Changes In Microbial Populations Research Articles

The effects of using multi-species probiotics in late-pregnant and lactating sows on milk quality and quantity, fecal microflora, and performance of their offspring.

The dietary probiotics in sows during gestation to lactation period have gained considerable attention with respect to their beneficial effects on sows and their piglets' performance and health. This study aimed to evaluate the effects of using probiotics in late-pregnant and lactating sows on milk quality, quantity, fecal microflora of sows, and growth performance of their offspring until weaning. Thirty-four sows were equally divided into two groups (control and treatment). Only those in the treatment group were fed 5 g of probiotics at 12 weeks of pregnancy, once daily for 7 weeks, until their piglets were weaned. Colostrum samples were collected at 3, 6, 12, and 24 h after farrowing and measured for immunoglobulin concentration. Percentages of fat, protein, and lactose in colostrum, colostrum production, total intake of immunoglobulin A (IgA), immunoglobulin G (IgG), fat, protein, and lactose, the change of fecal microflora of sows, and average daily gain of piglets were measured. The results showed that there were no significant differences in the concentrations of IgA, IgG, and IgM in colostrum and the percentages of fat, protein, lactose, solid-not-fat, and total solid in colostrum between the groups; however, the colostrum production at 24 h in the treatment group (6,075.29 mL) was higher than in the control group (4,809.54 mL). Higher total intakes of IgA and IgG as well as total intake of fat, protein, and lactose, particularly at 3 h after farrowing, were found in the treatment group. Probiotic supplementation remarkably altered the microbiota community at the phylum level. We found that Firmicutes and Bacteroidetes are the dominant phyla, present in the gut of more than 90% of pregnant and lactating sows. Changes in microbial proportions were observed due to the changes of pig production stage. The weaning weight of the treatment group was higher than in the control group (6.34 ± 1.71 vs. 4.84 ± 1.29 kg, respectively). Feeding of multi-species probiotic BACTOSAC-P™ during late pregnancy and lactation in sows positively influenced colostrum production. In this experiment, the use of BACTOSAC-P™ improved the yield of colostrum production. The high immunoglobulin concentration and high yield of the colostrum of sows with a diet supplemented with BACTOSAC-P™ significantly reduced piglet mortality during the suckling period. Furthermore, the probiotic diet induced changes in the fecal microbial population in sows by increasing the number of microorganisms from the Firmicutes phylum, which had positive effects on sow health and their piglets, leading to better piglet growth performance.

Thermal Therapy Modulation of the Psoriasis-Associated Skin and Gut Microbiome.

Psoriasis is a systemic immune-mediated disease primarily manifesting as skin redness and inflammation. Balneotherapy proved to be a successful non-pharmacological option to reduce the skin areas affected by the disease, but the specific mechanisms underlying this effect have not been elucidated yet. Here we test the hypothesis that the effect of thermal treatments on psoriatic lesions could be partially mediated by changes in the resident microbial population, i.e., the microbiome. In this study, we enrolled patients with psoriasis and monitored changes in their skin and gut microbiome after a 12-bath balneotherapy course with a combination of 16S rRNA amplicon sequencing and metagenomics. Changes in the resident microbiome were then correlated with thermal therapy outcomes evaluated as changes in Psoriasis Area and Severity Index (PASI) and Body Surface Area index (BSA). The amplicon sequencing analysis of the skin microbiome showed that after thermal treatment the microbiome composition of affected areas improved to approach that typical of unaffected skin. We moreover identified some low-abundance bacterial biomarkers indicative of disease status and treatment efficacy, and we showed via metagenomic sequencing that thermal treatments and thermal water drinking affect the fecal microbiome to host more species associated with favorable metabolic health. Changes in lower-abundance microbial taxa presence and abundance could be the basis for the positive effect of thermal water treatment and drinking on the cutaneous and systemic symptomatology of psoriasis.

Impacts to canine dermal microbiota associated with repeated bathing.

