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Purpose: Short-chain fatty acids (SCFA) are known for their anti-inflammatory properties and may also prevent against the development of metabolic diseases. This study investigated possible effects of two valeric acid esters, monovalerin (MV) and trivalerin (TV) in rats fed high-fat diets., Methods: Four groups of rats were given a low-fat diet (LF) or a high-fat control diet (HFC) with or without supplementation of MV or TV (5 g/kg) for 3 weeks (n = 7/group). SCFA (caecum, blood, liver and brain), succinic acid (liver), microbiota (caecum), lipid profile (liver and blood) and the inflammatory biomarker, lipopolysaccharide-binding protein (blood) were analysed at the end of the experiment., Results: Supplementation of MV and TV to a high-fat diet increased 1.5-fold the amounts of acetic acid in the brain and 1.7-fold serum concentration of valeric acid, whereas liver succinic acid was reduced by 1.5-fold. Although liver triglyceride levels were higher in both MV and TV groups compared with the LF group, liver LDL/HDL ratio was lower in the MV group (P < 0.05). The caecal microbiota composition was altered, with threefold higher abundance of Bacteroidetes and higher ratio of Bacteroidetes/Firmicutes in the MV group compared with the HFC and LF groups. Acetic acid in the brain was negatively correlated with TM7, family S24-7 and rc4-4, and positively associated to Tenericutes and Anaeroplasma., Conclusions: The present study shows that MV and TV in the specified dose can affect caecal microbiota composition and, therefore, bacterial metabolites in the liver, serum and brain as well as the lipid profile in the liver.

Objective: The current study investigated the effects of mulberry 1-deoxynijirimycin (DNJ) on the digestion ability, intestinal morphology, and intestinal barrier of rabbits. Methods: A total of 36 New Zealand White rabbits (male) about 45 days old (mean body weight of 1.05±0.04 kg) were reared and commercial diets were employed, and afterwards divided into three groups (n = 12) with different levels of DNJ extract additive in feed: T0 (0 g/kg), T1 (0.35 g/kg), T2 (0.7 g/kg) for 28 d. Results: The results demonstrated that T2 decreased the average daily gain (p<0.05). T1 and T2 decreased villus height and inflammatory factor levels as compared with T0 (p<0.05). DNJ significantly decreased the content of valeric acid (p<0.05). The content of acetic acid, propionic acid, iso butyric acid, iso valeric acid in T1 were higher than those in T0 and T2 (p<0.05). The content of butyric acid in T2 was lower than it in T0 and T1 (p<0.05). The content of caproic acid was firstly improved then reduced as the DNJ concentration improved (p<0.05). T2 significantly increased the abundance of dgA-11_gut_group and Christensenellaceae_R-7_group while decreased Bacteroide and Ralstonia as compared with T0 (p<0.05). Compared with T0, T1, and T2 significantly improved the gene expression of JAM2, JAM3, mucin4, mucin6 (p<0.05), T1 significantly decreased the expression of occluding while T2 significantly increased (p<0.05), T2 significantly increased the expression of claudin1 and claudin2 (p<0.05). Conclusion: DNJ at high level changed microbiome compositions, inhibited inflammation, and improved intestinal barrier while it decreased the growth performance and shorted villus height in rabbit jejunum by regulating short chain fatty acid compositions in rabbits. [ABSTRACT FROM AUTHOR]

Simple Summary: Pigs do not have endogenous enzymes capable of breaking some fiber components (xylans) found in cereal grains such as wheat. The unique capability of xylanase to break the xylan main chain and release bound glucose from the fiber structure makes it a suitable strategy to feed wheat-based diets to pigs, especially after weaning where, in addition to improving digestibility, xylanase can contribute to promote pig heath. We evaluated the effects of increasing levels of xylanase in wheat–soybean meal-based diets with reduced metabolizable energy on the growth performance, nutrient digestibility, fermentation products, and digesta viscosity in weaned pigs. As a result, xylanase did not affect growth indicators, such as body weight, average daily gain or feed efficiency. However, xylanase supplementation led to a lower incidence of diarrhea, especially in the second- and third-week post-weaning. In addition, nutrient digestibility, particularly fiber components, improved linearly, which was associated with a reduction in digesta viscosity in the colon and changes in cecal volatile fatty acid profiles. In conclusion, xylanase supplementation can improve fiber digestibility and reduce digesta viscosity in the hindgut, which could be related with decreasing the occurrence of looseness. However, its effects on growth were not expressive in wheat-based diets with energy reduction. (1) Background: This study aimed to evaluate the effects of dietary xylanase addition on growth performance, nutrient digestibility, volatile fatty acids, and digesta viscosity at different digestive sites in weaned pigs fed wheat–soybean meal-based diets with reduced metabolizable energy. (2) Methods: A total of 312 weaned pigs (5.1 ± 0.9 kg, 20 ± 2 days of age) were assigned to one of six dietary treatments. The experimental diets were formulated in a three-phase nursery feeding program: phase 1 (d0–d7), phase 2 (d8–d21), and phase 3 (d22–d42). The experimental diets consisted of a wheat–soybean meal-based diet formulated to meet pig requirements (positive control, PC); the PC diet with a reduction of 100 kcal of metabolizable energy (ME) (negative control, NC); and the NC diet with either 900, 1800, 3600, or 7200 units of xylanase. Feed disappearance and body weight were measured at d7, 14, 21, and 42 in the nursery phase. The pen fecal score was assessed daily from d0 to d14 and three times a week from d15 to d28. On d21–d24 of the experiment (12 pigs per day), one pig per pen was selected for sample collection: ileal, cecal, and mid-colon digesta for viscosity and ileal digesta, feces for nutrient digestibility, and feces and cecal digesta for the measurement of volatile fatty acid. (3) Results: The addition of xylanase to the NC diets did not improve pig growth performance (body weight, feed conversion ratio, and average daily gain; p > 0.10) during the entire nursery phase. In Week 2 and Week 3, pigs fed xylanase had a lower (χ2 < 0.05) incidence of fecal scores 3 and 4 (diarrhea) than the PC and NC diets. In addition, the apparent total tract digestibility of neutral detergent fiber and acid detergent fiber increased linearly (p < 0.1) in response to xylanase addition. Xylanase addition (900 to 7200 U) decreased digesta viscosity in the colon compared to the PC and NC diets. Furthermore, xylanase addition resulted in a lower (p < 0.05) concentration of acetic, propionic, butyric, valeric, and total volatile fatty acid in cecal samples compared to PC. The addition of xylanase resulted in greater acetic and valeric acid concentrations in cecal samples compared to the NC group (p < 0.10). (4) Conclusions: Xylanase addition can improve nutrient digestibility, particularly at the total tract level, and reduce viscosity in the hindgut, which could be related to decreasing the occurrence of looseness. However, its impact on growth performance was minimal in wheat–soybean meal-based diets with a reduction of 100 kcal of ME. [ABSTRACT FROM AUTHOR]

