Effects of subchronic and mild social defeat stress on the intestinal microbiota and fecal bile acid composition in mice.

The gut microbiota plays a crucial role in both the pathogenesis and alleviation of host depression by modulating the brain-gut axis. We have developed a murine model of human depression called the subchronic and mild social defeat stress (sCSDS) model, which impacts not only behavior but also the host gut microbiota and gut metabolites, including bile acids. In this study, we utilized liquid chromatography/mass spectrometry (LC/MS) to explore the effects of sCSDS on the mouse fecal bile acid profile. sCSDS mice exhibited significantly elevated levels of deoxycholic acid (DCA) and lithocholic acid (LCA) in fecal extracts, leading to a notable increase in total bile acids and 7α-dehydroxylated secondary bile acids. Consequently, a noteworthy negative correlation was identified between the abundances of DCA and LCA and the social interaction score, an indicator of susceptibility in stressed mice. Furthermore, analysis of the colonic microbiome unveiled a negative correlation between the abundance of CDCA and Turicibacter. Additionally, DCA and LCA exhibited positive correlations with Oscillospiraceae and Lachnospiraceae but negative correlations with the Eubacterium coprostanoligenes group. These findings suggest that sCSDS impacts the bidirectional interaction between the gut microbiota and bile acids and is associated with reduced social interaction, a behavioral indicator of susceptibility in stressed mice.

Using feces to indicate plastic pollution in terrestrial vertebrate species in western Thailand.

Plastic pollution is a widespread and growing concern due to its transformation into microplastics (MPs), which can harm organisms and ecosystems. This study, aimed to identify plastic pollution in the feces of terrestrial vertebrates using convenience sampling both inside and outside protected areas in Western Thailand. We hypothesized that MPs are likely to be detectable in the feces of all vertebrate species, primarily in the form of small black fragments. We predicted varying quantities of MPs in the feces of the same species across different protected areas. Furthermore, we expected that factors indicating human presence, landscape characteristics, scat weight, and the MP abundance in water, soils, and sediments would influence the presence of plastics in feces. Among 12 terrestrial species studied, potential MPs were found in 41.11% of 90 samples, totaling 83 pieces across eight species including the Asian elephant (Elephas maximus), Eld's deer (Rucervus eldii), Dhole (Cuon alpinus), Gaur (Bos gaurus), Sambar deer (Rusa unicolor), Wild boar (Sus scrofa), Northern red muntjac (Muntiacus vaginalis), and Butterfly lizard (Leiolepis belliana). Specifically, 3.61% of all potential MPs (three pieces) were macroplastics, and the remaining 96.39% were considered potential MPs with the abundance of 0.92 ± 1.89 items.scat-1 or 8.69 ± 32.56 items.100 g-1 dw. There was an association between the numbers of feces with and without potential plastics and species (χ2 = 20.88, p = 0.012). Most potential plastics were fibers (95.18%), predominantly black (56.63%) or blue (26.51%), with 74.70% smaller than two millimeters. Although there were no significant associations between species and plastic morphologies, colors, and sizes, the abundance classified by these characteristics varied significantly. FTIR identified 52.38% as natural fibers, 38.10% as synthetic fibers (rayon, polyurethane (PUR), polyethylene terephthalate (PET), polypropylene (PP), and PUR blended with cotton), and 9.52% as fragments of PET and Polyvinyl Chloride (PVC). Human-related factors were linked to the occurrence of potential plastics found in the feces of land-dwelling wildlife. This study enhances the understanding of plastic pollution in tropical protected areas, revealing the widespread of MPs even in small numbers from the areas distant from human settlements. Monitoring plastics in feces offers a non-invasive method for assessing plastic pollution in threatened species, as it allows for easy collection and taxonomic identification without harming live animals. However, stringent measures to assure the quality are necessitated to prevent exogenous MP contamination. These findings underscore the importance of raising awareness about plastic pollution in terrestrial ecosystems, especially regarding plastic products from clothing and plastic materials used in agriculture and irrigation systems.

Quantitative bile acid profiling in healthy adult dogs and pups from serum, plasma, urine, and feces using LC-MS/MS.

