Short-term exposure of dairy cows to pyrrolizidine alkaloids from tansy ragwort (Jacobaea vulgaris Gaertn.): effects on health and performance.

The increasing spread of ragworts is observed with concern. Ragworts like tansy ragwort (Jacobaea vulgaris Gaertn.) or marsh ragwort (J. aquatica) contain pyrrolizidine alkaloids (PA) which may induce hepatotoxic effects. Grazing animals usually avoid ragworts if their pasture management is appropriate. Preserved feed prepared from ragworts contaminated meadows may, however, lead to a significant exposure to PA. Previous studies on toxicity of PA for dairy cows revealed inconsistent results due to feeding ragwort plant material which was associated with heterogeneous PA exposure and thus failed to conclusively deduce critical PA doses. Therefore, the aim of the present study was to expose dairy cows (n = 4 per group) in a short-term scenario for 28 days with increasing PA doses (PA1: 0.47 mg PA/kg body weight (BW)/day (d); PA2: 0.95 mg PA/kg BW/d; PA3: 1.91 mg PA/kg BW/d) via oral administration by gavage of a defined PA-extract. While group PA3 was dosed with the PA-extract alone, groups PA2 and PA1 received PA-extracts blended in similar volumes with molasses to provide comparable amounts of sugar. Additionally, two control groups were treated either with water (CONWater) or with molasses (CONMolasses) to assess the effects of sugar without PA interference. While clinical traits including dry matter intake, milking performance, rectal body temperature, ruminal activity and body condition score (BCS) were not influenced by PA exposure, activities of enzymes indicative for liver damages, such as gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST) and glutamate dehydrogenase (GLDH), increased significantly over time at an exposure of 1.91 mg total PA/kg BW/d.

Dietary non-starch polysaccharides impair immunity to enteric nematode infection.

BACKGROUND: The influence of diet on immune function and resistance to enteric infection and disease is becoming ever more established. Highly processed, refined diets can lead to inflammation and gut microbiome dysbiosis, whilst health-promoting dietary components such as phytonutrients and fermentable fibres are thought to promote a healthy microbiome and balanced mucosal immunity. Chicory (Cichorium intybus) is a leafy green vegetable rich in fibres and bioactive compounds that may promote gut health. RESULTS: Unexpectedly, we here show that incorporation of chicory into semisynthetic AIN93G diets renders mice susceptible to infection with enteric helminths. Mice fed a high level of chicory leaves (10% dry matter) had a more diverse gut microbiota, but a diminished type-2 immune response to infection with the intestinal roundworm Heligmosomoides polygyrus. Furthermore, the chicory-supplemented diet significantly increased burdens of the caecum-dwelling whipworm Trichuris muris, concomitant with a highly skewed type-1 immune environment in caecal tissue. The chicory-supplemented diet was rich in non-starch polysaccharides, particularly uronic acids (the monomeric constituents of pectin). In accordance, mice fed pectin-supplemented AIN93G diets had higher T. muris burdens and reduced IgE production and expression of genes involved in type-2 immunity. Importantly, treatment of pectin-fed mice with exogenous IL-25 restored type-2 responses and was sufficient to allow T. muris expulsion. CONCLUSIONS: Collectively, our data suggest that increasing levels of fermentable, non-starch polysaccharides in refined diets compromises immunity to helminth infection in mice. This diet-infection interaction may inform new strategies for manipulating the gut environment to promote resistance to enteric parasites.

Exogenous enzymes, meal size, and meal frequency: effect on ileal and total tract digestibility of carbohydrates, and energy and fiber degradation in growing pigs fed a wheat-barley grain-based high-fiber diet.

When conducting a digestibility trial, pigs are usually fed only twice a day with a restricted feed intake which is not representative of the feeding conditions in a commercial farm. This study aimed to determine the effects of meal size and frequency, and exogenous enzymes (xylanase and phytase) on the digestibility of a high-fiber diet using porcine in vivo and in vitro approaches. Pigs (n = 6) were fitted with a T cannula, and each received all treatments using a 6 × 6 Latin square experimental design. The diets were supplemented (Enz) or not with a combination of xylanase and phytase and distributed into three feeding programs: one received two meals per day that met three times the maintenance energy requirement (2M), one received the same quantity of feed in eight meals (8M), and another received an amount that met five times the maintenance energy requirements in eight meals (8M+). For in vitro experiment, the degradability of fiber with or without xylanase supplementation only was determined. Enzyme supplementation increased apparent ileal digestibility (AID) of dry matter, starch, and degradation of insoluble non-starch polysaccharides (I-NSP) in all in vivo treatments (P < 0.05). The 2M compared with 8M increased the AID of starch and total tract digestibility of organic matter and I-NSP (P < 0.05). Enzyme supplementation decreased the content of insoluble arabinoxylan (P < 0.05) and increased arabinoxylan oligosaccharides (P < 0.05) in the in vivo ileal digesta and in vitro incubation. The results of this study confirm degradation by xylanase of the fiber fraction at the ileal level, which resulted in less fermentation of fiber in the large intestine. However, number and size of meals had little influence on feed digestibility. The consequences of shifting fiber fermentation more towards the upper part of the gastrointestinal tract need further investigation. The in vitro model provided a confirmation of the action of xylanase on the degradation of non-starch polysaccharides.