The volatile fatty acids (VFAs) productions, as well as particulate organics decomposition, soluble chemical oxygen demand (SCOD) yield, and the VFAs production pathways from mesophilic and thermophilic anaerobic fermentation in waste activated sludge were investigated. Batch experiments showed that the decomposition rate of volatile suspended solids (VSS), particulate carbohydrate (P–C) and particulate protein (P–P) followed the first-order kinetic model at different temperatures. However, the intermediates, accumulated in the process of protein or carbohydrate digestion had a more significant inhibitory effect on the production of VFAs during the mesophilic anaerobic acidification process. The production of VFAs by thermophilic anaerobic fermentation is 2086.05 mg COD/L, which is about twice the production under mesophilic conditions. Among them, the concentration and proportion of high molecular weight organic acids such as isobutyric acid (320.29 mgCOD/L) and isovaleric acid (745.75 mgCOD/L) are relatively high. Then 13C stable isotope labelling experiment demonstrated that, the decomposition of carbohydrates yields 77% acetic acid and 86% butyric acid, while protein breakdown produces 85% propionic acid and 99% valeric acid. This confirms that carbohydrates are more favourable for the formation of even-carbon organic acids, while proteins tend to yield odd-carbon organic acids. Additionally, this helps refine the pathway for valeric acid formation during anaerobic acidogenesis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although addition of pyrolyzed organic materials (biochars) to soil generally results in increased growth and physiological performance of plants, neutral and negative responses have also commonly been detected. Toxicity of organic compounds generated during pyrolysis, sorbed by biochars, and then released into the soil solution, has been implicated as a possible mechanism for such negative effects. Conversely, water-soluble biochar constituents have also been suggested to have "hormetic" effects (positive effects on plants at low concentrations); however, no specific compounds responsible have been identified. We investigated the relative phytotoxicity—and possible hormetic effects—of 14 organic compounds common in aqueous extracts of freshly produced lignocellulosic biochars, using seed germination bioassays. Of the compounds examined, volatile fatty acids (VFAs: acetic, propionic, butyric, valeric, caproic, and 2-ethylbutyric acids) and phenol, showed acute phytotoxicity, with germination-based ED50 values of 1–30 mmol L−1, and 2-ethylbutyric acid showed ED50 values of 0.1–1.0 mmol L−1. Other compounds (benzene, benzoic acid, butanone, methyl salicylate, toluene, and 2,4-di-tert-butylphenol) showed toxic effects only at high concentrations close to solubility limits. Although phytotoxic at high concentrations, valeric and caproic acid also showed detectable hormetic effects on seedlings, increasing radicle extension by 5–15% at concentrations of ~ 0.01–0.1 mmol L−1. These data support the hypothesis that VFAs are the main agents responsible for phytotoxic effects of lignocellulosic biochar leachates, but that certain VFAs also have hormetic effects at low concentrations and may contribute to positive effects of biochar leachates on early plant development in some cases. Highlights: 151 compounds were identified in leachates from 13 biochars. Among common compounds, volatile fatty acids (VFAs) and phenol showed the most pronounced phytotoxic effects. Some VFAs also had hormetic effects, enhancing radicle extension growth at low concentrations. Effects were consistent among test plant species but the smallest-seeded species showed the highest sensitivity. [ABSTRACT FROM AUTHOR]