Working dogs routinely operate in environmental conditions which may necessitate daily bathing to remove contaminants or soilage. The impacts of frequent or repeated bathing on the canine dermal microbiota are unknown. The objective of this study was to characterize changes in canine dermal microbial populations following repeated daily bathing. Labrador retrievers (n = 16) were bathed daily using a dilute dish detergent solution (1.6% detergent solution) over the course of 14 days. Dermal microbial DNA was collected via sterile swabs (n = 142) taken at days 0, 7, 14, 16, 21, 28, 35, 42, and 49 and analyzed for alpha diversity, beta diversity and relative abundance to assess changes in the dermal microbiota via 16 s sequencing. Results indicate that daily bathing significantly increased Shannon diversity, Chao1, and several rare amplicon sequence variants. Although typically reported in highest abundance, relative abundance was decreased in the phyla Actinobacteria, Firmicutes, and Proteobacteria (p < 0.05). Repeated daily bathing with dilute dish detergent significantly reduced normal healthy dermal microbial taxa and created significant changes in the dermal microbiota of canines. Disruption to the canine dermal microbiota may cause negative impacts to canine dermal health and require further investigation.

Microbiological Status, Physico-chemistry and Plant Performance in Spent Lubricating Oil (SLO) Polluted Soils Amended with Spiked Organic Fertilizer

Soil contaminations by spent lubricating oil (SLO) have been reported to be threatening as it can negatively impact soil macro/micro-flora, destroy the food chains, disrupt biogeochemical cycling of elements, thus reducing soil fertility/productivity, with attendant economic implications. This study evaluated the changes in microbial population and performance of plant in SLO polluted soils amended with different organic fertilizers. The fertilizers were produced from organic waste materials using aerobic composting technique; pollution was simulated in potted soils; soil toxicity were determined using Zea mays L. as test crop; microbial counts and physicochemical properties of the test soils were determined using standard microbiological and chemical protocols respectively. Apart from significant (P˂0.05) decrease in population of total heterotrophic bacteria (THB) and total fungal counts (TFC) (2.6×108 to 6.1×107 cfu/g and 2.3×105 to 1.7×105 cfu/g respectively), and increase in populations of hydrocarbon utilizing bacteria (HUB) and hydrocarbon utilizing fungi (HUF) (7.3×103 to 4.6×104 cfu/g and 8.0×103 to 1.7×104 cfu/g respectively) following contamination of soil with SLO at pollution level., results also revealed increase (improvements) in counts of all microbial groups at the end of remediation treatments. Mean microbial count in soils amended with different levels of fertilizer treatments (5%, 10%, and 15%) reflected a dose-dependent increase as follows: Ft2 ˃ Ft0 ˃ Ft4 for the 5% (3.7×108 cfu/g), 10% (9.2×107 cfu/g) and 15% (6.9×107 cfu/g) respectively. At 5% application, post remediation pH increased following the order: Ft0 ˃ Ft2 ˃ Ft4 (6.00, 5.34, and 4.90 respectively). The test crop, Zea mays L. recorded 100% and 62.5% germination in amended and unamended soils respectively. Leave length and chlorophyll index of Z. mays L. grown on remediated soils ranged between 35.10±0.40 – 52.85±0.05 (at 5% treatments); 32.60±0.10 – 56.55±0.35 (at 10% treatments); and 35.35±0.15 – 42.45±0.25 (at 15% treatments), compared with 30.30±0.80 – 50.55±0.75 (for PS) and 18.05±0.85 – 25.50±0.70 (for unamended CS). All test crops yielded except those grown on unamended soils. Conclusively, application of organic fertilizers to SLO polluted soils increased population of different groups of soil microbes, leading to increased breakdown of the pollutant and reduced soil toxicity.

