Influence of high- and low-fermentable dietary fibres in sows' diet on the colostrum potential against Clostridioides difficile toxin-induced effects in IPEC-J2 cells

Sow colostrum has been reported to protect the IPEC-J2 cells and piglet colon tissues from detrimental effect of Clostridioides difficile toxins. Since dietary fibre can influence the colostrum composition in sows, we hypothesised that it can also differentially affect the colostrum potential against C. difficile toxin-induced effects in IPEC-J2. IPEC-J2 were incubated with colostrum from sows fed either high-fermentable sugar beet pulp (SBP) or low-fermentable lignocellulose (LNC) fibres and in combination with the toxins and analysed by trans-epithelial electrical resistance (TEER) and cell viability using propidium iodide in flow cytometry. Toxins drastically decreased the integrity of IPEC-J2. Colostrum from the sows fed either SBP or LNC exerted protective effect against toxins on IPEC-J2 integrity and this effect was numerically superior in the SBP group. Differences in the percentages of TEER between different treatments were noted after 2 h (p = 0.043), 3 h (p = 0.017) and 4 h (p = 0.017) of incubation and a tendency for differences was noted after 5 h of incubation (p = 0.071). Colostrum from either SBP- or LNC-fed sows did not protect the IPEC-J2 from toxin-induced death. Colostrum of the sows fed either high-fermentable or low-fermentable fibres has a potential to protect IPEC-J2 from the loss of integrity, which may be important in protection from C. difficile-infection development in neonatal piglets.

Rumen microbial diversity, enteric methane emission and nutrient utilization of crossbred Karan-Fries cattle (Bos taurus) and Murrah buffalo (Bubalus bubalis) consuming varied roughage concentrate ratio

Dietary mix and host species have both been shown to have a significant impact on rumen microbial diversity, enteric methane emission and animal performance. The goal of this study was to see how the roughage concentrate ratio 70:30 (Low concentrate; LC) vs 40:60 (High concentrate; HC) and the host species crossbred cattle vs buffalo affected rumen microbial diversity, enteric methane emissions and nutrient utilization. Dry matter intake (kg/d) and dry matter percent digestibility were considerably (p < 0.05) higher in the HC ration and buffalo compared to LC ration and crossbred cattle, respectively. Both dietary mix and host species had a substantial (p < 0.05) impact on intake of various nutrients, including organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), and acid detergent fiber (ADF). Increased concentrate proportion in the ration improved nitrogen balance, resulting in increased average daily gain and considerably reduced methane (g/d) output (p < 0.05). Furthermore, 16S rRNA genes were sequenced using Oxford Nanopore Technology (ONT) and subsequently annotated using the Centrifuge workflow to uncover ruminal bacterial diversity. Firmicutes was considerably (p < 0.01) greater in the LC diet, whereas, Bacteroidetes was higher in the HC ration. Genus Prevotella dominated all rumen samples, and buffalo fed LC ration had significantly (p < 0.01) higher Oscillospira abundance. At the species level, simple sugar-utilizing bacteria such as Prevotella spp. and Selenomonas ruminantium predominated in the crossbred cattle, but fibrolytic bacteria such as Oscillospira guilliermondii were statistically (p < 0.01) more abundant in the buffalo. Overall, dietary mix and host species have both been shown to have a significant impact on rumen microbial diversity, enteric methane emission and animal performance, however, host species remained a major driving force to change ruminal community composition as compared to roughage concentrate ratio under similar environmental conditions.

Transcriptomic analysis reveals that non-forage or forage fiber source promotes rumen development through different metabolic processes in lambs

Dietary fiber supplementation can stimulate rumen development in lambs during the pre-weaning period. However, it is unclear whether different sources of fiber have varying effects on rumen development. This study aimed to investigate the molecular mechanism of rumen morphological and functional development based on non-forage or forage as a starter dietary fiber source. Twenty-four male Hu lambs with similar body weights (BW, 3.67 ± 0.08 kg) were selected and divided into two groups that received diets supplemented with either alfalfa hay (AH) or soybean hull (SH). At the age of 70 days, six lambs were slaughtered from each treatment group for rumen fermentation and morphological analyses. Three samples of the rumen tissue from the ventral sac were collected for transcriptomic analysis. The results identified 633 differentially expressed genes (DEGs), of which 210 were upregulated and 423 were downregulated in the SH group compared with those in the AH group. The upregulated DEGs were most enriched in the immune function and proteolysis pathways, whereas the downregulated DEGs were mainly involved in cell proliferation, apoptosis, and differentiation pathways. These findings indicated that non-forage as a starter dietary fiber source improved immune function and enhanced nitrogen utilization, whereas forage facilitated rumen morphological development.

Dry beans (Phaseolus vulgaris L.) modulate the kinetics of lipid digestion in vitro: Impact of the bean matrix and processing

The lipid-lowering effect of dry beans and their impact on lipid and cholesterol metabolism have been established. This study investigates the underlying mechanisms of this effect and explore how the structural integrity of processed beans influences their ability to modulate lipolysis using the INFOGEST static in vitro digestion model. Dietary fiber (DF) fractions were found to decrease lipolysis by increasing the digesta viscosity, leading to depletion-flocculation and/or coalescence of lipid droplets. Bean flours exhibited a more pronounced reduction in lipolysis compared to DF. Furthermore, different levels of bean structural integrity showed varying effects on modulating lipolysis, with medium-sized bean particles demonstrating a stronger reduction. Hydrothermal treatment compromised the ability of beans to modulate lipid digestion, while hydrostatic-pressure treatment (600 MPa/5min) enhanced the effect. These findings highlight that the lipid-lowering effect of beans is not solely attributed to DF but also to the overall bean matrix, which can be manipulated through processing techniques.