The GG genotype of the Patatin-like phosphatase domain-containing 3 (PNPLA3), dietary fat, short-chain fatty acids (SCFA) and branched-chain amino acids (BCAA) are linked with non-alcoholic fatty liver disease. We studied the impact of the quality of dietary fat on plasma (p) and fecal (f) SCFA and p-BCAA in men homozygous for the PNPLA3 rs738409 variant (I148M). Eighty-eight randomly assigned men (age 67.8 ± 4.3 years, body mass index 27.1 ± 2.5 kg/m2) participated in a 12-week diet intervention. The recommended diet (RD) group followed the National and Nordic nutrition recommendations for fat intake. The average diet (AD) group followed the average fat intake in Finland. The intervention resulted in a decrease in total p-SCFAs and iso-butyric acid in the RD group (p = 0.041 and p = 0.002). Valeric acid (p-VA) increased in participants with the GG genotype regardless of the diet (RD, 3.6 ± 0.6 to 7.0 ± 0.6 µmol/g, p = 0.005 and AD, 3.8 ± 0.3 to 9.7 ± 8.5 µmol/g, p = 0.015). Also, genotype relation to p-VA was seen statistically significantly in the RD group (CC: 3.7 ± 0.4 to 4.2 ± 1.7 µmol/g and GG: 3.6 ± 0.6 to 7.0 ± 0.6 µmol/g, p = 0.0026 for time and p = 0.004 for time and genotype). P-VA, unlike any other SCFA, correlated positively with plasma gamma-glutamyl transferase (r = 0.240, p = 0.025). Total p-BCAAs concentration changed in the AD group comparing PNPLA3 CC and GG genotypes (CC: 612 ± 184 to 532 ± 149 µmol/g and GG: 587 ± 182 to 590 ± 130 µmol/g, p = 0.015 for time). Valine decreased in the RD group (p = 0.009), and leucine decreased in the AD group (p = 0.043). RD decreased total fecal SCFA, acetic acid (f-AA), and butyric acid (f-BA) in those with CC genotype (p = 0.006, 0.013 and 0.005, respectively). Our results suggest that the PNPLA3 genotype modifies the effect of dietary fat modification for p-VA, total f-SCFA, f-AA and f-BA, and total p-BCAA. [ABSTRACT FROM AUTHOR]

Clostridium luticellarii is a recently discovered acetogen that is uniquely capable of producing butyric and isobutyric acid from various substrates (e.g. methanol), but it is unclear which factors influence its (iso)butyric acid production from H2 and CO2. We aimed to investigate the autotrophic metabolism of C. luticellarii by identifying the necessary growth conditions and examining the effects of pH and metabolite levels on product titers and selectivity. Results show that autotrophic growth of C. luticellarii requires the addition of complex nutrient sources and the absence of shaking conditions. Further experiments combined with thermodynamic calculations identified pH as a key parameter governing the direction of metabolic fluxes. At circumneutral pH (~6.5), acetic acid is the sole metabolic end product but C. luticellarii possesses the unique ability to co‐oxidize organic acids such as valeric acid under high H2 partial pressures (>1 bar). Conversely, mildly acidic pH (≤5.5) stimulates the production of butyric and isobutyric acid while partly halting the oxidation of organic acids. Additionally, elevated acetic acid concentrations stimulated butyric and isobutyric acid production up to a combined selectivity of 53 ± 3%. Finally, our results suggest that isobutyric acid is produced by a reversible isomerization of butyric acid, but valeric and caproic acid are not isomerized. These combined insights can inform future efforts to optimize and scale‐up the production of valuable chemicals from CO2 using C. luticellarii. [ABSTRACT FROM AUTHOR]

In order to explore the effects of supplementation of mineral salt bricks in warm season on rumen fermentation and microflora community of grazing yaks, a total of twelve 2.5-year-old male yaks with similar body weight were selected and randomly divided into two treatment groups with six replicates in each group. The control group was pure grazing, and the salt brick group was fed with grazing + supplementary feeding of mineral salt bricks. The results show that: the yields of acetic acid, butyric acid, isovaleric acid, valeric acid, total volatile fatty acids and ammonia nitrogen in the rumen of yaks in the salt brick group were significantly higher than those in the control group (P<0.05), but there was no significant difference in pH between the control group and the salt brick group on the 30th day of the experiment (P> 0.05). On the 60th and 90th day of the experiment, the pH of the salt brick group was significantly lower than that of the control group (P<0.05). Supplementation of mineral salt bricks could significantly reduce the relative abundance of Metha⁃ nobrevibacter, Christenellaceae, Christensenellaceae R-7 and other bacteria in the rumen of yaks (P< 0.05). It significantly increased the relative abundance of Proteobacteria, Actinobacteria, Rhodobacteraceae, Cellulomonadaceae (P<0.05). In summary, supplementation of mineral salt bricks in the warm season can change the activity of rumen microbial community in yaks, promote rumen fermentation, improve the production performance of yak. [ABSTRACT FROM AUTHOR]

The aim of this study comprises the effect of fermented grape pomace (FGP) in experimental total mixed rations (TMR) at different rates (0, 7.5%, 15%, and 22.5%) on the in vitro cumulative gas production (6th, 12th, 18th and 24th hours), methane production, ruminal fermentation values, pH and ammonia-nitrogen and straight and branched short-chain fatty acids (SCFA and BCFA) concentration. The method of in vitro total gas production was carried out in glass syringes. Ruminal in vitro methane production linearly decreased by adding up to 22.5% FGP in experimental TMR (p < 0.05). The molarities of acetic, propionic, butyric, and valeric acids in the in vitro fermentation fluid linearly decreased with the addition of FGP to TMR (p < 0.05). FGP up to 22.5% in experimental TMRs decreased the molarity of iso-valeric acid and iso-butyric acid from BSCFAs (p < 0.05). As a result, it was concluded that the use of FGP, containing a low level of total condensed tannins (TCTs), up to 22.5% in the experimental TMR based on dry matter (DM) did not adversely affect the in vitro ruminal fermentation value and had an anti-methanogenic effect. In addition, some SCFA (acetic, propionic, butyric, and valeric acids) molarities and iso-acid BSCFA (iso-butyric and iso-valeric acid) did not change up to 15% rate of FGP in the ration. Still, these values decreased by using a 22% rate of FGP. The dose-dependent effect of FGP on ruminal iso-acids has been associated with the ability of TCTs to inhibit ruminal protein degradation partially. [ABSTRACT FROM AUTHOR]

