Fecal Particles Research Articles

Addressing underestimation of waterborne disease risks due to fecal indicator bacteria bound in aggregates.

This study aims to identify and address significant limitations in current culture-based regulatory methods used for monitoring microbiological water quality. Specifically, these methods' inability to distinguish between planktonic forms and aggregates containing higher bacterial loads and associated pathogens may lead to a severe underestimation of exposure risks, with critical public health implications. We employed a novel methodology combining size fractionation with ALERT, an automated rapid method for comprehensive quantification of culturable fecal indicator bacteria (FIB). Our findings reveal a substantial and widespread presence of aggregate-bound indicator bacteria across various water matrices and geographical locations. Comprehensive bacterial counts consistently exceeded those obtained by traditional methods by significant multiples, such as an average of 3.4×at the Seine River 2024 Olympic venue, and occasionally up to 100×in irrigation canals and wastewater plant effluent. These results, supported by microscopic and molecular analyses, underscore a systematic bias in global water safety regulatory frameworks. Our research demonstrates the inadequacy of traditional culture-based techniques in assessing microbiological risks posed by aggregate-bound FIB and associated pathogens, particularly in water matrices affected by FIB-rich fecal particles from recent sewer overflows or sediment, which can carry higher infectious risks. Incorporating comprehensive FIB analysis techniques, including molecular methods and rapid culture-based approaches as shown in this study, offers a promising and effective solution to these risk assessment limitations.

Impact of a two-stage rumen cannulation on the health and rumen function of six lactating dairy cows.

To determine the impact of a two-stage rumen cannulation on the health and rumen function of lactating dairy cows. Experimental study. Six lactating Holstein cows. We performed a two-stage rumen cannulation in six Holstein cows that were 49 ± 11 days in milk. The following clinical health parameters and digestion-associated variables were analyzed on seven measurement days, from before the first surgery until 28 days after the second surgery: body temperature, heart rate, respiratory rate, pain score, rumen fill score, fecal score, wet sieving, auscultation and palpation of the rumen, bodyweight, body condition score, and activity. The pain score of the cows was constantly zero. Similarly, the body temperature and respiratory rate remained within physiological ranges, whereas the heart rate was slightly higher immediately after the second surgery. No differences were observed in rumen fill (2.00-2.67; p = .10) and fecal consistency scores (2.17-2.67; p = .42). The fecal particle size distribution showed negligible differences. The cows lost approximately 43 kg of bodyweight during the experiment (p < .01), which was reflected in a 0.5-point body condition score loss (p < .01). A temporary minimal negative effect of a two-stage rumenostomy on the health and body condition of early lactating Holstein cows was observed, whereas digestion was unaffected. Considering the limited sample size, further studies are required to substantiate these findings. Given that animals are appropriately medically managed, experimental rumenostomy of lactating dairy cows may not compromise their health or rumen function.

Dietary starch, non-starch polysaccharides and their interactions affect nutrient digestibility, faecal waste production and characteristics differentially in three salmonids: Rainbow trout, Atlantic salmon and Arctic charr

