Digestion Efficiency Research Articles

54 Effects of a new biosynthetic 6-phytase supplementation on nutrient digestibility, phytate disappearance and growth efficiency in weaning piglets fed low in calcium and digestible phosphorus diets

Abstract The objective of this study was to investigate the influence of adding graded levels of a new biosynthetic bacterial 6-phytase on nutrient digestibility, phytate disappearance and growth performance in weaned piglets. A total of 192 male weaned piglets with initial body weight of 8.70 ± kg, distributed in a randomized block design with four treatments and 24 replicate pens with 2 animals each for 42 d. The experimental diets included a phosphorus and Ca deficient diet (STTD of P/Ca = 0.21%/0.58% and 0.19%/0.54%, respectively, in post-weaning 1 and 2 diets) containing 0 (a control diet), 500, 1,000 or 1,500 FTU/kg diet. The diets were fed into 2 phases: post-weaning 1 and 2 from 1 to 14 and 15 to 42 d, respectively. Body weight and feed intake were measured at the end of each phase, and average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated for the overall experimental period. On d 42, ileal digesta samples were collected from 1 piglet/pen (n = 12 samples/treatment) for apparent ileal digestibility (AID) of Ca, P, and amino acids and phytate disappearance determination. Supplementation of diet with phytase from 0 to 1500 FTU/kg diet linearly improved (P < 0.01) AID of Ca. Both linear and quadratic effects (P < 0.001) was observed for AID of P and phytate-P. Increasing level of phytase supplementation resulted in linear and quadratic increases of Arg, His, Ile, Leu, Lys, Phe, Thr, Trp, Val, Ala, Asp, Cys, Glu, Ser, Tyr and total amino acids. Phytase supplementation increased (P < 0.0001) linearly Met and Pro, with an AID of Met showing a tendency (P = 0.09) for a quadratic increase. In addition, increasing phytase dose linearly increased (P = 0.006) the overall ADFI and ADG and decreased (P < 0.001) F:G ratio. Also, a tendency (P = 0.07) for quadratic effect of phytase was also observed on F:G ratio. These findings highlight that the supplementation of diets with the new bacterial 6-phytase significantly enhanced the utilization of nutrients, disappearance of phytate and performances of weaned piglets in a dose dependent manner.

Total Iodine Quantification and In Vitro Bioavailability Study in Abalone (Haliotis discus hannai) Using Inductively Coupled Plasma Mass Spectrometry.

The aim of this study is to determine the total iodine content in Korean abalone (Haliotis discus hannai) and to investigate the bioavailability of iodine using an in vitro method. This research paper focuses on total iodine quantification in abalone (Haliotis discus hannai) and its components (viscera and muscle) using inductively coupled plasma mass spectrometry (ICP-MS). Additionally, an in vitro bioavailability study explored iodine absorption potential. Abalone pretreatment involved both the European standard method (ES) and microwave-assisted extraction method (MAE). The limits of detection (LOD) were 0.11 ng/g for both ES and MAE, with a limit of quantification (LOQ) of 5.4 ng/g for MAE. Accuracy, assessed using a reference material (fish muscle, ERM-BB422), showed values of 1.5 ± 0.010 mg/kg for ES and 1.6 ± 0.066 mg/kg for MAE, within an acceptable range of 1.4 ± 0.42 mg/kg. Precision, evaluated using the Horwitz ratio (HorRat) with a reference material, was determined to be 0.45 for ES and 0.27 for MAE. Therefore, total iodine contents were estimated as 74 ± 2.2 µg/g for abalone viscera and 17 ± 0.77 µg/g for abalone muscle with ES, and 76 ± 1.0 µg/g for abalone viscera and 17 ± 0.51 µg/g for abalone muscle with MAE. Recovery tests demonstrated an acceptable range of 90-110%. In the in vitro bioavailability assessment, digestion efficiency yielded ranges of 42-50.2% for viscera and 67-115% for muscle. Absorption efficiency variations were determined as 37-43% for viscera and 48-75% for muscle.

