Fecal Pellets Research Articles

Altered intestinal barrier contributes to cognitive impairment in old mice with constipation after sevoflurane anesthesia.

Elderly patients have a high risk of developing postoperative cognitive dysfunction (POCD). Gastrointestinal disorders, such as constipation, in the elderly population may be involved in the pathogenesis of neurological disorders by promoting inflammatory responses due to a 'leaky gut'. General anesthetic sevoflurane may impair gastrointestinal function in elderly patients to trigger neurological complications following surgery. Therefore, we hypothesized that elderly individuals with gastrointestinal dysfunction may be more vulnerable to sevoflurane and consequently develop POCD. Aged mice were randomly divided into four groups: control (CTRL), CTRL+sevoflurane (Sev), slow transit constipation (STC), and STC + Sev. Mice in the STC and STC + Sev groups were intra-gastrically administrated loperamide (3 mg/kg, twice a day for 7 days) to induce a slow transit constipation (STC) model determined with fecal water content and the time of first white fecal pellet, whereas mice in the other groups received the similar volume of saline. One week later, mice in the CTRL+Sev group and STC + Sev group received 2% sevoflurane for 2 h. The gut permeability evaluated with 4-kDa fluorescein isothiocyanate (FITC)-dextran, serum cytokines, microglia density, TLR4/NF-κB signaling expression, and POCD-like behavioral changes were determined accordingly. The loperamide-induced STC mice had decreased fecal water content and prolonged time of first white fecal pellet. Sevoflurane exposure caused significantly increased gut permeability and serum cytokines, as well as the activation of microglia and the TLR4/NF-κB signaling pathway in the prefrontal cortex of the aged STC mice. Sevoflurane also caused cognitive impairment and emotional phenotype abnormality in aged STC mice. Aged STC mice were more vulnerable to sevoflurane anesthesia and consequently developed POCD-like behavioral changes. Our data suggest that gastrointestinal disorders including constipation may contribute to the development of POCD.

Transplanted ENSCs form functional connections with intestinal smooth muscle and restore colonic motility in nNOS-deficient mice

BackgroundEnteric neuropathies, which result from abnormalities of the enteric nervous system, are associated with significant morbidity and high health-care costs, but current treatments are unsatisfactory. Cell-based therapy offers an innovative approach to replace the absent or abnormal enteric neurons and thereby restore gut function.MethodsEnteric neuronal stem cells (ENSCs) were isolated from the gastrointestinal tract of Wnt1-Cre;R26tdTomato mice and generated neurospheres (NS). NS transplants were performed via injection into the mid-colon mesenchyme of nNOS−/− mouse, a model of colonic dysmotility, using either 1 (n = 12) or 3 (n = 12) injections (30 NS per injection) targeted longitudinally 1–2 mm apart. Functional outcomes were assessed up to 6 weeks later using electromyography (EMG), electrical field stimulation (EFS), optogenetics, and by measuring colorectal motility.ResultsTransplanted ENSCs formed nitrergic neurons in the nNOS−/− recipient colon. Multiple injections of ENSCs resulted in a significantly larger area of coverage compared to single injection alone and were associated with a marked improvement in colonic function, demonstrated by (1) increased colonic muscle activity by EMG recording, (2) faster rectal bead expulsion, and (3) increased fecal pellet output in vivo. Organ bath studies revealed direct neuromuscular communication by optogenetic stimulation of channelrhodopsin-expressing ENSCs and restoration of smooth muscle relaxation in response to EFS.ConclusionsThese results demonstrate that transplanted ENSCs can form effective neuromuscular connections and improve colonic motor function in a model of colonic dysmotility, and additionally reveal that multiple sites of cell delivery led to an improved response, paving the way for optimized clinical trial design.