Synthesis and secretion of bile acids (BA) is a key physiological function of the liver. In pathological conditions like portosystemic shunt, hepatic insufficiency, hepatitis, or cirrhosis BA metabolism and secretion are disturbed. Quantification of total serum BA is an established diagnostic method to assess the general liver function and allows early detection of abnormalities, liver disease progression and guidance of treatment decisions. To date, data on comparative BA profiles in dogs are limited. However, BA profiles might be even better diagnostic parameters than total BA concentrations. On this background, the present study analyzed and compared individual BA profiles in serum, plasma, urine, and feces of 10 healthy pups and 40 adult healthy dogs using ultra-high performance liquid chromatography coupled to electrospray ionization mass spectrometry. Sample preparation was performed by solid-phase extraction for serum, plasma, and urine samples or by protein precipitation with methanol for the feces samples. For each dog, 22 different BA, including unconjugated BA and their glycine and taurine conjugates, were analyzed. In general, there was a great interindividual variation for the concentrations of single BA, mostly exemplified by the fact that cholic acid (CA) was by far the most prominent BA in blood and urine samples of some of the dogs (adults and pups), while in others, CA was under the detection limit. There were no significant age-related differences in the BA profiles, but pups showed generally lower absolute BA concentrations in serum, plasma, and urine. Taurine-conjugated BA were predominant in the serum and plasma of both pups (68%) and adults (74-75%), while unconjugated BA were predominant in the urine and feces of pups (64 and 95%, respectively) and adults (68 and 99%, respectively). The primary BA chenodeoxycholic acid and taurocholic acid and the secondary BA deoxycholic acid and lithocholic acid were the most robust analytes for potential diagnostic purpose. In conclusion, this study reports simultaneous BA profiling in dog serum, plasma, urine, and feces and provides valuable diagnostic data for subsequent clinical studies in dogs with different kinds of liver diseases.

Angiotensin-converting enzymes 1 and 2 in the feces: presence and catalytic activity in the rat 2,4,6-trinitrobenzene sulfonic acid-induced model of colitis.

BACKGROUND AND AIM: Inflammatory bowel disease is challenging to diagnose. Fecal biomarkers offer noninvasive solutions. The renin-angiotensin-aldosterone system is implicated in intestinal inflammation. Angiotensin-converting enzyme (ACE) and angiotensin-converting enzyme 2 (ACE2) regulate its activity, but conflicting findings on these enzymes in colitis require further investigation. We aimed to assess ACE and ACE2 presence and activities in the feces, serum, and colon of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced rats. METHODS: Colitis was induced in male rats by rectal instillation of a 21% ethanolic TNBS solution. After rats' sacrifice, colonic portions, serum, and feces were collected. ACE and ACE2 presence in the feces was analyzed by western Blot, and colonic and serum enzymes' concentrations were quantified using ELISA kits. ACE activity was assessed using Hippuryl-His-Leu and Z-Phe-His-Leu as substrates. ACE2 activity was assessed using Mca-APK (Dnp) as a substrate in the presence and absence of DX600 (ACE2 inhibitor). RESULTS: An ACE isoform of ~70 kDa was found only in the feces of TNBS-induced rats. ACE concentration was higher than that of ACE2 in the serum and the inflamed colon. ACE N-domain activity was higher than that of the C-domain in all matrices. ACE2 activity was higher in the feces of TNBS-induced animals compared to controls. CONCLUSION: A 70 kDa ACE isoform only detected in the feces of TNBS-induced rats may have translational relevance. ACE N-domain seems to play a significant role in regulating colonic lesions. Further research using human samples is necessary to validate these findings.

Quantitative microbial risk assessment (QMRA) of the work of manual pit emptiers, commonly known as bayakous.

In Haiti, manual pit emptiers, known as bayakous, face significant health risks. They work by descending naked into latrine pits, exposing themselves to pathogens and contributing to environmental contamination. This study employs the quantitative microbial risk assessment (QMRA) method to evaluate the microbial risks associated with this practice, considering nine prevalent pathogens in Haiti. Three ingestion scenarios were developed: hand-to-mouth contact, ingestion while immersed in excreta, and a combination of both. A sensitivity analysis assessed the impact of input data on study outcomes. The results indicate a high probability of infection and illness during pit emptying operations annually for all scenarios and pathogens. Recommendations include adopting personal protective equipment (PPE) and using a manual Gulper waste pump to eliminate the need to descend directly into the pits, thereby reducing the risk of injury from sharp objects. The study proposes the establishment of intermediate disposal points approximately 5 km from collection sites to deter illegal dumping. National regulations and professionalization of the bayakou profession are suggested, along with awareness campaigns to promote PPE and Gulper pump usage. Addressing these issues is crucial for safeguarding the health of bayakou and public health in Haiti.