Waste management has emerged as a critical issue in aquaculture. In this study, we examined the impact of dietary starch and non-starch polysaccharides (NSP) content on nutrient digestibility, faecal waste production, faecal removal efficiency and the faecal characteristics in three salmonid species, namely rainbow trout (Oncorhynchus mykiss), Atlantic salmon (Salmo salar) and Arctic charr (Salvelinus alpinus). Four diets were formulated according to a 2 × 2 factorial design. The first factor, starch, was tested by including 0% gelatinised wheat flour (low starch) or 20% gelatinised wheat flour (high starch) in a plant-based basal diet. The second factor, NSP, was tested by adding 0% NSP source (low NSP) or 10% NSP source (high NSP). High NSP level was achieved by adding an equal mixture of soya hull (5%) and wheat bran (5%). Diets were tested in triplicates for each species and feeding was done restrictively. Experimental duration was 42 days for rainbow trout and Atlantic salmon and 49 days for Arctic charr. Among the three species investigated, Arctic charr had the lowest digestibility values for most nutrients, whereas rainbow trout and Atlantic salmon values were comparable. High starch level in the diet reduced the macronutrient (protein, fat and ash) digestibility in all three species. High starch and high NSP levels in the diet increased faecal waste production, with the effect being more pronounced for the NSP content of the diet. High dietary starch levels increased the proportion of smaller-sized particles, while high NSP content increased the ability of faecal particles to withstand mechanical stress. The high starch level in the diet lowered faecal removal efficiency but increased by high NSP content. The highest and lowest faecal removal efficiency was recorded for Atlantic salmon and Arctic charr, respectively. The amount of non-removed faeces accumulating in the system was increased by the high starch levels in rainbow trout and Atlantic salmon but remained unaffected by the NSP content of the diet across the species. No interaction effect between starch and NSP content of diets was observed for faecal removal efficiency and non-removed faeces. Among the three species investigated, Arctic charr had the maximum amount of non-removed faeces per kilogram of dry matter feed.

Faecal particle size distribution in relation to forage type and digestibility in horses: preliminary results

The study aimed to explore the connection between horses’ total tract apparent dry matter digestibility (ttaDMD) of various roughages and faecal particle size (FPS), to develop a tool to rank roughage digestibility. Six horses, varying in size and breed, were fed six distinct roughages (four cuts of fescue, perennial ryegrass/clover mix, and straw). Each feeding period lasted 16 days, with a 14-day adaptation phase. Faecal samples underwent wet sieving analysis. Roughage chemical composition was evaluated using NIRs. Faecal and roughage acid insoluble ash content were used to estimate ttaDMD and FPS was determined by wet sieving using a set of 6 sieves of different mesh sizes (S1 to S6; 6.50, 4.50, 2.36, 1.18, 0.6 and 0.15 mm respectively). The effects of roughage ttaDMD on FPS across sieves were analysed using GLM. Linear regressions and correlations were performed between faecal residues on each sieve and mesh sizes of the sieves to create a mathematical tool to rank ttaDMD based on FPS distribution. Increased ttaDMD was associated with larger FPS, with perennial ryegrass/clover mix (ttaDMD 74.44%) and straw (ttaDMD 44.57%) resulting in smaller and larger faecal particles respectively. Correlations were observed between ttaDMD, S1 and S2 (r = 0.639 and 0.668; p ≤ 0.001). The angular coefficient of the linear function between faecal residues on each sieve support the idea to estimate roughages digestibility from FPS (R2 = 0.4153). Consequently, determining faecal residues across sieves of varying mesh sizes could serve as an indirect method for ranking roughages digestibility.

Bio-efficacy of some plant extracts as a new acaricide for control of the house dust and stored product mites

ABSTRACT House mites frequently trigger allergic conditions. Although conventional treatments are effective, they can result in drug resistance and pose risks to the environment, human health, and non-target organisms. Therefore, this study evaluates new botanical extracts for their biological activities against Dermatophagoides pteronyssinus (Trouessart 1897; Pyroglyphidae), D. farinae (Hughes 1961; Pyroglyphidae), and Tyrophagus putrescentiae (Schrank 1781; Acaridae), not only to control them but also to reduce their allergens (dead bodies and faecal particles) by keeping them away. It is noteworthy that of these plants, Allium cepa L. (Alliaceae) and Solanum melongena L. (Solanaceae) peel extracts, as well as leaves of Hibiscus sabdariffa L. (Malvaceae), were tested for the first time in the present study as new bioacaricides, while Piper nigrum L. (Piperaceae) and H. sabdariffa leaves proved to be new botanical repellents for these mite species. Based on LC50 values, A. cepa, Beta vulgaris, and S. melongena extracts had the most potent toxic effects on these mite species, while extracts of Aloe vera, Capsicum annum, and P. nigrum had the strongest repellent activity against them at the highest concentration. These natural plant extracts may have valuable potential as new acaricidal products.

