SCFA Concentrations Research Articles

Rapid Dietary Shift in Podarcis siculus Resulted in Localized Changes in Gut Function.

AbstractNatural dietary shifts offer the opportunity to address the nutritional physiological characters required to thrive on a particular diet. Here, we studied the nutritional physiology of Podarcis siculus, with populations on Pod Mrčaru, Croatia, that have become omnivorous and morphologically distinct (including the development of valves in the hindgut) from their insectivorous source population on Pod Kopište. We compared gut structure and function between the two island populations of this lizard species and contrasted them with an insectivorous mainland out-group population in Zagreb. On the basis of the adaptive modulation hypothesis, we predicted changes in gut size and structure, digestive enzyme activities, microbial fermentation products (short-chain fatty acids [SCFAs]), and plant material digestibility concomitant with this dietary change. The Pod Mrčaru population had heavier guts than the mainland population, but there were no other differences in gut structure. Most of the enzymatic differences we detected were between the island populations and the out-group population. The Pod Mrčaru lizards had higher amylase and trehalase activities in their hindguts compared with the Pod Kopište population, and the Pod Kopište lizards had greater SCFA concentrations in their hindguts than the omnivorous Pod Mrčaru population. Interestingly, the differences between the Pod Mrčaru and Pod Kopište populations are primarily localized to the hindgut and are likely influenced by microbial communities and a higher food intake by the Pod Mrčaru lizards. Although subtle, the changes in hindgut digestive physiology impact the digestibility of plant material in adult lizards-Pod Mrčaru lizards had higher digestibility of herbivorous and omnivorous diets fed over several weeks in the laboratory than did their source population.

Lactose-Induced Chronic Diarrhea Results From Abnormal Luminal Microbial Fermentation and Disorder of Ion Transport in the Colon.

Diarrhea is one of the major abdominal symptoms in lactose-intolerant subjects. The changes in the large intestinal luminal environment and disorder of the epithelial ion transport in lactose-induced diarrhea remain unclear. The present study aimed to investigate the effect of an incremental high-lactose diet (IHLD, 30%/40%/50%) on luminal microbiota, microbiota-derived metabolite concentrations and colonic ion transport. Gut microbiota were analyzed by 16S rRNA amplicon sequencing and the concentration of SCFAs by gas chromatography, galactose, lactose and lactic acid through assay kit; Ussing chamber was performed to detect basal and stimulated ion transport; The expression and location of SCFA transporters, the Na-H exchanger 3(NHE3), cystic fibrosis transporter regulater (CFTR) and NKCC1 in the colon mucosa were analyzed by western and immunostaining. The concentrations of lactose, galactose and lactic acid of the cecal content were markedly increased (P < 0.01) and SCFA concentration was significantly decreased (P < 0.01). This was associated with depletion of the Lachnospiraceae NK4A136 group and Ruminococcaceae UCG-005 and increased relative abundance of Lactobacillus, escherichia-shigella and megamonas in the cecal microbiota. The expression of monocarboxylate transporter 1 was decreased in the colonic mucosa of the IHLD group. Low NHE3 expression and phosphorylation levels, and decreases in delta basal short circuit current after apical Na+ removal in the colonic mucosa of the IHLD group contributed to Na+ accumulation in the lumen and decrease stimulated Cl– secretion with low CFTR and NKCC1 expression would compensate for water and electrolyte loss during the diarrhea process. These results indicated that the persistence of the diarrhea state was maintained by abnormal colonic microbiota fermentation leading to high concentrations of lactose, galactose and lactic acid and low SCFAs in the lumen, and decreased Na+ absorption with the low NHE3 expression and phosphorylation levels.

Comparative study on glucomannans with different structural characteristics: Functional properties and intestinal production of short chain fatty acids

Glucomannans (GMs) from abundant natural resources have excellent processing properties and plentiful bioactivities. In current study, functional properties of GMs with different structural characteristics, including KGM from konjac, DOP from dendrobium, AGP40, ASP-4N, ASP-6N, & ASP-8N from aloe were determined. Results suggested that molecular weights (Mw) of GMs were positively correlated with their water absorption capacity, fat absorption capacity, and viscosity, while ratio of mannose/glucose showed negative effect. Higher degree of acetylation (DA) mainly corresponded to higher values of solubility and ζ-potential. Then, effects of the six GMs on general health status, serum biochemicals, and intestinal SCFAs production in mice were evaluated in vivo. Analysis of general health status and levels of serum biochemicals revealed that mice with consecutive supplementation of GMs for 14 days performed normally compared with those in control group. Interestingly, the productions of SCFAs (mainly acetate and butyrate) in the cecal and colonic contents were significantly promoted. Generally, higher concentrations of SCFAs were produced when mice were treated with GMs having higher Mw, ratio of glucose, and DA. The current investigation suggested that both functional and intestinal fermentation property of GMs were jointly determined by the monosaccharide composition, molecular weight, and degree of acetylation.

