Marked variations in gut microbial diversity, functions, and disease risk between wild and captive alpine musk deer.

Maintaining a healthy status is crucial for the successful captive breeding of endangered alpine musk deer (Moschus chrysogaster, AMD), and captive breeding programs are beneficial to the ex-situ conservation and wild population recovery of this species. Meanwhile, the gut microbiota is essential for host health, survival, and environmental adaptation. However, changes in feeding environment and food can affect the composition and function of gut microbiota in musk deer, ultimately impacting their health and adaptation. Therefore, regulating the health status of wild and captive AMD through a non-invasive method that targets gut microbiota is a promising approach. Here, 16S rRNA gene sequencing was employed to reveal the composition and functional variations between wild (N = 23) and captive (N = 25) AMD populations. The results indicated that the gut microbiota of wild AMD exhibited significantly higher alpha diversity (P < 0.001) and greater abundance of the phylum Firmicutes, as well as several dominant genera, including UCG-005, Christensenellaceae R7 group, Monoglobus, Ruminococcus, and Roseburia (P < 0.05), compared to captive AMD. These findings suggest that the wild AMD may possess more effective nutrient absorption and utilization, a more stable intestinal microecology, and better adaption to the complex natural environment. The captive individuals displayed higher metabolic functions with an increased abundance of the phylum Bacteroidetes and certain dominant genera, including Bacteroides, Rikenellaceae RC9 gut group, NK4A214 group, and Alistipes (P < 0.05), which contributed to the metabolic activities of various nutrients. Furthermore, captive AMD showed a higher level of 11 potential opportunistic pathogens and a greater enrichment of disease-related functions compared to wild AMD, indicating that wild musk deer have a lower risk of intestinal diseases and more stable intestinal structure in comparison to captive populations. These findings can serve as a valuable theoretical foundation for promoting the healthy breeding of musk deer and as a guide for evaluating the health of wild-released and reintroduced musk deer in the future. KEY POINTS: • Wild and captive AMD exhibit contrasting gut microbial diversity and certain functions. • With higher diversity, certain bacteria aid wild AMD's adaptation to complex habitats. • Higher potential pathogens and functions increase disease risk in captive AMD.

Research Progresses on the Function and Detection Methods of Insect Gut Microbes.

The insect gut is home to an extensive array of microbes that play a crucial role in the digestion and absorption of nutrients, as well as in the protection against pathogenic microorganisms. The variety of these gut microbes is impacted by factors such as age, diet, pesticides, antibiotics, sex, and caste. Increasing evidence indicates that disturbances in the gut microbiota can lead to compromised insect health, and that its diversity has a far-reaching impact on the host's health. In recent years, the use of molecular biology techniques to conduct rapid, qualitative, and quantitative research on the host intestinal microbial diversity has become a major focus, thanks to the advancement of metagenomics and bioinformatics technologies. This paper reviews the main functions, influencing factors, and detection methods of insect gut microbes, in order to provide a reference and theoretical basis for better research utilization of gut microbes and management of harmful insects.

Short-term exposure to enrofloxacin causes hepatic metabolism disorder associated with intestinal flora dysbiosis in adult marine medaka (Oryzias melastigma).

Enrofloxacin (ENR) is a widely used fluoroquinolone antibiotic that is frequently detected in the environment. Our study assessed the impact of short-term ENR exposure on the intestinal and liver health of marine medaka (Oryzias melastigma) using gut metagenomic shotgun sequencing and liver metabolomics. We found that ENR exposure resulted in imbalances of Vibrio and Flavobacteria and enrichments of multiple antibiotic resistance genes. Additionally, we found a potential link between the host's response to ENR exposure and the intestinal microbiota disorder. Liver metabolites, including phosphatidylcholine, lysophosphatidylcholine, taurocholic acid, and cholic acid, in addition to several metabolic pathways in the liver that are closely linked to the imbalance of intestinal flora were severely maladjusted. These findings suggest that ENR exposure has the potential to negatively affect the gut-liver axis as the primary toxicological mechanism. Our findings provide evidence regarding the negative physiological impacts of antibiotics on marine fish.

Stool microbiota show greater linkages with plasma metabolites compared to salivary microbiota in a multinational cirrhosis cohort.