Quantitative Risk Assessment of Wind-Supported Transmission of Highly Pathogenic Avian Influenza Virus to Dutch Poultry Farms via Fecal Particles from Infected Wild Birds in the Environment.

A quantitative microbial risk assessment model was developed to estimate the probability that the aerosolization of fecal droppings from wild birds in the vicinity of poultry farms would result in the infection of indoor-housed poultry with highly pathogenic avian influenza virus (HPAIv) in the Netherlands. Model input parameters were sourced from the scientific literature and experimental data. The availability of data was diverse across input parameters, and especially parameters on the aerosolization of fecal droppings, survival of HPAIv and dispersal of aerosols were uncertain. Model results indicated that the daily probability of infection of a single poultry farm is very low, with a median value of 7.5 × 10-9. Accounting for the total number of poultry farms and the length of the bird-flu season, the median overall probability of at least one HPAIv-infected poultry farm during the bird-flu season is 2.2 × 10-3 (approximately once every 455 years). This is an overall estimate, averaged over different farm types, virus strains and wild bird species, and results indicate that uncertainty is relatively high. Based on these model results, we conclude that it is unlikely that this introduction route plays an important role in the occurrence of HPAIv outbreaks in indoor-housed poultry.

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.

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 implicationsThe 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.

Effect of odontoplasty on intake, nutrient digestibility, and intake time of tifton hay in ponies

We aimed to evaluate the effects of dental correction on voluntary nutrient intake, time of intake, apparent digestibility and fecal particle size in Brazilian ponies. Twelve mares, with no history of previous dental treatments, housed in individual pens and fed a diet based on tifton 85 were used. The study comprised two consecutive experimental phases, pre and post dental treatment. Each phase consisted of 15 days for adaptation to the pen and treatment and 5 days for data collection, totaling 20 days. To calculate nutrient intake and digestibility coefficients, samples of diets, leftovers, and feces were analyzed for dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), crude fat (CF), mineral matter (MM), organic matter (OM), and non-fiber carbohydrates (NFC). Food intake time was recorded using a digital video recorder. Fecal particles were analyzed by wet sieving. Dental correction did not influence the intake of DM, CP, NDF, CF, and OM by the animals. However, there was an increase in NFC intake from 0.12 kg to 0.14 kg and in food intake time from 654.50 ± 138.98 to 774.95 ± 167.14. There was a decrease in the digestibility of CP from 0.08 kg to 0.04 kg and an increase in the digestibility of NDF from 0.65 kg to 0.82 kg. Although odontoplasty increased the time of hay intake and the digestibility of the fibrous fractions of the feed of ponies, it did not influence the intake of nutrients and the size of the fecal particles.

Integration of network pharmacology and experimental verifications reveals the Bian-Se-Tong mixture can alleviate constipation in STC rats by reducing apoptosis of Cajal cells via activating PI3K-Akt signaling pathway

Bian-Se-Tong mixture (BSTM) is an optimized formulation based on the classical prescription “Zhizhu pill”, which is widely used in the clinical treatment of slow-transit constipation (STC). The potential molecular mechanism of BSTM therapy for STC was investigated by network pharmacology prediction combined with animal experiments. The active components of BSTM were screened via the TCMSP platform. The GeneCards, OMIM and DrugBank databases were used to search for STC targets. With the help of the Biogenet tool, a protein interaction network between drugs and disease targets was constructed, and the intersection network of the two was extracted to obtain the key targets of BSTM in the treatment of STC. GO and KEGG enrichment analyses of key targets were carried out with Metascape. Loperamide hydrochloride was used to establish an STC rat model, and the key targets and related pathways were preliminarily verified. The important signaling pathways included the PI3K-Akt, MAPK, IL-17, cAMP, and cell cycle signaling pathways. The experimental results showed that BSTM treatment increased the body weight of STC rats and increased the fecal particle number, fecal water content and intestinal carbon ink promotion rate within 24 h. Further pathological changes in the colon of the rats were also observed. In-depth mechanistic studies have shown that BSTM can significantly reduce the apoptosis of intestinal Cajal cells, downregulate the expression of Bax and c-Caspase 3, upregulate the expression of Bcl-2 and c-kit, and promote the phosphorylation of AKT. The results showed that BSTM can significantly relieve constipation in STC rats via a mechanism related to activating the PI3K-Akt signaling pathway and improving Cajal cell apoptosis.

