The gill and gastrointestinal tract are primary entry routes for pathogens. The symbiotic microbiota are essential to the health, nutrition and disease of fish. Though the intestinal microbiota of Nile tilapia (Oreochromis niloticus) has been extensively studied, information on the mucosa-associated microbiota of this species, especially the gill and gastrointestinal mucosa-associated microbiota, is lacking. This study aimed to characterize the gill and gastrointestinal mucosa- and digesta-associated microbiota, as well as the intestinal metabolite profiles in the New Genetically Improved Farmed Tilapia (NEW GIFT) strain of farmed adult Nile tilapia by high-throughput sequencing and gas chromatography/mass spectrometry metabolomics. The diversity, structure, composition, and predicted function of gastrointestinal microbiota were significantly different across gastrointestinal regions and sample types (Welch t-test; p < 0.05). By comparing the mucosa- and digesta-associated microbiota, linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed that Pelomonas, Ralstoniapickettii, Comamonadaceae, and Staphylococcus were significantly enriched in the mucosa-associated microbiota, whereas many bacterial taxa were significantly enriched in the digesta-associated microbiota, including Chitinophagaceae, Cetobacterium, CandidatusCompetibacter, Methyloparacoccus, and chloroplast (LDA score > 3.5). Furthermore, Undibacterium, Escherichia–Shigella, Paeniclostridium, and Cetobacterium were dominant in the intestinal contents and mucosae, whereas Sphingomonasaquatilis and Roseomonasgilardii were commonly found in the gill and stomach mucosae. The Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2) analysis revealed that the predictive function of digesta-associated microbiota significantly differed from that of mucosa-associated microbiota (R = 0.8152, p = 0.0001). In addition, our results showed a significant interdependence between specific intestinal microbes and metabolites. Notably, the relative abundance values of several potentially beneficial microbes, including Undibacterium, Crenothrix, and Cetobacterium, were positively correlated with most intestinal metabolites, whereas the relative abundance values of some potential opportunistic pathogens, including Acinetobacter, Mycobacterium, Escherichia–Shigella, Paeniclostridium, Aeromonas, and Clostridiumsensustricto 1, were negatively correlated with most intestinal metabolites. This study revealed the characteristics of gill and gastrointestinal mucosa-associated and digesta-associated microbiota of farmed Nile tilapia and identified a close correlation between intestinal microbes and metabolites. The results serve as a basis for the effective application of targeted probiotics or prebiotics in the diet to regulate the nutrition and health of farmed tilapia.

Different provenances of Dendrobiums had characteristic chemicals and showed remarkable quantity discrepancy of common compositions. The similarity evaluation disclosed that the accumulation of volatile compounds in Dendrobium samples might be affected by their provenance. Principal component analysis showed that the first three components explained 85.9% of data variance, demonstrating a good discrimination between samples. Gas chromatography-mass spectrometry techniques, combined with chemometrics, might be an effective strategy for identifying the species and their provenance, especially in the assessment of tissue-cultured Dendrobium quality for use in raw herbal medicines.

BackgroundEupatilin, an active flavone separated from Artemisia species, has various biological activity such as anti-inflammatory activity. The aim of the present study was to find out the influence of eupatilin on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats.Material/MethodsThe administration of LPS was used to induce ALI; eupatilin was given 1 hour before the LPS administration. Lung structural damage of rats was analyzed by hematoxylin and eosin staining and the wet/dry lung ratio. The related inflammatory factors and lung injury markers were examined by enzyme-linked immunosorbent assay. The oxidative stress factors were analyzed by corresponding kits. The expression of peroxisome proliferator-activated receptor-α (PPAR-α) was assayed by western blot and immunohistochemical staining.ResultsThe results showed that eupatilin alleviated LPS-induced structural damage and decreased the wet/dry lung ratio concentration-dependently. Eupatilin decreased the level of surfactant protein (SP)-A, SP-D, and inflammatory factors such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, and monocyte chemo-attractant protein (MCP)-1. LPS trigged nitric oxide (NO) generation, improved the production of malondialdehyde (MDA) and lactate dehydrogenase (LDH) and decreased the activity of superoxide dismutase (SOD), which were reversed when rats treated with eupatilin in a concentration-dependent way. Besides, the expression of PPAR-α was increased under the treatment of eupatilin.ConclusionsCollectively, eupatilin alleviated LPS-induced ALI through inhibiting inflammation and oxidative stress in a concentration-dependent way, which was likely to be closely related with the activation of PPAR-α.

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