Prescribed Burning Alters Insects and Wood Decay in a Sagebrush-Steppe Rangeland in Southwestern Idaho, United States

Prescribed fall burning is commonly used worldwide on rangeland sites to enhance vegetation resources and restore disturbed ecosystems, but little is known about how it may alter microbial communities and insect activities. We used two site treatments (low- to moderate-burn severity plots and unburned control plots) at a high-elevation (2 100 m above sea level) shrub-steppe rangeland site. Four yr after the prescribed burn, captured insects primarily consisted of Coleoptera (beetles), Hymenoptera (ants, bees, and wasps), and Orthoptera (grasshoppers and crickets) species with similar or greater numbers captured on burned plots as compared with unburned plots. We used wood stakes to assess microbial population changes. Aspen (Populus tremuloides Michx.) and pine (Pinus taeda L.) wood stakes were placed horizontally on the soil surface and vertically into the mineral to determine microbially altered wood decay rates. In mineral soil, mass loss (wood decay) of both aspen and pine increased significantly in the burned plots after 5 yr. Surface aspen also had increased decay in the burned plots, but pine surface stakes were unaffected. Surprisingly, at this high-elevation site we also found subterranean termites (Reticulitermes tibialis Banks) feeding on both stake species, with greater numbers on aspen stakes in burned plots leading to greater wood mass loss and organic matter turnover rates. Our results suggest that that fall prescribed burning can enhance insect numbers and microbial decay in sagebrush-steppe ecosystems. Understanding these changes can help land managers predict the influence of fall prescribed burning operations on soil biological properties and insect communities.

Gut microbial regulation of innate and adaptive immunity after traumatic brain injury.

Acute care management of traumatic brain injury is focused on the prevention and reduction of secondary insults such as hypotension, hypoxia, intracranial hypertension, and detrimental inflammation. However, the imperative to balance multiple clinical concerns simultaneously often results in therapeutic strategies targeted to address one clinical concern causing unintended effects in other remote organ systems. Recently the bidirectional communication between the gastrointestinal tract and the brain has been shown to influence both the central nervous system and gastrointestinal tract homeostasis in health and disease. A critical component of this axis is the microorganisms of the gut known as the gut microbiome. Changes in gut microbial populations in the setting of central nervous system disease, including traumatic brain injury, have been reported in both humans and experimental animal models and can be further disrupted by off-target effects of patient care. In this review article, we will explore the important role gut microbial populations play in regulating brain-resident and peripheral immune cell responses after traumatic brain injury. We will discuss the role of bacterial metabolites in gut microbial regulation of neuroinflammation and their potential as an avenue for therapeutic intervention in the setting of traumatic brain injury.

Influence of alpine meadow deterioration on soil microbial communities in the Yangtze River source region

Introduction: Although soil microbial populations are a good predictor of soil texture, little is known about how they react to alpine meadow deterioration.Methods: This study utilized Illumina HiSeq sequencing to investigate the effects of alpine meadow degradation on soil microbial communities in the Yangtze River source basin at five different degradation levels [i.e., non–degraded (ND), slightly degraded (LD), moderately degraded (MD), severely degraded (SD), and very severely degraded (VD)].Results: The results indicated that bacterial and fungal α-diversity were not substantially different (p &amp;gt; 0.05) across the damaged alpine meadows, while β-diversity significantly differed (p &amp;lt; 0.01), indicating a higher variation in the microbial community due to alpine meadow degradation. Proteobacteria reduced considerably (p &amp;lt; 0.05) by 8.75%, 22.99%, and 24.65%, while Acidobacteria increased significantly (p &amp;lt; 0.05) by 41.67%, 85.20%, and 108.67%, in MD, SD, and VD compared with ND, respectively. Ascomycota declined significantly (p &amp;lt; 0.05) in the MD, whereas unclassified phyla rose significantly (p &amp;gt; 0.05) in the VD compared to the ND. The heatmaps of bacterial and fungal communities revealed two clusters: a ND, LD, and MD group and a SD and VD group, suggesting significant changes in soil microorganisms of alpine meadow in the SD and VD. Redundancy analysis (RDA) revealed that soil moisture, soil bulk density, soil organic carbon, total nitrogen, and plant biomass could explain 73.8% and 39.4% of the variance in bacterial and fungal community structure, respectively.Discussion: These findings imply that degradation of the alpine meadow impacts both plant and soil qualities, ultimately leading to changes in soil microbial populations in the Yangtze River’s source region.

