Does dietary inulin affect biological activity of a grapefruit flavonoid-rich extract?

<p>Abstract</p> <p>Background</p> <p>The aim of the study was to verify that the concomitant presence of grapefruit flavonoid extract with inulin in a Western-type diet may provide synergistic effects to the hindgut metabolism, as well as blood lipid and mineral profiles.</p> <p>Methods</p> <p>Forty male Wistar rats were distributed into 4 groups and fed for 28 days with diets rich in fat, cholesterol and protein. A two-way repeated measures ANOVA was applied to assess the effects of inulin (v. sucrose, 5% of the diet), the addition of dietary grapefruit flavonoid extract (diets without or with 0.3% of an extract from hard parts of grapefruit) and the interaction between these two dietary factors.</p> <p>Results</p> <p>When compared to the control sucrose-containing diet, the diet enriched with inulin led to typical changes within the caecum, the main part of hindgut fermentation in rats, such as acidification of the digesta, support of bifidobacteria growth and increase of propionate and butyrate production. The dietary grapefruit flavonoid extract without inulin increased the bulk and pH value of caecal digesta, whereas short-chain fatty acid concentration and the bifidobacteria population were lowered compared to the extract-free diets. Simultaneous dietary addition of both tested components decreased slightly the pH value and increased somewhat the bifidobacteria number and the propionate concentration, however to the level observed with the control sucrose-containing diet. With regard to blood lipids, dietary grapefruit flavonoid extract decreased the triglyceride concentration regardless of the dietary carbohydrate type.</p> <p>Conclusion</p> <p>Inulin does not provide any additional benefit to the blood lipid profile caused by the dietary application of grapefruit flavonoid extract and it does not counteract clearly detrimental effects of the extract in the hindgut. Adding grapefruit extract to the diet must be performed with caution due to possible adverse hindgut responses with overdoses.</p

Hranjiva vrijednost i fiziološki učinak hrane za štakore s dodatkom sirovih sjemenki lupine te sjemenki fermentiranih s pomoću kvasca Candida utilis

The growth and physiological responses of the rats to diet supplemented with raw and Candida utilis-fermented yellow and blue lupin seeds were determined. The diets containing soya bean meal, raw and fermented blue and yellow lupin were administered to eight rats in each diet group for four weeks. Yellow lupin seeds in the diets of rats improved significantly (p<0.05) feed intake, protein digestibility, body mass gain and protein efficiency ratio in comparison with blue lupin seeds. On the contrary, blue lupin seeds affected significantly (p<0.05) gastrointestinal fermentation processes in comparison with yellow lupin seeds. Fermentation of lupin seeds increased crude protein content and reduced phytate and oligosaccharide content. In the fermented products, a higher number of lactic acid bacteria and yeasts but reduced number of coliform bacteria was found. Fermentation by Candida utilis positively (p<0.05) aff ected protein digestibility of feed, body mass gain and protein efficiency ratio of rats, as well as the activity of some bacterial enzymes and cholesterol concentrations in the blood serum.U radu je ispitan utjecaj hranidbe štakora sjemenkama žute i plave lupine, sirovim ili fermentiranim s pomoću kvasca Candida utilis, na njihov rast i fiziološke promjene. Štakori su u grupama po osam jedinki hranjeni sojinom sačmom, te sirovim ili fermentiranim sjemenkama plave i žute lupine tijekom četiri tjedna. Sjemenke žute lupine znatno su povećale (p<0,05) unos hrane, probavljivost proteina i tjelesnu masu, te povećale omjer proteinske djelotvornosti u usporedbi sa sjemenkama plave lupine. Sjemenke su plave lupine pak bitno utjecale (p<0,05) na fermentacijske procese u gastrointestinalnom traktu, za razliku od žute lupine. Fermentacijom se u sjemenkama lupine povećao udjel sirovih proteina, a smanjio udjel fitata i oligosaharida. U fermentiranim je proizvodima pronađeno više bakterija mliječno-kiselog vrenja te kvasaca, a manje koliformnih bakterija. Fermentacija s pomoću kvasca Candida utilis pozitivno (p<0,05) je utjecala na probavljivost proteina, povećanje tjelesne mase i omjer proteinske djelotvornosti, koncentraciju kolesterola u krvi, te na aktivnost nekih bakterijskih enzima