The experiment was to investigate the effect of different doses of Artemisia annua water extract on rumen fermentation of dairy cows in vitro. Three healthy Holstein dairy cows with similar body conditions were selected as rumen fluid donors, and 0 (control group), 0.025% (H1 group), 0.050% (H2 group), 0.075% (H3 group) and 0.100% (H4 group) of Artemisia annua water extracts were added to the total mixed diet (TMR), respectively. Rumen fermentation parameters and fermentation gas components were determined after 24 h culture. The results showed that compared with control group, the pH value and NH3-N concentration in rumen fluid of cows in different dosages of Artemisia annua supplemental groups were significantly decreased (P<0.05), while the content of BCP was significantly increased (P<0.05). NH3-N content in rumen fluid of dairy cows in H2 group, H3 group and H4 group was significantly lower than that in control group and H1 group (P<0.05). The number of rumen fluid protozoa in H3 group and H4 group was significantly lower than that in control group (P<0.05). The content of carbon dioxide in rumen fluid of cows in H1 group, H2 group and H3 group was significantly higher than that in control group (P<0.05), and the content of hydrogen in rumen fluid of cows in H1 group, H2 group and H3 group was significantly lower than that in control group (P<0.05). Compared with control group, the concentrations of total volatile fatty acids, acetic acid, propionic acid and valeric acid of rumen fluid of cows in H2 group and H3 group increased significantly (P<0.05), and the concentration of isovaleric acid in rumen fluid of cows in the H3 group was significantly higher than that in other groups (P<0.05). The experiment indicates that adding water extract of Artemisia annua water extrac can reduce rumen pH value, inhibit protozoa reproduction and promote rumen fermentation, and the effect of 0.050%~0.075% dose group is better, especially 0.075% dose. [ABSTRACT FROM AUTHOR]

An anaerobic granular sludge was enriched to utilize H2/CO2 in a continuous gas‐fed up‐flow anaerobic sludge reactor by applying operating conditions expected to produce acetic acid, butyric acid, and ethanol. Three stages of fermentation were found: Stage I with acetic acid accumulation with the highest concentration of 35 mM along with a pH decrease from initial 6 to 4.5. In Stage II, H2/CO2 was replaced by 100% H2 to induce solventogenesis, whereas butyric acid was produced with the highest concentration of 2.5 mM. At stage III with 10 µM tungsten (W) addition, iso‐valeric acid, valeric acid, and caproic acid were produced at pH 4.5–5.0. In the batch tests inoculated with the enriched sludge taken from the bioreactor (day 70), however, methane production occurred at pH 6. Exogenous 15 mM acetate addition enhanced both the H2 and CO2 consumption rate compared to exogenous 10, 30, and 45 mM acetate by the enriched sludge. Exogenous acetate was failed to be converted to ethanol using H2 as electron donor by the enriched acetogens. [ABSTRACT FROM AUTHOR]

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: Epidemiological investigations show that long-term exposure to PM2.5 is directly related to asthma-like and other respiratory diseases. This study aims to further explore the pharmacological effect of Ephedra sinica polysaccharide (ESP) on lung injury caused by atmospheric PM2.5. Methods: To achieve the aim, we explored the therapeutic effect of ESP on an aggravated asthma-like mouse induced by PM2.5 combined with ovalbumin (OVA), and explored mechanisms underlying the connection between gut microbiota and lung function. Key findings: Preliminary results showed that ESP alleviated the symptoms of aggravated allergic asthma-like in mice; reduced the number of eosinophils in BALF; reduced the levels of serum Ig-E, IL-6, TNF-α, and IL-1β. Further qRT-PCR detected that ESP inhibited the NF-κB pathway. The final analysis detected by 16S rRNA and short chain fatty acid (SCFA) confirmed that ESP increased relative proportions of Bacteroides, Lactobacillus, Prevotella, Butyricicoccus and Paraprevotella, but decreased that of Enterococcus and Ruminococcus; increased acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, and isohexanic acid in the meanwhile. Conclusions: The study showed that ESP has a potential for future therapeutical applications in the prevention and treatment of asthma-like disease induced by PM2.5 and OVA via regulation of gut microbiota and SCFA. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the effect of essential oil mixture supplemented in drinking water on antioxidant capacity and intestinal health in geese. One hundred eight chicks (which were 3 days old) were randomly allocated to 3 groups and each group was allocated to 6 subgroups. Research groups have been as follows: C (Control; without supplementation); E1 (0.4 ml/L essential oil mixture supplementation) and E2 (0.8 ml/L essential oil mixture supplementation). The duration of the experiment was 13 weeks. In the first 4 weeks of the trial, the animals were fed for the chick period. In the last 9 weeks of the trial, geese were fed in the pasture under the conditions of Kars province. In the 4th week and at the end of the experiment, GSH exhibited a linear response (P=0.008 and P=0.004, respectively). However, MDA, GSH, SOD, GPx, CAT, nitric oxide, ceruloplasmin, albumin, total protein and globulin were not affected. At the end of the experiment, acetic acid, butyric acid, isocaproic acid and total short-chain fatty acid concentrations were linearly affected with the gradued level of essential oil mixture. There were no significant differences in propionic acid, isobutyric acid, valeric acid, isovaleric acid, caproic acid and BCFA concentrations. In conclusion, water containing essential oil mixture in geese can be used to improve antioxidant capacity and intestinal health. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Display omitted] • Quantification of SCFAs in preadolescent children plasma was performed. • Sex, age, and body weight-specific changes in plasma SCFA were revealed. • Acetic acid was found to be the most abundant SCFA in children's plasma. • Increased propanoic acid was observed in the plasma of the overweight group. • No sex-specific differences were observed in plasma SCFA concentrations. The purpose of this study is to explore the plasma short-chain fatty acid (SCFA) concentrations in 9–12-year-old Japanese children collected in the Hokkaido study, focusing on how factors such as age, sex, and body mass index (BMI) correlate with these levels. The Hokkaido Study on Children's Health is an ongoing longitudinal study since 2002, encompassing 20,926 pregnant women in Hokkaido Prefecture, Japan, between 2003 and 2012. We contacted 1881 children aged 9–12 born between April 2006 and January 2010, and 342 non-fasting plasma samples (boys = 181, girls = 161) were obtained from this cohort, alongside assessments of their height and weight. Plasma SCFA concentrations were determined using N,N -dimethylethylenediamine derivatization method coupled with liquid chromatography-mass spectrometry. Ethyl acetate was used to extract SCFAs from plasma, and the recovery ranged from 83 % to 108 %. Our findings indicate that acetic acid had the highest concentration across all age groups and sexes. The concentrations of butyric acid, valeric acid, and hexanoic acid increased with age, peaking in 12-year-old children. Conversely, the level of 4-hydroxy valeric acid showed a decreasing trend with increasing age groups. This study also explored the correlation between BMI and SCFA concentrations, comparatively higher level of propionic acid was observed in the overweight group. The results obtained in this study enhance our understanding of the role of SCFAs in the growth and development of children and provide a foundation for future nutritional intervention and health promotion strategies. [ABSTRACT FROM AUTHOR]

