Pulse processing affects gas production by gut bacteria during in vitro fecal fermentation

Comparative Study on the Effects of Selenium-Enriched Yeasts with Different Selenomethionine Contents on Gut Microbiota and Metabolites

Selenium is an essential trace element for human health, but it mainly exists in an inorganic form that cannot be directly absorbed by the body. Brewer's yeast efficiently converts inorganic selenium into bioavailable organic selenium, making selenium-enriched yeast highly significant for human health research. Selenomethionine (SeM) is an important indicator for evaluating the quality of selenium-enriched yeast. Brewer's yeast was selected as the experimental subject, and the digestion of this yeast (Brewer's yeast) was simulated using an in vitro biomimetic gastrointestinal reactor to evaluate the effects of selenium-enriched yeast with various SeM levels on the gut flora of a healthy population. The experimental design comprised normal yeast (control group, OR), yeast containing moderate SeM levels (selenium-enriched group, SE), yeast containing high SeM levels (high-selenium group, MU), and a commercially available group comprising selenium-enriched yeast tablets (MA). The MU group exhibited a significantly higher concentration of short-chain fatty acids than the OR and MA groups during 48 h of fermentation, with significant differences observed (p < 0.05). Sequencing results revealed that the MU group showed significantly increased relative abundances of Bacteroidetes and Actinobacteria, while exhibiting a decreased ratio of Firmicutes to Bacteroidetes, which may simultaneously affect multiple metabolic pathways in vivo. These findings support the theory that selenium-enriched yeast with a high SeM has a more positive effect on human health compared with traditional yeast and offer new ideas for the development and application of selenium-enriched yeast.

Evaluation of different mathematical models on fitting the in vitro gas production parameters in beef cattle

In vitro rumen gas production experiment was conducted with 57 kinds of feedstuff, which were categorized into energy feed, protein feed, and roughage, collected within China. Eight mathematical models were employed to describe the kinetics of in vitro rumen gas production. The results found that for energy feeds, protein feeds, and roughages, respectively, Michaelis-Menten (MM) or Logistic-Exponential with lag (LEL), MM, and Mitscherlich (MIT) exhibited the highest or shown no significant difference compared to the highest coefficient of determination (R2) (P < 0.05) for all categories of feed. Furthermore, regression estimation of intercept and slope for regression estimates of intercept and slope for Observed versus Predicted of aforementioned models shown no significant difference from 0 and 1, respectively (P < 0.05), except LEL for energy feed. Mean absolute error (MAE), root mean squared error of prediction (RMSEP), mean squared error of prediction (MSEP) of those models were relatively lower, with minimal systematic bias and regression bias. Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) rankings were higher compared with other models. Given these results, in studies where feedstuff categories are not distinguished or multiple feedstuffs categories are included, the MM model proves to be a good choice. MM or LEL was considered to better fit energy feedstuffs. The MM model was the optimal choice for fitting protein feedstuffs. MIT provided the best accuracy and moderate precision when fitting roughages.

Enterotype-Specific Effects of Red Beetroot (Beta vulgaris L.) Powder and Betanin on Human Gut Microbiota: A Preliminary Study Based on In Vitro Fecal Fermentation Model

Red beetroots, rich in betanin, may act as prebiotics and impact gut microbiota. Because the human gut microbiota is unique to each person, the effectiveness of prebiotics varies with the enterotype. In this study, we hypothesized that the effects of red beetroot powder (RP) and betanin pigment (BP) would differ depending on the enterotype. Fecal samples from 30 subjects were analyzed and categorized into three enterotypes: Phocaeicola, Prevotella, and Bifidobacterium. Feces were collected from one representative subject from each enterotype cluster for fermentation. Results showed that RP and BP affected microbiota composition and short-chain fatty acid (SCFA) production differently across enterotypes. The Bifidobacterium cluster showed significantly reduced alpha diversity, with the direction of change in the gut microbiota composition being different from that of other subjects. Additionally, SCFAs significantly increased, with the highest increase in the Bifidobacterium cluster. In this cluster, metabolic pathways related to SCFAs (i.e., starch and sucrose metabolism and glycolysis/gluconeogenesis) were altered. Conversely, Prevotella-dominant feces exhibited fewer changes in SCFAs and a lower increase in Bifidobacterium abundance than the others. These findings highlight that RP and BP elicit enterotype-specific responses in the gut microbiota composition and SCFA production, emphasizing the importance of enterotypes in personalized nutrition.