Assessing early postnatal development of the enteric glial network

The enteric glial network is instrumental in intestinal barrier maintenance and repair, but is immature at birth. At birth, enteric glia are restricted to the submucosal and myenteric plexuses, and are driven to populate the lamina propria by microbial colonization and changes in microbial populations at weaning. Our lab uses a comparative pig model to describe and quantify early postnatal development of the enteric glial network. We hypothesized the density and distribution of glial cell subtypes would change within the early postnatal period, illustrating early postnatal development and maturation of the enteric glial network. Using the iDISCO three-dimensional imaging technique, the glial network in 1-, 7-, 14-, and 21-day-old pigs was analyzed by adapting an algorithm to quantify the volume, maximum and mean intensities of glial markers of GFAP, Sox10, and S100β within manually isolated villi. In the lamina propria, GFAP density by volume decreases (P=0.0228) while S100β increases (P=0.0007) from 1- to 21- days. Between 1- and 21- days old Sox 10 tends to increase (P=0.2241, one-way ANOVA) - see graph. We believe this indicates GFAP+ cells change their expression profiles over the very early postnatal period to increase production of S100β, a known inflammatory mediator, which is participating in immune responses to colonizing bacteria, while Sox10 acts as a marker of proliferation. Understanding this early postnatal development will allow for modulation of this system, accelerating maturation of repair mechanisms. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The leaky gut and the gut microbiome in sepsis - targets in research and treatment.

Both a leaky gut (a barrier defect of the intestinal surface) and gut dysbiosis (a change in the intestinal microbial population) are intrinsic to sepsis. While sepsis itself can cause dysbiosis, dysbiosis can worsen sepsis. The leaky gut syndrome refers to a status with which there is an increased intestinal permeability allowing the translocation of microbial molecules from the gut into the blood circulation. It is not just a symptom of gastrointestinal involvement, but also an underlying cause that develops independently, and its presence could be recognized by the detection, in blood, of lipopolysaccharides and (1→3)-β-D-glucan (major components of gut microbiota). Gut-dysbiosis is the consequence of a reduction in some bacterial species in the gut microbiome, as a consequence of intestinal mucosal immunity defect, caused by intestinal hypoperfusion, immune cell apoptosis, and a variety of enteric neuro-humoral-immunity responses. A reduction in bacteria that produce short-chain fatty acids could change the intestinal barriers, leading to the translocation of pathogen molecules, into the circulation where it causes systemic inflammation. Even gut fungi might be increased in human patients with sepsis, even though this has not been consistently observed in murine models of sepsis, probably because of the longer duration of sepsis and also antibiotic use in patients. The gut virobiome that partly consists of bacteriophages is also detectable in gut contents that might be different between sepsis and normal hosts. These alterations of gut dysbiosis altogether could be an interesting target for sepsis adjuvant therapies, e.g., by faecal transplantation or probiotic therapy. Here, current information on leaky gut and gut dysbiosis along with the potential biomarkers, new treatment strategies, and future research topics are mentioned.

Changes in Soil Enzyme Activity and Microbial Population with Incorporation of Crop Residue along with Microbial Consortium in Black Cotton Soils

Changes in Soil Enzyme Activity and Microbial Population with Incorporation of Crop Residue along with Microbial Consortium in Black Cotton Soils

Ammonia-Oxidizing Bacteria Maintain Abundance but Lower amoA-Gene Expression during Cold Temperature Nitrification Failure in a Full-Scale Municipal Wastewater Treatment Plant.