Effects of native or partially defatted hemp seeds on hindgut function, antioxidant status and lipid metabolism in diet-induced obese rats

The aim was to compare the effects of a small amount of native and partially defatted hemp seeds on hindgut function, antioxidant status and lipid metabolism in rats fed a high-fat (HF) diet. After 8 weeks of experimental feeding, HF dietary feeding induced obesity and a series of metabolic disorders in rats. Supplementation of the HF diet with both seed forms increased the cecal SCFA concentrations and improved the antioxidant status of rats, especially glutathione metabolism in the liver. Dietary consumption of the defatted seeds decreased liver triglyceride accumulation, whereas it unfavorably increased the liver cholesterol content. By contrast, dietary consumption of the native seeds decreased the plasma cholesterol concentration, especially the non-HDL fraction, and increased hepatic expression of PPARγ. This study demonstrates that low and regular consumption of both seed forms attenuates disorders associated with an unbalanced diet, although their consumption is unable to prevent the development of obesity itself.

Residual effect of narasin on ruminal fermentation characteristics in lambs

This study aimed to evaluate the effect of narasin withdrawal on wethers ruminal fermentation characteristics. Four wethers cannulated at the rumen were subjected to a 4 × 4 Latin Square experimental design. The trial lasted 144 days, divided into 4 periods of 36 days each. The diet was composed by 950 g/kg of coastcross hay and 50 g/kg of ground corn, used as a carrier for the narasin. The experimental diets were defined by frequency of narasin offer: 1) no feed additives (N0); 2) 13 mg of narasin/kg of DM every 24 h (N13); 3) 26 mg of narasin/kg of DM every 48 h (N26), and 4) 39 mg of narasin/kg of DM every 72 h (N39). The narasin was offered for 25 days, and at the last 11 days of each period, all the animals received the same proportion of forage and concentrate, but without narasin inclusion (withdrawal period). Last day of narasin offering was denominated day 0 and the first day of withdrawal day 1. The fed offer and orts were daily recorded to determine de DMI and nutrient intake. Ruminal fluid was collected 6 h after concentrate offering from d0 to d11 to determine ruminal pH, SCFA and ammonia nitrogen. There was no difference for dry matter intake among treatments after narasin withdrawal. There was no treatment and day interaction for total SCFA concentration, molar proportion of acetate, butyrate, isobutyrate, valerate, isovalerate and rumen pH. Treatment and day interaction after narasin withdrawal interactions was observed for molar proportion of propionate (P < 0.01), Ac:Prop ratio (P = 0.03) and ammonia nitrogen concentration (P = 0.02). The increase in molar proportions of propionate for all narasin-containing treatments compared with the control was no significant by day 5 after narasin withdrawal (P ≥ 0.13). After narasin withdrawal, all doses of narasin inclusion decreased Ac:Prop ratio until day 3 after withdrawal (P ≤ 0.05) when compared with control diet. Effect of narasin on ruminal ammonia nitrogen concentration remained until day 3 after withdrawal (P ≤ 0.04), from day 4 there was no treatments effect (P ≥ 0.11) on ammonia nitrogen concentration. The data obtained from the present study demonstrate that narasin has a prolonged effect after withdrawal from the diet, being observed an effect on ruminal fermentation characteristics within 4 days after narasin withdrawal. These data suggest that the residual effect of narasin can be used as strategic feeding in situations where daily supplementation is not possible. Additionally, concerning scientific research using reversal designs, there is a need for a minimum of 5 days of washout between the experimental periods.