Practical implications of lowering dietary starch content on waste management in recirculating aquaculture systems operated with drum filtration or sedimentation in yellowtail kingfish (Seriola lalandi)

Dietary starch negatively affects faecal removal efficiency by sedimentation in yellowtail kingfish (Seriola lalandi). In general, research on waste management in recirculating aquaculture systems (RAS) is conducted on solid removal by sedimentation. However, most commercial farms operate with screen filtration. Compared to sedimentation, where the efficiency of removed faeces depends on faecal particle size and density, faecal removal by screen filtration is based on particle size and its stability. Accordingly, this study investigated the effect of dietary starch level on solid waste loading and faecal removal efficiency by different solid removal techniques, namely drum filtration and sedimentation. This was tested in six individual operating RAS over an experimental period of 47 days. The experimental period was divided into two consecutive phases (Phase 1 and Phase 2). During Phase 1 (42 days), the six independent RAS were operated with drum filtration, while during Phase 2 (5 days), the same RAS were operated with sedimentation. Two experimental diets, one with low starch (LS; 0% gelatinized wheat flour inclusion) and one with high starch (HS; 20% gelatinized wheat flour inclusion) levels, were formulated to test the effect of dietary starch level. HS diet negatively affected the apparent faecal waste production, apparent faecal removal efficiency by sedimentation, and the apparent amount of non-removed faeces. No dietary treatment effect was observed when RAS were operated with drum filtration. However, to achieve similar apparent faecal removal efficiency by drum filtration, the backwash frequency was on average 110% higher at HS RAS compared to LS RAS. This is likely to be related to both an increased apparent faecal waste production and the tendency for increased clogging of the drum filter screen at HS RAS throughout the experimental period. Overall, lowering dietary starch level has the potential to reduce solid loading (sedimentation) or improve drum filter performance (water usage) in RAS for yellowtail kingfish.

Interplay between particle size and microbial ecology in the gut microbiome.

Physical particles can serve as critical abiotic factors that structure the ecology of microbial communities. For non-human vertebrate gut microbiomes, fecal particle size (FPS) has been known to be shaped by chewing efficiency and diet. However, little is known about what drives FPS in the human gut. Here, we analyzed FPS by laser diffraction across a total of 76 individuals and found FPS to be strongly individualized. Contrary to our initial hypothesis, a behavioral intervention with 41 volunteers designed to increase chewing efficiency did not impact FPS. Dietary patterns could also not be associated with FPS. Instead, we found evidence that human and mouse gut microbiomes shaped FPS. Fecal samples from germ-free and antibiotic-treated mice exhibited increased FPS relative to colonized mice. In humans, markers of longer transit time were correlated with smaller FPS. Gut microbiota diversity and composition were also associated with FPS. Finally, ex vivo culture experiments using human fecal microbiota from distinct donors showed that differences in microbiota community composition can drive variation in particle size. Together, our results support an ecological model in which the human gut microbiome plays a key role in reducing the size of food particles during digestion. This finding has important implications for our understanding of energy extraction and subsequent uptake in gastrointestinal tract. FPS may therefore be viewed as an informative functional readout, providing new insights into the metabolic state of the gut microbiome.