Effects of replacing of alfalfa hay with Plantago lanceolata hay on digestibility, methane production and microbial protein production of total mixed diet

The aim of current experiment was to determine the effect of replacement of alfalfa hay with ribwort plantain (Plantago lanceolata) hay in ruminant diets on the fermentation parameters such as gas production, methane (CH4) production, true digestible dry matter (TDDM), true digestibility (TD), partitioning factor, microbial protein, and efficiency of microbial protein using in vitro gas production technique. The alfalfa hay was replaced with P. lanceolata hay in a diets isocaloric (2650 kcal/kg DM) and nitrogenic (17% CP kg DM) at the ratio of 0, 5, 10 and 15%. Partial substitution of alfalfa hay with P. lanceolata hay had no significant effect on gas and methane (ml/incubated substrate or %) production whereas the partial substitution had a significant effect on TDDM, TD, gas (ml/digested DM), CH4 (ml ml/digested DM) and microbial MP of diets. The replacement of alfalfa hay with ribwort plantain hay shifted the fermentation pattern from gas and methane production to microbial protein production. Therefore alfalfa hay can be replaced with ribwort plantain hay with high digestibility and anti-methanogenic potential in ruminant diets up to 15% to decrease methane production and improve microbial protein production. However further in vivo experiments are required to determine the effect of replacement on feed intake and animal production.

STUDY OF ANGIOTENSIN-I CONVERTING ENZYME INHIBITORY PEPTIDES DERIVED FROM Ficus pumila var. awkeotsang SEEDS HYDROLYSATE

Hypertension also known as high blood pressure that has associated with multi-metabolic pathways such as the renin-angiotensin-aldosterone system (RAAS). There have been several synthetic ACE inhibitory drugs used clinically as therapeutics for hypertension. However, synthetic drugs showed side effects on human health after long-term use. Therefore, alternative natural ACE inhibitors from food-derived are necessary to develop. The study aimed to examine the activity of angiotensin-I converting enzyme inhibitory peptides derived from Ficus pumila var. awkeotsang seeds hydrolysate and to study the efficiency of enzymatic digestion. This study used four enzymes (trypsin, pepsin, thermolysin, and chymotrypsin) to release bioactive peptides from Ficus pumila var. awkeotsang seeds that could exhibit an antihypertensive effect. The results showed that Ficus pumila var. awkeotsang trypsin hydrolysate has the highest ACEI activity, 90.37%, and the IC50 reached 169±3.5 µg/mL. Then, the hydrolysate produced by trypsin has the highest degree of hydrolysis, 4%, after 8 hours of incubation. Hence, Ficus pumila var. awkeotsang seeds hydrolysate could develop as an alternative natural product that is responsible for ACE-inhibitory activity.

Drug repurposing: identification of SARS-CoV-2 potential inhibitors by virtual screening and pharmacokinetics strategies.

The coronavirus disease 2019 (COVID-19) pandemic caused global health, economic, and population loss. Variants of the coronavirus contributed to the severity of the disease and persistent rise in infections. This study aimed to identify potential drug candidates from fifteen approved antiviral drugs against SARS-CoV-2 (6LU7), SARS-CoV (5B6O), and SARS-CoV-2 spike protein (6M0J) using virtual screening and pharmacokinetics to gain insights into COVID-19 therapeutics. We employed drug repurposing approach to analyze binding performance of fifteen clinically approved antiviral drugs against the main protease of SARS-CoV-2 (6LU7), SARS-CoV (5B6O), and SARS-CoV-2 spike proteins bound to ACE-2 receptor (6M0J), to provide an insight into the therapeutics of COVID-19. AutoDock Vina was used for docking studies. The binding affinities were calculated, and 2-3D structures of protein-ligand interactions were drawn. Rutin, hesperidin, and nelfinavir are clinically approved antiviral drugs with high binding affinity to proteins 6LU7, 5B6O, and 6M0J. These ligands have excellent pharmacokinetics, ensuring efficient absorption, metabolism, excretion, and digestibility. Hesperidin showed the most potent interaction with spike protein 6M0J, forming four H-bonds. Nelfinavir had a high human intestinal absorption (HIA) score of 0.93, indicating maximum absorption in the body and promising interactions with 6LU7. Our results indicated that rutin, hesperidin, and nelfinavir had the highest binding results against the proposed drug targets. The computational approach effectively identified SARS-CoV-2 inhibitors. COVID-19 is still a recurrent threat globally and predictive analysis using natural compounds might serve as a starting point for new drug development against SARS-CoV-2 and related viruses.

