Oral administration of omega-3 polyunsaturated fatty acids (PUFAs) to rodents and humans is associated with an increase in gut bacteria that are predicted to synthesise short-chain fatty acids (SCFAs). We tested the hypothesis that physiological levels of omega-3 PUFAs in the distal intestinal lumen (1-50 μg/mL) are associated with increased SCFA synthesis in an in vitro fermentation model using faecal slurry from 10 healthy participants (mean age 30 years), with and without exogenous dietary fibres. SCFAs were measured by gas chromatography-flame ionisation detection (n = 10), and changes in bacterial composition were analysed by shotgun metagenomic sequencing (n = 6). In the presence of omega-3 PUFAs, there was a mean 9.3% (no inulin; P = 0.03) and 19.3% (+ 0.01 mg/mL inulin; P = 0.01) increase in total SCFA concentration at 24 h compared with paired control fermentations. Omega-3 PUFAs had a limited effect on the fermentation model microbiome in the absence of inulin. However, omega-3 PUFAs (50 μg/mL) were associated with increased abundance of Bifidobacteriaceae compared with paired control fermentations, if inulin (0.01 mg/mL) was present. Prebiotic activity of omega-3 PUFAs drives SCFA synthesis in an in vitro colonic fermentation model and is augmented by the soluble fibre inulin.

Climate change and eutrophication contribute to proliferation of cyanobacteria and cyanotoxins in aquatic environments. Conventional treatments can be ineffective to remove high cell densities of cyanobacteria and dissolved toxins. Therefore, alternative mitigation strategies are required to effectively remove these contaminants at source. In a previous photocatalytic study (Menezes et al., 2021a), UV-A irradiation was used as a light control system, however, UV-A irradiation was shown to be effective in the removal of the cyanobacterium Microcystis aeruginosa PCC 7813 and four microcystins. In this study, a chemical-free water treatment approach using photoinduced photolysis was explored by using UV-A 365 nm LED irradiation, a low-energy wavelength near the visible light spectrum, for the effective removal of cyanobacteria and toxins. Six Microcystis aeruginosa strains (SCIENTO, NIES1099, B2666, PCC7820, 7813 and 7806) were exposed to UV-A 365 nm irradiation for seven days. Photosynthetic activity significantly decreased after 24 h, with samples showing little to no photosynthetic activity by the end of the investigation. Total microcystin concentrations (intra- and extracellular) decreased in UV-A treated samples with 86 % removal of combined microcystins. Notably, microcystins removal varied by analogue (94 % of MC-RR was removed compared to 9 % of MC-YR). Furthermore, nutrients in the cyanobacteria growth medium used in lab-scale experiments, such as nitrate and iron, enhanced the UV-A photolytic degradation of microcystins, reflecting the potential for environmental conditions to amplify treatment effects. This study represents the first proposal of a UV-A LED-based photolytic method for cyanobacterial and cyanotoxin removal, offering a transformative, low-energy and chemical-free water treatment.

The( 13)C-sucrose breath test (C-13-SBT) has been proposed to estimate sucrase-isomaltase (SIM) activity and is a promising test for SIM deficiency, which can cause gastrointestinal symptoms, and for intestinal mucosal damage caused by gut dysfunction or chemotherapy. We previously showed how various summary measures of the( 13)C-SBT breath curve reflect SIM inhibition. However, it is uncertain how the performance of these classifiers is affected by test duration. We leveraged C-13-SBT data from a cross-over study in 16 adults who received 0, 100, and 750 mg of Reducose, an SIM inhibitor. We evaluated the performance of a pharmacokinetic-model-based classifier, rho, and three empirical classifiers (cumulative percent dose recovered at 90 min (cPDR90), time to 50% dose recovered, and time to peak dose recovery rate), as a function of test duration using receiver operating characteristic (ROC) curves. We also assessed the sensitivity, specificity, and accuracy of consensus classifiers. Test durations of less than 2 h generally failed to accurately predict later breath curve dynamics. The cPDR90 classifier had the highest ROC area-under-the-curve and, by design, was robust to shorter test durations. For detecting mild SIM inhibition, rho had a higher sensitivity. We recommend C-13-SBT tests run for at least a 2 h duration. Although cPDR90 was the classifier with highest accuracy and robustness to test duration in this application, concerns remain about its sensitivity to misspecification of the CO(2 )production rate. More research is needed to assess these classifiers in target populations.