In this study, we explore the relationship between community structure and transcriptional activity of ammonia-oxidizing bacteria during cold temperature nitrification failure in three parallel full-scale sequencing batch reactors (SBRs) treating municipal wastewater. In the three reactors, ammonia concentrations increased with declines in wastewater temperature below 15°C. We quantified and sequenced 16S rRNA and ammonia monooxygenase (amoA) gene fragments in DNA and RNA extracts from activated sludge samples collected from the SBRs during the warmer seasons (summer and fall) and when water temperatures were below 15°C (winter and spring). Taxonomic community composition of amoA genes and transcripts did not vary much between the warmer and colder seasons. However, we observed significant differences in amoA transcript copy numbers between fall (highest) and spring (lowest). Ammonia-oxidizing bacteria of the genus Nitrosomonas sp. could maintain their population abundance despite lowering their amoA gene expression during winter and spring. In spite of relatively low population abundance, an amoA amplicon sequence variant (ASV) cluster identified as most similar to the amoA gene of Nitrosospira briensis showed the highest amoA transcript-to-gene ratio throughout all four seasons, indicating that some nitrifiers remain active at wastewater temperatures below 15°C. Our results show that 16S rRNA and amoA gene copy numbers are limited predictors of cell activity. To optimize function and performance of mixed community bioprocesses, we need to collect high-resolution quantitative transcriptomic and potentially proteomic data to resolve the response of individual species to changes in environmental parameters in engineered systems. IMPORTANCE The diverse microbial community of activated sludge used in biological treatment systems exhibits dynamic seasonal shifts in community composition and activity. Many wastewater treatment plants in temperate/continental climates experience seasonal cold temperature nitrification failure. "Seasonal nitrification failure" is the discharge of elevated concentrations of ammonia (greater than 4 mg/liter) with treated wastewater during the winter (influent wastewater temperatures below 13°C). This study aims at expanding our understanding of how ammonia-oxidizing bacteria in activated sludge change in activity and growth across seasons. We quantified the ammonia monooxygenase (amoA) gene and transcript copy numbers using real-time PCR and sequenced the amoA amplicons to reveal community structure and activity changes of nitrifying microbial populations during seasonal nitrification failure in three full-scale sequencing batch reactors (SRBs) treating municipal wastewater. Relevant findings presented in this study contribute to explain seasonal nitrification performance variability in SRBs.

Forages and pastures symposium: forage biodegradation: advances in ruminal microbial ecology.

The rumen microbial ecosystem provides ruminants a selective advantage, the ability to utilize forages, allowing them to flourish worldwide in various environments. For many years, our understanding of the ruminal microbial ecosystem was limited to understanding the microbes (usually only laboratory-amenable bacteria) grown in pure culture, meaning that much of our understanding of ruminal function remained a "black box." However, the ruminal degradation of plant cell walls is performed by a consortium of bacteria, archaea, protozoa, and fungi that produces a wide variety of carbohydrate-active enzymes (CAZymes) that are responsible for the catabolism of cellulose, hemicellulose, and pectin. The past 15 years have seen the development and implementation of numerous next-generation sequencing (NGS) approaches (e.g., pyrosequencing, Illumina, and shotgun sequencing), which have contributed significantly to a greater level of insight regarding the microbial ecology of ruminants fed a variety of forages. There has also been an increase in the utilization of liquid chromatography and mass spectrometry that revolutionized transcriptomic approaches, and further improvements in the measurement of fermentation intermediates and end products have advanced with metabolomics. These advanced NGS techniques along with other analytic approaches, such as metaproteomics, have been utilized to elucidate the specific role of microbial CAZymes in forage degradation. Other methods have provided new insights into dynamic changes in the ruminal microbial population fed different diets and how these changes impact the assortment of products presented to the host animal. As more omics-based data has accumulated on forage-fed ruminants, the sequence of events that occur during fiber colonization by the microbial consortium has become more apparent, with fungal populations and fibrolytic bacterial populations working in conjunction, as well as expanding understanding of the individual microbial contributions to degradation of plant cell walls and polysaccharide components. In the future, the ability to predict microbial population and enzymatic activity and end products will be able to support the development of dynamic predictive models of rumen forage degradation and fermentation. Consequently, it is imperative to understand the rumen's microbial population better to improve fiber degradation in ruminants and, thus, stimulate more sustainable production systems.