Reducing Greenhouse Gas Emissions in Beef Cattle Farming through the Implementation of Animal Welfare Principles, as Part of Sustainable Rural Area Development

The beef cattle farming industry is facing a dual challenge - the need to reduce greenhouse gas emissions to combat climate change and the imperative to enhance the daily weight gain of cattle to meet growing global demand for meat. The integration of animal welfare principles stands out as a crucial and multifaceted solution that not only mitigates greenhouse gas emissions but also improves the daily weight gain of beef cattle. The results of this study indicate that the implementation of animal welfare guidelines plays a pivotal role in reducing greenhouse gas emissions. By providing cattle with appropriate nutrition, minimizing stress, and ensuring a healthy and stress-free environment, the emission of methane, a potent greenhouse gas, can be significantly lowered. This approach is not just ecologically responsible; it is essential for meeting international climate commitments and preserving the health of the planet's ecosystems. In addition to its environmental benefits, the integration of animal welfare practices has a profound economic impact. Healthy and content cattle are more likely to exhibit efficient digestion and increased feed utilization, leading to higher daily weight gains. This directly improves the productivity and profitability of beef cattle farming operations. Furthermore, the production of higher-quality meat from well-cared-for animals can drive market demand and revenue, strengthening the industry's economic viability.

Enhanced anaerobic digestion of landfill leachate based on a novel redox mediator: Synergistic mechanism of enhancing extracellular electron transfer

The presence of recalcitrant compounds and toxic substances in landfill leachate results in low anaerobic digestion (AD) efficiency and poor methane production performance. Strengthening the extracellular electron transfer of microorganisms represents an effective approach to promote the AD of landfill leachate. In this study, a novel redox mediator (FeNC-RM) was synthesized through the combination of metal and non-metal doping, intensifying the stable operation of the landfill leachate AD system. Through characterization techniques including X-ray photoelectron spectroscopy and X-ray diffraction, it was observed that FeNC-RM possesses a larger specific surface area, abundant functional groups, and exceptional electrochemical performance. By adding FeNC-RM, the stability and efficiency of the medium-temperature AD system in the treatment of landfill leachate were improved: Obtained a high removal of chemical oxygen demand which was increased by 30 % compared to the control group and enhanced the specific methanogenic activity by 57.5 % compared to the control group. The electron transport system (ETS) activities of the experimental groups with the addition of RMs were all significantly higher than those of the control group, and the ETS activity of the sludge from the FeNC-RM group was 79.6 % higher than that of the control group. Through a comprehensive analysis of the underlying mechanism, it was determined that three aspects synergistically facilitated electron transfer: FeNC-RM, endowed with electrochemical capabilities, assumed a pivotal role in establishing a conduit for electron transport, thus promoting the synthesis of extracellular humic substances and augmenting electron transport activity. Furthermore, the microbial community was optimized by FeNC-RM, thereby fostering a co-nutritional mechanism between hydrolytic acidification bacteria and methanogens, establishing a direct interspecific electron transport pathway. In this study, an “endogenous + exogenous” electron transport model based on the enhanced extracellular electron transport pathway facilitated by FeNC-RM was proposed. This study offered valuable contributions to the advancement of anaerobic treatment technology for landfill leachate.

Co-digestion of peach biowaste and parboiled rice effluent: Characterization of feedstocks and renewable energy possibility

The co-digestion of a peach biowaste and parboiled rice effluent mixed with a sludge digester was investigated using a lab-scale biodigester. The biomasses used in the system were characterized by physical-chemical and microbiological analyses. Variations in substrate/inoculum (S/I) ratio of 1:1, 1:2, and 3:2, with different percentages of peach bagasse of 0%, 5%, and 10% in the substrate combination (peach bagasse + effluent), were performed. The study found that co-digestion of peach bagasse and parboiled rice effluent with digester sludge resulted in higher biomethane production, with reactors II and IV showing the best combination of factors both with a proportion of 3:2 (S/I). Reactor IV showed the maximum production of 27.51 mL CH4 with a substrate composition of 10% peach bagasse and 90% effluent. The physical-chemical properties of the co-digestion substrate were optimal for anaerobic digestion, and the microbial community adapted to enhance biodegradation. The maximum COD removal was found in reactor IV at 88.06%, followed by reactor V at 82.10%. In contrast, the 1:2 (S/I) ratio in reactor I showed the lowest methane production. Furthermore, the co-digestion process resulted in stable and efficient digestion, indicating it is a viable alternative for treating rice parboiling effluent and peach waste.