Uncovering the impact of sea mud-containing diet on fecal fragmentation and its potential environmental risks in recirculating aquaculture system of Apostichopus japonicus

A deep understanding of fecal characteristics and fragmentation mechanism is crucial for effectively removing the solid particles in recirculating aquaculture system (RAS) of Apostichopus japonicus, however, the underlying mechanism was still unclear. This study investigated the effects of diet with different sea mud addition on the fecal characteristics and microbiota. The experimental diet were the mixture of commercial feed and sea mud at the ratio of 1:1, 1:2, 1:3, 1:4 and 1:5, in which the added amount of sea mud was 50 %, 66.67 %, 75 %, 80 % and 83.33 %, respectively. The results showed that, at the end of aquaculture, Dx(50) in group 1:3 was the highest, while group 1:5 was the lowest. The fecal particle size distribution (PSD) appeared multi peak with the increase of sea mud addition. At the end of aquaculture, group 1:3 possessed the highest microbial diversity. BugBase phenotype prediction found that the microbial phenotypes in group 1:4 were mainly involved in functional expression, such as stress tolerance and potential pathogenicity. Significant correlation between environmental factors and fecal microbiota were found. Correlation analysis between fecal particle size and fecal microbiota showed that the abundance of pathogenic bacteria such as Vibrio, was higher on fecal particles with dispersed PSD. And NH4+-N removal rate decreased when Dx(10) decreased and Dx(90) increased. Thus, it was recommended that sea mud addition in diet should be <75 % in A. japonicus RAS.

Improved fecal particle size profile in Rainbow Trout fed feeds containing different ratios of animal meal and plant protein concentrates: Effect on nitrogen and phosphorus partitioning

AbstractObjectiveOur objective in this study was to evaluate the effects of fish meal replacement with plant and animal protein sources accompanied by a feed binder on nitrogen (N) and phosphorus (P) partitioning in Rainbow Trout Oncorhynchus mykiss feces.MethodsThree diets in which fish meal (FM; reference diet) was completely replaced with a combination of poultry meal (PM), corn protein concentrate, soy protein concentrate, and guar gum (binder) were evaluated to determine the portioning of N and P in fecal particle size‐classes (fines: &lt;0.6 mm; mid‐size particles: 0.6–1.2 mm; large particles: &gt;1.2 mm) and compared with a commercial feed for Rainbow Trout. Feces were evaluated for particle size composition and the content of total N (TN) and total P (TP) in each size‐class.ResultThere was a significant difference in fecal particle size composition for trout fed the experimental diets compared to those given the commercial feed. Fish that received the four experimental diets produced feces with approximately 43% large particles and 24% fines compared to 6% and 67% for trout that were fed the commercial diet. The TN in feces was significantly higher for trout that were fed the FM diet (3.84%) than for trout fed the FM‐free diets, and TN also declined linearly (2.68, 1.91, and 1.59%) as the content of PM was replaced with plant‐based protein. A diet × particle size interaction effect on fecal N content was also observed in which a significant increase in TN from large particles compared with fines occurred for the experimental FM diet, but there was little difference between size‐classes for the non‐FM‐based feeds. The feces of trout fed the FM diet contained more TP (100,007 μg/g) than the feces of fish receiving the FM‐free diets (46,751–72,659 μg/g), likely due to higher dietary P content of FM. However, TP concentrations followed a similar trend as TN in the FM‐free feeds, declining as the proportion of plant protein sources increased (and as PM decreased). The large fecal particles (72,235 μg/g) contained more TP than the mid‐size particles (68,926 μg/g) or fines (61,974 μg/g), which could be due to leaching in the latter two particle size‐classes, as the potential for solubility likely increased as particle size decreased.ConclusionThese findings may have important implications for improving the fecal particle size profile for sedimentation and removal of regulated nutrients through the formulation of Rainbow Trout feeds in replacement of FM with plant protein.

HantaNet: A New MicrobeTrace Application for Hantavirus Classification, Genomic Surveillance, Epidemiology and Outbreak Investigations.