Dietary Fiber and Its Potential Role in Obesity: A Focus on Modulating the Gut Microbiota

Dietary fiber is a carbohydrate polymer with ten or more monomeric units that are resistant to digestion by human digestive enzymes, and it has gained widespread attention due to its significant role in health improvement through regulating gut microbiota. In this review, we summarized the interaction between dietary fiber, gut microbiota, and obesity, and the beneficial effects of dietary fiber on obesity through the modulation of microbiota, such as modifying selective microbial composition, producing starch-degrading enzymes, improving gut barrier function, reducing the inflammatory response, reducing trimethylamine N-oxide, and promoting the production of gut microbial metabolites (e.g., short chain fatty acids, bile acids, ferulic acid, and succinate). In addition, factors affecting the gut microbiota composition and metabolites by dietary fiber (length of the chain, monosaccharide composition, glycosidic bonds) were also concluded. Moreover, strategies for enhancing the biological activity of dietary fiber (fermentation technology, ultrasonic modification, nanotechnology, and microfluidization) were subsequently discussed. This review may provide clues for deeply exploring the structure-activity relationship between dietary fiber and antiobesity properties by targeting specific gut microbiota.

Cactus cladodes for dairy goats: what is the best fiber source?

This study evaluated the effect of different fiber sources supplied with cactus cladodes in diets on the intake and digestibility of nutrients, ingestive behavior, milk yield, and composition of dairy goats. The fiber sources were corn silage, sorghum silage, Digitaria pentzii Stent. hay, and sugarcane bagasse. Twelve Saanen goats with an average weight of 48.9 ± 7.3 kg and average production of 2.8 ± 0.7 kg of milk/day were assigned in three simultaneous 4 × 4 Latin squares (four animals, four treatments, and four experimental periods). There was no difference between the fiber sources for intake (P > 0.05) of dry matter (2.58 kg/day), organic matter (2.30 kg/day), crude protein (0.385 kg/day), neutral detergent fiber (0.895 kg/day), non-fibrous carbohydrates (0.858 kg/day), and metabolizable energy (5.66 Mcal/day). Also, the fiber sources did not influence dry matter and nutrient digestibility (P > 0.05). The association of cactus cladodes with silages, hay, and sugarcane bagasse did not change milk production, milk production corrected for 3.5% of fat and corrected for energy (2.78; 2.53 and 2,55 kg/day, respectively), in addition to milk composition (P > 0.05). No differences were observed in ingestive behavior (P > 0.05). Any fiber sources evaluated are recommended.

Ferulic acid production from wheat bran by integration of enzymatic pretreatment and a cold-adapted carboxylesterase catalysis

High-value chemical production from natural lignocellulose transformation is a reliable waste utilization approach. A gene encoding cold-adapted carboxylesterase in Arthrobacter soli Em07 was identified. The gene was cloned and expressed in Escherichia coli to obtain a carboxylesterase enzyme with a molecular weight of 37.2 KDa. The activity of the enzyme was determined using α-naphthyl acetate as substrate. Results showed that the optimum enzyme activity of carboxylesterase was at 10 °C and pH 7.0. It was also found that the enzyme could degrade 20 mg enzymatic pretreated de-starched wheat bran (DSWB) to produce 235.8 μg of ferulic acid under the same conditions, which was 5.6 times more than the control. Compared to the chemical strategy, enzymatic pretreatment is advantageous because it is environmentally friendly, and the by-products can be easily treated. Therefore, this strategy provides an effective method for high-value utilization of biomass waste in agriculture and industry.

Combined resistant dextrin and low-dose Mg oxide administration increases short-chain fatty acid and lactic acid production by gut microbiota

The consumption of resistant dextrin improves constipation, while its fermentation and degradation by the intestinal microbiota produce short-chain fatty acids (SCFA) and lactic acid, which have beneficial effects on host metabolism and immunity. Mg oxide (MgO) is an important mineral that is used to treat constipation. Therefore, resistant dextrin and MgO are often administered together to improve constipation. However, limited information is available regarding the effect of this combination on SCFA and lactic acid production. Crl:CD1(ICR) mice were fed a Mg-free diet with 5% resistant dextrin, followed by oral administration of MgO. We collected the cecum contents and measured SCFA and lactic acid levels. Additionally, the human subjects received resistant dextrin and Mg supplements as part of their habitual diet. The results of this study demonstrate that intestinal microbiota cannot promote SCFA and lactic acid production in the absence of Mg. In a mouse model, low doses of MgO promoted the production of SCFA and lactic acid, whereas high doses decreased their production. In humans, the combined consumption of resistant dextrin and Mg supplements increased the production of SCFA and lactic acid. The production of SCFA and lactic acid from dietary fiber may be augmented by the presence of MgO.