Rapid and Complete Digestion of Refractory Geological Samples Using Ultrafine Powder for Accurate Analyses of Trace Elements.

Complete sample digestion is a prerequisite for acquiring high-quality analytical results for geological samples. Closed-vessel acid digestion (bomb) has typically been used for the total digestion of refractory geological samples. However, the long digestion time (4-5 days) and insoluble fluoride complexes still pose challenges for digesting refractory geological samples using this approach. In this study, an efficient and simplified digestion technique combining ultrafine powders from planetary ball milling with bomb digestion was developed for trace element analysis of refractory geological samples: peridotite and granitoid. The method shows two significant improvements compared with previous approaches. (1) By performing dry planetary ultrafine milling, the initial 200 mesh peridotite (<74 μm) could be reduced to 800 mesh (<20 μm) in 6 min at a ball-to-powder mass ratio of approximately 15 using 3 mm tungsten carbide milling balls. (2) Complete peridotite and granitoid dissolution were achieved in approximately 2 h, 60 times faster than what is achievable using previous methods (2 h vs 120 h). Moreover, ultrafine powders effectively suppressed insoluble fluoride formation during bomb digestion. A suite of peridotite and granitoid reference materials were measured to evaluate the stability of this method. This efficient, simple, and reliable sample digestion method could benefit geological, food, environmental, and other fields requiring solid sample decomposition via wet acid, fusion, combustion, or dry ashing.

Anaerobic mono-digestion and co-digestion of food waste and mixed sewage sludge: A comparative analysis of metabolic patterns and taxonomic profiles

This study systematically compares the anaerobic mono-digestion and co-digestion of food waste (FW) and sewage sludge to understand the effects of feedstock composition on biogas yield and microbial community structure. The results showed that FW mono-digestion is optimal for methane production, achieving a peak yield of 377.25 ± 29.55 mL/g volatile solids fed (VSfed) but also generated significant quantities of hydrogen (151.59 ± 1.35 mL H2/g VS) during initial hydrolysis and acidogenesis phases. In contrast, waste-activated sludge (WAS) mono-digestion results in significantly lower methane yields (206.63 ± 1.18 mL/g VSfed). However, co-digesting FW with WAS enhances process stability, reducing the lag phase duration, albeit with an 8 % decrease in methane production relative to the theoretical potential. Further, it was observed when WAS was co-digested with primary sludge (PS), leading to a 34 % increase in methane yield compared to WAS mono-digestion. Soluble protein breakdown was highly efficient in WAS and PS treatments, exceeding 80 %, while FW treatments achieved less than 14 % degradation. Taxonomic analysis revealed a dominance of Firmicutes, specifically Clostridium sensu stricto 1, in FW reactors, whereas WAS and PS reactors supported a more diverse microbial community structure. Enzyme analysis indicated an upward trend in cellulase activity in WAS and PS reactors over time. These insights emphasize the importance of selecting appropriate feedstock combinations to enhance methane production, offering a pathway to more efficient anaerobic digestion processes and improved biogas recovery from organic waste.

Liver transcriptome and physiological analyses preliminarily revealed the adaptation mechanisms of Amur grayling (Thymallus arcticus grubei, Dybowski, 1869) fry for dietary lipid nutrition.