Extrusion treatment of rice bran insoluble fiber generates specific niches favorable for Bacteroides during in vitro fermentation

To investigate the morphological changes of insoluble fiber and their effects on microbiota modulation, particularly Bacteroides, rice bran insoluble fibers were extruded at different feed moisture levels (E20, E40, and E60). The physicochemical properties and SEM revealed that E20 exhibited the highest water holding capacity and displayed the most fragmented edges. E40 had the highest swelling holding capacity and displayed the most lamellar gaps. E60 showed minimal change in physicochemical properties but had a rough surface. After 48h fermentation, E40 showed the highest levels of Bacteroides and SCFAs. E20 and E60 resulted in a modest increase in Bacteroides abundance. SEM showed that bacteria were attached to fragmented edges, loosened lamellar gaps, and rough surfaces of the extruded insoluble fibers. The results suggested that Bacteroides gained a competitive advantage within the extrusion treatment created structural changes. Extrusion treatment can be used to generate specific niches favorable for Bacteroides.

Variations in the dairy wastewater properties and bacterial diversity of each unit in membrane-enclosed anaerobic lagoon treatment process in Heilongjiang Province

In order to meet the land use requirements of the treated wastewater from high density polyethylene (HDPE) membrane-enclosed anaerobic lagoons, the physical and chemical properties of the wastewater in an HDPE membrane-enclosed anaerobic lagoon were measured. The total nitrogen content (TN) in wastewater treated in membrane-enclosed anaerobic lagoons is 3165 and 1510 mg/L in winter and summer respectively. The wastewater can be used as liquid organic fertilizer, partly replacing chemical fertilizer. The safety dosage of the wastewater was 21.48 t/ha for rice and 9.54 t/ha for corn, respectively. Meanwhile, the wastewater has the characteristics of high salt (conductivity>16.0 mS/cm) and high organic matter content (COD>16,900 mg/kg). Therefore, the potential negative effects of the wastewater on soil salinity and pH should be assessed. 16S rRNA was used to investigate the bacterial population structure and assess potential biological risks of land use of the wastewater. The wastewater from lagoon has the least and the most bacterial abundance in summer and winter, respectively. The bacterial diversity of wastewater samples from lagoon is the most. 21 and 24 phyla were detected in winter and summer samples respectively. Clostridium is the absolute dominant bacteria in the summer water samples and the absolute dominant bacteria is Trichococcus in winter water samples. Several animal and plant bacterial pathogens such as Campylobacter, Corynebacterium, Facklamia and Erysipelothrix can be detected in the wastewater samples. More than 70% of pathogenic bacteria such as Campylobacter, Facklamia, Erysipelothrix and Acholeplasma can be removed by lagoon in summer, but only about 99% of Corynebacterium is still in the lagoon (XYH). While more than 60% of Corynebacterium, Facklamia and Erysipelothrix are not removed in winter. So the biological risk of land use of anaerobic pond wastewater needs to be considered.