Technogenic parent materials drive Technosols humus system formation on an industrial brownfield

The study of humus systems provides a lot of information on soil ecological functioning, such as fauna functional community, soil nutrient status, organic matter decomposition, and microbial food web. Technosols have highly heterogeneous physicochemical properties and so far, their humus systems are poorly described and the mechanisms behind their formation are still largely to be studied. In order to fill this knowledge gap, this study was conducted to get better understanding of the factors involved in the development of different Technosols humus system after brownfield rehabilitation. Our sampling strategy followed a pollution diagnostic report and allowed to cope with the spatial heterogeneity of the studied area. We studied 24 soil profiles and identified 3 different humus systems on two different rehabilitation substrates: 7 Mull, 3 Amphi and 14 Techno-moder. Our results showed that the development of zoOH horizon resulted from the nature of underlying horizons but not from the main litter type. On Techno-moder, the accumulation of organic matter in the form of fecal pellets as a zoOH horizon resulted in an increase of 130% of nitrogen on soil surface. Contrary to what was expected, we did not find a threshold of heavy metals leading to the formation of zoOH horizon, with highest lead concentration found in the A horizon of Mull systems. Transmission electron microscopy (TEM) analysis showed that neoformed organic matter is biochemically stabilized as condensed polyphenols and melanized hyphae. EDX analysis revealed that such ultrastructures are associated with Ca and Zn that may explain their stability on the Technosols surface. Development of zoOH horizon on Technosols built from coking plant by-products allowed to improve soil surface chemical and biological properties. The evolution of the humus systems as a result of vegetation succession and microbial community composition should be further studied to specify the mechanisms involved in Technosols humus system dynamics.

A Before‐After Control‐Impact experiment reveals that culling reduces the impacts of invasive deer on endangered peatlands

Abstract Invasive deer have undesirable impacts on native ecosystems. Culling is commonly used to reduce those impacts, but is expensive and sometimes controversial. It is therefore important to robustly assess how culling reduces the impacts of invasive deer. We conducted a Before‐After Control‐Impact (BACI) experiment to determine how culling affects the impacts of invasive sambar deer Cervus unicolor in an endangered alpine peatland ecosystem in south‐eastern Australia. We established two blocks, each with four 4300‐ha experimental units, in which two units were randomly assigned to a treatment of deer culling and the other two were non‐treatment areas. Sambar deer relative abundance (faecal pellet count) and three impacts (ground degradation, pugging intensity and water turbidity) in three peatland features (peatlands, natural pools and sambar deer wallows) were surveyed before and after culling was implemented. We used four metrics to quantify the culling intensity in each treatment unit: treatment versus non‐treatment, number of deer culled on each unit, deer culled within a 500‐m buffer of impact monitoring sites and local probability of use by the cullers (1‐ha grid). The effects of culling on deer abundance and impacts were estimated using Bayesian generalised linear mixed models. Our analysis revealed that the effect of culling differed between the two experimental blocks. In one block, culling reduced deer abundance and three impacts. In the other block, culling did not reduce deer abundance but reduced three impacts and increased two impacts. The effects of culling were generally stronger when culling was estimated using finer‐scale (500‐m) than coarser‐scale (experimental unit) culling metrics. Synthesis and applications. Our study provides experimental evidence that culling invasive sambar deer reduces some of their undesirable impacts on endangered peatlands. That not all impacts were reduced by culling suggests that some effects of invasive species are slow to recover or require higher culling intensities to be reversed.

Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean: a stable isotope approach