Environmental pH is a critical parameter for maintenance of the gut microbiota. Here, the impact of pH on the gut microbiota luminal and mucosal community structure and short chain fatty acid (SCFA) production was evaluated i n vitro , and data compiled to reveal a donor-independent response to an increase or decrease in environmental pH. The results found that raising environmental pH significantly increased luminal community richness and decreased mucosal community evenness. This corresponded with an increased abundance of Ruminococcaceae Ruminococcus and Erysipelotrichaceae Erysipelatoclostridium , and a decreased abundance of Coriobacteriaceae Collinsella and Enterobacteriaceae Shigella for both the luminal and mucosal communities. Total SCFA levels were significantly higher, primarily due to an increase in acetic and 2-methylbutanoic acids. Lowering pH decreased luminal community evenness and decreased mucosal community evenness and richness. This corresponded with an increased abundance of Lachnospiraceae Enterocloster, Veillonellaceae Megasphaera, Veillonellaceae Sporomusa, Erysipelotrichaceae Eubacterium , and Alcaligenaceae Sutterella , and decreased abundance of Odoribacteraceae Butyricimonas, Fusobacteriaceae Fusobacterium, Veillonellaceae Phascolarctobacterium , and multiple Enterobacteriaceae species for both the luminal and mucosal communities. Total SCFA levels were significantly lower, with an observed drop in acetic and propionic acids, and increased butyric and valeric acids. Taken together, these results indicate that alterations to environmental pH can modulate the gut microbiota community structure and function, and some changes may occur in a donor-independent manner. [ABSTRACT FROM AUTHOR]

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Anaerobic fermentation is one of the important ways for the utilization of livestock and poultry manure resources. As an important intermediate product, volatile fatty acids can well reflect the degradation process of organic substances, and its real-time detection is of great significance for online monitoring of the fermentation process. In this study, a near-infrared real-time dynamic detection device and a digestate circulation loop system were designed based on an online bypass detection method on an existing laboratory-type anaerobic fermentation system, and the feasibility of online and real-time detection of total volatile fatty acids and individual volatile fatty acids such as acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid and TVFA were investigated. Specifically, the online bypass system includes an online detection device and a digestate circulation loop system. The core of the online detection device is to use the near infrared spectrometer (MicroNIR pat-u, 950-1 650 nm) to collect the optical information of digestate online in real time. The spectral acquisition mode is transflectance mode, which can obtain the spectral information of digestate to the greatest extent. The digestate circulation loop system is able to drain the digestate to the online detection site. After the detection, the loop system is cleaned by water and dried by hot air, so as to avoid the cross contamination between the two measurements and ensure the correct optical information collected by the spectrometer each time. This study takes pig manure anaerobic fermentation process as the research object. The experiment lasts for 60 days. The optical information of the anaerobic fermentation process is collected daily by the near-infrared spectrometer of the online bypass system, and the digestate samples are collected for chemical analysis at the same time. The volatile fatty acid content determined by gas chromatography and the collected optical information of digestate were used to establish a quantitative analysis model. Finally, the quantitative analysis model was used to realize the dynamic detection of volatile fatty acids in the anaerobic fermentation process, in which the chemometrics algorithms were used including the spectrum preprocessing algorithm (1st derivative, Autoscale, SNV) and partial least squares modeling algorithm. The results show that the designed online detection scheme and calibration model have a good effect on the dynamic real-time detection of volatile fatty acid content, and even if the concentration of isobutyric acid is relatively low (5/10 000), it can still achieve a more accurate detection. The results were that the Rp²=0.811, RPD=2.055 and RSD=2.288% for the acetic acid, the Rp²=0.849, RPD=2.116 and RSD=2.195% for the propionic acid, the Rp²=0.968, RPD=5.555 and RSD=2.132% for the isobutyric acid, the Rp²=0.889, RPD=2.701 and RSD=1.846% for the butyric acid, the Rp²=0.94, RPD=3.843 and RSD=3.444% for the isovaleric acid, the Rp²=0.889, RPD=2.751 and RSD=2.387% for the valeric acid, the Rp²=0.734, RPD=1.846 and RSD=2.150% for the total volatile fatty acids. Based on the online detection scheme proposed in this study, near-infrared spectroscopy technology can achieve fast, online, and real-time dynamic detection of volatile fatty acids in the anaerobic fermentation process. In the next step, this research can be carried out in a plant-scale biogas project with online bypass system, so as to realize the long-term detection of biogas project by near-infrared technology, providing real-time data support for regulating anaerobic fermentation process, generating income for enterprises and reducing economic losses. [ABSTRACT FROM AUTHOR]