Toxicity of cadmium on dynamic human gut microbiome cultures and the protective effect of cadmium-tolerant bacteria autochthonous to the gut

Cadmium (Cd) is a heavy metal toxic to the gut microbiome. In this study, we cultivated two human gut microbiomes (A and B) in bioreactors with Cd at 0 and 20 ppm for 7 days to investigate effects of Cd on the gut microbiome and to isolate Cd-tolerant bacteria autochthonous to the gut. Cd showed profound toxicity, abolishing butyrate production, depleting microbes in microbiome B, and simplifying microbiome A to a small Cd-tolerant community after 2 d of incubation. When spiked into the Cd-sensitive microbiome B, the Cd-tolerant community from microbiome A and isolates from that community worked synergistically with microbiome B to enhance butyrate production and maintained this synergism at Cd concentrations up to 5 ppm. Bacteria isolated from this Cd-tolerant community included Enterococcus faecium, Enterobacter cloacae, Lactococcus lactis, and Lactobacillus taiwanensis species. This work demonstrates a straightforward method for identifying Cd-tolerant bacteria autochthonous to the human gut that synergize with the microbiome to protect against Cd-related loss of butyrate production.

A Comparative Study of the Effects of Whole Cereals and Refined Cereals on Intestinal Microbiota

Cereals are one of the most important foods on which human beings rely to sustain basic life activities and are closely related to human health. This study investigated the effects of different steamed buns on intestinal microbiota. Three steamed buns were prepared using refined flour (RF), 1:1 mixed flour (MF), and whole wheat flour (WF). In vitro digestion simulations were conducted using a bionic gastrointestinal reactor (BGR) to examine their influence on intestinal microbiota. The results showed that at 0.5% addition, butyric acid and short-chain fatty acids in WF were significantly different from those in RF and MF (p < 0.05). WF also promoted the proliferation of beneficial microbiota, such as Megamonas and Subdoligranulum. At 0.5%, 1.0%, and 1.5% additions of WF, acetic acid and short-chain fatty acids at 1.5% WF increased by 1167.5% and 11.4% from 0.5% WF, respectively, and by 20.2% and 7.6% from 1.0% WF, respectively. WF also promoted the proliferation of Bifidobacterium, Lactobacillus, and Bacteroides and inhibited the growth of pathogenic microbiota, such as Streptococcus, Enterococcus, and Klebsiella. These findings support the consumption of whole cereals and offer insights into the development of new functional foods derived from wheat.

In Vitro Modulation of Rumen Fermentation by Microbiota from the Recombination of Rumen Fluid and Solid Phases

Rumen microbiota transplantation (RMT) can improve rumen fermentation and ruminant performance. However, due to the microbial distinction in the fluid and solid phases, the current understanding of their specific roles in RMT is insufficient. Thus, this study was conducted to determine the effects of the microbiota from the recombination of the rumen fluid and solid phases on in vitro fermentation. The rumen fresh fluid (FF) and fresh solid (FS) phases were collected, and FS was washed for the fresh solid washing solution (FW). The fractions of FF, FS, and FW were autoclaved to obtain autoclaved fluid (AF), solid (AS), and washing solution (AW). Then, these phases were recombined to form eight treatments: FFFS, FFAS, FFFW, FFAW, AFFS, AFAS, AFFW, and AFAW. After 24 h of fermentation, the gas production in AFFS, FFFS, and FFAS was significantly higher than that of other groups. AFAS and AFAW had significantly lower alpha diversity than did other groups. The solid phase was enriched with fiber-degrading bacteria, including Treponema, Succinivibrio, and Ruminococcus. The fluid phase was dominated by Prevotella, Christensenellaceae R-7 group, and Rikenellaceae RC9 gut group. The washing solution had more Ruminobacter, Lachnospiraceae, and Fibrobacter. Moreover, the double-autoclaved phases displayed increased abundances of harmful bacteria, as AFAS and AFAW had higher Streptococcus and Prevotellaceae YAB2003 group abundances. A network analysis showed that the signature microbiota in AFAS and AFAW were negatively associated with the keystone microbiota in the other groups. In summary, the recombination of the solid phase and the autoclaved fluid phase had the best in vitro fermentation result, which provided certain references for RMT. IMPORTANCE This is the first study to systematically evaluate the in vitro fermentation efficiency of diets by bacteria harvested and recombined from the fluid and solid phases of rumen contents, and it took into account the effect of washing the rumen solid phase. Using "reconstituted rumen content", this study confirmed that bacteria from different fractions of the rumen digesta resulted in different fermentation production of diets and found the characteristic bacteria in each phase of rumen contents. Our data reveal that the bacteria in the solid phase have more positive effects on the in vitro fermentation parameters, that the combination of the autoclaved fluid phase and the fresh solid phase have the most ideal fermentation effect, and that the autoclave process significantly influenced the microbial composition and increased the abundance of harmful bacteria. This study provides a landmark reference for the future use of rumen microbiota transplantation to improve animal feed utilization and growth performance.