BACKGROUND:Environmental enteric dysfunction (EED) causes malnutrition in children in low-resource settings. Stable-isotope breath tests have been proposed as noninvasive tests of altered nutrient metabolism and absorption in EED, but uncertainty over interpreting the breath curves has limited their use. The activity of sucrose-isomaltase, the glucosidase enzyme responsible for sucrose hydrolysis, may be reduced in EED. We previously developed a mechanistic model describing the dynamics of the 13C-sucrose breath test (13C-SBT) as a function of underlying metabolic processes. OBJECTIVES:This study aimed to determine which breath test curve dynamics are associated with sucrose hydrolysis and with the transport and metabolism of the fructose and glucose moieties and to propose and evaluate a model-based diagnostic for the loss of activity of sucrase-isomaltase. METHODS:We applied the mechanistic model to 2 sets of exploratory 13C-SBT experiments in healthy adult participants. First, 19 participants received differently labeled sucrose tracers (U-13C fructose, U-13C glucose, and U-13C sucrose) in a crossover study. Second, 16 participants received a sucrose tracer accompanied by 0, 100, and 750 mg of Reducose, a sucrase-isomaltase inhibitor. We evaluated a model-based diagnostic distinguishing between inhibitor concentrations using receiver operator curves, comparing with conventional statistics. RESULTS:Sucrose hydrolysis and the transport and metabolism of the fructose and glucose moieties were reflected in the same mechanistic process. The model distinguishes these processes from the fraction of tracer exhaled and an exponential metabolic process. The model-based diagnostic performed as well as the conventional summary statistics in distinguishing between no and low inhibition [area under the curve (AUC): 0.77 vs. 0.66-0.79] and for low vs. high inhibition (AUC 0.92 vs. 0.91-0.99). CONCLUSIONS:Current summary approaches to interpreting 13C breath test curves may be limited to identifying only gross gut dysfunction. A mechanistic model-based approach improved interpretation of breath test curves characterizing sucrose metabolism.

Restriction of energy intake is an effective strategy for achieving body mass loss(1). However, it leads to gastrointestinal appetite hormonal changes, which are expected to enhance hunger, reduce satiety, and possibly impair the ability to comply with prescribed intervention(2). Exercise interventions, on the other hand, did not modify gastrointestinal appetite hormones(3) and there is some evidence that postprandial appetite hormone responses after a low carbohydrate-high fat meal (LCHF) are more favorable than after high carbohydrate-low fat meal (HCLF) meal (4). This study investigated how energy-restricted diets based on LCHF and HCLF meals and combined with exercise affect body weight, and gastrointestinal appetite hormones and explored the relationship between body mass changes and changes in gastrointestinal appetite hormones.Twenty-seven overweight and obese females (age: 35 ± 9.35 years, BMI: 31.64 ± 5.08 kg/m2) completed a randomized parallel design study and underwent a 4-week intervention consisting of brisk walking combined with either consumption of calorie-restricted HCLF or LCHF diet. Participants underwent a 5-hour experimental trial before and after the interventions, which included body weight measurements and fasting and postprandial blood sample collection for gastrointestinal appetite hormone measurements.Both interventions significantly reduced body mass (HCLF group, −2.1 ± 1.7 Kg: LCHF group, -1.7 ± 1.7 Kg, P < 0.05 for both groups), but changes between the groups were not significant (P>0.05). Body mass changes were individual and ranged from -0.4 kg to −5.3 kg and from +1 kg to −4.4 kg in the HCLF and LCHF groups, respectively. The interventions had no impact on mean values of time- averaged postprandial concentrations of ghrelin, PYY, and GLP-1 but there was large individual variability in changes of these hormones. Results combined from both groups revealed that changes in ghrelin ranged from +549.3 to -407.7 pg/ml, in PYY from −132.5 to + 96.4 pg/ml and in GLP-1 from −6.6 to +19.5 pg/ml. Correlation, investigated on the data from both groups combined, between changes in body mass and changes in ghrelin (r = −0.18, P= 0.41), PYY (r = −0.04, P =0.87), and GLP-1 (r = 0.11, P = 0.64) were not significant.In conclusion, the extent of body mass loss during interventions based on restricted energy intake diets combined with exercise is not related to the carbohydrate and fat content of the diet. Our findings also suggest that the success of body mass loss cannot be predicted by changes in postprandial concentrations of gastrointestinal appetite hormones.