Chemopreventive effects of raw and roasted oat flakes after in vitro fermentation with human faecal microbiota

The aim of the present study was to analyse chemopreventive effects of oat flakes under consideration of processing. Thin and thick flakes were roasted and subjected to an in vitro digestion and fermentation. Fermentation supernatants (FS) were characterised and chemopreventive effects were analysed in LT97 colon adenoma cells. Compared to the fermentation control, pH values were decreased (from pH 6.3 to pH 5.0) and concentrations of SCFA, in particular butyrate, were increased in oat FS (2.6-fold, on average). Ammonia levels were not altered. Oat FS significantly decreased cell growth time- and dose-dependently. Caspase 3 activity was significantly increased (9.7-fold, on average). Oat FS slightly increased the mRNA expression of CAT (2.0-fold), SOD2 (1.7-fold) and GSTP1 (2.8-fold), on average, while GPX1 mRNA (0.3-fold) was decreased. The results indicate a chemopreventive potential of in vitro digested oat flakes regarding colon cancer development mediated mostly by growth inhibition and apoptosis, unaffected by roasting.

Dietary Hemp Seeds More Effectively Attenuate Disorders in Genetically Obese Rats than Their Lipid Fraction

Hemp seeds are rich in PUFAs and other bioactives that can attenuate the development of obesity-related disorders; however, the extent to which their lipid fraction is responsible for this effect is unknown. We hypothesized that hemp seed or hemp oil supplementation can attenuate genetically determined disorders and that the former are more effective in doing so. Lean and obese male Zucker rats, aged 8 wk, weighing 174±4.2g and 223±3.8g, respectively, were allocated to 4 groups. The lean (LC) and obese controls (OC) were fed a standard diet, whereas the other 2 obese groups were fed a modified diet in which hemp oil (4% diet; O+HO) or hemp seeds (12% diet; O+HS) were included. All diets had the same proportions of protein (18%), fat (8%), and fiber (5%) and a similar carbohydrate proportion (∼52%). Diets fed to O+HO and O+HS had similar fatty acid profiles. After 4 wk, markers of gut and liver function, antioxidant status, and lipid metabolism were measured. The total SCFA concentration in the cecal digesta was lower in OC (64.8±4.21µmol/g) compared with LC (78.1±2.83µmol/g) (P≤0.05), whereas it was greater in O+HS (89±4.41µmol/g) compared with LC, OC, and O+HO (69.7±2.68µmol/g) (P≤0.05). Plasma total cholesterol was greater in OC (6.20±0.198mmol/L) and O+HO (5.60±0.084mmol/L) compared with LC (2.71±0.094mmol/L) (P≤0.05); in O+HS, the concentration did not differ from the other groups (5.16±0.278mmol/L). The liver cholesterol concentration was greater in OC (1.79±0.379mg/g) compared with the other groups (1.28-1.43mg/g) (P≤0.05). Hepatic expression of peroxisome proliferator-activated receptor γ was lower in OC (11.9±0.93 units) compared with LC (17.3±1.3 units) (P≤0.05), whereas it was greater in O+HS (19.2±1.04 units) compared with OC and O+HO (14.0±1.33 units) (P≤0.05). Dietary hemp seeds more effectively attenuate metabolic disorders in genetically obese rats than the oil extracted from them, which suggests that the lipid fraction is only partly responsible for these effects.

Effect of chicory inulin-type fructan–containing snack bars on the human gut microbiota in low dietary fiber consumers in a randomized crossover trial

The low intake of dietary fiber compared to recommended amounts has been referred to as the dietary fiber gap. The addition of fiber to snack foods could favorably alter gut microbiota and help individuals meet intake recommendations. Our objective was to examine the effect of low- and moderate-dose fiber-containing snack bars, comprising mainly chicory root inulin-type fructans (ITF), on gut microbiota in healthy adults with habitual low dietary fiber intake using 16S ribosomal RNA-based approaches. In 2 separate 4-wk, placebo-controlled, double-blind, crossover trials, 50 healthy adults with low dietary fiber intake were randomly assigned to receive isocaloric snack bars of either moderate-dose fiber (7 g/d) or control in Trial 1 (n=25) or low-dose fiber (3 g/d) or control in Trial 2 (n=25), with 4-wk washout periods. Fecal microbiota composition and inferred function, fecal SCFA concentration, gastrointestinal (GI) symptoms, dietary intake, and quality of life were measured. Compared with the control group, the moderate-dose group showed significant differences across multiple microbial taxa, most notably an increased relative abundance of the Bifidobacterium genus from (mean±SEM) 5.3%±5.9% to 18.7%±15.0%. With low-dose ITF, significant increases in Bifidobacterium were no longer present after correction for multiple comparisons but targeted analysis with qPCR showed a significant increase in Bifidobacterium. Predictive functional profiling identified changes in predicted function after intake of the moderate- but not the low-dose bar. Fecal SCFAs were affected by time but not treatment. There were no between-group differences in GI symptoms. Importantly, fiber intake increased significantly with the moderate- and low-dose bars. In healthy adults, adding 3 or 7 g ITF to snack bars increased Bifidobacterium, a beneficial member of the gut microbial community. The addition of ITF to food products could help reduce the dietary fiber gap prevalent in modern life.This trial was registered at clinicaltrials.gov as NCT03042494.