Inter-annual variation in the microplastics abundance in feces of the Baird's tapir (Tapirus bairdii) from the Selva Maya, México.

Microplastics (MPs) are found in a wide range of ecosystems, from the Arctic to the deep ocean. However, there is no data on their presence in terrestrial mammals that inhabit the Selva Maya. The aim of this study is to detect the presence of MPs in the feces of the Baird's tapir (Tapirus bairdii) from the region of Calakmul, located in the Yucatan Peninsula, Mexico. We analyzed 129 fecal samples collected during 2017 and 2018, obtaining 57 and 72 samples during the rainy and dry seasons respectively. Sixty-eight percent of the samples contained 743 MPs with a mean of 19.3 ± 28.1 MPs/kg of dry weight (DW) feces in both years. An inter-annual variation in the average abundance of microplastic was observed during the two-year period (2017-2018), with a 72 % increase in these plastic particles in feces. Fourteen polymers were identified, with ethylene vinyl acetate (EVA), polypropylene (PP) and polyester (PES) being the most abundant during both years. Although the effects of MPs on the health of tapirs are not known, their presence is cause for concern. There is an urgent need for the implementation of appropriate plastic waste management programs in communities of the Selva Maya to diminish the consumption of MPs in species including humans where they pose a significant risk to health. ENVIRONMENTAL IMPLICATIONS: The use of plastics worldwide is increasing every day, so the presence of microplastics is and will continue to be a major environmental problem. It is known that contaminants can adhere to plastics, making them hazardous materials. Microplastics can contaminate remote areas such as Biosphere Reserves. Terrestrial species such as the tapir can ingest microplastics, putting their health at risk. Knowing the dispersion of microplastics is very important in order to manage them properly, taking into account their emission sources and type of polymer.

Determination of six short-chain fatty acids in rat feces using headspace solid-phase dynamic extraction coupled with GC-MS.

Short-chain fatty acids (SCFAs) are organic acids with carbon atoms less than six, released through fermentation products by intestinal microbiome, having multiple physiological activities. Considering weak acidity and high volatility, derivatization or liquid-liquid extraction is essential, which is time consuming. Headspace-solid-phase dynamic extraction (HS-SPDE) coupled with gas chromatography-mass spectrometry is automated and effortless to determine SCFAs in rat feces. The extraction procedure is performed by aspirating and discharging the headspace cyclically through a steel needle, coated with an inner polyethylene glycol sorbent. The key parameters of SPDE were optimized including coating type, incubation time and temperature, and number of extraction strokes. Besides, salting-out was conducted. Then, a method by HS-SPDE-GC-MS was established and validated. It only took 3-min incubation time, 4.5 min extraction time, and 13 min chromatographic separation in a run. The recovery, linearity, limit of quantification, and stability were evaluated. Then, the proposed method was applied to analyze rat feces including 18 rats with liver injury and 23 normal controls. Mann-Whitney U test indicated that the concentrations of six SCFAs in normal rat feces were higher than those with liver injury. This method provides a choice for fast, solvent-free, automated, and high-throughput analysis of SCFAs.

Extraction of Proteins from Microbiome of Livestocks.

The development of high throughput methods has enabled the study of hundreds of samples and metaproteomics is not the exception. However, the study of thousands of proteins of different organisms represents different challenges from the protein extraction to the bioinformatic analysis. Here, the sample preparation, protein extraction and protein purification for livestock microbiome research throughout metaproteomics are described. These methods are essential because the quality of the final protein pool depends on them. For that reason, the following workflow is a combination of different chemical and physical methods that intend an initial separation of the microbial organisms from the host cells and other organic materials, as well as the extraction of high concentrate pure samples.

Household dog fecal composting: Current issues and future directions.

