Voedingsvezels als vallen voor schadelijke darmbacteriën

Ziekteverwekkende bacteriën binden zich in de darm aan specifieke celreceptoren. Door voedingsvezels aan te bieden die overeenkomsten vertonen met deze receptoren, kunnen bacteriën worden misleid. Zij binden zich dan ook aan de voedingsvezels en niet per se aan de darmcellen, en worden vervolgens via de feces uitgescheiden en zo in aantal verminder

Inhibition of Binding of the AB5-Type Enterotoxins LT-I and Cholera Toxin to Ganglioside GM1 by Galactose-Rich Dietary Components

Cholera, travelers' diarrhea, or colibacillosis in pigs can possibly be prevented or attenuated by dietary provision of competitive inhibitors that react with the GM1-binding sites of the enterotoxins cholera toxin (CT), human Escherichia coli heat-labile enterotoxin of serogroup I (LTh-I), and porcine LT-I (LTp-I). The interfering efficiency of natural substances with binding of the toxins to the gangliosid receptor GM1 was tested using a specially adapted GM1-coated-microtiter-well enzyme-linked immunosorbent assay. The substances tested for their GM1 displacing capacity were galactose-containing or -related saccharides from bovine milk, skim milk powder, galactan from gum arabic, food stabilizers as well as ground fenugreek seed and soy bean constituents that contain galactomannans, the galactopolysaccharides agar and agarose, and larch wood and other plant materials that contain arabinogalactans. Skim milk powder, compared with the pure milk saccharides tested, interfered to a higher extent with LTh-I (65–66% inhibition at 5mg test substance/mL) and CT binding (63–67% inhibition at 5mg test substance/mL) when supplied before or simultaneously with the toxins in the GM1-enzyme-linked immunosorbent assay. Ground fenugreek seed counteracted GM1 binding of 5ng LTh-I/mL as well as 5ng and 1µg LTp-I/mL (43–65% inhibition at 5mg test substance/mL), and 4ng CT/mL (61–92% inhibition at 5mg test substance/mL) very efficiently when supplied before the toxin–GM1 complex had formed. With 50mg/mL fenugreek seed, inhibition percentages of even 92–99% were reached for LTh-I and CT binding. Efforts to resolve already bound toxin from GM1 with the test substances were less effective than preincubations and concurrent incubations

Inhibition of Binding of the AB5-Type Enterotoxins LT-I and Cholera Toxin to Ganglioside GM1 by Galactose-Rich Dietary Components

Cholera, travelers' diarrhea, or colibacillosis in pigs can possibly be prevented or attenuated by dietary provision of competitive inhibitors that react with the GM1-binding sites of the enterotoxins cholera toxin (CT), human Escherichia coli heat-labile enterotoxin of serogroup I (LTh-I), and porcine LT-I (LTp-I). The interfering efficiency of natural substances with binding of the toxins to the gangliosid receptor GM1 was tested using a specially adapted GM1-coated-microtiter-well enzyme-linked immunosorbent assay. The substances tested for their GM1 displacing capacity were galactose-containing or -related saccharides from bovine milk, skim milk powder, galactan from gum arabic, food stabilizers as well as ground fenugreek seed and soy bean constituents that contain galactomannans, the galactopolysaccharides agar and agarose, and larch wood and other plant materials that contain arabinogalactans. Skim milk powder, compared with the pure milk saccharides tested, interfered to a higher extent with LTh-I (65–66% inhibition at 5mg test substance/mL) and CT binding (63–67% inhibition at 5mg test substance/mL) when supplied before or simultaneously with the toxins in the GM1-enzyme-linked immunosorbent assay. Ground fenugreek seed counteracted GM1 binding of 5ng LTh-I/mL as well as 5ng and 1µg LTp-I/mL (43–65% inhibition at 5mg test substance/mL), and 4ng CT/mL (61–92% inhibition at 5mg test substance/mL) very efficiently when supplied before the toxin–GM1 complex had formed. With 50mg/mL fenugreek seed, inhibition percentages of even 92–99% were reached for LTh-I and CT binding. Efforts to resolve already bound toxin from GM1 with the test substances were less effective than preincubations and concurrent incubations

Growth and activity of ANME clades with different sulfate and sulfide concentrations in presence of methane