Cyclocarya paliurus polysaccharide alleviates liver inflammation in mice via beneficial regulation of gut microbiota and TLR4/MAPK signaling pathways

The study was to investigate the anti-inflammatory effect of Cyclocarya paliurus polysaccharides (CP) on carbon tetrachloride (CCl4) induced mice and explore its underlying mechanism. Based on a mouse model of CCl4 induced liver inflammation and pretreatment with CP. Results showed that CP significantly decreased the levels of the proinflammatory cytokines (NO, TNF-α, IL-1β) as well as the proteins expression levels of COX-2 and iNOS in the liver. TLR4 and MAPK pathways were down-regulated after CP administration. Furthermore, 16S rDNA showed that CP increased the Firmicutes/Bacteroidetes ratio and the abundance of probiotics (Unclassified Clostridiales) as well as decreased abundances of pathogenic bacteria (Proteobacteria, Helicobacter and Aerococcus) compared to model group. Moreover, CP treatment increased the SCFAs levels in CCl4 induced mice. These findings suggested that CP act as prebiotics in ameliorating the liver inflammation in mice caused by CCl4 through regulating the gut microbiota composition and increasing the concentration of SCFAs.

Fecal Microbiota Transplantation (FMT) Alleviates Experimental Colitis in Mice by Gut Microbiota Regulation.

Inflammatory bowel disease (IBD) is an increasing global burden and a predisposing factor to colorectal cancer. Although a number of treatment options are available, the side effects could be considerable. Studies on fecal microbiota transplantation (FMT) as an IBD intervention protocol require further validation as the underlying mechanisms for its attenuating effects remain unclear. This study aims to demonstrate the ameliorative role of FMT in an ulcerative colitis (UC) model induced by dextran sulfate sodium (DSS) and elucidate its relative mechanisms in a mouse model. It was shown that FMT intervention decreased disease activity index (DAI) levels and increased the body weight, colon weight and colon length of experimental animals. It also alleviated histopathological changes, reduced key cytokine expression and oxidative status in the colon. A down-regulated expression level of genes associated with NF-κB signaling pathway was also observed. The results of 16S rRNA gene sequencing showed that FMT intervention restored the gut microbiota to the pattern of the control group by increasing the relative abundance of Firmicutes and decreasing the abundances of Bacteroidetes and Proteobacteria. The relative abundances of the genera Lactobacillus, Butyricicoccus, Lachnoclostridium, Olsenella and Odoribacter were upregulated but Helicobacter, Bacteroides and Clostridium were reduced after FMT administration. Furthermore, FMT administration elevated the concentrations of SCFAs in the colon. In conclusion, FMT intervention could be suitable for UC control, but further validations via clinical trials are recommended.

Pretreatment with Yeast-Derived Complex Dietary Polysaccharides Suppresses Gut Inflammation, Alters the Microbiota Composition, and Increases Immune Regulatory Short-Chain Fatty Acid Production in C57BL/6 Mice