Dog feces are a known source of nutrient, pathogen, and plastic pollution that can harm human and ecosystem health. Home composting may be a more environmentally sustainable method of managing dog feces and reducing this pollution. While composting is an established method for recycling animal manures into low-risk soil conditioners for food production, few studies have investigated whether household-scale compost methods can safely and effectively process dog feces for use in backyard edible gardens. A broad range of literature on in situ composting of dog feces is evaluated and compared according to scale, parameters tested, and compost methods used. Studies are analyzed based on key identified knowledge gaps: appropriate compost technologies to produce quality soil conditioner on small scales, potential for fecal pathogen disinfection in mesophilic compost conditions, and biodegradation of compostable plastic dog waste bags in home compost systems. This review also discusses how existing methods and quality standards for commercial compost can be adapted to dog fecal home composting. Priorities for future research are investigation of household-scale aerobic compost methods and potential compost amendments needed to effectively decompose dog feces and compostable plastic dog waste bags to produce a good-quality, sanitized, beneficial soil conditioner for use in home gardens. Integr Environ Assess Manag 2024;00:1-16. © 2024 The Author(s). Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

A Decrease in the Hardness of Feces with Added Glucosylceramide Extracted from Koji In Vitro-A Working Hypothesis of Health Benefits of Dietary Glucosylceramide.

Skin barrier function, prevent colon cancer, head and neck cancer, and decrease liver cholesterol. However, the mechanism of action has not yet been elucidated. In this study, we propose a new working hypothesis regarding the health benefits and functions of glucosylceramide: decreased fecal hardness. This hypothesis was verified using an in vitro hardness test. The hardness of feces supplemented with glucosylceramide was significantly lower than that of the control. Based on these results, a new working hypothesis of dietary glucosylceramide was conceived: glucosylceramide passes through the small intestine, interacts with intestinal bacteria, increases the tolerance of these bacteria toward secondary bile acids, and decreases the hardness of feces, and these factors synergistically result in in vivo effects. This hypothesis forms the basis for further studies on the health benefits and functions of dietary glucosylceramides.

Use of Deep-Amplicon Sequencing (DAS), Real-Time PCR and In Situ Hybridization to Detect H. pylori and Other Pathogenic Helicobacter Species in Feces from Children.

BACKGROUND: Detecting Helicobacter pylori in fecal samples is easier and more comfortable than invasive techniques, especially in children. Thus, the objective of the present work was to detect H. pylori in feces from children by molecular methods as an alternative for diagnostic and epidemiological studies. METHODS: Forty-five fecal samples were taken from pediatric patients who presented symptoms compatible with H. pylori infection. HpSA test, culture, real-time quantitative PCR (qPCR), fluorescence in situ hybridization (FISH), direct viable count associated with FISH (DVC-FISH), and Illumina-based deep-amplicon sequencing (DAS) were applied. RESULTS: No H. pylori colonies were isolated from the samples. qPCR analysis detected H. pylori in the feces of 24.4% of the patients. In comparison, DVC-FISH analysis showed the presence of viable H. pylori cells in 53.3% of the samples, 37% of which carried 23S rRNA mutations that confer resistance to clarithromycin. After DAS, H. pylori-specific 16S rDNA sequences were detected in 26 samples. In addition, DNA from H. hepaticus was identified in 10 samples, and H. pullorum DNA was detected in one sample. CONCLUSION: The results of this study show the presence of H. pylori, H. hepaticus, and H. pullorum in children's stools, demonstrating the coexistence of more than one Helicobacter species in the same patient. The DVC-FISH method showed the presence of viable, potentially infective H. pylori cells in a high percentage of the children's stools. These results support the idea that fecal-oral transmission is probably a common route for H. pylori and suggest possible fecal-oral transmission of other pathogenic Helicobacter species.

Paenalcaligenes faecalis sp. nov., a novel species of the family Alcaligenaceae isolated from chicken faeces.

A Gram-negative, motile, rod-shaped aerobic and alkalogenic bacterium, designated as strain YLCF04T, was isolated from chicken faeces. Its growth was optimal at 28 °C (range, 10-40 °C), pH 8 (range, pH 6-9) and in 1 % (w/v) NaCl (range, 0-10 %). It was classified to the genus Paenalcaligenes and was most closely related to Paenalcaligenes hominis CCUG 53761AT (97.5 % similarity) based on 16S rRNA gene sequence analysis. Average nucleotide identity and digital DNA-DNA hybridization values between YLCF04T and P. hominis CCUG 53761AT were 76.3 and 18.2 %, respectively. Strain YLCF04T has a genome size of 2.7 Mb with DNA G+C content of 46.3 mol%. Based on its phylogenetic, genomic, phenotypic and biochemical characteristics, strain YLCF04T represents a novel species of the genus Paenalcaligenes, for which the name Paenalcaligenes faecalis sp. nov. is proposed. The type strain is YLCF04T (=CCTCC AB 2022359T= KCTC 92789T).