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The selection of sampling bags for odour measurement by olfactometry is critical and challenging since the loss of odorants during storage and transportation is usually high. However, there are no recommendations or limitations on the storage time for the standard Triangle odour bag method used in China. In order to optimise the selection of sampling bags, selected types of sampling bags (Fluode, BOPET, FEP and Tedlar) were tested and compared by using selected key odorants (dimethyl sulphide, 2-butanone, 2,3-butanedione, 4-methylphenol, indole, skatole, acetic acid, propanoic acid, butyric acid, valeric acid and hexanoic acid). The concentrations of key odorants were detected by PTR-MS. Firstly, background contamination was tested, with total amount of background pollutants produced by Tedlar being significantly higher than the other three types of sampling bags, while FEP and BOPET had less background contaminants. Secondly, recovery tests showed that the SOAV (sum of odour activity values) recoveries after 24 h of storage of Fluode, Tedlar, FEP and BOPET were 19.5%, 24.2%, 47.7% and 27.7%, respectively. FEP had better recovery than others, especially for the storage of 4-methylphenol (~55% recovery after 48 h), which is one of the key odorants emitted from intensive pig production. Finally, the recovery tests for 2,3-butanedione were performed under various conditions and results indicated that the storage of 2,3-butanedione in sampling bags depends on bag type (e.g. single bags or double bags), initial concentration level (10 ppbv, 100 ppbv or 1000 ppbv), the inner surface area-to-volume ratio and light condition (dark, natural light or LED light). • Four types of sampling bag (Fluode, FEP, BOPET and Tedlar) were tested. • Background contaminant concentrations from Tedlar bags were significantly higher. • FEP showed best performance for recovery of tested odorants especially p-cresol. • Recovery of 2,3-butanedione depends on initial concentration and storage conditions. [ABSTRACT FROM AUTHOR]

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This study aims to develop a mathematical model to estimate the initial flux of volatile fatty acids (VFAs) in the direct contact membrane distillation (DCMD) process. VFAs are toxic and emit odors. However, they have recently been recognized as valuable raw materials. Water and VFAs can be separated together using membrane distillation (MD). Water vapor and volatile compounds can pass through the membrane pores. They move toward the permeate side. Flux occurs not only for water but also for VFAs in DCMD process due to the volatility of VFAs. Parameters affecting the flux of VFAs were identified. Their relationship was confirmed experimentally. Acetic acid, butyric acid, and valeric acid were selected as target compounds because they have different Henry's constants and hydrophobicity. The ionization of acid solution varies depending on pH. MD tests were performed under various pH conditions. The flux of VFAs was observed to vary depending on the pH. The flux of VFAs was found to be proportional to the ionization fraction (α 0) of the feed solution. Therefore, the model was developed to reflect the ionization fraction. An empirical formula was derived to predict the flux of VFAs using experimental data. A statistical analysis supported that the flux predicted by the model fitted very well with the observed flux. Additionally, experiments were performed with acid solutions of various concentrations. The concentration range applicable to the derived empirical formula was validated. The developed model can provide further insight into the relationship between flux and pH. [Display omitted] • Development of a model to predict the flux of VFAs in a DCMD system. • The flux of VFAs is significantly affected by the ionization with pH. • The flux of VFAs was suggested as J s = k s , t o t K H , s , f f n C s , f , α 0 , f − K H , s , p f n C s , p , α 0 , p . • Modeling provided more understandings of mass transport of VFAs in DCMD. [ABSTRACT FROM AUTHOR]

• A thermophilic methane-fed culture was enriched from a thermal hot spring. • The culture enabled PHB production from methane at 55 °C. • Addition of propionic acid or valeric acid induced PHBV production. • The highest 3 HV fraction was ˜100 mol%. • Methane availability delivered enhanced PHA productivity. The production of polyhydroxyalkanoates (PHAs) from methane is limited to mesophiles and thus suffers from high energy requirements for cooling. To address this issue, the use of thermophilic processes is gaining interest, as this strategy may deliver improved economic feasibility for PHA production. This study reports the first thermophilic PHA-producing culture grown on methane at 55 °C in fill-and-draw batch reactors. Harvested cells were incubated with various combinations of methane, propionic acid and valeric acid to assess their capacity for the synthesis of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV). Only PHB was produced when fed with methane alone. The addition of odd-carbon-number fatty acids resulted in higher PHA content with 3 HV fractions in the range of 15–99 mol%, depending on the types of fatty acids added. Acetic acid addition enhanced the synthesis of 3HB monomer, but not of 3 HV. On increasing the temperature to 58 °C, PHA productivity was not significantly affected. [ABSTRACT FROM AUTHOR]