Hantaviruses zoonotically infect humans worldwide with pathogenic consequences and are mainly spread by rodents that shed aerosolized virus particles in urine and feces. Bioinformatics methods for hantavirus diagnostics, genomic surveillance and epidemiology are currently lacking a comprehensive approach for data sharing, integration, visualization, analytics and reporting. With the possibility of hantavirus cases going undetected and spreading over international borders, a significant reporting delay can miss linked transmission events and impedes timely, targeted public health interventions. To overcome these challenges, we built HantaNet, a standalone visualization engine for hantavirus genomes that facilitates viral surveillance and classification for early outbreak detection and response. HantaNet is powered by MicrobeTrace, a browser-based multitool originally developed at the Centers for Disease Control and Prevention (CDC) to visualize HIV clusters and transmission networks. HantaNet integrates coding gene sequences and standardized metadata from hantavirus reference genomes into three separate gene modules for dashboard visualization of phylogenetic trees, viral strain clusters for classification, epidemiological networks and spatiotemporal analysis. We used 85 hantavirus reference datasets from GenBank to validate HantaNet as a classification and enhanced visualization tool, and as a public repository to download standardized sequence data and metadata for building analytic datasets. HantaNet is a model on how to deploy MicrobeTrace-specific tools to advance pathogen surveillance, epidemiology and public health globally.

Dental Correction Does Not Alter Postprandial Nutrient Concentrations in Healthy Mares

Irregular wear patterns are theorized to cause poor feed digestion and weight loss in the horse. The objective of this study was to test the hypothesis that dental correction would increase postprandial nutrient concentrations and reduce fecal particle size (FPS) in clinically healthy mares. The study was conducted in 16 mares of mature age (4–17) who had not received dental care in the previous year. A diet consisting of ad libitum Coastal Bermudagrass hay and 1.36 kg of a pelleted feed was fed daily prior to and during the study. Eight mares received dental work and eight served as untreated controls. While the consumption of a concentrate meal increased plasma concentrations of glucose and amino acids at 90 minutes postfeeding (P < .001), dental correction did not have an influence on plasma nutrient concentrations (P > .1). On day 56, untreated control horses had a larger percent of large FPS than horses having received dental correction (14.7 ± 0.1 vs. 12.5 ± 0.1; P = .028). Dental correction may improve mechanical digestion of feed, but this does not translate to altered postprandial plasma nutrient concentrations following the consumption of a concentrate meal.

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.

Dietary Exogenous α-Amylase Modulates the Nutrient Digestibility, Digestive Enzyme Activity, Growth-Related Gene Expression, and Diet Degradation Rate of Olive Flounder (Paralichthys olivaceus).

In this study, a 12-week feeding experiment was conducted to characterize the effects of exogenous α-amylase on the growth, feed utilization, digestibility, plasma α-amylase activity, feed degradation rate, and fecal particle size of olive flounder (Paralichthys olivaceus). Diet was supplemented with 0 (AA0; control), 100 (AA100), 200 (AA200), or 400 (AA400) mg/kg of α-amylase, respectively. Fish (273.1 ± 2.3 g) were stocked into 12 tanks (25 fish/1,000-L tank) and 3 tanks were randomly selected for each diet group. As a result, α-amylase was found to have no significant effects (p ≥ 0.05) on the growth, feed utilization parameters, and whole-body proximate compositions. α-Amylase-treated fish exhibited only a significant increase in the apparent digestibility coefficient of carbohydrates compared to the controls. In addition, in vitro analyses revealed that α-amylase dose-dependently increased (p < 0.05) the feed degradation rate, while photographs of the intestinal content after 2, 4, and 8 h of feeding demonstrated an improved degradation rate in the α-amylase-treated groups. Plasma α-amylase content was higher in the AA200 and AA400 groups, whereas the control group produced significantly larger-sized fecal particles (90% size class) than these two groups. In the intestine, no changes were observed in the expression levels of the immune-related TNF-α, IL-1β, IL-2, immunoglobulin-M, HSP-70, lysozyme, and amylase alpha-2A. However, growth-related genes IGF-1, IGF-2, TGF-β3, and growth hormone genes were upregulated in muscle tissues. Collectively, exogenous α-amylase has positive roles in the modulation of the digestibility coefficient, blood α-amylase concentration, growth-related gene expression, and diet degradation for improved digestion in olive flounder.