Label-free quantitative proteomics reveals the potential mechanisms of insoluble dietary fiber from okara in improving hepatic lipid metabolism of high-fat diet-induced mice

The high purity insoluble dietary fiber (IDF) from okara is a natural component with a potentially positive effect on a high-fat diet (HFD)-induced hepatic metabolic disorders, although its regulatory mechanism remains unclear. This study aims to elucidate the potential pathways and key proteins of IDF for the amelioration of hepatic lipid metabolism in mice fed with HFD. Here, we used label-free quantitative proteomics technology to quantity and identify differentially expressed proteins in the liver that are associated with IDF treatment. The differentially expressed proteins were assessed by GO annotation and KEGG pathways. Western blot and qRT-PCR analyses were conducted to validate the potential targets regulated by IDF. In total, 73 differentially expressed proteins were identified, of which 27 were up-regulated (FC > 1.5) and 46 were down-regulated (FC < 0.667). GO analysis suggested that differentially expressed proteins were mainly located in the cell and organelles, regulated biological processes, and were associated with enzyme activity and molecular binding. The KEGG pathway enrichment analysis further demonstrated glycolysis/gluconeogenesis, pyruvate metabolism, TCA cycle, arginine biosynthesis, alanine, aspartate and glutamate metabolism, and retinol metabolism were affected. The combination of proteomics, Western blot, and qRT-PCR suggested that ACS, ACLY, GOT1, GLS2, NAGS, CYP4A10, CYP3A25, and CYP2A5 in these pathways might be key proteins for IDF intervention. Taken together, our findings elucidate new mechanisms involved in how IDF affects hepatic metabolism, provide important information for the functional food industries, and improve the added value of okara. SIGNIFICANCE: Okara is evidenced as a high-quality by-product with several nutritional components, especially dietary fiber (50-60%) labeled as "The Seventh Nutrient". Previous studies have shown that IDF has a positive potential effect on a high-fat diet (HFD)-induced hepatic metabolic disorders, but its molecular mechanism remains unclear. To elucidate the therapeutic mechanism of IDF at the protein level, a label-free quantitative proteomic analysis was used to identify the dynamic changes of the liver proteome between HIDF and HFD groups in this study. These results provide a new perspective for exploring the therapeutic mechanism of IDF at the protein level and enlightenment for promoting the comprehensive utilization of okara.

Altering palmitic acid and stearic acid ratios in the diet of early-lactation Holsteins under heat stress: Feed intake, digestibility, feeding behavior, milk yield and composition, and plasma metabolites

The objective of this study was to evaluate the effects of varying the ratio of dietary palmitic (C16:0; PA) and stearic (C18:0; SA) acids on nutrient digestibility, production, and blood metabolites of early-lactation Holsteins under mild-to-moderate heat stress. Eight multiparous Holsteins (body weight = 589 ± 45 kg; days in milk = 51 ± 8 d; milk production = 38.5 ± 2.4 kg/d; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design (21-d periods inclusive of 7-d data collection). The PA (88.9%)- and SA (88.5%)-enriched fat supplements, either individually or in combination, were added to diets at 2% of dry matter (DM) to formulate the following treatments: (1) 100PA:0SA (100% PA + 0% SA), (2) 66PA:34SA (66% PA + 34% SA), (3) 34PA:66SA (34% PA + 66% SA), and (4) 0PA:100SA (0% PA + 100% SA). Diets offered, in the form of total mixed rations, were formulated to be isonitrogenous (crude protein = 17.2% of DM) and isocaloric (net energy for lactation = 1.69 Mcal/kg DM), with a forage-to-concentrate ratio of 40:60. Ambient temperature-humidity index averaged 72.9 throughout the experiment, suggesting that cows were under mild-to-moderate heat stress. No differences in DM intake across treatments were detected (mean 23.5 ± 0.64 kg/d). Increasing the dietary proportion of SA resulted in a linear decrease in total-tract digestibility of total fatty acids, but organic matter, DM, neutral detergent fiber, and crude protein digestibilities were not different across treatments. Decreasing dietary PA-to-SA had no effect on the time spent eating (340 min/d), rumination (460 min/d), and chewing (808 min/d). As dietary PA-to-SA decreased, milk fat concentration and yield decreased linearly, resulting in a linear decrease of 3.5% fat-corrected milk production and milk fat-to-protein ratio. Feed efficiency expressed as kg 3.5% fat-corrected milk/kg DM intake decreased linearly with decreasing the proportion of PA-to-SA in the diet. Treatments had no effect on milk protein and lactose content. A linear increase in de novo and preformed fatty acids was identified as the ratio of PA to SA decreased, while PA and SA concentrations of milk fat decreased and increased linearly, respectively. A linear reduction in blood nonesterified fatty acids and glucose was detected as the ratio of PA to SA decreased. Insulin concentration increased linearly from 10.3 in 100PA:0SA to 13.1 µIU/mL in 0PA:100SA, whereas blood β-hydroxybutyric acid was not different across treatments. In conclusion, the heat-stressed Holsteins in early-lactation phase fed diets richer in PA versus SA produced greater fat-corrected milk and were more efficient in converting feed to fat-corrected milk.