Adequate dietary fibre (25-30g/day) is essential in a healthy diet preventing several health problems (1) . Age-related changes reduce gut function and increase risk of constipation. A better understanding of fibre in those over 60y is required. This study aimed to measure fibre intake in those over 60y in Kuwait using the Kuwaiti Food Frequency Questionnaire for fibre (KWFFQ-DF) and explore local food sources of fibre and laxative use. Recruitment was conducted Dec 2022 to April 2023 in Geriatric Health Services in Kuwait and geriatric units across the six main governorates in Kuwait. The study was approved by the University of Glasgow Research Ethics Committee (project No. 200220066) and the Medical Research Ethics Committee of the Ministry of Health in Kuwait (project No 9512018)18). The validated KWFFQ-DF assessed intake of total fibre (TDF), soluble fibre (SF) and insoluble fibre and included seven food groups and 134 food items. The last two questions asked if the participant consumed supplementary fibre and if they took laxatives (type and amount). The associations between fibre intake and gender, age and governorate and between TDF and laxative use were assessed by Chi squared test ( P < 0.05 considered significant). The study recruited 210 people (61 males and 149 females; 61- 96y (median 66y). BMI ranged from 18 to 68 (median 29). Mean TDF intake was 28.7 g/d (SD 6.6; 13 to 46 g/ day). Most participants (n= 186, 89%) did not use laxatives. Several foods high in fibre were frequently consumed by participants including dates, as a snack with coffee eaten 2-6 times/day at 2.2 g TDF per portion and almonds once a day as a snack with 12 g of TDF. Whole grain toast, eaten 1-2 times daily contributed 4g TDF but with eggs or cheese at breakfast so higher in fat. Other key sources were barley bread, (8g TDF), vegetable soup, 2-4 times a week (4 g/d TDF) and Tabouleh Salad, typically eaten with grilled meat or chicken at 2g/d TDF. There was no significant association between fibre intake and gender (χ2= 1.033; P < 0.597) or governorates (χ2= 14.66; P < 0.145). However, the findings identified a significant association between fibre intake and age of participants (χ2= 10.066; P < 0.039). Moreover, there was a highly significant negative association between the TDF intake and laxative use frequency (χ2= 25.63, P <0.001). In contrast to some populations, fibre intake for people in Kuwait over 60y is within dietary guidelines and laxative use is low. Foods high in fibre in Kuwaiti cuisine can be, however, associated with high calories due to the sugar and fat content and may be associated with high BMI. The consequences of this need to be explored. Acknowledgements We would like to express our sincere gratitude to Dr Ali Alqattan and the medical team at the Geriatric Clinic in Mubarak Hospital for their valuable assistance in facilitating the interviews with participants in this research project.