• Membrane separation of VFA and suspended particles possible via ultrafiltration. • Most nanofiltration/reverse osmosis membranes let pass nearly only acetic acid. • With special reverse osmosis membranes the VFA-concentration can be highly enlarged. • By liquid-liquid extraction, a separation of polar and nonpolar acids can be done. • Gain of high concentrated acid mixture by subsequent organic phase distillation. In this study the separation of volatile fatty acids (VFAs) from biogas plant hydrolysates and from each other was investigated. This creates the possibility to make the biogas process more profitable by selling these marketable volatile fatty acids (e.g. butyric acid, caproic acid, valeric acid) as isolates or as highly concentrated mixtures. Four kinds of screw-pressed liquid hydrolysates were used: sugar beet, grass cut and grass-corn hydrolysate from a bench-scale unit as well as a corn-triticale hydrolysate from a real biogas plant. The separation and the concentration of the VFAs were carried out by nanofiltration (NF) and reverse osmosis (RO). It was possible to separate acetic acid from the other acids in the permeate but only in low concentrations (0.25%). All VFAs were enriched in the retentate anyway. With the membrane SWC4 (RO) a total mass concentration enrichment of about factor 19 could be reached (from 7 g/l to 134.6 g/l). A further approach for concentration and separation of the investigated VFAs was their extraction with organic solvents (diethyl ether (DEE), methyl-isobutyl-ketone (MIBK)), followed by a consecutive distillation of the solvent. In this manner it was possible to extract the rather nonpolar butyric acid, valeric acid and caproic acid nearly completely, while the polar, shorter-chain VFAs remained in the aqueous phase. After distillation of the organic solvent, a highly concentrated mixture of butyric acid, valeric acid and caproic acid could be obtained (c VFA;DEE = 805 g/l). As the liquid hydrolysate still contained suspended particles, which possibly could clog the NF and RO membranes and disturb the extraction, tests were carried out to remove these particles by microfiltration (MF) and ultrafiltration (UF). UF membranes with separation limits from 10 kDa to 50 kDa proved to be the best. An assessment of the probably most valuable acid product was carried out against market prices for the individual acids and against calculated possible extractable yields for a hydrolysate of a 250 kW biogas plant. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Anaerobic digestion (AD) is an established method for sustainable energy production. Anaerobic digestion model No.1 (ADM1) was used to simulate methane production (MP) and volatile fatty acid (VFA) concentrations at different ammonium concentrations. In accordance with the incomplete description of several biochemical reactions and the omission of several reaction processes, ADM1 was modified with the consideration of acetic acid inhibition and valeric acid existence. ADM1_ac (ADM1 added acetic acid inhibition) could obtain better simulation accuracy of MP (goodness‐of‐fit value = 0.945), and VFA concentrations (goodness‐of‐fit values > 0.39) were all higher than ADM1_original, but cannot explain the valeric acid production. ADM1_va (ADM1 added valeric acid existence) could achieve better simulation of valeric acid (achieving a breakthrough of zero), nevertheless the accuracy of propionic and butyric acids was poorer than ADM1_ac with differences between experimental and simulation values were 5%–10% lower. With both factors coordinated, MP and VFA concentrations could be simulated accurately by ADM1_ac_va (ADM1 added acetic acid inhibition and valeric acid existence), with the highest goodness‐of‐fit values (>0.85). The results of a verification experiment with ADM1_ac_va simulation further indicated that acetic acid inhibition and valeric acid as new component were both important in ADM1. Practitioner points: ADM1_ac could simulate MP and acetate, propionate and butyrate concentrations better.ADM1_va could explain the valerate production during AD of glucose.ADM1_ac_va could simulate AD process quite accurately, with the highest goodness‐of‐fit values (>0.85).Acetate inhibition and valerate existence were both important and should be considered in ADM1. [ABSTRACT FROM AUTHOR]

• Mcl-PHA biosynthesis from different central metabolic routes was tested at low DO. • De novo mcl-PHA synthesis was not induced by oxygen limitation in P. putida LS46. • The content of monomers from β-oxidation intermediates was enriched at low DO. • The oxygen transfer rate could be used to control the content of certain monomers. Biosynthesis of medium chain length polyhydroxyalkanoates (mcl-PHAs) requires oxygen, but little is known of how mcl-PHA production is impacted in low dissolved oxygen (DO) environments, particularly when synthesized from monomers obtained via a de novo pathway. Growth and mcl-PHA synthesis characteristics under microaerophilic bioreactor conditions were observed in Pseudomonas putida LS46 when grown on carbon substrates requiring a de novo pathway, to varying extent, for mcl-PHA synthesis. Negligible PHA accumulated from glucose, acetic acid, or valeric acid under oxygen limitation (DO ≤ 0.15 mg L−1), while final mcl-PHA content reached 19.5% of cell dry mass (CDM) from hexanoic acid. The C6 content of the polymer obtained under low DO was 10% higher than in a DO excess (NH 4 -limited) control experiment, with less of the C10 monomers indicative of de novo synthesis. In all cases, the carbon-to-PHA yield was poor (< 0.1 C-mol C-mol−1). We conclude that, as opposed to utilizing β-oxidation intermediates, de novo biosynthesis of mcl-PHA using P. putida LS46 is not favorable in microaerophilic environments. In addition to scale-up implications, this work also suggests that lowering the bioreactor oxygen transfer rate can decrease the contribution of monomers incorporated using de novo synthesis for carbon feedstocks with mixed composition. [ABSTRACT FROM AUTHOR]