BACKGROUND AND AIMS: Cirrhosis is associated with changes in gut microbiota in both saliva and stool. The relative linkage patterns of stool versus saliva microbiota with systemic metabolomics are unclear and may differ across countries. We hypothesized that stool microbiota have greater linkages with plasma metabolites than saliva microbiota, which may depend on country of origin. METHODS: Age-balanced controls and outpatient patients with cirrhosis, compensated and decompensated, from the USA and Mexico (MX) underwent plasma collection and dietary recall. Plasma metabolomics were analysed using nuclear magnetic resonance spectroscopy. Microbiota in stool and saliva samples were analysed using 16S rRNA analyses. Correlation network differences between both saliva and stool gut microbiota and plasma metabolites were compared between subject groupings and within/between countries. RESULTS: A total of 313 age-balanced subjects-135 USA (47 control, 48 compensated and 40 decompensated) and 178 MX (71 control, 56 compensated and 51 decompensated)-were enrolled. Cirrhosis severity, including lactulose and rifaximin use, were comparable. Plasma metabolites differed with advancing cirrhosis, between countries and according to 90-day hospitalizations. Correlation networks demonstrated more microbiome-metabolite linkages in stool compared to saliva in both populations, although there were no salivary correlation metrics across decompensated subjects in either country. Stool Lactobacillus showed a positive correlation to plasma lactate in decompensated cirrhosis from MX but not USA. CONCLUSIONS: Stool microbiota were more extensively linked with systemic metabolites than were saliva microbiota, irrespective of cirrhosis severity and country. These changes were more prominent in decompensated cirrhosis and were centred around plasma lactate, which might reflect the interaction of diet and lactulose therapy.

Polystyrene microplastics alter the intestinal microbiota function and the hepatic metabolism status in marine medaka (Oryzias melastigma).

To assess the potential effects of microplastics (MPs) on gut microbiome, a simple investigation of gut microbial structure is not sufficient, and the function and association of gut microbial structure with host health should also be taken into account. Here, the effects of two particle sizes (2 and 200 µm) of polystyrene MPs (PS-MPs) on the gut microbiota of medaka were evaluated following oral administration at 0.3 and 3.0 µg/mg for 28 days. No change in body length and gut histopathology damage were observed. However, the exposure to PS-MPs significantly decreased fish body weight and disrupted the liver anti-oxidative status. The PS-MPs caused a shift in the gut microbial structure of medaka accompanied by changes in community function, including significant environmental stress, increased carbon degradation/fixation activities, and partially modified nitrogen/phosphorus/sulfur metabolic abilities. Furthermore, the PS-MPs exposure disturbed the glycolipid/tyrosine/energy metabolism and the endocrine balance. A potential correlation between the gut microecology and host response to PS-MPs exposure was also observed. These results indicated that the PS-MPs may contribute to gut-liver axis disruption, which could be the underlying toxicological mechanisms of PS-MPs exposure. This work has improved our knowledge about the relationship between gut microbiota dysbiosis and host metabolic disorders following MPs exposure.

Metabolomics and microbial composition increase insight into the impact of dietary differences in cirrhosis.

BACKGROUND & AIMS: Dietary changes can modulate gut microbiota and interact with cirrhosis. Our prior study demonstrated that microbial diversity was higher in cirrhotics from Turkish vs the USA, which was associated with lower risk of 90-day hospitalizations. We aimed to define gut microbial functional and metabolomic changes to increase insight into benefits of the Mediterranean compared to Western diets. METHODS: In all, 139 Turkish (46 controls/50 compensated/43 decompensated) and 157 American subjects (48 controls/59 compensated/50 decompensated) were studied. Turkish subjects consumed a modified Mediterranean diet with daily fermented milk intake, whereas Americans consumed a Western diet. Predicted gut microbial functionalities and plasma metabolomics were compared between/within countries. Correlation network differences between microbiota and metabolites in cirrhotics from Turkey vs the USA were evaluated. RESULTS: Predicted microbial function showed lower amino acid, bioenergetics and lipid pathways, with functions related to vitamin B, glycan, xenobiotic metabolism, DNA/RNA synthesis, in cirrhotics from Turkey compared to the USA. Plasma metabolomics demonstrated higher relative lactate levels in Turkey vs the USA. The metabolite changes in decompensated cirrhosis, compared to controls, showed similar trends in Turkey and the USA, with reduced lipids and phosphocholines. Phosphocholines were significantly lower in patients hospitalized in 90 days (P = .03). Correlation networks in cirrhotics demonstrated linkage differences between beneficial taxa, Blautia and Oscillispira, and lactate and unsaturated lipids, in Turkey compared to American patients. CONCLUSIONS: A modified Mediterranean diet was associated with altered plasma metabolomics and beneficially alters microbiota functionality and correlations compared to Western diet in cirrhosis. These altered diet-microbial interactions could potentially affect the 90-day hospitalization risk.