Abstract. The biological carbon pump is responsible for much of the decadal variability in the ocean carbon dioxide (CO2) sink, driving the transfer of carbon from the atmosphere to the deep ocean. A mechanistic understanding of the ecological drivers of particulate organic carbon (POC) flux is key both to the assessment of the magnitude of the ocean CO2 sink and for accurate predictions as to how this will change with changing climate. This is particularly important in the Southern Ocean, a key region for the uptake of CO2 and the supply of nutrients to the global thermocline. In this study we examine sediment-trap-derived particle fluxes and stable isotope signatures of carbon (C), nitrogen (N), and biogenic silica (BSi) at a study site in the biologically productive waters of the northern Scotia Sea in the Southern Ocean. Both deep (2000 m) and shallow (400 m) sediment traps exhibited two main peaks in POC, particulate N, and BSi flux: one in austral spring and one in summer, reflecting periods of high surface productivity. Particulate fluxes and isotopic compositions were similar in both deep and shallow sediment traps, highlighting that most remineralisation occurred in the upper 400 m of the water column. Differences in the seasonal cycles of isotopic compositions of C, N, and Si provide insights into the degree of coupling of these key nutrients. We measured increasing isotopic enrichment of POC and BSi in spring, consistent with fractionation during biological uptake. Since we observed isotopically light particulate material in the traps in summer, we suggest physically mediated replenishment of lighter isotopes of key nutrients from depth, enabling the full expression of the isotopic fractionation associated with biological uptake. The change in the nutrient and remineralisation regimes, indicated by the different isotopic compositions of the spring and summer productive periods, suggests a change in the source region of material reaching the traps and associated shifts in phytoplankton community structure. This, combined with the occurrence of advective inputs at certain times of the year, highlights the need to make synchronous measurements of physical processes to improve our ability to track changes in the source regions of sinking particulate material. We also highlight the need to conduct particle-specific (e.g. faecal pellets, phytoplankton detritus, zooplankton moults) isotopic analysis to improve the use of this tool in assessing particle composition of the sinking material and to develop our understanding of the drivers of biogeochemical fluxes.

Zooplankton derived organic matter as a food source for benthic coral

Zooplankton derived organic matter, such as fecal pellets and carcasses, may be a vital source of nutrients for benthic corals. In shallow tropical reefs, settling particles (organic matter) often reach the benthos, in contrast with deeper systems where the particles are recycled/transformed prior to reaching the benthos. Furthermore, zooplankton fecal pellets aggregate together and entrain additional organic matter, aiding in the transference of organic matter to reefs. These settling particles can be ingested by coral as a supplement to the nutrients obtained from their symbionts (zooxanthellae). Settling particles can provide essential lipids, which are produced by phytoplankton and repackaged by zooplankton, to coral reefs. Settling particles collected in the Upper Florida Keys Reef Tract were used to evaluate the role of zooplankton in the transportation of organic matter. The general chemical composition remained constant in the sediment particles, and total sediment flux generally decreased as distance from shore increased. Through lipid and stable isotope analyses, zooplankton sources were determined to contribute approximately 50% of the total lipid content in the particles with smaller contributions coming from phytoplankton, bacteria, vascular plants, and coral. The repackaging of phytoplankton derived organic matter by zooplankton demonstrates zooplankton as a primary driver of settling particles in coral reefs. The shallow water column in the reef habitat results in less recycling and remineralization of sediment particles compared to the open ocean, leading to the direct transport of organic matter from the surface to the benthos. Therefore, zooplankton abundance and composition play a vital role in determining the availability of organic matter and settling particles on coral reefs. Without zooplankton transporting organic matter throughout the water column reefs would likely decline, meaning it is imperative that zooplankton derived organic matter is considered when studying coral reefs.

Tuta absoluta-Specific DNA in Domestic and Synanthropic Vertebrate Insectivore Feces.

The ecology of greenhouse pests generally involves parasitoid or predatory insects. However, we investigated whether the leaf miner Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) is part of the diet of domestic and synanthropic vertebrate animals, such as birds, reptiles, and mammals, and that take part in an ecosystem that contains a high density of tomato greenhouses. Feces from domesticated partridges, common quails, and chickens, as well as from wild lizards were collected within tomato greenhouses, and fecal pellets from bats, swallows, common swifts, and house martins living in the vicinity of tomato greenhouses were collected outside. The efficiencies of three different DNA extraction methods were compared on bird, reptile, and mammal stool samples, and the DNA extracts were analyzed using probe real-time PCR for the presence of T. absoluta DNA. The results showed that bats fed on the pest, which was also part of the diet of several bird species: partridges and common quails kept within tomato greenhouses and swallows and common swifts living outside but in the vicinity of tomato greenhouses. In addition, fecal samples of three lizard species living near tomato crops also tested positive for T. absoluta DNA. The results suggest that aerial foraging bats and insectivorous birds are part of ecosystems that involve leaf miners and tomato greenhouses.

Berberine-containing natural-medicine with boiled peanut-OIT induces sustained peanut-tolerance associated with distinct microbiota signature.