Extensive geochemical data showed that significant methane oxidation activity exists in marine sediments. The organisms responsible for this activity are anaerobic methane-oxidizing archaea (ANME) that occur in consortia with sulfate-reducing bacteria. A distinct zonation of different clades of ANME (ANME-1, ANME-2a/b and ANME-2c) exists in marine sediments, which could be related to the localized concentrations of methane, sulfate and sulfide. In order to test this hypothesis we performed long-term incubation of marine sediments under defined conditions with methane as a headspace gas: low or high sulfate (±4 and ±21 mM, respectively) in combination with low or high sulfide (±0.1 and ±4 mM, respectively) concentrations. Control incubations were also performed, with only methane, high sulfate or high sulfide. Methane oxidation was monitored and growth of subtypes ANME-1, ANME-2a/b, and ANME-2c assessed using qPCR analysis. A preliminary archaeal community analysis was performed to gain insight into the ecological and taxonomic diversity. Almost all of the incubations with methane had methane oxidation activity, with the exception of the incubations with combined low sulfate and high sulfide concentrations. Sulfide inhibition occurred only with low sulfate concentrations, which could be due to the lower Gibbs free energy available as well as sulfide toxicity. ANME-2a/b appear to mainly grow in incubations which had high sulfate levels and methane oxidation activity, whereas ANME-1 did not show this distinction. ANME-2c only grew in incubations with only sulfate addition. These findings are consistent with previously published in situ profiling analysis of ANME subclusters in different marine sediments. Interestingly, since all ANME subtypes also grew in incubations with only methane or sulfate addition, ANME may also be able to perform anaerobic methane oxidation under substrate limited conditions or alternatively perform additional metabolic processes

Effects of faba beans and faba bean hulls on the expression of selected genes in the small intestine of piglets

In a small intestinal segment perfusion (SISP) study in pigs, effects were studied of intestinal perfusion of ground faba beans (Vicia faba), faba bean hulls, or saline on intestinal net fluid absorption in intestinal segments either challenged or not with an enterotoxigenic Escherichia coli (ETEC). After an 8-h perfusion, piglets were euthanized and small intestinal mucosa samples were collected for analysis of expression level of a selected set of genes (APOC3, TIMP1, AQP8, MMP1, MUC13, and PAP) using real-time quantitative PCR (qPCR). Perfusion with ground faba beans and faba bean hulls and challenge with ETEC affected (P <0.05) expression of several of genes in the intestinal mucosa. Expression of APOC3, TIMP1, AQP8, MMP1, and PAP was correlated with net fluid absorption in the small intestine of pigs

Effect of rumen-protected choline supplementation on liver and adipose gene expression during the transition period in dairy cattle

We previously reported that supplementation of rumen-protected choline (RPC) reduces the hepatic triacylglycerol concentration in periparturient dairy cows during early lactation. Here, we investigated the effect of RPC on the transcript levels of lipid metabolism-related genes in liver and adipose tissue biopsies, taken at wk -3, 1, 3, and 6 after calving, to elucidate the mechanisms underlying this RPC-induced reduction of hepatic lipidosis. Sixteen multiparous cows were blocked into 8 pairs and randomly allocated to either 1 of 2 treatments, with or without RPC. Treatments were applied from 3 wk before to 6 wk after calving. Both groups received a basal diet and concentrate mixture. One group received RPC supplementation, resulting in an intake of 14.4 g of choline per day, whereas controls received an isoenergetic mixture of palm oil and additional soybean meal. Liver and adipose tissue biopsies were taken at wk -3, 1, 3, and 6 to determine the mRNA abundance of 18 key genes involved in liver and adipose tissue lipid and energy metabolism. Milk samples were collected in wk 1, 2, 3, and 6 postpartum for analysis of milk fatty acid (FA) composition. The RPC-induced reduction in hepatic lipidosis could not be attributed to altered lipolysis in adipose tissue, as no treatment effect was observed on the expression of peroxisome proliferator-activated receptor ¿, lipoprotein lipase, or FA synthase in adipose tissue, or on the milk FA composition. Rumen-protected choline supplementation increased the expression of FA transport protein 5 and carnitine transporter SLC22A5 in the liver, suggesting an increase in the capacity of FA uptake and intracellular transport, but no treatment effect was observed on carnitine palmitoyl transferase 1A, transporting long-chain FA into mitochondria. In the same organ, RPC appeared to promote apolipoprotein B-containing lipoprotein assembly, as shown by elevated microsomal triglyceride transfer protein expression and apolipoprotein B100 expression. Cows supplemented with RPC displayed elevated levels of glucose transporter 2 mRNA and a reduced peak in pyruvate carboxylase mRNA immediately after calving, showing that supplementation also resulted in improved carbohydrate metabolism. The results from this study suggest that RPC supplementation reduces liver triacylglycerol by improved FA processing and very-low-density lipoprotein synthesis, and RPC also benefits hepatic carbohydrate metabolism

Influence of DGAT1 polymorphism on response of dairy cows to ruminal supplementation of linseed oil

The DGAT1 gene encodes for the diacylglycerol acyltransferase enzyme which catalyzes the final step in triacylglycerol synthesis. Various polymorphisms have been reported for DGAT1. One of them, the K232A DGAT1 polymorphism in which lysine as the 232nd amino acid is replaces by alanine, is associated with increased milk yield, lower fat and protein concentrations (Grisart et al., 2001) and altered milk fatty acid (FA) composition (Schennink et al.,2007). Milk FA composition is, on the other hand, also affected by nutritional factors including dietary FA composition (Sterk et al., 2011). Until now, no literature data could be retrieved to establish whether the response in milk FA composition of dairy cows to changes in dietary FA composition is influenced by DGAT1 polymorphism. Therefore, a study was performed with 8 rumen-cannulated dairy cows in mid-lactation with different DGAT1 polymorphism, receiving either palm fat or linseed oil