To reduce cost and also utilize locally produced ingredients, pig diets nowadays can include a large proportion of fiber-rich ingredients. Exogenous enzymes can be added to diets to improve their digestibility and limit negative effects of fiber. Usually, when conducting a digestibility trial, pigs are fed only twice a day with a restricted feed intake which is not representative of feeding conditions in a commercial farm. This study aimed to determine the effect of meal size and frequency, and enzyme supplementation on digestibility of a diet rich in fiber in growing pigs and in vitro. The diets were supplemented (Enz) or not with xylanase and phytase, and according to different size and frequency: one treatment was pig receiving two meals per day with five times the maintenance energy requirement (2M), another received the same quantity of feed in eight meals (8M), and the last received an amount close to ad libitum feeding in eight meals (8M+). An in vitro experiment was also conducted to look at degradability of fiber with and without xylanase. The results showed that xylanase allows degradation of fiber and increases digestibility of dry matter, starch, and energy. The number and size of meals have little influence on digestibility.

Pre-diagnostic plasma enterolactone concentrations and breast cancer prognosis among postmenopausal women - The Danish Diet, Cancer and Health cohort.

BACKGROUND & AIMS: High intakes of the phytoestrogen lignans and high blood concentrations of its main biomarker, enterolactone, has been associated with a better breast cancer prognosis. We investigated the association between pre-diagnostic plasma concentrations of enterolactone and breast cancer prognosis (i.e. recurrence, breast cancer-specific mortality and all-cause mortality). METHODS: Plasma and data was available from the Danish Diet, Cancer and Health cohort. Information on treatment and clinical characteristics from registries and clinical databases and both pre-diagnostic and diagnostic plasma measurement of enterolactone on a sub-set. Enterolactone was quantified in plasma using a high-throughput LC-MS/MS method. We followed 1457 breast cancer cases from date of diagnosis and until censoring or end-of-follow-up (median 9 years), during this time 404 died (250 of breast cancer) and 267 experienced recurrence. Cox proportional hazards models were used to estimate hazard ratios (HR) with 95% confidence intervals (CI). RESULTS: Plasma enterolactone were borderline significantly associated with lower breast cancer-specific mortality (HRdoubling = 0.93, 95% CI:0.86, 1.00, P = 0.0501), but not associated with all-cause mortality (HRdoubling = 0.95, 95% CI:0.89, 1.01) and recurrence (HRdoubling = 0.96, 95% CI: 0.89, 1.04) in the models adjusted for smoking, schooling, BMI, physical activity and use of menopausal hormones. Adjusting further for clinical characteristics and treatment did not change the results considerably. In the sensitivity analyses, an inverse association was found with all-cause and breast cancer-specific mortality for those where blood was collected ≤5 years before diagnosis. CONCLUSIONS: Overall, no clear association was found between pre-diagnostic plasma concentrations of enterolactone and breast cancer prognosis.

Postprandial PYY increase by resistant starch supplementation is independent of net portal appearance of short-chain fatty acids in pigs.

Increased dietary fiber (DF) fermentation and short-chain fatty acid (SCFA) production may stimulate peptide tyrosine-tyrosine (PYY) secretion. In this study, the effects of hindgut SCFA production on postprandial PYY plasma levels were assessed using different experimental diets in a porto-arterial catheterized pig model. The pigs were fed experimental diets varying in source and levels of DF for one week in 3×3 Latin square designs. The DF sources were whole-wheat grain, wheat aleurone, rye aleurone-rich flour, rye flakes, and resistant starch. Postprandial blood samples were collected from the catheters and analyzed for PYY levels and net portal appearance (NPA) of PYY was correlated to NPA of SCFA. No significant effects of diets on NPA of PYY were observed (P > 0.05), however, resistant starch supplementation increased postprandial NPA of PYY levels by 37 to 54% compared with rye-based and Western-style control diets (P = 0.19). This increase was caused by higher mesenteric artery and portal vein PYY plasma levels (P < 0.001) and was independent of SCFA absorption (P > 0.05). The PYY levels were higher in response to the second daily meal compared with the first daily meal (P < 0.001), but similar among diets (P > 0.10). In conclusion, the increased postprandial PYY responses in pigs fed with different levels and sources of DF are not caused by an increased SCFA absorption and suggest that other mechanisms such as neural reflexes and possibly an increased flow of digesta in the small intestine may be involved. The content of DF and SCFA production did not affect PYY levels.