Gut microbiota influence food allergy. We showed that the natural compound berberine reduces IgE and others reported that BBR alters gut microbiota implying a potential role for microbiota changes in BBR function. We sought to evaluate an oral Berberine-containing natural medicine with a boiled peanut oral immunotherapy (BNP) regimen as a treatment for food allergy using a murine model and to explore the correlation of treatment-induced changes in gut microbiota with therapeutic outcomes. Peanut-allergic (PA) mice, orally sensitized with roasted peanut and cholera toxin, received oral BNP or control treatments. PA mice received periodic post-therapy roasted peanut exposures. Anaphylaxis was assessed by visualization of symptoms and measurement of body temperature. Histamine and serum peanut-specific IgE levels were measured by ELISA. Splenic IgE+B cells were assessed by flow cytometry. Fecal pellets were used for sequencing of bacterial 16S rDNA by Illumina MiSeq. Sequencing data were analyzed using built-in analysis platforms. BNP treatment regimen induced long-term tolerance to peanut accompanied by profound and sustained reduction of IgE, symptom scores, plasma histamine, body temperature, and number of IgE+ B cells (p <0.001 vs Sham for all). Significant differences were observed for Firmicutes/Bacteroidetes ratio across treatment groups. Bacterial genera positively correlated with post-challenge histamine and PN-IgE included Lachnospiraceae, Ruminococcaceae, and Hydrogenanaerobacterium (all Firmicutes) while Verrucromicrobiacea. Caproiciproducens, Enterobacteriaceae, and Bacteroidales were negatively correlated. BNP is a promising regimen for food allergy treatment and its benefits in a murine model are associated with a distinct microbiota signature.

Dietary starch level affects nutrient digestibility, faecal waste production and characteristics in yellowtail kingfish (Seriola lalandi) depending on the level of fish meal replacement

Yellowtail kingfish have a poor faecal integrity when fed with pelleted diets which may be due to the presence of dietary starch. Moreover, whether dietary starch interacts with plant protein ingredients, is not known. In this study, we investigated the effect of dietary starch level, protein source and their interaction effect on faecal waste production and characteristics (visual appearance, faecal removal efficiency and particle size distribution (PSD)). Four diets were formulated according to a 2 × 2 factorial design (starch level × protein source). The effect of starch level was tested by either including 0% (LS - low starch, 4% starch) or 20% gelatinized wheat flour (HS - high starch, 20% starch). FM diets contained fish meal as protein source, whilst at FM/P diets approximately 65% of the fish meal was replaced by plant protein ingredients. Twelve tanks were stocked with 21 fish (mean initial weight 53 g) and fish performance, nutrient digestibility, faecal waste production and characteristics were evaluated over a 36-day experimental period. Both starch level and protein source affected the organic matter digestibility (p < 0.05). The effects of starch and protein source were additive regarding macro nutrient digestibility indicated by the absence of an interaction effect (p > 0.05). Growth was similar between the FM and FM/P at low starch diets (p < 0.05), but was reduced at the FM/P at high starch inclusion level (p < 0.05). The high starch and FM/P diets resulted in more faecal waste production (p < 0.05). Faecal integrity of yellowtail kingfish was adversely affected by starch inclusion. Fish receiving low starch diets excreted faecal pellets and short strings, while faecal waste collected from fish receiving high starch diets was classified as inconsistent. This was also reflected in a higher faecal removal efficiency and larger faecal PSD for fish receiving the low starch diets compared to the high starch diets (p < 0.05). No protein source or interaction effect was observed for faecal removal efficiency (p > 0.05). Consequently, lowering starch level and excluding plant protein ingredients reduced the amount of non-removed faeces by 71.1% and 30.6%, respectively. In summary, our study showed that the reduction of dietary starch offers possibilities to replace fish meal with plant protein ingredients without limiting growth performance in yellowtail kingfish. Moreover, lowering dietary starch level may have the potential to reduce solid loading in recirculating aquaculture systems for yellowtail kingfish.

