Effects of encapsulated butyrate and salinomycin on gut leakage and intestinal inflammation in broilers.

1. The objectives of this study were to i) compare the effects of a commercial product providing encapsulated butyrate (EB) in combination with salinomycin in diets of broilers with impaired intestinal integrity and ii) to identify easy-to-measure biomarkers to evaluate intestinal integrity and health.2. In total, 672 one-day-old male broilers (Ross 308) were randomly assigned to three experimental groups (eight replicates/group): no dietary supplement (control); EB (500 mg/kg, UltraGuard™-DUO, Devenish, Ireland); salinomycin (69 mg/kg feed, Sacox® 120). Impaired gut integrity was induced by a 10 times overdose of a commercially attenuated live vaccine against coccidiosis (Hipracox®, Hipra) on d 17 combined with a grower feed providing rye (50 g/kg diet).3. Improved intestinal integrity and functionality were reflected by reduced fluorescein isothiocyanate-dextran (FITC-D) plasma levels, reduced bacterial translocation to the liver (on d 21) and increased plasma colouration level on d 21 after dietary supplementation of salinomycin, compared to a non-supplemented control diet. Both EB and salinomycin reduced plasma levels of D-lactate (P < 0.05).4. An anti-inflammatory effect of salinomycin was indicated as the transient increase in circulating monocytes observed in the EB and control group from 20 to 28 d of age was slightly but not significantly reduced, in the salinomycin-fed group. Interestingly, greater expression of tumour necrosis factor α (TNF-α) and mucin 2 (MUC2) genes (P = 0.039 and P = 0.067, respectively) were detected in the group receiving salinomycin.5. These effects may have collectively contributed to the significantly improved performance of broilers supplemented with salinomycin. The results indicated that EB at 500 mg/kg in feed, in contrast to salinomycin, neither supported gut health nor modulated intestinal integrity in broilers.

Butyrate supplementation to pregnant mice elicits cytoprotection against colonic injury in the offspring.

BACKGROUND: Maternal diet during pregnancy can impact progeny health and disease by influencing the offspring's gut microbiome and immune development. Gut microbial metabolism generates butyrate, a short-chain fatty acid that benefits intestinal health. Here we assess the effects of antenatal butyrate on the offspring's gastrointestinal health. We hypothesized that antenatal butyrate supplementation will induce protection against colitis in the offspring. METHODS: C57BL/6 mice received butyrate during pregnancy and a series of experiments were performed on their offspring. RNA sequencing was performed on colonic tissue of 3-week-old offspring. Six-8-week-old offspring were subjected to dextran sulfate sodium-induced colitis. Fecal microbiome analysis was performed on the 6-8-week-old offspring. RESULTS: Antenatal butyrate supplementation dampened transcript enrichment of inflammation-associated colonic genes and prevented colonic injury in the offspring. Antenatal butyrate increased the offspring's stool microbiome diversity and expanded the prevalence of specific gut microbes. CONCLUSIONS: Antenatal butyrate supplementation resulted in downregulation of genes in the offspring's colon that function in inflammatory signaling. In addition, antenatal butyrate supplementation was associated with protection against colitis and an expanded fecal microbiome taxonomic diversity in the offspring. IMPACT: Dietary butyrate supplementation to pregnant mice led to downregulation of colonic genes involved in inflammatory signaling and cholesterol synthesis, changes in the fecal microbiome composition of the offspring, and protection against experimentally induced colitis in the offspring. These data support the mounting evidence that the maternal diet during pregnancy has enduring effects on the offspring's long-term health and disease risk. Although further investigations are needed to identify the mechanism of butyrate's effects on fetal gut development, the current study substantiates the approach of dietary intervention during pregnancy to optimize the long-term gastrointestinal health of the offspring.

Calcium bioavailability of calcium L-threonate in healthy Chinese subjects measured with stable isotopes (44Ca and 4²Ca).

PURPOSE: Calcium L-threonate is a novel drug that was developed for the treatment of osteoporosis and as a calcium supplement. However, calcium bioavailability of this drug is unknown due to lack of effective evaluation methods. In this study, we sought to measure the bioavailability of calcium L-threonate with a double-label stable isotope method. METHODS: Fourteen healthy Chinese subjects were enrolled in the clinical study and were given 300 mg calcium L-threonate tablets containing 40 mg (44)Ca after an intravenous injection of 4 mg (42)Ca solution (as calcium chloride). Fractional urine samples were collected at the following time intervals: 0-3, 3-6, 6-9, 9-13, 13-24, 24-36 and 36-48 h. The abundance ratios of (44)Ca/(40)Ca and (42)Ca/(40)Ca in the urine were determined with thermal-ionization mass spectrometry (TI-MS). The calcium bioavailability was estimated by calculating the true fractional calcium absorption (TFCA) using the abundance ratios of (44)Ca/(40)Ca and (42)Ca/(40)Ca. RESULTS: The bioavailability of calcium L-threonate in 14 healthy Chinese subjects was 26.49 ± 9.39 %. There was good agreement between TFCA from the 24 to 36 h and the 36 to 48 h urine pool, indicating that calcium balance was achieved at 24 h after dosing. The TFCA of the subjects did not statistically correlate with total urinary calcium excretion (0-48 h). There were no serious adverse events in this study. CONCLUSIONS: The bioavailability of calcium L-threonate in humans was successfully determined by estimating TFCA with the double-label stable isotope method, thus providing a useful approach for the evaluation of bioavailability of calcium formulations.