Alterations in the gut virome are associated with type 2 diabetes and diabetic nephropathy

ABSTRACT Although changes in gut microbiome have been associated with the development of T2D and its complications, the role of the gut virome remains largely unknown. Here, we characterized the gut virome alterations in T2D and its complications diabetic nephropathy (DN) by metagenomic sequencing of fecal viral-like particles. Compared with controls, T2D subjects, especially those with DN, had significantly lower viral richness and diversity. 81 viral species were identified to be significantly altered in T2D subjects, including a decrease in some phages (e.g. Flavobacterium phage and Cellulophaga phaga). DN subjects were depleted of 12 viral species, including Bacteroides phage, Anoxybacillus virus and Brevibacillus phage, and enriched in 2 phages (Shigella phage and Xylella phage). Multiple viral functions, particularly those of phage lysing host bacteria, were markedly reduced in T2D and DN. Strong viral-bacterial interactions in healthy controls were disrupted in both T2D and DN. Moreover, the combined use of gut viral and bacterial markers achieved a powerful diagnostic performance for T2D and DN, with AUC of 99.03% and 98.19%, respectively. Our results suggest that T2D and its complication DN are characterized by a significant decrease in gut viral diversity, changes in specific virus species, loss of multiple viral functions, and disruption of viral-bacterial correlations. The combined gut viral and bacterial markers have diagnostic potential for T2D and DN.

73 Comparison of fecal particle size of Thoroughbred broodmares and their yearlings

Fecal particle size (FPS) may be an indicator of chewing efficiency and digestive function in horses. The objective of this study was to evaluate the effect of horse age on FPS by comparing FPS measured by wet sieving analysis between 6 mares (12.8 ± 2.8 y) and their yearlings (1.18 ± 0.06 y). Both groups were housed on pasture with access to alfalfa hay and fed 2.73–3.64 kg/d of concentrate feed formulated for breeding and growing horses. Feces were collected by free catch, and divided into subsamples. One subsample was used for dry matter (DM) determination and the remaining samples were frozen until analysis. Before analysis, samples were thawed and duplicate aliquots containing 3.8 g of DM were soaked overnight in 200 mL of water. The amount of sample needed to contain 3.8 g of DM was calculated using the predetermined sample DM. Samples were washed over a set of 203.2 mm stainless steel sieves (VWR, Radnor, PA) with sieve openings of 4, 2, 1, 0.5, 0.25, 0.125 and 0.063 mm using a standardized water flow rate of 6 L/min for 5 min. Each sieve was rinsed clean into a beaker from which particles were filtered onto dried, pre-weighed filter paper for DM determination. Particles passing the smallest sieve were not collected but the amount was calculated by difference between total DM sieved and DM retained on all sieves.Weighted mean FPS and percent DM retained on each sieve as a percent of total DM sieved were analyzed using paired t-test procedure in SPSS V28. There was no difference in weighted mean FPS between mares (1.59 mm ± 0.09) and yearlings (1.47 mm ± 0.06) (P > 0.05). There was no difference in the percentage of DM retained on the 3 largest and 2 smallest sieves between mares and yearlings (P > 0.05). Compared with yearlings, there were trends for mares to have greater DM retained on sieves with diameter 0.5 mm (P = 0.096) and 0.25 mm (P = 0.08). Mean ± SE percent DM retained for mares and yearlings, respectively, was 9.6% ± 1.6 and 6.95% ± 1.2 (4 mm sieve), 12.70% ± 1.09 and 10.65% ± 1.08 (2 mm sieve), and 12.48% ± 0.89 and 12.19% ± 1.7 (1 mm sieve). Soluble DM calculated by difference as DM escaping the smallest sieve was greater in yearling samples compared with mare samples (37.02 vs 29.88%; P = 0.019). The small sample size of this study is a limitation but suggests there may be differences in fecal particle size distribution between mare and yearling pairs that warrant further investigation.