Effects of exogenous amylolytic or fibrolytic enzymes inclusion on in vitro fermentation of lactating dairy cow diets in a dual-flow continuous-culture system

The objective of this study was to determine the effects of including exogenous amylolytic or fibrolytic enzymes in a diet for high-producing dairy cows on in vitro ruminal fermentation. Eight dual-flow continuous-culture fermentors were used in a replicated 4 × 4 Latin square. The treatments were control (CON), a xylanase and glucanase mixture (T1), an α-amylase mixture (T2), or a xylanase, glucanase, and α-amylase mixture (T3). Treatments were included at a rate of 0.008% of diet dry matter (DM) for T1 and T2 and at 0.02% for T3. All treatments replaced the equivalent amount of soybean meal in the diet compared with CON. All diets were balanced to have the same nutrient composition [30.2% neutral detergent fiber (NDF), 16.1% crude protein (CP), and 30% starch; DM basis], and fermentors were fed 106 g/d divided into 2 feedings. At each feeding, T2 was pipetted into the respective fermentor and an equivalent amount of deionized water was added to each fermentor to eliminate potential variation. Experimental periods were 10 d (7 d for adaptation and 3 d for sample collection). Composite samples of daily effluent were collected and analyzed for volatile fatty acids (VFA), NH3-N, and lactate concentrations, degradability of DM, organic matter, NDF, CP, and starch, and flow and metabolism of N. Samples of fermentor contents were collected from each fermentor at 0, 1, 2, 4, 6, and 8 h after feeding to determine kinetics of pH, NH3-N, lactate, and VFA concentrations over time. All data were analyzed using PROC GLIMMIX of SAS (SAS Institute Inc.), and the repeated variable of time was included for kinetics measurements. Treatment did not affect mean pH, degradability, N flow and metabolism, or the concentrations of VFA, NH3-N, or lactate in the effluent samples. Treatment did not affect pH, acetate:propionate ratio, or the concentrations of lactate, NH3-N, total VFA, acetate, propionate, butyrate, isobutyrate, valerate, or caproate. However, the concentration of total VFA tended to change at each time point depending upon the treatment, and T2 tended to have a greater proportion of 2-methylbutyrate and isovalerate than CON, T1, or T3. As 2-methylbutyrate and isovalerate are branched-chain VFA that are synthesized from branched-chain amino acids, T2 may have an increased fermentation of branched-chain amino acids or decreased uptake by fibrolytic microorganisms. Although we did not observe changes in N metabolism due to the enzymes, there could be changes in microbial populations that utilize branched-chain VFA. Overall, the tested enzymes did not improve in vitro ruminal fermentation in the diet of high-producing dairy cows.

Type 2 Diabetes and the Microbiome.

Diabetes represents one of the most significant, and rapidly escalating, global healthcare crises we face today. Diabetes already affects one-tenth of the world's adults-more than 537 million people, numbers that have tripled since 2000 and are estimated to reach 643 million by 2030. Type 2 diabetes (T2D), the most prevalent form, is a complex disease with numerous contributing factors, including genetics, epigenetics, diet, lifestyle, medication use, and socioeconomic factors. In addition, the gut microbiome has emerged as a significant potential contributing factor in T2D development and progression. Gut microbes and their metabolites strongly influence host metabolism and immune function, and are now known to contribute to vitamin biosynthesis, gut hormone production, satiety, maintenance of gut barrier integrity, and protection against pathogens, as well as digestion and nutrient absorption. In turn, gut microbes are influenced by diet and lifestyle factors such as alcohol and medication use, including antibiotic use and the consumption of probiotics and prebiotics. Here we review current evidence regarding changes in microbial populations in T2D and the mechanisms by which gut microbes influence glucose metabolism and insulin resistance, including inflammation, gut permeability, and bile acid production. We also explore the interrelationships between gut microbes and different T2D medications and other interventions, including prebiotics, probiotics, and bariatric surgery. Lastly, we explore the particular role of the small bowel in digestion and metabolism and the importance of studying small bowel microbes directly in our search to find metabolically relevant biomarkers and therapeutic targets for T2D.