Simulated Swine Digestion and Gut Microbiota Fermentation of Hydrolyzed Copra Meal.

This study aimed to compare the effects of hydrolyzed copra meal (HCM) inclusion at 1% on its in vitro digestibility and the microbiota and cecum fermentation using the gut microbiota of weaned swine, targeting microbial community and short-chain fatty acids (SCF). For this reason, three treatments were considered: control (no copra meal), 1% non-hydrolyzed copra meal (CM), and 1% HCM. Non-defatted copra meal was hydrolyzed and analyzed (reducing sugars and total carbohydrates) in our laboratory. For digestion, microbiota identification, and fermentation assays, fresh fecal samples from two weaned pigs (1 month old) were used. Three replicates of each treatment were employed. HCM was more digestible, with approximately 0.68 g of hydrolysate recovered after simulated digestion compared to 0.82 g of hydrolysate recovered from CM. This was shown by Scanning Electron Microscope (SEM) images. Also, the three swine shared the majority of microbial species identified at the phylum and family levels. There were no differences (p > 0.05) between treatments in the microbial community and SCFA during fermentation. However, higher Chao-1 and Shannon indexes were observed in CM and HCM treatments. HCM was also found to be capable of preserving Actinobacterota and Proteobacteria at the phylum level, while at the family level, both treatments may help Lactobacillaceae, Peptostreptococcaceae, Lachnospiraceae, and Ruminococcaceae survive in the long term. Also, there was a potential trend of increasing acetic acid and butyric acid in the CM and HCM treatments. While HCM shows promise in potentially modulating the gut microbiota of weaned swine, additional research is required to investigate the effects of higher doses of HCM on swine performance parameters.

Quantifying fecal and plasma short-chain fatty acids in healthy Thai individuals.

Short-chain fatty acids (SCFAs) are involved in important physiological processes such as gut health and immune response, and changes in SCFA levels can be indicative of disease. Despite the importance of SCFAs in human health and disease, reference values for fecal and plasma SCFA concentrations in healthy individuals are scarce. To address this gap in current knowledge, we developed a simple and reliable derivatization-free GC-TOFMS method for quantifying fecal and plasma SCFAs in healthy individuals. We targeted six linear- and seven branched-SCFAs, obtaining method recoveries of 73-88% and 83-134% in fecal and plasma matrices, respectively. The developed methods are simpler, faster, and more sensitive than previously published methods and are well suited for large-scale studies. Analysis of samples from 157 medically confirmed healthy individuals showed that the total SCFAs in the feces and plasma were 34.1 ± 15.3 µmol/g and 60.0 ± 45.9 µM, respectively. In fecal samples, acetic acid (Ace), propionic acid (Pro), and butanoic acid (But) were all significant, collectively accounting for 89% of the total SCFAs, whereas the only major SCFA in plasma samples was Ace, constituting of 93% of the total plasma SCFAs. There were no statistically significant differences in the total fecal and plasma SCFA concentrations between sexes or among age groups. The data revealed, however, a positive correlation for several nutrients, such as carbohydrate, fat, iron from vegetables, and water, to most of the targeted SCFAs. This is the first large-scale study to report SCFA reference intervals in the plasma and feces of healthy individuals, and thereby delivers valuable data for microbiome, metabolomics, and biomarker research.

White feces syndrome in shrimp: Comprehensive understanding of immune system responses.

White feces syndrome (WFS) is a multifactorial disease that affects global shrimp production. The diagnostic approach to identify WFS involves traditional and molecular scientific methods by examining histopathology, bioassays, PCR (polymerase chain reaction), and calorimetric estimation. The pathogenesis of WFS is closely associated with Vibrio spp., intestinal microbiota (IM) dysbiosis, and Enterocytozoon hepatopenaei (EHP). It also has caused over 10-15 % loss in the aquaculture industry and is also known to cause retardation, lethargy and slowly leading to high mortality in shrimp farms. Therefore, it is necessary to understand the molecular mechanisms processed under the association of IM dysbiosis, Vibrio spp., and EHP to analyze the impact of disease on the innate immune system of shrimp. However, only very few reviews have described the molecular pathways involved in WFS. Hence, this review aims to elucidate an in-depth analysis of molecular pathways involved in the innate immune system of shrimp and their response to pathogens. The analysis and understanding of the impact of shrimp's innate immune system on WFS would help in developing treatments to prevent the spread of disease, thereby improving the economic condition of shrimp farms worldwide.