Metabolite Profiling of Pleurotus ostreatus Grown on Sisal Agro-Industrial Waste Supplemented with Cocoa Almond Tegument and Wheat Bran

Pleurotus ostreatus is an edible fungus with high nutritional value that uses industrial and agricultural lignocellulosic residues as substrates for growth and reproduction. Understanding their growth metabolic dynamics on agro-industrial wastes would help to develop economically viable and eco-friendly biotechnological strategies for food production. Thus, we used UHPLC/MS/MS and GNPS as an innovative approach to investigate the chemical composition of two strains of P. ostreatus, coded as BH (Black Hirataki) and WH (White Hirataki), grown on sisal waste mixture (SW) supplemented with 20 % cocoa almond tegument (CAT) or 20 % of wheat bran (WB). Metabolite dereplication allowed the identification of 53 metabolites, which included glycerophospholipids, fatty acids, monoacylglycerols, steroids, carbohydrates, amino acids, and flavonoids. This is the first report of the identification of these compounds in P. ostreatus, except for the steroid ergosterol. Most of the metabolites described in this work possess potential biological activities, which support the nutraceutical properties of P. ostreatus. Thus, the results of this study provide essential leads to the understanding of white-rot fungi chemical plasticity aiming at developing alternative biotechnologies strategies for waste recycling.

Metabolic signature of 13C-labeled wheat bran consumption related to gut fermentation in humans: a pilot study

PURPOSE

The aim of this pilot study was to analyze concomitantly the kinetics of production of 13C-labeled gut-derived metabolites from 13C-labeled wheat bran in three biological matrices (breath, plasma, stools), in order to assess differential fermentation profiles among subjects.

METHODS

Six healthy women consumed a controlled breakfast containing 13C-labeled wheat bran biscuits. H2, CH4 and 13CO2, 13CH4 24 h-concentrations in breath were measured, respectively, by gas chromatography (GC) and GC-isotope ratio mass spectrometry (GC-IRMS). Plasma and fecal concentrations of 13C-short-chain fatty acids (linear SCFAs: acetate, propionate, butyrate, valerate; branched SCFAs: isobutyrate, isovalerate) were quantified using GC-combustion-IRMS. Gut microbiota composition was assessed by16S rRNA gene sequencing analysis.

RESULTS

H2 and CH4 24 h-kinetics distinguished two groups in terms of fermentation-related gas excretion: high-CH4 producers vs low-CH4 producers (fasting concentrations: 45.3 ± 13.6 ppm vs 6.5 ± 3.6 ppm). Expired 13CH4 was enhanced and prolonged in high-CH4 producers compared to low-CH4 producers. The proportion of plasma and stool 13C-butyrate tended to be higher in low-CH4 producers, and inversely for 13C-acetate. Plasma branched SCFAs revealed different kinetics of apparition compared to linear SCFAs.

CONCLUSION

This pilot study allowed to consider novel procedures for the development of biomarkers revealing dietary fiber-gut microbiota interactions. The non-invasive assessment of exhaled gas following 13C-labeled fibers ingestion enabled to decipher distinct fermentation profiles: high-CH4 producers vs low-CH4 producers. The isotope labeling permits a specific in vivo characterisation of the dietary fiber impact consumption on microbiota metabolite production.

CLINICAL TRIAL REGISTRATION

The study has been registered under the number NCT03717311 at ClinicalTrials.gov on October 24, 2018.

Physical effectiveness of corn silage fractions stratified with the Penn State Particle Separator for lactating dairy cows

This study evaluated the physical effectiveness of whole-plant corn silage (CS) particles stratified with the Penn State Particle Separator, composed of 19- and 8-mm-diameter sieves and a pan, for lactating dairy cows. Eight Holstein cows (27.6 ± 2.8 kg/d of milk, 611 ± 74 kg body weight; 152 ± 83 d in milk) were assigned to two 4 × 4 Latin squares (22-d periods, 16-d adaptation), where one square was formed with rumen-cannulated cows. Three CS particle fractions were manually isolated using the 8- and 19-mm diameter sieves and re-ensiled in 200-L drums. The 4 experimental diets were (% dry matter): (1) CON (control): 17% forage neutral detergent fiber (NDF) from CS (basal roughage), 31.5% starch, and 31.9% NDF; (2) PSPan: 17% forage NDF from CS + 9% NDF from CS particles <8 mm, 25.9% starch, and 37.9% NDF; (3) PS8: 17% forage NDF from CS + 9% NDF from CS particles 8 to 19 mm, 25.5% starch, and 38.3% NDF; and (4) PS19: 17% forage NDF from CS + 9% NDF from CS particles >19 mm, 24.9% starch, and 38.8% NDF. Cows fed PS8 had greater dry matter intake and energy-corrected milk yield (22.4 and 26.9 kg/d, respectively) than cows fed CON (20.8 and 24.7 kg/d) and PS19 (21.2 and 24.8 kg/d), but no difference was detected between PSPan (21.6 and 25.8 kg/d) and other treatments. Milk fat concentration was greater for PS8 than CON, with intermediate values for PSPan and PS19. Milk fat yield was greater for cows fed PS8 than CON and PS19, and cows fed PSPan secreted more fat than CON cows but were not different from cows fed the other 2 diets. Cows fed CON had a lower meal frequency than cows fed PSPan, shorter meal and rumination times than PS8, and greater meal size and lower rates of rumination and chewing than the other 3 diets. Total chewing per unit of NDF was higher for PS8 than PSPan, although neither treatment differed from CON or PS19. Cows fed PS19 had higher refusal of feed particles >19 mm than cows fed CON and PSPan. The refusal of dietary NDF and undigested NDF in favor of starch were all greater for PS19 than on the other treatments. Cows fed PS19 had a greater proportion of the swallowed bolus and rumen digesta with particles >19 mm than the other 3 diets. Cows fed CON had the lowest ruminal pH and greatest lactate concentration relative to the other 3 diets. Plasma lipopolysaccharide was higher for cows fed CON and PSPan than for cows fed PS8 and PS19, and serum d-lactate tended to be lower on PSPan than for CON and PS8. In summary, the inclusion of CS fractions in a low-forage fiber diet (CON) reduced signs of ruminal acidosis. Compared with CS NDF <8 and >19 mm, CS NDF with 8- to 19-mm length promoted better rumen health and performance of dairy cows. These results highlight the importance of adjusting CS harvest and formulating dairy diets based on the proportion of particles retained between the 8- and 19-mm sieves.