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Background: The rapid production of gas during the colonic fermentation of highly soluble fermentable fibres may cause unpleasant gastrointestinal symptoms. In vivo feeding studies are often used to assess symptomatic response to fibres; however, in vitro fermentation studies are quicker, cheaper, and more reproducible. The aim of this study was to validate an in vitro colonic fermentation model of gas production against in vivo experiences of symptoms following inulin consumption. Methods: Healthy volunteers (n = 21, 18–65 y/o, M/F) provided a stool sample used to inoculate an in vitro colonic fermentation model. Fermentation bottles containing faecal slurry, a fermentation medium, and a fibre substrate (inulin) were incubated at 37 °C for 24 h in a shaking water bath. The total gas production (mL) over 24 h (minus control) was measured. Each stool donor added 15 g inulin to a low-fibre diet and recorded experiences of gastrointestinal symptoms for 48h. In vitro gas production and in vivo symptom experience were compared for each donor following tertile classification. Low in vitro gas production was classed as <45mL (<1st quartile of dataset), medium as 45–78 mL (1st quartile–3rd quartile), and high as >78 mL (>3rd quartile). In vivo symptom response was classed as low if symptoms were mild and/or short-lived (<1 h duration); medium if moderate and/or prolonged (1 h); and high when abdominal pain or multiple prolonged (3 h) symptoms occurred. Results: In vitro gas production was high in six cases (29%); medium in ten (48%); and low in five (24%). Symptom experience was high in seven cases (33%); medium in five (24%); and low in nine (43%). The same classification occurred in 57% of cases and classification into adjacent categories occurred in 43%; no complete misclassification occurred. Agreement between the methods was fair: weighted kappa = 0.378 (p < 0.01). Discussion: The level of agreement between the in vitro model of gas production and in vivo symptom reports, and the absence of any cases of complete misclassification, is promising. This simple in vitro batch-fermentation model may be used in future to screen fibres for their potential impact on gastrointestinal symptoms. This will help develop strategies to increase fibre consumption generally and optimise their use in food reformulation.

The influence of macronutrient composition of meals consumed the day before and the day including morning exercise session on gastrointestinal appetite hormones and post-meal insulin sensitivity in overweight men - Volume 82 Issue OCE3

Carbon stable isotope breath tests offer new opportunities to better understand gastrointestinal function in health and disease. However, it is often not clear how to isolate information about a gastrointestinal or metabolic process of interest from a breath test curve, and it is generally unknown how well summary statistics from empirical curve fitting correlate with underlying biological rates. We developed a framework that can be used to make mechanistic inference about the metabolic rates underlying a 13 C breath test curve, and we applied it to a pilot study of 13 C-sucrose breath test in 20 healthy adults. Starting from a standard conceptual model of sucrose metabolism, we determined the structural and practical identifiability of the model, using algebra and profile likelihoods, respectively, and we used these results to develop a reduced, identifiable model as a function of a gamma-distributed process, a slower, rate-limiting process, and a scaling term related to the fraction of the substrate that is exhaled as opposed to sequestered or excreted through urine. We demonstrated how the identifiable model parameters impacted curve dynamics and how these parameters correlated with commonly used breath test summary measures. Our work develops a better understanding of how the underlying biological processes impact different aspect of 13 C breath test curves, enhancing the clinical and research potential of these 13 C breath tests.

Low-cost pyrolysis units such as flame curtain pyrolysis kilns are gaining popularity for biochar production. However, the processes that govern the working of such units are not well understood. Here, emissions, temperatures and mass loss are monitored in real-time during kiln operation, followed by extensive biochar sampling. We found that by adjusting the layering rates of feedstock during kiln operation, we can obtain a biochar yield (28 wt% with a fixed carbon content of 65 wt%) comparable to that produced from the same feedstock in a continuous-scale pyrolysis unit, highlighting the importance of systematic guidelines for optimal kiln operation.

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Many compounds produced by cyanobacteria act as serine protease inhibitors, such as the tetrapeptides aeruginosins (Aer), which are found widely distributed. The structural diversity of Aer is intriguingly high. However, the genetic basis of this remains elusive. In this study, we explored the genetic basis of Aer synthesis among the filamentous cyanobacteria Planktothrix spp. In total, 124 strains, isolated from diverse freshwater waterbodies, have been compared regarding variability within Aer biosynthesis genes and the consequences for structural diversity. The high structural variability could be explained by various recombination processes affecting Aer synthesis, above all, the acquisition of accessory enzymes involved in post synthesis modification of the Aer peptide (e.g., halogenases, glycosyltransferases, sulfotransferases) as well as a large-range recombination of Aer biosynthesis genes, probably transferred from the bloom-forming cyanobacterium Microcystis. The Aer structural composition differed between evolutionary Planktothrix lineages, adapted to either shallow or deep waterbodies of the temperate climatic zone. Thus, for the first time among bloom-forming cyanobacteria, chemical diversification of a peptide family related to eco-evolutionary diversification has been described. It is concluded that various Aer peptides resulting from the recombination event act in chemical defense, possibly as a replacement for microcystins.