Diet effects on colonic health influence the efficacy of Bin1 mAb immunotherapy for ulcerative colitis

Ulcerative colitis (UC) is an idiopathic disease of the large intestine linked to high fat-high protein diets, a dysbiotic microbiome, and a metabolome linked to diet and/or aberrant circadian rhythms associated with poor sleeping patterns. Understanding diet-affected factors that negatively influence colonic health may offer new insights into how to prevent UC and enhance the efficacy of UC immunotherapy. In this preclinical study, we found that standard or high fiber diets in mice positively influenced their colonic health, whereas a high fat-high protein diet negatively influenced colonic health, consistent with clinical findings. Animals fed a high fat/high protein diet experienced obesity and a reduced colon length, illustrating a phenotype we suggest calling peinosis [hunger-like-condition; Greek, peina: hunger; osis: condition], as marked by a lack of nutrient energy remaining in fecal pellets. Notably, a high fat/high protein diet also led to signs of muscle weakness that could not be explained fully by weight gain. In contrast, mice on a high fiber diet ranked highest compared to other diets in terms of colon length and lack of muscle weakness. That said, mice on a high fiber diet were more prone to UC and toxic responses to immunotherapy, consistent with clinical observations. Recent studies have suggested that a standard diet may be needed to support the efficacy of immunotherapeutic drugs used to prevent and treat UC. Here we observed that protection against UC by Bin1 mAb, a passive UC immunotherapy that acts by coordinately enforcing intestinal barrier function, protecting enteric neurons, and normalizing the microbiome, was associated with increased colonic levels of healthful short-chain fatty acids (SCFA), particularly butyric acid and propionic acid, which help enforce intestinal barrier function. This work offers a preclinical platform to investigate how diet affects UC immunotherapy and the potential of dietary SCFA supplements to enhance it. Further, it suggests that the beneficial effects of passive immunotherapy by Bin1 mAb in UC treatment may be mediated to some extent by promoting increased levels of healthful SCFA.

The potential of Lecane rotifers in microplastics removal

Dealing with hard-to-degrade plastics pollution of terrestrial and aquatic environments is one of the most urgent problems of the modern world. The smallest fraction (<5 mm) called micro-plastics (MP) has been found everywhere from ice in Greenland, streams, rivers, soil and even in the human placenta. The goal of our research was to assess the ability of rotifers Lecane inermis to remove micro-plastics suspended in the water column. In the experiments we investigated specific interactions between MP, biofilm and rotifers specialized in feeding on biofilm. We hypothesized that MP adhere to the biofilm and after ingestion by rotifers could be extracted from the water in the form of compact conglomerates excreted with fecal pellets. In these experiments, we demonstrated that: (i) the rotifers preferentially ingest microplastics embedded in biofilm, (ii) the presence of microplastics does not affect growth and fecundity of rotifers, and (iii) that MP aggregation is significantly improved by the presence of biofilm, additionally enhanced in the presence of rotifers. Our findings will help to understand the role of micro-grazers, such as L. inermis feeding on biofilm, in the fate of MP in nature. In the longer term, our results could help to develop biotechnological tools for MP removal from the aquatic environment.

Deconvolving mechanisms of particle flux attenuation using nitrogen isotope analyses of amino acids

AbstractParticulate organic matter settling out of the euphotic zone is a major sink for atmospheric carbon dioxide and serves as a primary food source to mesopelagic food webs. Degradation of this organic matter encompasses a suite of mechanisms that attenuate flux, including heterotrophic metabolic processes of microbes and metazoans. The relative contributions of microbial and metazoan heterotrophy to flux attenuation, however, have been difficult to determine. We present results of compound specific nitrogen isotope analysis of amino acids of sinking particles from sediment traps and size‐fractionated particles from in situ filtration between the surface and 500 m at Ocean Station Papa, collected during NASA EXPORTS (EXport Processes in the Ocean from RemoTe Sensing). With increasing depth, we observe: (1) that, based on the δ15N values of threonine, fecal pellets dominate the sinking particle flux and that attenuation of downward particle flux occurs largely via disaggregation in the upper mesopelagic; (2) an increasing trophic position of particles in the upper water column, reflecting increasing heterotrophic contributions to the nitrogen pool and the loss of particles via remineralization; and (3) increasing δ15N values of source amino acids in submicron and small (1–6 μm) particles, reflecting microbial particle solubilization. We further employ a Bayesian mixing model to estimate the relative proportions of fecal pellets, phytodetritus, and microbially degraded material in particles and compare these results and our interpretations of flux attenuation mechanisms to other, independent methods used during EXPORTS.