Impact of different dietary fibre sources on production performance, bacterial composition and metabolites in the caecal contents of rabbits

This study was conducted to investigate the effects of different dietary fibre sources on growth performance, gastrointestinal tract development, caecal fermentation and bacterial composition in the caecal contents of rabbits. A total of 120 35-day-old weaned Minxinan black rabbits were divided into three groups and fed a diet composed of peanut straw powder (Group A), alfalfa powder (Group B) and soybean straw powder (Group C) as the main fibre source. The final body weight and average daily gain in Group B were higher than those in Group C, and the average daily feed intake and feed conversion ratio in Group A were lower than those in Group C (p < 0.05). The relative weights of the stomach, small intestine and caecum of rabbits in Group C were higher than those in Groups of B and A, and the relative weights of the caecal contents in Group C were lower than those in Groups A or B (p < 0.05). The pH value and propionic acid, butyric acid and valeric acid concentrations in the caecum of Group C were lower than those in the caecum of Groups A or B, and the concentration of acetic acid in the caecum was lower (p < 0.05). The dominant microbes in the caecal contents of Minxinan black rabbits were Firmicutes, Bacteroidetes and Proteobacteria at the phylum level, and the number of species, Chao1 index and ACE index measured was different between the B-C and A-C groups (p < 0.05). Different dietary fibre sources could affect the growth performance, gastrointestinal tract development and intestinal microbiota of rabbits, and the nutritional value of alfalfa powder was better than that of peanut straw and soybean straw.

Bamboo forage in Peruvian Amazon: a potential feed for cattle

During the dry and rainy seasons of the Northeastern Zone of Peru, a chemical characterization of five species of bamboo prevalent in the area (Guadua lynnclarkiae, G. takahashiae, Bambusa vulgaris, G. weberbaueri, and Dendrocalamus asper) was conducted. Then, the effect of supplementing bamboo leaves (0, 20, and 40% inclusion of D. asper) on the intake and live weight gain of 18 Gyr × Holstein heifers was evaluated for 28 days. Among the species evaluated, D. asper has the greatest crude protein (CP) concentration (158-166 g/kg Dry matter- DM), post-ruminal CP supply (127 g/kg DM), and in vitro organic matter digestibility (444-456 g/kg DM) but similar concentrations of crude ash (124 g/kg DM), calcium (2.4-2.8 mg/g), phosphorus (0.7-2.1 mg/g), protein fractions A, B1, B2, B3, C (45, 5, 35, 56, and 17g/kg DM, respectively), rumen-undegraded CP (31% CP), neutral detergent fiber (NDF, 685g/kg DM), and acid detergent fiber (ADF, 357 g/kg DM) than the other species evaluated. Dry matter intake was higher in the control treatment and in the 20% bamboo leaf inclusion treatment than in the 40% bamboo inclusion treatment. Intake of CP and NDF decreased with the increase in bamboo inclusion. Despite the differences in DM, CP, and NDF intake, the live weight gain remained similar across treatments. However, there was a greater feed conversion in the 20% bamboo leaf inclusion treatment. During the dry season, bamboo leaves can be used as an alternative supplement at a maximum inclusion of 20% without affecting the live weight gain.

Detection of changes in regional colonic fermentation in response to supplementing a low FODMAP diet with dietary fibres by hydrogen concentrations, but not by luminal pH

BACKGROUND

Carbohydrate fermentation plays a pivotal role in maintaining colonic health with excessive proximal and deficient distal fermentation being detrimental.

AIMS

To utilise telemetric gas- and pH-sensing capsule technologies for defining patterns of regional fermentation following dietary manipulations, alongside conventional techniques of measuring fermentation.

METHODS

In a double-blind crossover trial, 20 patients with irritable bowel syndrome were fed low FODMAP diets that included no extra fibre (total fibre content 24 g/day), or additional poorly fermented fibre, alone (33 g/day) or with fermentable fibre (45 g/day) for 2 weeks. Plasma and faecal biochemistry, luminal profiles defined by tandem gas- and pH-sensing capsules, and faecal microbiota were assessed.