Integrated metabolomics and serum-feces pharmacochemistry-based network pharmacology to reveal the mechanisms of an herbal prescription against ulcerative colitis.

BACKGROUND: CDD-2103 is an herbal prescription used to treat ulcerative colitis (UC). This study aimed to uncover its mechanism by integrating metabolomics and serum-feces pharmacochemistry-based network pharmacology. METHODS: A DSS-induced chronic colitis mice model was used to evaluate the anti-colitis effect of CDD-2103. Serum and feces metabolomics were conducted to identify differential metabolites and pathways. In the serum-feces pharmacochemistry study, biological samples were collected from rats treated with CDD-2103. Then, network pharmacology was utilized to predict the targets of the identified compounds. Critical genes were extracted through the above-integrated analysis. The interactions between targets, CDD-2103, and its compounds were validated through molecular docking, immunoblotting, and enzyme activity assays. RESULTS: CDD-2103 alleviated ulcerous symptoms and colonic injuries in colitis mice. Metabolomics study identified differential metabolites associated with tryptophan, glycerophospholipid, and linoleic acid metabolisms. The serum-feces pharmacochemistry study revealed twenty-three compounds, which were subjected to network pharmacology analysis. Integration of these results identified three key targets (AHR, PLA2, and PTGS2). Molecular docking showed strong affinities between the compounds and targets. PTGS2 was identified as a hub gene targeted by most CDD-2103 compounds. Immunoblotting and enzyme activity assays provided further evidence that CDD-2103 alleviates UC, potentially through its inhibitory effect on cyclooxygenase-2 (COX-2, encoded by PTGS2), with alkaloids and curcuminoids speculated as crucial anti-inflammatory compounds. CONCLUSION: This integrated strategy reveals the mechanism of CDD-2103 and provides insights for developing herbal medicine-based therapies for UC.

Investigating the biological relevance of measuring gastrointestinal cortisol metabolite levels to assess stress responses in Atlantic salmon (Salmo salar L.) after an acute stress.

Monitoring stress levels of farmed Atlantic salmon (Salmo salar) is important to ensure fish welfare and optimize farm operations. Feces could be a promising matrix for assessing stress responses in fish, based on their properties of low-invasive sampling and allowing repeated sampling over time. Meanwhile, elevated levels of cortisol metabolites (CMs) in feces indicate the increases in plasma cortisol levels (PLA) after exposure to acute stress. However, the dynamics of fecal CMs following acute stress in Atlantic salmon remain unclear. In this study, a confinement stress involving chasing and crowding was conducted to investigate the responses of gastrointestinal CMs to an acute stressor in Atlantic salmon. The post-smolts, with an average weight of 155.21 g, were sampled before and at 30 min, 1.5, 6, 12, 18, 24, 36, and 48 h after the onset of stress. Blood and gastrointestinal contents from the stomach, proximal intestine, and distal intestine of each fish were collected and subsequently analyzed, using competitive enzyme-linked immunosorbent assay (ELISA). The results demonstrated that the pre-stress level of PLA was low (4.28 ± 6.13 ng/ml) and reached a peak within 30 min following stress. The levels of CMs in gastrointestinal contents from stomach (SCMs), proximal intestine (PCMs), and distal intestine (DCMs) in pre-stress group were 0.82 ± 0.50, 18.31 ± 6.14 and 16.04 ± 6.69 ng/g, respectively. Gastrointestinal CMs increased significantly within 30 min and the peak levels of SCMs (3.51 ± 3.75 ng/g), PCMs (68.19 ± 23.71 ng/g) and DCMs (65.67 ± 23.37 ng/g) were found at 1.5 h post-stress. The significant increases in PCMs and DCMs post-stress validate the biological relevance of measuring intestinal CMs for assessing acute stress responses in Atlantic salmon. No significant difference was noted between PCMs and DCMs across all samples, suggesting that intestinal contents can serve as a suitable matrix compared with feces when measuring the responses of CMs to acute stress. The time lag between the peak of PLA levels and their reflection in the intestinal contents exceeded 1 h, indicating that using intestinal contents as a matrix to assess stress levels in fish can extend and delay the sampling window. This study highlights valuable guidance for determining the optimal times to utilize intestinal contents for measuring stress responses, providing further insights into the dynamics of fecal CM following acute stress.

Unveiling Small-Sized Plastic Particles Hidden behind Large-Sized Ones in Human Excretion and Their Potential Sources.