Highlight • An electron beam was used to decompose volatile fatty acids (VFAs). • Decomposition characteristics by various influential factors were investigated. • The removal efficiency was increased with an increase of the molecular weight of these compounds. • The RE of all target VFAs were highest when used with O 2 as a background gas. • Valeric acid was decomposed to more low molecular weight acids by electron beam irradiation. Abstract Volatile fatty acids (VFAs) are representative odorous compounds. This study was carried out to decompose VFAs using electron beam irradiation. Acetic acid, propionic acid, butyric acid, isovaleric acid, and valeric acid were used as target VFAs. In order to confirm the decomposition efficiency and characteristics by various influential factors, experiments on the absorbed dose, background gas, and initial concentration were performed. The results confirmed that the removal efficiency increased with an increase of the absorbed dose. In addition, the removal efficiency was increased with an increase of the molecular weight of these compounds (in the following order: acetic acid < propionic acid < butyric acid < isovaleric acid < valeric acid). The removal efficiencies of all target VFAs were highest when used with O 2 as a background gas. We found the lowest removal efficiency at the He atmosphere. The results of by-product analysis confirmed that valeric acid was decomposed into butyric acid and propionic acid, and then decomposed into acetic acid. That is, high molecular weight acids would be decomposed into low molecular weight acids by electron beam irradiation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Four different volatile fatty acids were used for sustainable biological nutrient removal. • High concentrations of acetic acid appear to benefit the proliferation of Defluviicoccus. • Valeric acid, commonly found in fermented sludge, appear to benefit nitrification. • The presence of VFAs with high molecular weight indicated to benefit denitrification. • DPAO capable of using nitrite as electron acceptor belonging to Clade IIC were existent. Different ratios of four volatile fatty acids (VFAs) were used as the primary feed to a laboratory scale biological nutrient reactor during four operational stages. The reactor performed efficiently over 500 days of operation with over 90% dissolved phosphorus and over 98% ammonium-nitrogen (NH 4 +-N) removal. Through in the first experimental phase, acetate and propionate were present in a significant proportion as carbon sources, the relative abundance of Candidatus Accumulibacter, a potential polyphosphate accumulating organism, increased from 10% to 57% and the Defluviicoccus genus, a known glycogen accumulating organism (GAO), decreased from 41% to 5%. Further tests indicated the presence of denitrifying phosphorus accumulating organisms (DPAO) belonging to Clade IIC, that could use nitrite as the electron acceptor during P-uptake. In general, VFAs favored the increase of the genus Defluviicoccus and Candidatus Accumulibacter. High relative abundance of Defluviicoccus did not affect the stability and the performance of the BNR process. [ABSTRACT FROM AUTHOR]

Tricyclic diesters were synthesized in yields of 70.4-90.8% by the addition of С2-С5 monobasic carboxylic acids to tricyclo[5.2.1.02,6]dec-3-еn-8-yl acetate in the presence of a BF3·OEt2 catalyst. One of the synthesized diesters, tricyclodec-3,8-diyl diacetate, has a pleasant smell with a citrus scent and can be used in different perfume compositions as a flavoring. [ABSTRACT FROM AUTHOR]

SHANK3 is a scaffolding protein that binds to various synaptic proteins at the postsynaptic density (PSD) of excitatory glutamatergic synapses. SHANK3 is not only strongly implicated in autism spectrum disorders (ASD) but also plays a critical role in human Phelan-McDermid syndrome (22q13.3 deletion syndrome). Accumulated experimental evidence demonstrates that the zebrafish model system is useful for studying the functions of ASD-related gene during early development. However, many basic features of shank3 transcript expression in zebrafish remain poorly understood. Here, we investigated temporal, spatial, and isoform-specific expression patterns of shank3 during zebrafish development on the basis of previous researches and the differential effects of each shank3 transcript expression after exposure to valproic acid (VPA), an ASD-associated drug. At first, we observed that both shank3a and shank3b were barely expressed at very early ages (before 24 h post-fertilization (hpf)), whereas their expression levels were increased and mainly enriched in the nervous system after 24 hpf. Secondly, all of the six shank3 transcripts gradually increased during the first 7 hpf and then decreased. Subsequently, they exhibited a second increasing peak between 1 month post-fertilization (mpf) and adulthood. Thirdly, VPA treatment affected the isoform-specific expression of zebrafish shank3. In particular, the mRNA expression levels of those isoforms that contain a SAM domain were significantly increased, whereas the mRNA expression level of those which contained an ANK domain but without a SAM domain was decreased. To conclude, our findings support the molecular diversity of shank3 in zebrafish and provide a molecular framework to understand the isoform-specific function of shank3 in zebrafish. [ABSTRACT FROM AUTHOR]

Short-Chain Fatty Acids are one of the vital metabolites generated by the fermentation of dietary fiber in the gastrointestinal tract through bacterial fermentation and play an essential role in human health. This a study aimed to evaluate the effects of different fermentation conditions, including temperature (30, 42 °C), salt concentrations (2, 4 and 6%), pH (4.5, 5 and 6), and their interaction effects on the production of short-chain fatty acids (acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid) by Lactobacillus fermentum ATCC 9338, Lactobacillus fermentum 19SH and Lactobacillus acidophilus ATCC 4356. Once grown under different fermentation conditions, supernatants and pellets of fermentation media were separated, and then SCFAs were measured using Gas chromatography/mass spectrometry (GC-MS). Results revealed that fatty acid content was altered in each fermentation condition, and the highest amount after lactic acid belonged to propionic acid. Accordingly, Lb. Fermentum 19sh, Lb. Fermentum ATCC9938, and Lb. Acidophilus ATCC4356 produced the highest levels of isovaleric acid, acetic acid, propionic acid, isobutyric acid, butyric acid, and valeric acids, respectively. The results indicated a relationship between the production of short-chain fatty acids and the growth of bacterial strains and cell membrane characteristics. • Lower temperature and less NaCl concentration enhance the production of short-chain fatty acids. • The production of short-chain fatty acids depends on the bacterial growth pattern. • Following lactic acid, the major short-chain fatty acid produced belonged to propionic acid. • The short-chain fatty acid content depends on the type of bacterial strain. • Changing the pH of the culture medium is effective in the short-chain fatty acid content. [ABSTRACT FROM AUTHOR]