RESULTS

Plasma short-chain fatty acid (SCFA) concentrations (μmol/L) were median (IQR) 121 (100-222) with fibre combination compared with 66 (44-120) with poorly fermented fibre alone (p = 0.028) and 74 (55-125) control (p = 0.069), but no differences in faecal content were observed. Luminal hydrogen concentrations (%), but not pH, were higher in distal colon (mean 4.9 [95% CI: 2.2-7.5]) with fibre combination compared with 1.8 (0.8-2.8) with poorly fermented fibre alone (p = 0.003) and 1.9 (0.7-3.1) control (p = 0.003). Relative abundances of saccharolytic fermentative bacteria were generally higher in association with supplementation with the fibre combination.

CONCLUSIONS

A modest increase in fermentable plus poorly fermented fibres had minor effects on faecal measures of fermentation, despite increases in plasma SCFA and abundance of fermentative bacteria, but the gas-sensing capsule, not pH-sensing capsule, detected the anticipated propagation of fermentation distally in the colon. The gas-sensing capsule technology provides unique insights into localisation of colonic fermentation.

TRIAL REGISTRATION

ACTRN12619000691145.

The Effect of Dietary Oat Consumption and Its Constituents on Fat Storage and Obesity

This review is to summarize and analyze the currently available knowledge concerning the action of oat (Avena sativa L.) consumption on obesity, as well as possible constituents and extra- and intracellular mediators responsible for its anti-obesity effect. The oat constituents could reduce fat storage via several mediatory mechanisms - brain centers regulating appetite, gastrointestinal functions, gut bacteria, fat synthesis and metabolism and maybe via changes in oxidative processes, steroid hormones receptors and adipose tissue vascularization. Several oat constituents (starch, fiber and beta-glucan) could have anti-obesity properties, whilst one oat constituent (starch or fiber) could affect fat storage via several mechanisms of action.

The effects of feeding α-amylase-enhanced corn silage with different dietary starch concentrations to lactating dairy cows on milk production, nutrient digestibility, and blood metabolites

Corn silage is one of the most common ingredients fed to dairy cattle. Advancement of corn silage genetics has improved nutrient digestibility and dairy cow lactation performance in the past. A corn silage hybrid with enhanced endogenous α-amylase activity (Enogen, Syngenta Seeds LLC) may improve milk production efficiency and nutrient digestibility when fed to lactating dairy cows. Furthermore, evaluating how Enogen silage interacts with different dietary starch content is important because the ruminal environment is influenced by the amount of rumen fermentable organic matter consumed. To evaluate the effects of Enogen corn silage and dietary starch content, we conducted an 8-wk randomized complete block experiment (2-wk covariate period, 6-wk experimental period) with a 2 × 2 factorial treatment arrangement using 44 cows (n = 11/treatment; 28 multiparous, 16 primiparous; 151 ± 42 d in milk; 668 ± 63.6 kg of body weight). Treatment factors were Enogen corn silage (ENO) or control (CON) corn silage included at 40% of diet dry matter and 25% (LO) or 30% (HI) dietary starch. Corn silage used in CON treatment was a similar hybrid as in ENO but without enhanced α-amylase activity. The experimental period began 41 d after silage harvest. Feed intake and milk yield data were collected daily, plasma metabolites and fecal pH were measured weekly, and digestibility was measured during the first and final weeks of the experimental period. Data were analyzed using a linear mixed model approach with repeated measures for all variables except for body condition score change and body weight change. Corn silage, starch, week, and their interactions were included as fixed effects; baseline covariates and their interactions with corn silage and starch were also tested. Block and cow served as the random effects. Plasma glucose, insulin, haptoglobin, and serum amyloid A concentrations were unaffected by treatment. Fecal pH was greater for cows fed ENO versus CON. Dry matter, crude protein, neutral detergent fiber, and starch digestibility were all greater for ENO than CON during wk 1, but differences were less by wk 6. The HI treatments depressed neutral detergent fiber digestibility compared with LO. Dry matter intake (DMI) was not affected by corn silage but was affected by the interaction of starch and week; in wk 1, DMI was similar but by wk 6, cows fed HI had 1.8 ± 0.93 kg/d less DMI than LO cows. Milk, energy-corrected milk, and milk protein yields were 1.7 ± 0.94 kg/d, 1.3 ± 0.70 kg/d, and 65 ± 27 g/d greater for HI than LO, respectively. In conclusion, ENO increased digestibility but it did not affect milk yield, component yields, or DMI. Increasing dietary starch content improved milk production and feed efficiency without affecting markers of inflammation or metabolism.

Biochemical limitations of Bacillus thuringiensis based biopesticides production in a wheat bran culture medium