β-Glucans (BGs), a group of complex dietary polysaccharides (CDPs), are available as dietary supplements. However, the effects of orally administered highly purified BGs on gut inflammation are largely unknown. The aim of this study was to investigate the impact of orally administering highly purified, yeast-derived BG (YBG; β-1,3/1,6-d-glucan) on susceptibility to colitis. Eight-week-old C57BL/6 (B6) mice were used in a series of experiments. Experiment (Expt) 1: male and female mice were treated every day, for 40 d, with saline (control) or 250 μg YBG, followed by 2.5% (wt:vol) dextran sulfate sodium (DSS) in drinking water during days 30-35; and colitis severity and intestinal immune phenotype were determined. Expt 2: female B6 mice were treated with saline or YBG for 30 d and intestinal immune phenotype, gut microbiota composition, and fecal SCFA concentrations were determined. Expt 3: female B6 mice were treated as in Expt 2, given drinking water with or without antibiotics [Abx; ampicillin (1g/L), vancomycin (0.5g/L), neomycin (1g/L), and metronidazole (1g/L)] during days 16-30, and gut immune phenotype and fecal SCFA concentrations were determined. Expt 4: female B6 Foxp3-green fluorescent protein (-GFP) reporter mice were treated as in Expt 3, and intestinal T-regulatory cell (Treg) frequencies and immune phenotypes were determined. Expt 5: female mice were treated as in Expt 1, given drinking water with or without antibiotics during days 16-40, and colitis severity and intestinal cytokine production were determined. Compared with controls, the YBG group in Expt 1 exhibited suppressive effects on features of colitis, such as loss of body weight (by 47%; P<0.001), shortening of colon (by 24%; P=0.016), and histopathology severity score (by 45%; P=0.01). The YBG group of Expt 2 showed a shift in the abundance of gut microbiota towards Bacteroides (by 16%; P=0.049) and Verrucomicrobia (mean±SD: control=7.8±0.44vs. YBG=21.0±9.6%) and a reduction in Firmicutes (by 66%; P<0.001). The YBG group also showed significantly higher concentrations of fecal SCFAs such as acetic (by 37%; P=0.016), propionic (by 47%; P=0.026), and butyric (by 57%; P=0.013) acids. Compared with controls, the YBG group of Expt 2 showed higher frequencies of Tregs (by 32%; P=0.043) in the gut mucosa. Depletion of gut microbiota in the YBG group of mice caused diminished fecal SCFA concentrations (Expt 3) and intestinal Treg frequencies (Expt 4). Compared with the YBG group, the YBG-(Abx) group of Expt 5 showed aggravated colitis features including loss of body weight (by >100%; P<0.01) and colonic inflammation score (by 42%; P=0.04). Studies using B6 mice show that dietary BGs are beneficial for promoting intestinal health when the gut microbiota is intact. However, these CDPs may produce adverse effects if gut microbiota is compromised.

Nutrient Restriction has Limited Short-Term Effects on Gut, Immunity, and Brain Development in Preterm Pigs

Extrauterine growth restriction (EUGR) in preterm infants is associated with higher morbidity and impaired neurodevelopment. Early nutrition support may prevent EUGR in preterm infants, but it is not known if this improves organ development and brain function in the short and long term. Using pigs as models for infants, we hypothesized that diet-induced EUGR impairs gut, immunity, and brain development in preterm neonates during the first weeks after birth. Forty-four preterm caesarean-delivered pigs (Danish Landrace×Large White×Duroc, birth weight 975±235g, male:female ratio 23:21) from 2 sows were fed increasing volumes [32-180mL/(kg·d)] of dilute bovine milk (EUGR group) or the same diet fortified with powdered bovine colostrum for 19 d (CONT group, 50-100% higher protein and energy intake than the EUGR group). The EUGR pigs showed reduced body growth (-39%, P < 0.01), lower plasma albumin, phosphate, and creatine kinase concentrations (-35 to 14%, P < 0.05), increased cortisol and free iron concentrations (+130 to 700%, P < 0.05), and reduced relative weights of the intestine, liver, and spleen (-38 to 19%, all P < 0.05). The effects of EUGR on gut structure, function, microbiota, and systemic immunity were marginal, although EUGR temporarily increased type 1 helper T cell (Th1) activity (e.g. more blood T cells and higher Th1-related cytokine concentrations on day 8) and reduced colon nutrient fermentation (lower SCFA concentration; -45%, P < 0.01). Further, EUGR pigs showed increased relative brain weights (+19%, P < 0.01), however, memory and learning, as tested in a spatial T-maze, were not affected. Most of the measured organ growth, and digestive, immune, and brain functions showed limited effects of diet-induced EUGR in preterm pigs during the first weeks after birth. Likewise, preterm infants may show remarkable physiological adaptation to deficient nutrient supply during the first weeks of life although early life malnutrition may exert negative consequences later.

Resistant starch supplementation increases crypt cell proliferative state in the rectal mucosa of older healthy participants.