The Amur grayling (Thymallus arcticus grubei Dybowski, 1869), a species of potentially economic and research value, is renowned for its tender meat, exquisite flavor, and high nutritional contents. This study was conducted to investigate the physiological adaptation mechanisms to dietary lipids in Amur grayling fry (with average initial weight 4.64±0.03 g). This study involved a 56-day feeding trial with diets containing varying lipid levels (9.07%, 12.17%, 15.26%, 18.09%, 21.16%, and 24.07%, designated as GL1 through GL6, respectively) to explore the impact of dietary lipids on growth performance, intestinal digestion, liver antioxidative function, and transcriptomic profiles. Results showed that The group receiving 18% dietary lipid exhibited a markedly higher weight gain rate (WGR) and specific growth rate compared to other groups, alongside a reduced feed conversion ratio (FCR), except in comparison to the 15% lipid group. Activities of lipase in pancreatic secretion and amylase in stomach mucosa peaked in the 18% lipid treatment group, indicating enhanced digestive efficiency. The liver of fish in this group also showed increased activities of antioxidative enzymes and higher levels of glutathione and total antioxidative capacity, along with reduced malondialdehyde content compared to the 9% and 24% lipid treatments. Additionally, serum high-density lipoprotein cholesterol levels were highest in the 18% group. Transcriptomic analysis revealed four significant metabolic pathways affected: Cholesterol metabolism, Fat digestion and absorption, PPAR signaling, and Fatty acid degradation, involving key genes such as Lipase, Lipoprotein lipase, Fatty acid-binding protein, and Carnitine palmitoyltransferase I. These findings suggest that the liver of Amur grayling employs adaptive mechanisms to manage excessive dietary lipids. Quadratic regression analysis determined the optimal dietary lipid levels to be 16.62% and 16.52%, based on WGR and FCR, respectively. The optimal dietary lipid level for juvenile Amur grayling appears to be around 18%, as evidenced by improved growth performance, digestive function, balanced serum lipid profile, and enhanced liver antioxidative capacity. Exceeding this lipid threshold triggers both adaptive and potentially detrimental liver responses.

Enhancing anaerobic digestion efficiency in dairy waste water treatment: a comprehensive review of enzyme-based pre-treatment by microorganisms in South Africa

ABSTRACT The escalating global demand for dairy products due to population growth has led to increased production in the dairy industry, resulting in a significant rise in wastewater generation. This wastewater, laden with contaminants such as fats, oils, and greases (FOGs), biological oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, and phosphorus, poses a threat to freshwater sources. Anaerobic digestion (AD) is considered the optimal treatment method for dairy wastewater, but the high-fat content poses challenges like reactor clogging. To overcome this, various authors propose and implement an enzymatic pre-treatment strategy that improves FOG and organic content removal, increases biogas production, and addresses economic and environmental concerns. Despite the proven efficacy of enzymatic pre-treatment, a significant drawback is the associated cost. However, it remains a promising strategy for enhancing the biodegradability of complex organic compounds in dairy effluents. This review delves into the crucial role of enzyme-producing microorganisms in enhancing AD efficiency for dairy wastewater treatment, emphasizing their potential benefits and addressing the economic and environmental considerations associated with this approach.

The flow pattern effects of hydrodynamic cavitation on waste activated sludge digestibility

The disintegration of raw sludge is of importance for enhancing biogas production and facilitates the degradation of substrates for microorganisms so that the efficiency of digestion can be increased. In this study, the effect of hydrodynamic cavitation (HC) as a pretreatment approach for waste activated sludge (WAS) was investigated at two upstream pressures (0.83 and 1.72 MPa) by using a milli-scale apparatus which makes sludge pass through an orifice with a restriction at the cross section of the flow. The HC probe made of polyether ether ketone (PEEK) material was tested using potassium iodide solution and it was made sure that cavitation occurred at the selected pressures. The analysis on chemical effects of HC bubbles collapse suggested that not only cavitation occurred at low upstream pressure, i.e., 0.83 MPa, but it also had high intensity at this pressure. The pretreatment results of HC implementation on WAS were also in agreement with the chemical characterization of HC collapse. Release of soluble organics and ammonium was observed in the treated samples, which proved the efficiency of the HC pretreatment. The methane production was improved during the digestion of the treated samples compared to the control one. The digestion of treated WAS sample at lower upstream pressure (0.83 MPa) resulted in higher methane production (128.4 mL CH4/g VS) compared to the treated sample at higher upstream pressure (119.1 mL CH4/g VS) and control sample (98.3 mL CH4/g VS). Thus, these results showed that the HC pretreatment for WAS led to a significant increase in methane production (up to 30.6%), which reveals the potential of HC in full-scale applications.