The impact of protein source and grain inclusion on digestibility, fecal metabolites, and fecal microbiome in adult canines

This study was conducted to determine the effect of animal protein inclusion rate and grain-free or grain-inclusive diets on macronutrient digestibility, fecal characteristics, metabolites, and microbiota in mixed-breed hounds and Beagles. Four experimental extruded kibble diets were made with varying amounts of animal protein and carbohydrates: 1) high animal protein, grain-inclusive (HA-GI), 2) low animal protein, grain-free (LA-GF), 3) low animal protein, grain-inclusive (LA-GI), and 4) high animal protein, grain-free (HA-GF). Thirty-two Beagles and 33 mixed-breed hounds were assigned to 1 of the 4 treatment groups in a completely randomized design that lasted 180 d. All diets were similar in chemical composition and well-digested by the animals. In general, for fecal metabolites, mixed-breed hounds had a greater concentration of total short-chain fatty acid (SCFA) and ammonia and lower indole concentration than Beagles (P < 0.05). In mixed-breed hounds, LA-GF had a greater (P < 0.05) total SCFA concentration than HA-GI and LA-GI; however, this was not observed in Beagles. There were greater concentrations of ammonia, phenol, and indole in HA-GI than in LA-GF (P < 0.05). Breed-affected fecal primary bile acid (BA) concentration, as mixed-breed hounds had a greater concentration of cholic acid (CA) than Beagles (P < 0.05). Mixed-breed hounds fed LA-GF resulted in greater CA concentrations than HA-GI and LA-GI (P < 0.05). Dogs who consumed LA-GF had lower fecal secondary BA content than the other groups (P < 0.05). The distribution of the fecal microbiota community differed in LA-GF compared with the other groups, with lower α-diversity. However, dogs fed LA-GF had the largest difference in composition with greater Selenomonadaceae, Veillonellaceae, Lactobacillaceae, Streptococcus, Ligilactobacillus, Megamonas, Collinsella aerofaciens, and Bifidobacterium sp. than the other groups. A significant breed effect was noted on nutrient digestibility, fecal metabolites, and microbiota. A treatment effect was observed in LA-GF as it resulted in greater fecal SCFA, lower protein fermentative end products, greater fecal primary BAs, lower fecal secondary BA concentrations, and shifts in fecal microbiota.

Edible Plant Sprouts: Health Benefits, Trends, and Opportunities for Novel Exploration

The consumption of plant sprouts as part of human day-to-day diets is gradually increasing, and their health benefit is attracting interest across multiple disciplines. The purpose of this review was to (a) critically evaluate the phytochemicals in selected sprouts (alfalfa, buckwheat, broccoli, and red cabbage), (b) describe the health benefits of sprouts, (c) assess the recent advances in sprout production, (d) rigorously evaluate their safety, and (e) suggest directions that merit special consideration for further novel research on sprouts. Young shoots are characterized by high levels of health-benefitting phytochemicals. Their utility as functional ingredients have been extensively described. Tremendous advances in the production and safety of sprouts have been made over the recent past and numerous reports have appeared in mainstream scientific journals describing their nutritional and medicinal properties. However, subjects such as application of sprouted seed flours in processed products, utilizing sprouts as leads in the synthesis of nanoparticles, and assessing the dynamics of a relationship between sprouts and gut health require special attention for future clinical exploration. Sprouting is an effective strategy allowing manipulation of phytochemicals in seeds to improve their health benefits.