Bacillus thuringiensis, a gram-positive sporulating bacteria found in the environment, produces, during its sporulation phase, crystals responsible for its insecticidal activity, constituted of an assembly of pore-forming δ-endotoxins. This has led to its use as a biopesticide, an eco-friendly alternative to harmful chemical pesticides. To minimize production cost, one endemic Bacillus thuringiensis sv. kurstaki (Btk) strain Lip, isolated from Lebanese soil, was cultivated in a wheat bran (WB) based medium (IPM-4-Citrus project EC n° 734921). With the aim of studying the biochemical limitations of Btk biopesticide production in a wheat bran based medium, the WB was sieved into different granulometries, heat treated, inoculated with Btk Lip at flask scale, then filtered and separated into an insoluble and a permeate fractions. Several biochemical analyses, ie. bio performances, starch, elemental composition, total nitrogen and ashes, were then conducted on both fractions before and after culture. On a morphological level, two populations were distinguished, the fine starch granules and the coarse lignocellulosic particles. The biochemical analyses showed that both the raw and sieved WB have a similar proteins content (0.115 g/gdm WB), water content (0.116 g/gdm WB) and elemental composition (carbon: 45%, oxygen: 37%, nitrogen: 3%, hydrogen: 6%, ashes: 5%). The starch content was 17%, 14% and 34% and the fermentable fraction was estimated to 32.1%, 36.1% and 51.1% respectively for classes 2, 3 and 4. Both the elemental composition and Kjeldahl analyses showed that the nitrogen is the limiting nutrient of the culture.

Enhanced expression of xylanase in Aspergillus niger enabling a two-step enzymatic pathway for extracting β-glucan from oat bran

The high cost and process complexity limit the enzymatic extraction of β-glucan. In this study, β-glucan was extracted from oat bran in a two-step enzymatic pathway using a recombinant strain of Aspergillus niger AG11 overexpressing the endogenous xylanase (xynA) and amylolytic enzyme. First, co-optimization of promoter and signal peptide and a fusion of glucoamylase (glaA) fragment were integrated into the β-glucosidase (bgl) locus to improve xynA expression. Then, the optimized expression cassette was simultaneously integrated into bgl, α-amylase amyA, and acid α-amylase ammA loci, yielding the Rbya with 3,650-fold and 31.2% increase in xynA and amylolytic enzyme activity than the wild-type strain, respectively. Finally, Rbya's supernatants at 72 h (rich in xynA and amylolytic enzyme) and 10 d (rich in proteases) were used to decompose xylan/starch and proteins in oat bran, respectively, to obtain 85.1% pure β-glucan. Rbya could be a robust candidate for the cost-effective extraction of β-glucan.

Improvement of energy metabolism associated with NUTRIOSE® soluble fiber, a dietary ingredient exhibiting prebiotic properties, requires intestinal gluconeogenesis

While the prevalence of obesity progresses worldwide, the consumption of sugars and dietary fiber increases and decreases, respectively. In this context, NUTRIOSE® soluble fiber is a plant-based food ingredient with beneficial effects in Humans. Here, we studied in mice the mechanisms involved, particularly the involvement of intestinal gluconeogenesis (IGN), the essential function in the beneficial effects of dietary fibers. To determine whether NUTRIOSE® exerts its beneficial effects via the activation of IGN, we studied the effects of dietary NUTRIOSE® on the development of obesity, diabetes and non-alcoholic fatty liver disease (NAFLD), which IGN is able to prevent. To assert the role of IGN in the observed effects, we studied wild-type (WT) and IGN-deficient mice. In line with our hypothesis, NUTRIOSE® exerts metabolic benefits in WT mice, but not in IGN-deficient mice. Indeed, WT mice are protected from body weight gain and NAFLD induced by a high calorie diet. In addition, our data suggests that NUTRIOSE® may improve energy balance by activating a browning process in subcutaneous white adipose tissue. While the gut microbiota composition changes with NUTRIOSE®, this is not sufficient in itself to account for the benefits observed. On the contrary, IGN is obligatory in the NUTRIOSE® benefits, since no benefit take place in absence of IGN. In conclusion, IGN plays a crucial and essential role in the set-up of the beneficial effects of NUTRIOSE®, highlighting the interest of the supplementation of food with healthy ingredients in the context of the current obesity epidemic.

Influence of fiber-rich co-products on nutrient and energy digestibility and utilization in sows

Co-products from the food and agricultural industries can potentially be used to replace concentrated high value grain crops in diets for sows. The co-products are typically high in fiber and with diverse composition. Energy digestibility and utilization are generally high in sows fed fiber-rich feedstuff, but nitrogen digestion and utilization may be compromised. The purpose of this study was to quantify the apparent total tract digestibility (ATTD) of nutrients and utilization of energy and nitrogen in empty non-lactating sows fed six different fiber-rich co-products (FRCP). Brewers spent grain (BSG), pea hull (PH), potato pulp (PP), pectin residue (PR), sugar beet pulp (SBP) and seed residue (SR) were mixed into a basal diet (BD) with as high an inclusion level as possible, or the BD was fed solely to 8 empty sows in a Youden square incomplete cross-over design. The collection period consisted of a total collection period of five days, of which two days were in a respiration chamber. The sows had a gross energy (GE) intake between 28.5 and 42.3 MJ/d; greatest for the PH fed sows and lowest for the PP fed sows. The ATTD of dry matter, organic matter, GE and N did not differ among the BD and the PH and SBP fed sows, while the ATTDs of all nutrients and energy were intermediate for PR and BSG lowest in SR fed sows (P &lt; 0.01). The differences were caused by variation in digestible and metabolizable energy content of the FRCP ingredients, which was lowest for SR, intermediate for PR followed by BSG and greatest for SBP, PP and PH (P &lt; 0.001). Total heat production (HP) did not differ among treatments but the non-activity related HP was highest in SR fed sows and lowest in PH and SBP fed sows (P &lt; 0.05). Retention of energy was greatest following the PH and BD (7.42 and 2.19 MJ/d, respectively), intermediate for PP, SBP and BSG fed sows (-0.22 to -0.69 MJ/d) and lowest for the PR and SR fed sows (-4.26 and -6.17 MJ/d, respectively) (P &lt; 0.001). From a sow feeding perspective, SBP and PH have the potential to partly replace high value grain crops due to high ATTD of all nutrients and because sows can efficiently utilize energy and protein. In contrast, SR and PR show low ATTD of nutrients and energy, thereby compromising the nutritive value. Potato pulp and BSG also have the potential to be included in sow diets, but caution should be taken because of compromised N utilization and thereby increased environmental impact.