Potential mechanisms of propionate degradation and methanogenesis in anaerobic digestion coupled with microbial electrolysis cell system: Importance of biocathode

Microbial electrolysis cells (MEC) have the potential for enhancing the efficiency of anaerobic digestion (AD). In this study, microbiological and metabolic pathways in the biocathode of anaerobic digestion coupled with microbial electrolysis cells system (AD-MEC) were revealed to separate bioanode. The biocathode efficiently degraded 90 % propionate within 48 h, leading to a methane production rate of 3222 mL·m-2·d-1. The protein and heme-rich cathodic biofilm enhanced redox capacity and facilitated interspecies electron transfer. Key acid-degrading bacteria, including Dechloromonas agitata, Ignavibacteriales bacterium UTCHB2, and Syntrophobacter fumaroxidans, along with functional proteins such as cytochrome c and e-pili, established mutualistic relationships with Methanothrix soehngenii. This synergy facilitated a multi-pathway metabolic process that converted acetate and CO2 into methane. The study sheds light on the intricate microbial dynamics within the biocathode, suggesting promising prospects for the scalable integration of AD-MEC and its potential in sustainable energy production.

Fulvic acid-mediated efficient anaerobic digestion for kitchen wastewater: Electrochemical and biochemical mechanisms

Fulvic acid, prevalent in humus derived from the anaerobic digestion of kitchen wastewater, is crucial in organic matter transformation. However, its effects and underlying mechanisms remain unclear. In this study, the fate of anaerobic digestion of artificial and kitchen wastewater with different fulvic acid contents was investigated. The results showed that 125 mg/L fulvic acid resulted in a 64.02 and 51.72 % increase in methane production in synthetic and kitchen wastewater, respectively. Fulvic acid acted as an electron mediator and increased substrate oxidation by boosting NAD and ATP levels, thereby increasing microbial metabolic rates and ensuring an adequate substrate for methane generation. Isotope analysis suggested that fulvic acid boosts the conversion of volatile fatty acids to methane via the interspecies electron transfer pathway. Gene expression analysis revealed that cytochrome c, FAD, and other electron transport coenzymes were upregulated by fulvic acid, thereby enhancing substrate utilisation and biogas quality. Fulvic acid presented a dual stimulatory and inhibitory effect on anaerobic digestion, with concentrations over 125 mg/L diminishing its positive impact. This dual effect may stem from the properties and concentrations of fulvic acid. This study revealed the effect mechanism of fulvic acid and provided insights into the humus performance in anaerobic digestion

Allophane improves anaerobic digestion of chicken manure by alleviating ammonia inhibition and intensifying direct interspecies electron transfer

Synthesized allophane was employed in anaerobic digestion of chicken manure to improve the stability and methane production under ammonia inhibition. Adding 0.5 %, 1.0 % and 1.5 % (w/w) allophane increased the methane production by 261 ∼ 350 % compared with the group without allophane addition. Further investigation indicated that the maximum adsorption capacity of allophane for NH4+-N achieved at 261.9 mg/g; it suggested that allophane adsorption potentially alleviated the ammonia inhibition, which also was reflected by the increase in the activity of the related enzyme, such as coenzyme F420. Moreover, allophane addition also intensified the direct interspecies electron transfer (DIET) in anaerobic digestion; it can be well supported by the increased relative abundance of Methanosaeta and Methanosarcina involved in the DIET. Overall, the improved anaerobic digestion via alleviating ammonia inhibition and intensifying DIET by allophane was elucidated comprehensively, which can contribute to the development of a functional additive for efficient anaerobic digestion in practical application.

Effects of thermophily-relevant temperature variation and sex on digestive performance in pythons

Different physiological performances are often optimized at slightly varying temperatures, which can lead to ectotherms selecting higher body temperatures during certain physiological efforts (e.g., digestion, reproduction). Such thermophilic responses can lead to temperature-based tradeoffs between two physiological activities with differing optimal temperatures or between optimizing a physiological activity and water balance, as water loss is elevated at higher temperatures. For example, ectotherms will often select a higher body temperature after consuming a meal, but the extent to which body temperature is elevated after eating is affected by its hydric state. Despite this known hydration state-based suppression of thermophily associated with digestion, the impact of this reduced body temperature on digestion performance is unknown. Accordingly, we determined whether small, thermophily-relevant changes in body temperature impact digestive efficiency or passage time and whether sex influenced the extent of the effect. Eighteen (9 female and 9 male) Children's pythons (Antaresia childreni) each consumed a meal at three temperatures (29 °C, 30 °C, and 31 °C), and gut passage time and digestive efficiency were determined. We found that neither metric was affected by temperature over the range tested. However, digestive efficiency was significantly impacted by the interaction between sex and temperature with males having significantly lower digestive efficiency than females at 31 °C, but not 29 °C or 30 °C. Our results provide insight into the effects of temperature on digestive physiology across narrow temperature ranges as well as demonstrate a sex-based difference in digestive physiology.