Health risks of microplastic exposure have drawn growing global concerns due to the widespread distribution of microplastics in the environment. However, more evidence is needed to understand the exposure characteristics of microplastics owing to the limitation of current spectrum technologies, especially the missing information on small-sized particles. In the present study, laser direct infrared spectroscopy and thermal desorption-gas chromatography-mass spectrometry combined pyrolysis using a tubular furnace (TD-GC/MS) were employed to comprehensively detect the presence of plastic particles down to 0.22 µm in human excreted samples. The results showed that polyethylene (PE), polyvinyl chloride, PE terephthalate (PET), and polypropylene dominated large-sized (>20 µm) and small-sized plastic plastics (0.22-20 µm) in feces and urine. Moreover, fragments accounted for 60.71 and 60.37% in feces and urine, respectively, representing the most pervasive shape in excretion. Surprisingly, the concentration of small-sized particles was significantly higher than that of large-sized microplastics, accounting for 56.54 and 50.07% in feces (345.58 µg/g) and urine (6.49 µg/mL). Significant positive correlations were observed between the level of plastic particles in feces and the use of plastic containers and the consumption of aquatic products (Spearman correlation analysis, p < 0.01), suggesting the potential sources for plastic particles in humans. Furthermore, it is estimated that feces was the primary excretory pathway, consisting of 94.0% of total excreted microplastics daily. This study provides novel evidence regarding small-sized plastic particles, which are predominant fractions in human excretion, increasing the knowledge of the potential hazards of omnipresent microplastics to human exposure.

Study on Changes in Gut Microbiota and Microbiability in Rabbits at Different Developmental Stages.

This study used feces from 0-day-old (36 rabbits), 10-day-old (119 rabbits), and 60-day-old (119 rabbits) offspring rabbits and their corresponding female rabbits (36 rabbits) as experimental materials. Using 16s rRNA sequencing, the study analyzed the types and changes of gut microbiota in rabbits at different growth and development stages, as well as the correlation between gut microbiota composition and the weight of 60-day-old rabbits. All experimental rabbits were placed in the same rabbit shed. Juvenile rabbits were fed solid feed at 18 days of age and weaned at 35 days of age. In addition to identifying the dominant bacterial phyla of gut microbiota in rabbits at different age stages, it was found that the abundance of Clostridium tertium and Clostridium paraputrificum in all suckling rabbits (10-day-old) was significantly higher than that in rabbits fed with whole feed (60-day-old) (p < 0.05), while the abundance of Gram-negative bacterium cTPY13 was significantly lower (p < 0.05). In addition, Fast Expected Maximum Microbial Source Tracing (FEAST) analysis showed that the contribution of female rabbits' gut microbiota to the colonization of offspring rabbits' gut microbiota was significantly higher than that of unrelated rabbits' gut microbiota (p < 0.05). The contribution of female rabbits' gut microbiota to the colonization of gut microbiota in 0-day-old rabbits was significantly higher than that to the colonization of gut microbiota in the 10- and 60-day-old rabbits (p < 0.05). Finally, the correlation between gut microbiota composition and body weight of 60-day-old rabbits was analyzed based on a mixed linear model, and six ASVs significantly affecting body weight were screened. The above results provide important theoretical and practical guidance for maintaining gut health, improving growth and development performance, and feeding formulation in rabbits.

Comparative Study of Bacterial Microbiota Differences in the Rumen and Feces of Xinjiang Brown and Holstein Cattle.

Xinjiang Brown cattle are a unique and widely distributed breed of dual-purpose cattle in the Xinjiang area of China, whose milk production performance differs from Holstein cattle. It has been known that variations in bacterial species of the gastrointestinal tract influence milk protein, fat, and lactose synthesis. However, the microbiota differences between Xinjiang Brown and Holstein cattle are less known. This study aims to compare the bacterial community composition of the rumen and feces of these two cattle breeds under the same dietary and management conditions. The 16s rRNA sequencing data and milk production of 18 Xinjiang Brown cows and 20 Holstein cows on the same farm were obtained for analysis. The results confirmed differences in milk production between Xinjiang Brown and Holstein cattle. Microbiota with different relative abundance between these two cattle breeds were identified, and their biological functions might be related to milk synthesis. This study increases the understanding of the differences in microbiota between Xinjiang Brown and Holstein cattle and might provide helpful information for microbiota composition optimization of these dairy cattle.