Cyanobacteria and their toxins are a threat to drinking water safety as increasingly cyanobacterial blooms (mass occurrences) occur in lakes and reservoirs all over the world. Photocatalytic removal of cyanotoxins by solar light active catalysts is a promising way to purify water at relatively low cost compared to modifying existing infrastructure. We have established a facile and low-cost method to obtain TiO2 and g-C3N4 coated floating photocatalysts using recycled glass beads. g-C3N4 coated and TiO2+g-C3N4 co-coated beads were able to completely remove microcystin-LR in artificial fresh water under both natural and simulated solar light irradi-ation without agitation in less than 2 h. TiO2 coated beads achieved complete removal within 8 h of irradiation. TiO2+g-C3N4 beads were more effective than g-C3N4 beads as demonstrated by the increase reaction rate with reaction constants, 0.0485 min(-1) compared to 0.0264 min(-1) respectively, with TiO2 alone found to be considerably slower 0.0072 min(-1). g-C3N4 based photocatalysts showed a similar degradation pathway to TiO2 based photocatalysts by attacking the C6-C7 double bond on the Adda side chain.

Objective: Mother’s own milk (MOM) is the optimal feed for premature infants but may not always be sufficiently available. Alternative feeding includes donor human milk (DONOR), with or without fortification and preterm formula. This study evaluated the association between early feeding with exclusively and predominantly MOM (MAINLY-MOM) versus MOM supplemented with fortified DONOR (MOM + DONOR) or preterm formula (MOM + FORMULA) and in-hospital growth and neonatal morbidities. Method: This was a multicentre (n = 13 units) cohort study of infants born at <32 weeks’ gestation. Data captured at the point of care were extracted from the UK National Neonatal Research Database. The study groups were defined based on feeding patterns within the first 2 weeks of life using predefined cut-offs. The primary outcome was the in-hospital growth rate. Results: Data from 1,272 infants were analysed. Infants fell into two groups: extremely preterm (EPT) infants and very preterm (VPT) infants, born after <28 weeks and 28 to <32 weeks of gestation, respectively. Only 11 of 365 EPT infants received formula supplements, precluding a useful comparison of MOM + DONOR and MOM + FORMULA. There was no difference in median (25th–75th centile) growth velocity over the first 30 days of life between the MAINLY-MOM (n = 248) and MOM + DONOR (n = 106) groups: 10 (8–13) versus 10 (7–13) g/kg/day. Similarly, for VPT infants, there was no difference in growth velocities between MAINLY-MOM (n = 407), MOM + DONOR (N = 196), and MOM + FORMULA (N = 304): 11 (8–14) versus 11 (8–14) versus 11 (8–14) g/kg/day. Head growth did not differ (p value = 0.670). Cox regression analysis showed no difference in time to discharge between feeding types or any difference in major neonatal morbidities. In both EPT and VPT infants, growth velocity from the time of regaining birth weight to discharge was significantly lower in the MAINLY-MOM group compared to the MOM-DONOR group (EPT: 12.5 [11–14.2] vs. 14 [12.3–15.9] p = 0.45, VPT 13.5 [11–15.7] vs. 14.5 [12.6–16.8] p = 0.015). Conclusion: Early feeding with fortified DONOR, in comparison to formula, to supplement MOM was not associated with any differences in short-term growth, length of stay, and neonatal morbidities. However, early feeding with mainly maternal milk, compared to maternal milk supplemented with DONOR, was associated with significantly lower overall weight gain.