Resistant Starch but Not Enzymatically Modified Waxy Maize Delays Development of Diabetes in Zucker Diabetic Fatty Rats.

Background: The incidence of type 2 diabetes (T2D) is increasing worldwide, and nutritional management of circulating glucose may be a strategic tool in the prevention of T2D.Objective: We studied whether enzymatically modified waxy maize with an increased degree of branching delayed the onset of diabetes in male Zucker diabetic fatty (ZDF) rats.Methods: Forty-eight male ZDF rats, aged 5 wk, were divided into 4 groups and fed experimental diets for 9 wk that contained 52.95% starch: gelatinized corn starch (S), glucidex (GLU), resistant starch (RS), or enzymatically modified starch (EMS). Blood glucose after feed deprivation was assessed every second week; blood samples taken at run-in and at the end of the experiment were analyzed for glycated hemoglobin (HbA1c) and plasma glucose, insulin, and lipids. During weeks 2 and 8, urine was collected for metabolomic analysis.Results: Based on blood glucose concentrations in feed-deprived rats, none of the groups developed diabetes. However, in week 9, plasma glucose after feed deprivation was significantly lower in rats fed the S and RS diets (13.5 mmol/L) than in rats fed the GLU and EMS diets (17.0-18.9 mmol/L), and rats fed RS had lower HbA1c (4.9%) than rats fed the S, GLU, and EMS (5.6-6.1%) diets. The homeostasis model assessment of insulin resistance was significantly lower in rats fed RS than in rats fed the other diets (185 compared with 311-360), indicating that rats fed the S, GLU, and EMS diets were diabetic, and a 100% higher urine excretion during week 8 in rats fed the GLU and EMS diets than that of rats fed S and RS showed that they were diabetic. Urinary nontargeted metabolomics revealed that the diabetic state of rats fed S, GLU, and EMS diets influenced microbial metabolism, as well as amino acid, lipid, and vitamin metabolism.Conclusions: EMS did not delay the onset of diabetes in ZDF rats, whereas rats fed RS showed no signs of diabetes.

Distinct difference in absorption pattern in pigs of betaine provided as a supplement or present naturally in cereal dietary fiber.

The net absorption of betaine and choline was determined for 4 h after the first meal of the day in three experiments with porto-arterial catheterized pigs in which betaine was added as a supplement to a low-betaine diet (n=4 pigs) and compared to the net absorption of betaine and choline from high-fiber breads differing in amount and source of dietary fiber (two experiments, n=6 pigs each). Plasma betaine peaked after 30 min when betaine was fed as a supplement, whereas it peaked after 120-180 min when high-fiber breads were fed. Plasma betaine showed no diet×time interaction after feeding with high-fiber breads, indicating that the absorption kinetic did not differ between fiber sources. The net absorption of choline was not affected by the experimental diets. In conclusion, betaine in cereal sources has to be liberated from the matrix prior to absorption, causing delayed absorption.

Resistant starch and arabinoxylan augment SCFA absorption, but affect postprandial glucose and insulin responses differently.

The effects of increased colonic fermentation of dietary fibres (DF) on the net portal flux (NPF) of carbohydrate-derived metabolites (glucose, SCFA and, especially, butyrate), hormones (insulin, C-peptide, glucagon-like peptide 1 and glucose-dependent insulinotropic peptide) and NEFA were studied in a healthy catheterised pig model. A total of six pigs weighing 59 (SEM 1·6) kg were fitted with catheters in the mesenteric artery and in the portal and hepatic veins, and a flow probe around the portal vein, and included in a double 3 × 3 cross-over design with three daily feedings (at 09.00, 14.00 and 19.00 hours). Fasting and 5 h postprandial blood samples were collected after 7 d adaptation to each diet. The pigs were fed a low-DF Western-style control diet (WSD) and two high-DF diets (an arabinoxylan-enriched diet (AXD) and a resistant starch-enriched diet (RSD)). The NPF of insulin was lower (P= 0·04) in AXD-fed pigs (4·6 nmol/h) than in RSD-fed pigs (10·5 nmol/h), despite the lowest NPF of glucose being observed in RSD-fed pigs (203 mmol/h, P= 0·02). The NPF of total SCFA, acetate, propionate and butyrate were high, intermediate and low (P< 0·01) in AXD-, RSD- and WSD-fed pigs, respectively, with the largest relative increase being observed for butyrate in response to arabinoxylan supplementation. In conclusion, the RSD and AXD had different effects on the NPF of insulin and glucose, suggesting different impacts of arabinoxylan and resistant starch on human health.