There is strong evidence that foods containing dietary fibre protect against colorectal cancer, resulting at least in part from its anti-proliferative properties. This study aimed to investigate the effects of supplementation with two non-digestible carbohydrates, resistant starch (RS) and polydextrose (PD), on crypt cell proliferative state (CCPS) in the macroscopically normal rectal mucosa of healthy individuals. We also investigated relationships between expression of regulators of apoptosis and of the cell cycle on markers of CCPS. Seventy-five healthy participants were supplemented with RS and/or PD or placebo for 50 d in a 2 × 2 factorial design in a randomised, double-blind, placebo-controlled trial (the Dietary Intervention, Stem cells and Colorectal Cancer (DISC) Study). CCPS was assessed, and the expression of regulators of the cell cycle and of apoptosis was measured by quantitative PCR in rectal mucosal biopsies. SCFA concentrations were quantified in faecal samples collected pre- and post-intervention. Supplementation with RS increased the total number of mitotic cells within the crypt by 60 % (P = 0·001) compared with placebo. This effect was limited to older participants (aged ≥50 years). No other differences were observed for the treatments with PD or RS as compared with their respective controls. PD did not influence any of the measured variables. RS, however, increased cell proliferation in the crypts of the macroscopically-normal rectum of older adults. Our findings suggest that the effects of RS on CCPS are not only dose, type of RS and health status-specific but are also influenced by age.

The early life microbiota protects neonatal mice from pathological small intestinal epithelial cell shedding.

The early life gut microbiota plays a crucial role in regulating and maintaining the intestinal barrier, with disturbances in these communities linked to dysregulated renewal and replenishment of intestinal epithelial cells. Here we sought to determine pathological cell shedding outcomes throughout the postnatal developmental period, and which host and microbial factors mediate these responses. Surprisingly, neonatal mice (Day 14 and 21) were highly refractory to induction of cell shedding after intraperitoneal administration of liposaccharide (LPS), with Day 29 mice showing strong pathological responses, more similar to those observed in adult mice. These differential responses were not linked to defects in the cellular mechanisms and pathways known to regulate cell shedding responses. When we profiled microbiota and metabolites, we observed significant alterations. Neonatal mice had high relative abundances of Streptococcus, Escherichia, and Enterococcus and increased primary bile acids. In contrast, older mice were dominated by Candidatus Arthromitus, Alistipes, and Lachnoclostridium, and had increased concentrations of SCFAs and methyamines. Antibiotic treatment of neonates restored LPS‐induced small intestinal cell shedding, whereas adult fecal microbiota transplant alone had no effect. Our findings further support the importance of the early life window for microbiota‐epithelial interactions in the presence of inflammatory stimuli and highlights areas for further investigation.

Effect of Hydrothermal Treatment of Depigmented Turmeric (Curcuma longa L.) on Cecal Fermentation in Rats

AbstractRaw depigmented turmeric powder (TP) and hydrothermally treated TP (HT‐TP) contain non‐digestible saccharides with fiber and RS contents of 53.3% and 39.9%, respectively. Starch granules in TP and HT‐TP are observed under a petrographic microscope. The native and partly digested starch granules hydrolyzed by digestive enzymes, are also observed under SEM. In an animal study, cecal total SCFA concentration in rats fed 10% TP diet followed by 10% HT‐TP diet is (p &lt; 0.05) higher than the control diet, while acetate and n‐butyrate concentrations in 10% HT‐TP diet are (p &lt; 0.05) lower than in the 10% TP diet, which is still higher than the control diet. These data indicate that starch in HT‐TP is resistant to gelatinization and/or enzymatic digestion; thus, HT‐TP may be a useful food material conducive for increasing intestinal fermentation.

The effect of synbiotic preparations on the intestinal microbiota and her metabolism in broiler chickens

The aim of the research was to determine the effect of newly elaborated synbiotic preparations on the count of dominant intestinal microorganisms, on the profile of fatty acids (short chain – SCFA and branched chain – BCFA), the lactic acid produced and the performance of chickens. The studies determined the composition of the dominant intestinal microbiota with use of the culture method. The fatty acid profile was also determined using the high-performance liquid chromatography method (HPLC). Moreover, the performance of chickens was determined such as the daily cumulative mortality rate, the feed conversion ratio (FCR) and the European Production Efficiency Factor (EPEF). It was found that synbiotics had a beneficial effect on parameters of the performance of chickens, and also resulted in increase in the count of beneficial bacteria and to the restriction in growth of potential pathogens in the gastrointestinal tract. Synbiotics caused an increase in the concentration of lactic acid and SCFA and a decrease in the concentration of BCFA in the broiler’s excreta. These results showed a beneficial effect of the tested synbiotics on the intestinal microbiota, their metabolism and the performance of broiler chickens. The elaborated synbiotics can be successfully used as feed additives for broiler chickens.

