn significantly promoted the expressions of IL-22 and IgA. Dietary Zn-Gly supplementation significantly decreased pro-inflammatory genes IL-8 and TNF-α expression levels and TNF-α protein expression in jejunum. Additionally, Zn significantly reduced the gene and protein expression of TLR4, MYD88 and NF-κB p65. CONCLUSIONS: Zn-Gly improved duck BW and alleviated intestinal injury by regulating intestinal morphology, barrier function and gut inflammation-related signal pathways TLR4/MYD88/NF-κB p65.

Glucagon-like peptide 2 attenuates intestinal mucosal barrier injury through the MLCK/pMLC signaling pathway in a piglet model.

Glucagon-like peptide-2 (GLP-2), an intestinotrophic hormone, has drawn considerable attention worldwide due to its potential to promote intestinal development. We investigated the effects and mechanisms of GLP-2 against lipopolysaccharide (LPS)-induced intestinal inflammation and injury both in vitro and in vivo. Forty healthy piglets weaned at the age of 28 days with similar body weight (BW) were assigned to four in vivo treatments with ten piglets each: (i) nonchallenged control; (ii) LPS-challenged control; (iii) LPS + low dose GLP-2; and (iv) LPS + high dose GLP-2. Piglets were subcutaneously injected with phosphate-buffered saline supplemented with GLP-2 at doses of 0, 0, 2, and 10 nmol/kg BW per day for seven consecutive days. The piglets were challenged with an intraperitoneal injection with 100 µg/kg LPS on day 14 to induce intestinal damage. After that, the gene and protein expression levels of representative tight junction proteins and myosin light-chain kinase (MLCK)/phosphorylated myosin light chain (pMLC), as well as proinflammatory cytokine levels were determined using quantitative reverse transcription polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay methods. A high dose of GLP-2 pretreatment increased intestinal permeability by downregulating and redistributing tight junction proteins (p < .05), for example, zona occluden-1 (ZO-1) and occludin. GLP-2 decreased the transcription of proinflammatory cytokines genes including interleukin-1ß (IL-1ß), IL-6, IL-8, and tumor necrosis factor-α in small intestines (p < .05). GLP-2 prevented the LPS-induced increase in the expression of MLCK dose-dependently and the increase in pMLC levels in the duodenum, jejunum, and ileum. To assess further the protective effect of GLP-2 on LPS-induced intestinal barrier injury after weaning and its possible mechanism, an in vitro intestinal epithelial barrier model was established with IPEC-J2 monolayers and treated with 100 µg/ml LPS with or without 1 × 10-8 mol/L GLP-2 pretreatment. The in vitro analysis included control, LPS, and GLP-2 + LPS treatments. GLP-2 treatment alleviated the destructive effect of LPS on barrier permeability by restoring the expression and ultrastructure of ZO-1 and occludin (p < .05). In addition, GLP-2 reversed the LPS-induced MLCK hyperexpression and pMLC hyperphosphorylation (p < .05). Taken together, our findings revealed a mechanism by which GLP-2 alleviated LPS-challenged intestinal barrier injury and inflammation in weaned piglets and IPEC-J2 cells via the MLCK/pMLC signaling pathway.

Exiguobacterium flavidum sp. nov., isolated from the Red Maple Lake.

A Gram-stain-positive, motile, facultatively anaerobic, non-sporing, and rod-shaped bacterial strain, designated HF60T, was isolated from the Red Maple Lake of Guizhou Province, China. The DNA G+C content of the strain HF60T was 55.0 %. The predominant isoprenoid quinones were identified as MK-7 (56.4 %) and MK-8 (35.7 %). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and aminophosphoglycolipid. The major fatty acids were anteiso-C13 : 0, iso-C15 : 0, C16 : 0 and iso-C13 : 0. The strain had cell wall peptidoglycan type A3α l-Lys-Gly. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain HF60T belonged to the genus Exiguobacterium and was most closely related to Exiguobacterium sibiricum JCM 13490T (97.2 % 16S rRNA gene sequence similarity), followed by Exiguobacterium undae DSM 14481T (97.1 %), Exiguobacterium antarcticum DSM 14480T (96.9 %) and Exiguobacterium aurantiacum NBRC 14763T (94.5 %). The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness indicated that strain HF60T can be considered to represent a novel species of the genus Exiguobacterium, for which the name Exiguobacterium flavidum sp. nov. is proposed, The type strain is HF60T (=MCCC 1H00336T=KCTC 33987T).

Marinomonas agarivorans sp. nov., an agar-degrading marine bacterium isolated from red algae.

A Gram-stain-negative, aerobic and curved-rod-shaped bacterium, designated QM202T, was isolated from red algae (Gracilaria blodgettii). Cells of strain QM202T were 0.2-0.3 µm wide and 1.0-2.5 µm long, catalase-negative and oxidase-positive. The strain exhibited an agar-degrading activity. It was motile by means of a single polar flagellum. Optimal growth occurred at 28-30 °C, pH 7.0-7.5 and in the presence of 2.0-3.0 % (w/v) NaCl. The DNA G+C content was 41.4 mol%. The isoprenoid quinone was identified as Q-8. Phophatidylethanolamine and phosphatidylglycerol were the predominant phospholipids. The dominant fatty acids were C18:1ω7c, C16:0 and C16:1ω7c and/or iso-C15:0 2-OH. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain QM202T belonged to the genus Marinomonas. The closest described neighbour in terms of 16S rRNA gene sequence identity was Marinomonas blandensis MED121T (95.5 %). The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness indicated that strain QM202T can be considered to represent a novel species, Marinomonas agarivorans sp. nov. The type strain is QM202T (=KCTC 52475T=MCCC 1H00145T).

Kineobactrum sediminis gen. nov., sp. nov., isolated from marine sediment.

A novel Gram-stain-negative, rod-shaped marine bacterium, designated strain F02T, was isolated from a marine saltern in Weihai, PR China. The cells of strain F02T were approximately 0.8-1.0×3.0-4.0 µm and motile by means of a polar flagellum. Strain F02T grew optimally at 33-35 °C, pH 7.5 and in the presence of 3.0 % (w/v) NaCl. Strain F02T showed oxidase- and catalase-positive activities. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain F02T belonged to the family Halieaceae and exhibited 16S rRNA gene sequence similarities of 96.6 and 96.4 % to the type strains of Chromatocurvus halotolerans and Parahaliea mediterranea, respectively. The major cellular fatty acids of strain F02T were C18 : 1ω7c, C16 : 1ω7c, C15 : 0 and C18 : 1ω9c. The major polar lipids of strain F02T were phosphatidylglycerol, phosphatidylethanolamine and one unidentified aminolipid. Strain F02T contained Q-8 as the sole respiratory quinone. The genomic DNA G+C content was 58.4 mol%. The genome sequences of strain F02T and Chromatocurvus halotolerans DSM 23344T had an OrthoANI value of 70.5 %, and the average amino acid identity value between the two genomes was 62.6 %. The sequence similarity value between the rpoB genes of strain F02T and Chromatocurvus halotolerans DSM 23344T was 79.5 %. On the basis of polyphasic analysis, strain F02T represents a novel species in a new genus, for which the name Kineobactrum sediminis gen. nov., sp. nov. is proposed. The type strain is F02T (=KCTC 52616T=MCCC 1H00224T).