Effects of vegetation and topography on snowshoe hare relative abundance at the southern range periphery

AbstractThe conservation of snowshoe hares (Lepus americanus) and their habitat is a major focus in the American West, largely because of their importance to the federally threatened Canada lynx (Lynx canadensis). Understanding the habitat relationships of snowshoe hare populations at the southern periphery of their distribution is particularly important because a warming climate is reducing the mesic forests and persistent snow cover they require. Using fecal pellet density as an index, we examined the factors influencing snowshoe hare relative abundance at 2 study areas in the Southern Rocky Mountains by comparing suites of candidate models containing fine‐scale vegetation and topographical covariates. The Birdseye Gulch study area is within an extensive area containing high elevations, mesic forests, and Canada lynx occurrence. The Three Peaks study area consists of an isolated zone of high elevation and mesic forests surrounded by inadequate habitat and is absent of Canada lynx. Mean hare pellet density in Birdseye Gulch was 2.48 pellets ± 0.46 (SE)/ (n = 49) versus 2.24 ± 0.48/m2 (n = 57) at Three Peaks. Models containing fine‐scale vegetation variables best explained pellet densities at Birdseye Gulch. Pellet densities at Three Peaks were best explained by topographical variables, with much unexplained variation within all models. The differing trends in these areas may be due to the absence of resident Canada lynx at Three Peaks and differences in topography between the areas. Our results indicate that snowshoe hare populations can persist in the type of isolated habitat that is increasingly common at the southern range periphery; however, the use of vegetation management to conserve habitat in these areas may be less effective because of weaker associations with vegetation structure.

Sources of Polycyclic Aromatic Hydrocarbons in Fecal Pellets of a Marphysa Species (Annelida: Eunicidae) in the Yoro Tidal Flat, Japan.

The fecal pellets of Marphysa sp. E sensu Abe et al. (2019) (Annelida, Eunicidae) living in the Yoro tidal flat (Ichihara, Chiba, Japan) contain high levels of polycyclic aromatic hydrocarbons (PAHs), and the concentrations rapidly decrease over time. To investigate the origin of the high-concentration PAHs in the fecal pellets and food sources of the worms, the PAH concentrations, carbon and nitrogen stable isotope ratios (δ13C and δ15N), total organic carbon, and total nitrogen for two types of sediment (sands and reduced muds), fecal pellets, and the body of the worms were determined. The PAH concentrations and chemical properties of the fecal pellets were similar to those of the reduced muds (20-30 cm sediment depth). The δ13C, δ15N, and C/N values of reduced muds were the same as the typical values of terrestrial C3 plants, suggesting that reduced muds were derived from terrestrial plants. These data indicated that the worms selectively take up reduced muds containing high levels of PAHs. The δ13C and δ15N values of the worm bodies indicated that the worms did not use the organic carbon derived from terrestrial C3 plants as primary nutrition. Taking into consideration their selective uptake of reduced muds, excretion, and subsequent rapid decrease of PAHs in the fecal pellets, the worms could contribute to the remediation of chemical pollutants in the tidal flat sediments.

Habitat selection of endangered Amami rabbits on Tokuno-Shima Island in Japan as assessed by counting fecal pellet groups on roads

Abstract Understanding the habitat selection patterns of animals is important for developing land-use plans for species conservation. The death of endangered Amami rabbits (Pentalagus furnessi), which are found only on two islands in Japan, due to vehicle collisions is a serious problem. To reduce the incidence of road kill and conserve the population of Amami rabbits, factors that contribute to the species’ proximity to roads need to be examined. We examined the habitat selection of Amami rabbits by counting their fecal pellet groups on roads on Tokuno-Shima Island, Japan. We obtained 101 presence observations, which revealed that Amami rabbits select areas close to natural forests, farmlands, and rivers and areas with steeper slopes. The selection by the species of natural forest and farmland is likely due to the availability of herbaceous and shrub plants at forest edges and crops and weeds in farmland for foraging. The high utilization of steep-sloping terrain could help Amami rabbits minimize predation risk from the native habu pit viper (Protobothrops flavoviridis). The frequent utilization of forest edges and farmland by Amami rabbits increases their risk of becoming road kill and the risk of crop damage, which are serious problems on the island. To prevent Amami rabbits from crossing roads and reduce crop damage, fences should be constructed particularly in high-rabbit-density areas, and should not facilitate population fragmentation of the species.