Nutrient availability of roughages in isocaloric and isonitrogenous diets alters the bacterial networks in the whole gastrointestinal tract of Hu sheep

BACKGROUND

The nutrient availability of roughages could affect the dietary utilization efficiency of ruminants even in isocaloric and isonitrogenous diets. Here, we analyzed the bacterial composition and their metabolic pathways in the gastrointestinal tracts (GITs) of Hu sheep fed with wheat straw (WS) instead of alfalfa (AL) in isocaloric and isonitrogenous diets, trying to explore the reasons from the perspective of GITs bacterial network structure changes.

RESULTS

We employed 16S rRNA gene sequencing in combination with the Kruskal-Wallis test, Spearman correlation analysis, and other statistical methods to describe the microbiota composition in the GITs of Hu sheep. The results showed after the roughage was replaced from AL to WS, the most positive response occurred in the rumen microbiota, resulting in a more obvious microbiological and functional redundancy phenomenon. Whereas extended biogeographic studies of the GITs bacterial community found opposite results for the hindgut microbiota and metabolism networks compared to the forestomach. The abundance of fiber-degrading bacteria such as Prevotella, Oscillospiraceae NK4A214 group, and Treponema was significantly increased in GITs, but low-efficiency crude fiber degradation inhibited energy use efficiency, the pentose phosphate pathway, gluconeogenesis, and volatile acid synthesis. In addition, dietary shifting from AL to WS decreased the abundance of beneficial bacteria such as the Lachnospiraceae NK3A20 group and Alistipes, thereby enhancing the underlying inflammatory response.

CONCLUSIONS

These findings suggest that feeding untreated WS affected the structure and function of the bacterial network in the GITs due to limited total digestible nutrients, and in particular increases the complexity of the rumen bacterial network, and limit the abundance of bacteria involved in the crude fiber degradation in the hindgut.

Rye Dietary Fiber Components upon the Influence of Fermentation Inoculated with Probiotic Microorganisms

Rye flour is used as the main ingredient of sourdough bread, which has technological and gastronomic benefits and increased nutritional value. The transformations observed during fermentation and baking may enable the conversion or degradation of rye dietary fiber carbohydrates built mainly of arabinoxylans, fructans, and β-glucans. This study aimed to determine the dynamics of the changes in the contents of complex carbohydrates in sourdoughs inoculated with potential probiotic microorganisms as well as the polysaccharide composition of the resulting bread. Sourdoughs were inoculated with the potential probiotic microorganisms Saccharomyces boulardii, Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, and Bacillus coagulans, and spontaneous fermentation was performed as a control. Samples of the sourdoughs after 24 and 48 h of fermentation and of bread obtained with these sourdoughs were analyzed for the content of individual dietary fiber components. The present study demonstrated that the treatments applied contributed to an increased total content of arabinoxylans in the breads, and the inoculation of the sourdoughs with the potential probiotic strains improved their solubility in water. The use of the S.boulardii strain may seem prospective as it allowed for the greatest reduction in fructans in the rye bread. Rye sourdough bread is an attractive source of dietary fiber and can be modified for different nutritional needs.

Forage potential of several halophytic species grown on saline soil in arid environments

This study was carried out to evaluate the forage quantity and quality of several halophyte species grown in arid-saline environments. After identifying 44 halophytic species in the region and considering the potential of quantitative and qualitative forage production, 13 species from four families, i.e. Amaranthaceae, Asteraceae, Leguminosae and Convolvulaceae, and eight genera were selected for further evaluation. These species differed significantly in terms of both forage quantity, measured in terms of fresh (FW) and dry weight (DW), and forage quality assessed in terms of tissue water content (TWC), ash, nitrogen content (N), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), dry matter digestibility and metabolizable energy (ME). The highest fresh and dry weights were obtained from Suaeda ferticosa (1006.3 g and 306.3 g, respectively) and Noaea mucronata (909.3 g and 309 g, respectively). However, based on forage quality characteristics, Alhagi maurorum, Bassia scoparia, Noaea mucronata, Halostachys belangriana and Cressa cretica showed the best forage potential. Values of ash, CP, ADF, NDF and ME measured in the halophytes species ranged between 7.9% and 33.2%, 6.2% and 15.8%, 30.0% and 50.3%, 33.2% and 56.4%, 5.6 and 8.7 MJ kg^-1, respectively. The forage quality of the evaluated halophytic plants was influenced by unfavorable environmental conditions such as high soil salinity and low rainfall, however, these species can be considered as new sources of forage. Nevertheless, further studies are needed to improve the quality of such halophytic species by reducing the ash content and increasing the ME.