Rectal instillation of butyrate provides a novel clinically relevant model of noninflammatory colonic hypersensitivity in rats.

BACKGROUND & AIMS: The treatment of irritable bowel syndrome (IBS), characterized by abdominal pain and bloating, is empirical and often poorly efficient. Research lacks suitable models for studying the pathophysiologic mechanisms of the colonic hypersensitivity and new pharmacologic targets. The present study aimed to develop a novel model of colonic hypersensitivity possessing several of the characteristics encountered in patients with IBS. METHODS: Rats received enemas of a butyrate solution (8-1000 mmol/L) twice daily for 3 days. A time course was determined for colonic hypersensitivity (colorectal distention test) and referred cutaneous lumbar hyperalgesia (von Frey hairs). Macroscopic and histologic analyses were performed on colonic mucosa. The efficacy of morphine, U50488H (a kappa opioid agonist), and trimebutine on the 2 pain parameters was determined. Finally, the involvement of peptidergic C-fibers was evaluated using capsaicin-pretreated animals and treatments with calcitonin gene-related peptide (CGRP) and neurokinin 1 receptor antagonists. RESULTS: Butyrate enemas induced a sustained, concentration-dependent colonic hypersensitivity and, to a lesser extent, a referred cutaneous mechanical hyperalgesia, particularly in female rats, but no macroscopic and histologic modifications of the colonic mucosa, as observed in patients with IBS. Both pain parameters were sensitive to morphine, U50488H, trimebutine, neonatal capsaicin treatment, and the CGRP receptor antagonist but not to the neurokinin 1 receptor antagonist. CONCLUSIONS: These results present our noninflammatory model of chronic colonic hypersensitivity as a useful novel tool for studying IBS. The CGRP receptor antagonist-induced reduction of colonic hypersensitivity suggests that CGRP receptors may provide a promising target for treatment of IBS.

Treatment of left-sided ulcerative colitis with butyrate enemas: a controlled trial.

BACKGROUND: The colonic mucosa is highly dependent upon the presence of luminal nutrients. This dependence is most marked in the distal colon. The major luminal nutrients are short chain fatty acids that are produced as a by-product of colonic fermentation of carbohydrates. Butyrate appears to be the short chain fatty acid most avidly metabolized by the colonic mucosa. It has been suggested that ulcerative colitis is, at least in part, related to an energy deficiency state of the colonic mucosa which may be secondary to impaired short chain fatty acid production, uptake or utilization. The objective of this study was to determine if butyrate given as enema therapy is effective in the treatment of active distal ulcerative colitis. METHODS: Thirty-eight patients with distal ulcerative colitis were randomly assigned to receive nightly butyrate (n = 19) or saline/placebo (n = 19) enemas. Butyrate enemas consisted of 60 mL of 80 mM sodium butyrate titrated to a pH of 7.0. Patients were assessed clinically and endoscopically at baseline and at 3 and 6 weeks follow-up. Pre- and post-treatment mucosal biopsies were assessed histologically. Response to therapy was determined by changes in a 12-point clinical disease activity index score based on patient symptoms, endoscopic mucosal appearance and physicians' global assessment. RESULTS: Clinical improvement was noted in seven of 19 (37%) butyrate-treated patients and nine of 19 (47%) placebo-treated patients (P = 0.51). Clinical remission was achieved in three patients in each group (16%). No toxicity was observed in either treatment arm. CONCLUSIONS: The results suggests that once nightly 60 mL butyrate enemas (80 mmol/L) are not efficacious in the treatment of distal ulcerative colitis.

Influence of butyrate on lipid metabolism, survival, and differentiation of colon cancer cells.

The present work was designed to study the differentiating effect of butyrate on LS174T cells after modification of their lipids with long-chain fatty acid (LCFA) supplementation. The LCFAs 18:1(n-9), 18:2(n-6), 20:4(n-6), 20:5(n-3), and 22:6(n-3) bound to added to the media of confluent cells for eight days. The fatty acid-to-albumin ratio was 3:1. The concentration of fatty acids in the media was 100 microM. On the last day, half of the flasks were treated with 2 mM butyrate. The data indicate that supplementation with polyunsaturated LCFAs having 20-22 carbon atoms resulted in a significant reduction in cell density and viability, whereas all LCFA supplementation reduced differentiation as measured by alkaline phosphatase activity. Butyrate treatment increased the density, viability, and differentiation of the tumor cells. The effect of butyrate on differentiation was mainly with cells supplemented with 18:1, 20:5, and 22:6. In the absence of LCFA supplementation, butyrate reduced the concentration of 22:5(n-6) in the cellular lipids. Also, butyrate modified the LCFAs incorporated in cells supplemented with 18:2 and 20:5, with changes occurring in 20:5(n-3), 22:5(n-3), and 22:5(n-6). Thus the present study suggests an interaction between butyrate and LCFA on differentiation and LCFA metabolism of human colon cancer cells.