Objectives Environmental enteropathy (EE) is a subclinical disorder highly prevalent in tropical and disadvantaged populations and is thought to play a role in growth faltering in children, poor responses to oral vaccines, and micronutrient deficiencies. This study aims to evaluate the potential of a non-invasive breath test based on stable isotopes for evaluation of impaired digestion and absorption of sucrose in EE. Methods We optimized a 13 C-sucrose breath test ( 13 C-SBT) in 19 young adults in Glasgow, United Kingdom. In a further experiment (in 18 adults) we validated the 13 C-SBT using Reducose, an intestinal glucosidase inhibitor. We then compared the 13 C-SBT to intestinal mucosal morphometry, immunostaining for sucrose-isomaltase (SI) expression, and SI activity in 24 Zambian adults with EE. Results Fully labeled sucrose (0.3 mg/kg) provided clear breath enrichment signals over 2–3 h in both British and Zambian adults, more than fivefold higher than naturally enriched sucrose. Reducose dramatically impaired 13 C-sucrose digestion, reducing 4 h 13 CO 2 breath recovery by > 50%. Duodenal biopsies in Zambian adults confirmed the presence of EE, and SI immunostaining was present in 16/24 adults. The kinetics of 13 CO 2 evolution were consistently faster in participants with detectable SI immunostaining. Although sucrase activity was strongly correlated with villus height ( r = 0.72; P < 0.05) after adjustment for age, sex and body mass index, there were no correlations between 13 C-SBT and villus height or measured sucrase activity in pinch biopsies. Conclusion A 13 C-SBT was developed which was easy to perform, generated clear enrichment of 13 CO 2 in breath samples, and clearly reports sucrase activity. Further work is needed to validate it and understand its applications in evaluating EE.

Scotch Whisky is an important global commodity which generates extensive co-product known as pot ale or spent wash (> 10 L co-product per L whisky). Whilst this is often used as fertiliser or animal feed, a proportion requires disposal resulting in cost to the distillery along with the negative impact on the carbon footprint due to transportation. This study examined the composition of the soluble fraction of pot ale from twenty-two distilleries in Scotland in order to assess the potential for resource recovery and transition to a more circular economy. The results reinforced previous studies, demonstrating that pot ale is an excellent source of protein with a potential for recovery >150, 000 t per annum in Scotland based on Whisky production data. Lactic acid, an important industrial platform chemical, was the major organic acid produced with concentrations ranging from 0.3 to 6.6 g L-1, representing a potential opportunity for recovery for applications such as manufacture of biodegradable polylactic acid for plastics (> 15,000 t per annum based on mean values). Other important platform chemicals, succinic acid and lysine were also identified and considered in sufficient amounts for future use. Pot ale was also shown to contain significant amounts of critical raw materials, magnesium and phosphate, which could be reclaimed for use in fertiliser/feed supporting the development of a new circular economy whilst at the same time reducing the burden of mining and transportation on the environment. The data in this study demonstrated a potential 13.8 kt recoverable phosphate per annum representing more than half of the annual fertiliser consumption in Scotland. Whisky co-products can contribute to sustainable energy, food and platform chemicals with the added value that metal concentrations are not sufficiently high to prevent its utilisation.

The intestinal microbiota plays a major role in infant health and development. However, the role of the breastmilk microbiota in infant gut colonisation remains unclear. A systematic review was performed to evaluate the composition of the breastmilk microbiota and evidence for transfer to/colonisation of the infant gut. Searches were performed using PUBMED, OVID, LILACS and PROQUEST from inception until 18th March 2020 with a PUBMED update to December 2021. 88 full texts were evaluated before final critique based on study power, sample contamination avoidance, storage, purification process, DNA extraction/analysis, and consideration of maternal health and other potential confounders. Risk of skin contamination was reduced mainly by breast cleaning and rejecting the first milk drops. Sample storage, DNA extraction and bioinformatics varied. Several studies stored samples under conditions that may selectively impact bacterial DNA preservation, others used preculture reducing reliability. Only 15 studies, with acceptable sample size, handling, extraction, and bacterial analysis, considered transfer of bacteria to the infant. Three reported bacterial transfer from infant to breastmilk. Despite consistent evidence for the breastmilk microbiota, and recent studies using improved methods to investigate factors affecting its composition, few studies adequately considered transfer to the infant gut providing very little evidence for effective impact on gut colonisation.