Responses of Okra and Soil Microbial Population Changes to the Application of Tithonia Manure &amp;nbsp;

Yield reduction in okra production is mostly associated with cultivation of marginal lands or continuous land cultivation. Hence, the need for sustainable approach to resuscitating soil fertility through Tithonia diversifolia manure application may alter microbial population. Two soil depths [Topsoil (0-15 cm) and Subsoil (15-30 cm)], three levels of Tithonia manure applications (control, half recommended and recommended at 120 kg N/ha) and three okras varieties (Clemson spineless, LD88 and NHAe 47-4) were evaluated in completely randomized design replicated thrice. Soil bacterial and fungal colonies were higher in the topsoil compared to the subsoil and increased with increase in level of tithonia manure application under topsoil, while the inverse was observed under subsoil condition for bacteria colony-forming units and mycorrhizal spore count. Under topsoil, LD88 variety treated with recommended rate of tithonia manure had the highest biomass dry matter (79.4 g). Significantly higher leaf area (395.92 mm2) and biomass dry matter (66.89 g) were produced by NHAe 47-4 and Clemson spineless treated with recommended rate of tithonia manure compared to their respective controls (181.37 mm2and 29.63 g) under subsoil. Varieties LD88 and Clemson spineless combined with recommended rates of tithonia manure were suggested for topsoil and subsoil conditions, respectively.

Cobalt oxide nanoparticles as a new strategy for enhancing methane production from anaerobic digestion of noxious aquatic weeds

This study investigated the effect of cobalt oxide nanoparticles (Co3O4-NPs) supplementation on anaerobic microbial population changes and anaerobic digestion (AD) performance and production. Co3O4-NPs (3 mg/L) showed the maximum enhancement of biogas yield over the cow dung (CD) as control and the co-digestion process of CD with water hyacinth (WH) by 58.9 and 27.2 %, respectively. Furthermore, methane (CH4) yield was enhanced by 89.96 and 43.4 % over CD and co-digestion processes, respectively. Additionally, the microbiological assessment analysis using VIT® gene probe technology showed that Co3O4-NPs enhance the viability of total bacterial cells by 9 %. The techno-economic analysis reflects the revenue of this strategy on the highest net energy content of biogas, which was achieved with 3 mg/L Co3O4-NPs and was 428.05 kWh with a net profit of 67.66 USD/m3 of the substrate. Therefore, nanoparticle supplementation to the AD process can be considered a promising approach to enhance biogas and CH4.

Use of feed additives to improve feed efficiency and growth of feedlot cattle

The producers must observe feed efficiency (FE) and profitability in feedlot cattle under scenarios of high production costs associated with feeding. The most efficient and persistant way to change FE is using genetic tools. However, genetic selection in cattle is slow compared to the use of feed addititves, which work to stabilize ruminal pH, induce beneficial changes in the rumen microbial population, and increase efficiency in energy and protein metabolism. The literature is extensive about antibiotics, ionophores, and non-ionophores increasing FE. Nowadays, the use of "naturals" products as growth promoters has gained great relevance, and promising results has been reported. ). Therefore, this study aimed to review the use of feed additives in beef cattle feeding.

Knowledge-informed data-driven modeling for sparse identification of governing equations for microbial inactivation processes in food

Prevention of the growth of harmful microorganisms in food products is an important requirement for ensuring food safety and quality. Mathematical models to predict the quantitative changes in microbial populations in food to the variations of environmental conditions are useful tools in this regard. While equations for microbial inactivation have typically been formulated based on polynomial functions, empirical choice of the model order and terms not only results in over- or underfitting, but also makes it difficult to identify key factors governing the target variable. To address this issue, we present a data-driven modeling pipeline that enables 1) automatic discovery of model equations through parsimonious selection of relevant terms from a pre-built library and 2) subsequent evaluation of the impacts of individual terms on the model output. Through case studies using literature data, we evaluated the effectiveness of our pipeline in predicting the D-value (i.e., the time taken to reduce microbial population to 10% of the initial level) as a function of multiple factors including temperature, pH, water activity, NaCl content, and phosphate level. In doing this, we determined basic functional forms of input and output variables based on their pre-known relationships, e.g., by accounting for the Arrhenius dependence of D-value on temperature. Incorporation of such theoretical knowledge into the pipeline improved model accuracy. Using the Akaike information criterion, we optimally determined hyperparameters that control a trade-off between model accuracy and sparsity. We found the literature models benchmarked in this study to be over- or under-determined and consequently proposed better structured and more accurate equations. The subsequent global sensitivity analysis allowed us to evaluate the context-dependent impacts of key factors on the D-value. The pipeline presented in this work is readily applicable to many other related non-linear systems without being limited to microbial inactivation datasets.