Functional Redundant Microbiome Enhanced Anaerobic Digestion Efficiency under Ammonium Inhibition Conditions.

Revealing the role of functional redundancy is of great importance considering its key role in maintaining the stability of microbial ecosystems in response to various disturbances. However, experimental evidence on this point is still lacking due to the difficulty in "manipulating" and depicting the degree of redundancy. In this study, manipulative experiments of functional redundancy were conducted by adopting the mixed inoculation strategy to evaluate its role in engineered anaerobic digestion systems under ammonium inhibition conditions. The results indicated that the functional redundancy gradient was successfully constructed and confirmed by evidence from pathway levels. All mixed inoculation groups exhibited higher methane production regardless of the ammonium level, indicating that functional redundancy is crucial in maintaining the system's efficiency. Further analysis of the metagenome-assembled genomes within different functional guilds revealed that the extent of redundancy decreased along the direction of the anaerobic digestion flow, and the role of functional redundancy appeared to be related to the stress level. The study also found that microbial diversity of key functional populations might play a more important role than their abundance on the system's performance under stress. The findings provide direct evidence and highlight the critical role of functional redundancy in enhancing the efficiency and stability of anaerobic digestion.

Synergistic digestibility effect by planktonic natural food and habitat renders high digestion efficiency in agastric aquatic consumers

A digestibility enhancing effect of natural food on stomachless fish model (Cyprinus carpio) was verified by fluorogenic substrate assays of enzymatic activities in experimental pond carp gut flush and planktonic food over a full vegetative season. Then compared with size-matched conspecific grown artificially (tank carp) and an advanced omnivore species possessing true stomach (tilapia, Oreochromis niloticus). Results suggested activities of digestive enzymes (except amylolytic) were significantly higher in pond carp (p ≤ 0.05) than in the size-matched tank carp. Even compared to tilapia, pond carp appeared superior (p < 0.05; proteolytic or chitinolytic activities) or comparable (p > 0.05; phosphatase or cellulolytic activities). Amylolytic, chitinolytic, and phosphatases activities in pond carp gut significantly increased (p ≤ 0.01) over season. Several orders-of-magnitude higher enzymatic activities were detected in planktonic natural food than expressed in carp gut. Amino acid markers in planktonic food revealed a higher share of zooplankton (microcrustaceans), but not phytoplankton, synchronized with higher activities of complex polysaccharide-splitting enzymes (cellulolytic and chitinolytic) in fish gut. Periods of clear water phase low in chlorophyll-a and nutrients, but high in certain zooplankton (preferably cladocerans), may create a synergistic digestibility effect in pond carp. We conclude aquatic ecosystem components (natural food, water, microbiota) enhance fishes' hydrolyzing capabilities of C/N/P macromolecules and even their complex polymers such as cellulose, chitin, and maybe phytate (to be validated), to the extent that being stomachless is not an issue. Aquatic nutritional ecologists may consider that laboratory-based understandings of digestibility may underestimate digestion efficiency of free-ranging fish in ponds or lakes.

Recent advances in high-performance liquid chromatography tandem mass spectrometry techniques for analysis of DNA damage and epigenetic modifications

Environmental exposure would cause DNA damage and epigenetic modification changes, potentially resulting in physiological dysfunction, thereby triggering diseases and even cancer. DNA damage and epigenetic modifications are thus promising biomarkers for environmental exposures and disease states. Benefiting from its high sensitivity and accuracy, high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) is considered the “gold standard technique” for investigating epigenetic DNA modifications. This review summarizes the recent advancements of UHPLC-MS/MS-based technologies for DNA damage and epigenetic modifications analysis, mainly focusing on the innovative methods developed for UHPLC-MS/MS-related pretreatment technologies containing efficient genomic DNA digestion and effective removal of the inorganic salt matrix, and the new strategies for improving detection sensitivity of liquid chromatography-mass spectrometry. Moreover, we also summarized the novel hyphenated techniques of the advanced UHPLC-MS/MS coupled with other separation and analysis methods for the measurement of DNA damage and epigenetic modification changes in special regions and fragments of chromosomes.