Our good neighbors: Understanding ecosystem services provided by insectivorous bats in Rwanda.

Bats are prodigious consumers of agricultural and forest pests, and are, therefore, a natural asset for agricultural productivity, suppressing populations of such pests. This study provides baseline information of diet of 143 bats belonging to eight insectivorous bat species from agricultural areas of Rwanda while evaluating the effectiveness of bats as pest suppressors. Using DNA metabarcoding to analyze bat fecal pellets, 85 different insect species were detected, with 60% (n = 65), 64% (n = 11) and 78% (n = 9) found to be agricultural pests from eastern, northern and western regions, respectively. Given the high percentages of agricultural pests detected, we submit that Rwandan insectivorous bats have the capacity for biocontrol of agricultural pests. Rwandan bat populations should be protected and promoted since they may foster higher crop yields and sustainable livelihoods.

Seasonal and spatial variability of vertical particle flux along the Beagle Channel (Southern Patagonia)

The Beagle Channel is a 300-km long passage connecting the Pacific and Atlantic Oceans at ~55° S, where glaciers and river streams meet subantarctic waters. Here we present the first evaluation of downward fluxes and composition of particulate matter in the channel. Settling particle fluxes were collected by sequential sediment traps deployed in two contrasting areas: one in the western part of the channel, corresponding to an early post-glacial environment (site A) and a second, fully deglaciated, river-dominated environment (site B) in the eastern part. In early summer, fluxes at both sites are driven by organic matter produced in spring, with peak organic carbon fluxes of 289 and 413 mg C m−2 d−1 at sites A and B, respectively (C:N ratios of 7.3 and 6.3, respectively). During winter, the fluxes of fecal pellets, particulate organic carbon (POC) and particulate nitrogen (PON) were at their minimum. At site A (integrated annual POC flux of 74 g C m−2 yr−1), seasonality was weak and the flux was driven by ballast material (>95% of total particle flux) of glacial origin year-around, which also promotes the POC export. According to isotopic and taxonomic analyses performed at site A, the low seasonality in the organic component of the flux appears to be mainly related to autochthonous production of nano- and picophytoplankton during autumn and winter, later replaced by microphytoplankton fluxes during spring and summer. At site B, ballast material accounted for <60% of total mass flux and the POC flux showed a marked seasonality with a well-defined maximum after the spring phytoplankton bloom. Regarding the contribution of zooplankton, fecal pellets of appendicularians dominated at the western sector of the channel (site A) while Munida gregaria pellets dominated the flux at the eastern site (site B). This work is a contribution to ongoing efforts to unveil the physical and biogeochemical variables driving the biological carbon pump and the land-sea connections in this high-latitude ecosystem threatened by climate change.