Changes in the population and functional profile of bacteria and fungi in the rhizosphere of Suaeda salsa is driven by invasion of Spartina alterniflora

Changes in rhizosphere microbial populations and their functions in response to Spartina alterniflora root invasion could potentially reveal part of the mechanism of Suaeda salsa degradation. In this study, rhizosphere soils were collected from regions where S. alterniflora (SA) and S. salsa (SS) grew independently as well as rhizosphere soil from mixed growth regions (namely MSA and MSS) before applying high-throughput sequencing technology to study the characteristics of microbial communities. The results showed that the physicochemical properties of the rhizosphere soils were different between the groups of samples. However, based on the multi-factor PERMANOVA analysis, only EC and NO3−-N were found to significantly influence the microbial communities’ composition. Furthermore, α diversity indices and β diversity analyses revealed that the diversity and structure of rhizosphere microbial community changed in varying degrees after invasion. Compared with SS, the most abundant bacteria phylum namely Tenericutes, Firmicutes, Proteobacteria and Actinobacteria in MSS were identified as major species that increased significantly in abundance in response to S. alterniflora root invasion, while the composition of fungal community did not change. Furthermore, PICRUSt analysis revealed that the higher abundance of signal transduction, membrane transport, cell motility and certain disease-related functional pathways of MSA and MSS could be conducive to the colonization and survival of bacterial pathogens. Additionally, the analysis of the FUNGuild database confirmed that a higher proportion of pathotroph and pathogen. This could very likely cause S. salsa to be more susceptible to soil pathogenic fungi in mixed growth region. In contrast, the increase of the saprotroph-symbiotroph could be beneficial for the colonization and expansion of S. alterniflora. This study provides a new perspective for elucidating the driving mechanism by microorganisms behind S. salsa’s degradation following S. alterniflora’s invasion.

Evaluating the efficacy of slow-releasing carbon source tablets for in situ biological heterotrophic denitrification of groundwater.

Slow-releasing precipitating tablets (SRPTs) and slow-releasing floating tablets (SRFTs) were formulated to release fumarate as a carbon source (CS) and/or electron donor (ED) in an in situ biological heterotrophic denitrification system. These tablets were prepared using pharmaceutical manufacturing. Soil column tests were conducted to evaluate nitrate denitrification efficacy, microbial population changes, and mass balance of fumarate and potential electron acceptors. Significant and simultaneous consumption of both fumarate and nitrate, and the production and consumption of nitrite were observed in both SRPT-treated and SRFT-treated soil columns. These results suggest that SRPT and SRFT releasing fumarate, induce heterotrophic biological denitrification. In the SRPT- and SRFT-treated columns, 65% and 73% of fumarate were associated with heterotrophic denitrification, respectively. Particularly, surplus citric acid, originally designed to serve as a floating agent, was utilized for 36% and 28% for SRFT flotation and denitrification, respectively. The results of 16s RNA analyses revealed that a bacterium that shared 99% 16s rRNA sequence similarity with those of Azoarcus sp. AN9, and Pseudogulbenkiania sp. NH8B, a facultative heterotrophic denitrifier, was detected in the column effluent. This study confirms that SRPT and SRFT can effectively operate long-term in situ biological denitrification processes, because it is possible to supply detailed CS and/or ED uniformly by applying both SRPT and SRFT in the well.