Effects of high-fiber diets enriched with carbohydrate, protein, or unsaturated fat on circulating short chain fatty acids: results from the OmniHeart randomized trial

Short chain fatty acids (SCFAs; e.g., acetate, propionate, and butyrate) are produced by microbial fermentation of fiber in the colon. Evidence is lacking on how high-fiber diets that differ in macronutrient composition affect circulating SCFAs. We aimed to compare the effects of 3 high-fiber isocaloric diets differing in %kcal of carbohydrate, protein, or unsaturated fat on circulating SCFAs. Based on previous literature, we hypothesized that serum acetate, the main SCFA in circulation, increases on all high-fiber diets, but differently by macronutrient composition of the diet. OmniHeart is a randomized crossover trial of 164 men and women (≥30 y old); 163 participants with SCFA data were included in this analysis. We provided participants 3 isocaloric high-fiber (∼30 g/2100 kcal) diets, each for 6 wk, in random order: a carbohydrate-rich (Carb) diet, a protein-rich (Prot) diet (protein predominantly from plant sources), and an unsaturated fat-rich (Unsat) diet. We used LC-MS to quantify SCFA concentrations in fasting serum, collected at baseline and the end of each diet period. We fitted linear regression models with generalized estimating equations to examine change in ln-transformed SCFAs from baseline to the end of each diet; differences between diets; and associations of changes in SCFAs with cardiometabolic parameters. From baseline, serum acetate concentrations were increased by the Prot (β: 0.24; 95% CI: 0.12, 0.35), Unsat (β: 0.21; 95% CI: 0.10, 0.33), and Carb (β: 0.12; 95% CI: 0.01, 0.24) diets; between diets, only Prot compared with Carb was significant (P=0.02). Propionate was decreased by the Carb (β: -0.10; 95% CI: -0.16, -0.03) and Unsat (β: -0.10; 95% CI: -0.16, -0.04) diets, not the Prot diet; between diet comparisons of Carb vs. Prot (P=0.006) and Unsat vs. Prot (P=0.002) were significant. The Prot diet increased butyrate (β: 0.05; 95% CI: 0.00, 0.09) compared with baseline, but not compared with the other diets. Increases in acetate were associated with decreases in insulin and glucose; increases in propionate with increases in leptin, LDL cholesterol, and blood pressure; and increases in butyrate with increases in insulin and glucose, and decreases in HDL cholesterol and ghrelin (Ps<0.05). Macronutrient composition of high-fiber diets affects circulating SCFAs, which are associated with measures of appetite and cardiometabolic health. This trial was registered at clinicaltrials.gov as NCT00051350.

Consumption of an Oil Palm Fruit Extract Promotes Large Bowel Health in Rats

Oil palm fruit is widely used for edible oils, but the health benefits of other components are relatively unknown. We examined if consuming a polyphenol-rich extract of the fruit, from a vegetation by-product of oil processing, which also contains fibre, has gastro-intestinal benefits in rats on a Western-type diet (WD). The oil palm preparation (OPP) was added to food (OPP-F) or drinking water (OPP-D) to provide 50 mg of gallic acid equivalents (GAE)/d and compared to effects of high amylose maize starch (HAMS; 30%) in the diet or green tea extract (GT; 50 mg GAE/d) in drinking water over 4 wk. OPP treatments induced some significant effects (P < 0.05) compared to WD. OPP-D increased caecal digesta mass, caecal digesta concentrations of total SCFA, acetate and propionate (OPP-F increased caecal butyrate concentration), the numbers of mucus-producing goblet cells per colonic crypt, and caecal digesta abundance of some bacteria which may provide benefit to the host (Faecalibacterium prausnitzii, Akkermansia muciniphila and Ruminococcus gnavus). HAMS induced similar effects but with greater potency and had a broader impact on microbe populations, whereas GT had minimal impacts. These results suggest dietary OPP may benefit the large bowel.