Similar metabolic responses in pigs and humans to breads with different contents and compositions of dietary fibers: a metabolomics study.

BACKGROUND: In nutritional studies, pigs are often used as models for humans because of nutritional and physiologic similarities. However, evidence supporting similar metabolic responses to nutritional interventions is lacking. OBJECTIVE: The objective was to establish whether pigs and humans respond similarly to a nutritional intervention. Using metabolomics, we compared the acute metabolic response to 4 test breads between conventional pigs (growing) and adult human subjects (with the metabolic syndrome). DESIGN: Six catheterized pigs and 15 human subjects were tested in a randomized crossover design with 4 breads: white-wheat bread low in dietary fiber, rye bread with whole-rye kernels, and 2 white-wheat breads supplemented with either wheat arabinoxylan or oat ß-glucan. Blood samples drawn -15, 30, and 120 min postprandially were analyzed by untargeted liquid chromatography-mass spectrometry metabolomics. RESULTS: We found that the postprandial responses, as reflected in blood metabolomes, are similar in pigs and humans. Twenty-one of 26 identified metabolites that were found to be different between the species were qualitatively similar in response to the test breads, despite different basal metabolome concentrations in the plasma of pigs and humans. Humans had higher contents of phosphatidylcholines, oleic acid, and carnitine in plasma, possibly reflecting a higher intake of meats and fats. In pigs, betaine, choline, creatinine, tryptophan, and phenylalanine were higher, probably because of the higher doses of bread provided to the pigs (per kg body weight) and/or because of their growing status. Acute metabolic differences in these metabolites induced by the breads were, however, comparable between the 2 species. CONCLUSION: Our results indicate that pigs are a suitable model for human metabolic studies in food research. The human trial was registered at clinicaltrials.gov as NCT01316354. The animal experiment was conducted according to a license obtained by the Danish Animal Experiments Inspectorate, Ministry of Food, Agriculture and Fisheries, Danish Veterinary and Food Administration.

Effect of enzymatic treatment of different starch sources on the in vitro rate and extent of starch digestion.

Gelatinized wheat, potato and waxy maize starches were treated enzymatically in order to increase the degree of branching of the amylopectin fraction and thereby change the starch degradation profile towards a higher proportion of slowly digestible starch (SDS). The materials were characterized by single-pulse (1)H HR-MAS NMR spectroscopy and in vitro digestion profile according to the Englyst procedure. Using various concentrations and incubation times with branching enzyme (EC 2.4.1.18) without or with additional treatment with the hydrolytic enzymes; ß-amylase (EC 3.2.1.2), α-glucosidase (EC 3.2.1.20), or amyloglucosidase (EC 3.2.1.3) the proportion of α-(1-6) linkages was increased by up to a factor of 4.1, 5 and 5.8 in waxy maize, wheat and potato starches, respectively. The proportion of SDS was significantly increased when using hydrolytic enzymes after treatment with branching enzyme but it was only for waxy maize that the proportion of α-(1-6) bonds and the in vitro digestion profile was significantly correlated.

Plasma enterolactone and risk of colon and rectal cancer in a case-cohort study of Danish men and women.

This case-cohort study examined the association between plasma enterolactone concentration and incidence of colon and rectal cancer in the Diet, Cancer and Health cohort, which enrolled 57,053 participants aged 50-64. Information about diet and lifestyle was obtained by questionnaire, and data on prescriptions of antibiotics were obtained from the Danish Prescription Registry. Cases diagnosed during 5.9 years of follow-up and a randomly selected sample of the cohort had a plasma sample analyzed for enterolactone by time-resolved fluoro-immuno assay. Associations were analyzed by Cox proportional hazards model. A total of 244 colon cancer cases, 137 rectal cancer cases, and 370 sub-cohort members were included in the statistical analyses. For each doubling in enterolactone concentration, we found lower risk of colon cancer among women [IRR (95% CI) = 0.76 (0.60-0.96)] and a tendency toward lower risk of rectal cancer [IRR (95% CI) = 0.83 (0.60-1.14)]. Among men, a doubling in enterolactone tended to be associated with higher risk of colon cancer [IRR (95% CI) = 1.09 (0.89-1.34)] and was associated with statistically significantly higher risk of rectal cancer [IRR (95% CI) = 1.74 (1.25-2.44)]. Exclusion of antibiotics users strengthened the results slightly. In conclusion, with higher enterolactone levels, we found lower risk of colon cancer among women and higher risk of rectal cancer among men.