239-LB: Erythropoietin Alters Fat Mass and Gut Microbial Composition

Erythropoietin is an essential hormone for promoting erythropoiesis. Erythropoietin also stimulates angiogenesis, affects fat metabolism and can promote survival in cells expressing erythropoietin receptor. Here, we found that erythropoietin reduces fat mass, decreasing epididymis fat pad mass and subcutaneous fat pad mass of Tg6 male mice that express high transgenic erythropoietin. However, how erythropoietin activity in the gut improves fat mass and glucose metabolism is not known. Tg6 male mice have increased microvilli height and intestine length. High erythropoietin changes the gut microbiota by altering β-diversity that includes increasing the abundance of Bifidobacterium and reducing the Lactobacillaceae in Tg6 male mice. EPO decreased lactate dehydrogenase (LDHa) expression and reduces lactate production from intestinal endothelial cells that affects the gut microbiota components. Accompanying the altered microbiome are increased intestinal short-chain fatty acid levels that can affect fat metabolism. Transplantation of fecal pellet from Tg6 male mice into antibiotic treated male wild type mice reduces fat mass and mimics the lean phenotype of Tg6 mice. Conversely, transplanting feces from WT mice into Tg6 mice resulted in increased fat mass in Tg6 mice. Wild type male mice treated with erythropoietin show improved glucose tolerance and also exhibit increased intestine length and changes in the gut microbiota with increase in Bifidobacterium and decrease in Lactobacillaceae, analogous to changes in Tg6 male mice. Our results on erythropoietin activity in the gut to change gut morphology and remodel the gut microbiome provide a new mechanism by which EPO affects fat metabolism. Key words: EPO; EPOR; gut microbial composition; fat mass Disclosure W. Yin: None. H. Rogers: None. X. An: None. M. Gassmann: None. C. T. Noguchi: None.

Acceleration of postoperative recovery with brief intraoperative vagal nerve stimulation mediated via the autonomic mechanism.

Postoperative recovery is largely dependent on the restoration of gastrointestinal motility. The aim of this study was to investigate the effects and mechanisms of intraoperative vagus nerve stimulation (iVNS) on postoperative recovery from abdominal surgery in rats. The Nissen fundoplication surgery was performed on two groups of rats: sham-iVNS group and iVNS group (VNS was performed during surgery). Animal's behavior, eating, drinking and feces' conditions were monitored at specific postoperative days. Gastric slow waves (GSWs) and electrocardiogram (ECG) were recorded; blood samples were collected for the assessment of inflammatory cytokines. (1) iVNS shortened initiate times to water and food intake (p = 0.004) and increased the number of fecal pellets (p < 0.05, vs. sham-iVNS) and the percentage of water content in fecal pellets (p < 0.05). (2) iVNS improved gastric pace-making activity at 6 h after surgery reflected as a higher percentage of normal slow waves (p = 0.015, vs. sham-iVNS). (3) iVNS suppressed inflammatory cytokines at 24 h after surgery compared to sham-iVNS (TNF-α: p = 0.001; IL-1β: p = 0.037; IL-6: p = 0.002). (4) iVNS increased vagal tone compared to sham-iVNS group at 6 h and 24 h after the surgery (p < 0.05). Increased vagal tone was correlated with a faster postoperative recovery to start water and food intake. Brief iVNS accelerates postoperative recovery by ameliorating postoperative animal behaviors, improving gastrointestinal motility and inhibiting inflammatory cytokines mediated via the enhanced vagal tone.

Metabolic Disturbances in the Gut-brain Axis of a Mouse Model of MPTP-induced Parkinsonism Evaluated by Nuclear Magnetic Resonance

Parkinson's Disease is a synucleinopathy that primarily affects the dopaminergic cells of the central nervous system, leading to motor and gastrointestinal disturbances. However, intestinal peripheral neurons undergo a similar neurodegeneration process, marked by α-synuclein (αSyn) accumulation and loss of mitochondrial homeostasis. We investigated the metabolic alterations in different biometrics that compose the gut-brain axis (blood, brain, large intestine, and feces) in an MPTP-induced mouse model of sporadic Parkinson's Disease. Animals received escalating administration of MPTP. Tissues and fecal pellets were collected, and the metabolites were identified through the untargeted Nuclear Magnetic Resonance spectroscopic (1H NMR) technique. We found differences in many metabolites from all the tissues evaluated. The differential expression of metabolites in these samples mainly reflects inflammatory aspects, cytotoxicity, and mitochondrial impairment (oxidative stress and energy metabolism) in the animal model used. The direct evaluation of fecal metabolites revealed changes in several classes of metabolites. This data reinforces previous studies showing that Parkinson’s disease is associated with metabolic perturbation not only in brain-related tissues, but also in periphery structures such as the gut. In addition, the evaluation of the microbiome and metabolites from gut and feces emerge as promising sources of information for understanding the evolution and progression of sporadic Parkinson's Disease.