P139 EFFECT OF LYSOSOMAL SHORT CHAIN FATTY ACID DELIVERY ON IMMUNE RESPONSE

Abstract Short chain fatty acids (SCFAs) are known as metabolites produced from gut microbiome fermenting dietary fibers and resistant starch. They are regulators of the interplay between the microbiome and its host and may have a role in the pathogenesis of inflammatory bowel disease (IBD). Free SCFAs influence intestinal epithelial and immune cells (e.g. macrophages and primary monocytes) through activation of free fatty acid receptors FFAR2 and FFAR3, inhibition of histone deacetylases (HDAC) and as a source of energy. SCFAs are known to impact cytokine production and differentiation of immune cells (e.g. Tumor necrosis factor alpha (TNFa), Interleukin (IL)-10, IL-6, IL-18, IL-1ß). We investigated the role of SCFAs in dextran sulfate sodium-induced colitis and their effect on the cytokine production by primary human immune cells. Treatment with SCFAs (acetate, propionate or butyrate) stimulated release of IL-1ß and IL-18 by buffy coat leukocytes or U937 cells without causing increased expression of corresponding genes. This raises the possibility of activation via the NLRP3 (NOD-, LRR- and pyrin domain- containing protein 3) inflammasome. NLRP3 is a multimeric inflammasome complex. Once activated, NLRP3 inflammasome releases caspase 1 leading to formation of mature IL-1ß and IL-18. Recent studies have shown that IL-1ß promotes phagocytosis and clearance of bacteria and aids the gut in eliciting an effective response in early stages of IBD. We asked whether this effect is mediated via surface or lysosomal (phagosomal) receptors? To answer this question, we prepared a series (SYD010) of novel compounds which are able to accumulate in the phagolysosome of immune cells through their macrolide backbone and deliver SCFAs, bound as esters to the lumen of the activated lysosome. In vitro, together with LPS stimulation, the substances modulated secretion of TNFa, IL-1ß, IL-10 and IL-6 at concentrations about 100x lower than free SCFAs (Figure 1). When tested in a DSS colitis mouse model, the SYD010 series caused a decrease in diarrhea scoring compared to the vehicle-treated control group at a concentration of 0.1 mg/kg (Figure 2) which corresponds to a total dose of ca. 100 nmol/kg (the compounds are systemically distributed). This is lower than the known luminal concentrations of SCFAs which is in the range of 40 mM. Our underlying hypothesis is that lysosomal reception of SCFAs leads to beneficial immune modulation in colitis in so far as stimulation of IL-1ß release promotes bacterial clearance. Furthermore, that concentrative uptake to the phagolysosome leads to enhanced stimulation of these receptors leading to responses at lower ambient concentrations or doses. We are assessing this substance class as potential IBD therapeutics. Figure 1. Effect of sodium butyrate or CSY4286 (lysosomal butyrate donor) on cytokine production by U937 cells. Supernatants were harvested after 24 h (IL-6) and 48 h (IL-1ß, IL-6) incubation with the test substances and cytokines determined by ELISA. The dotted line represents levels with LPS stimulation alone. SEM was applied for error bars. Figure 2. Results from DSS-induced (2.5% in drinking water) IBD study in BALB/c mice (8 mice per group). Scoring of body weight and diarrhea score over 8 days (a and b show data from final day of study). SEM was applied for error bars.

Holly polyphenols alleviate intestinal inflammation and alter microbiota composition in lipopolysaccharide-challenged pigs.

The effect of holly polyphenols (HP) on intestinal inflammation and microbiota composition was evaluated in a piglet model of lipopolysaccharide (LPS)-induced intestinal injury. A total of twenty-four piglets were used in a 2 × 2 factorial design including diet type and LPS challenge. After 16 d of feeding with a basal diet supplemented with or without 250 mg/kg HP, pigs were challenged with LPS (100 μg/kg body weight) or an equal volume of saline for 4 h, followed by analysis of disaccharidase activities, gene expression levels of several representative tight junction proteins and inflammatory mediators, the SCFA concentrations and microbiota composition in intestinal contents as well as proinflammatory cytokine levels in plasma. Our results indicated that HP enhanced intestinal disaccharidase activities and reduced plasma proinflammatory cytokines including TNF-α and IL-6 in LPS-challenged piglets. Moreover, HP up-regulated mRNA expression of intestinal tight junction proteins such as claudin-1 and occludin. In addition, bacterial 16S rRNA gene sequencing showed that HP altered hindgut microbiota composition by enriching Prevotella and enhancing SCFA production following LPS challenge. These results collectively suggest that HP is capable of alleviating LPS-triggered intestinal injury by improving intestinal disaccharidase activities, barrier function and SCFA production, while reducing intestinal inflammation.