Sastav i biološka svojstva etanolnih ekstrakata korijena, kore, sjemenja i listova cikorije

The chemical composition of the ethanol extracts of chicory root, peel, seed and leaf has been determined, in particular their inulin and phenolic fractions. The root and peel extracts were characterized by large mass fractions of inulin (60.1 and 46.8 g per 100 g of fresh mass, respectively), predominantly with degree of polymerization in the range from 3 to 10, while phenolics, determined as caffeoylquinic acids, made up 0.5 and 1.7 g per 100 g of fresh mass, respectively. The leaf and seed extracts had decidedly lower mass fractions of inulin (1.7 and 3.2 g per 100 g of fresh mass, respectively) and higher mass fractions of phenolics (9.6 and 4.22 g per 100 g of fresh mass, respectively) recognized as caffeoylquinic acids, chicoric acid and quercetin glucuronide. The biological properties of a non-inulin fraction from each extract were determined on Wistar rats fed with diets rich in fructose and saturated fat, as a model of metabolic changes related to westernization of human eating habits. The diets contained the same amount of inulin (6 %) with various phenolic fractions. Some changes were noted in the microbial enzymatic activity of the caecum after feeding for 4 weeks with the diet containing the highest mass fraction of phenolics (0.208 %), derived from the mixture of peel and seed extracts (decreased activity of β-galactosidase and β-glucuronidase), as well as with the diet containing leaf extract (decreased β-glucuronidase activity). All the diets showed no essential influence on the caecal concentration and profile of short-chain fatty acids, except acetate, whose concentration decreased significantly in rats fed with the diet enriched with root extract. The addition of peel and leaf extracts to the fructose diets significantly increased the serum antioxidant capacity of lipophilic substances. The study indicates that parts of chicory and its byproducts might be a source of valuable compounds to improve the physiological activity of inulin.Određen je kemijski sastav etanolnih ekstrakata (tj. udjeli inulina i fenola) korijena, kore, sjemenja i listova cikorije. Ekstrakti korijena i kore sadržavali su velike masene udjele inulina, i to u 100 g svježe tvari: korijen 60,1 g i kora 46,8 g, pri čemu je stupanj polimerizacije bio od 3 do 10. Maseni udjel fenola (derivata kofeinske kiseline) u 100 g svježe tvari bio je u ekstraktu korijena 0,5 g, a u ekstraktu kore 1,7 g. Ekstrakti lišća i sjemenja imali su kudikamo manji udjel inulina u 100 g svježe tvari (ekstrakt lišća 1,7 g i ekstrakt sjemenja 3,2 g) i veći maseni udjel fenola u 100 g svježe tvari (ekstrakt lišća 9,6 g i ekstrakt sjemenja 4,22 g). Biološka svojstva fenola, tj. njihov utjecaj na metaboličke promjene prouzročene zapadnjačkim načinom prehrane, ispitana su na štakorima Wistar kojima je davana hrana bogata fruktozom i zasićenim masnim kiselinama. Hrana je sadržavala isti udjel inulina, a različite masene udjele fenola, ovisno o dodanom ekstraktu. Nakon 4 tjedna prehrane hranom s najvećim udjelom fenola od 0,208 % uočene su promjene u aktivnosti enzima mikrobnog podrijetla, izoliranih iz slijepoga crijeva štakora. Utvrđeno je da hrana koja sadržava mješavinu ekstrakata kore i sjemenja smanjuje aktivnost β-galaktozidaze i β-glukuronidaze, dok hrana koja sadržava ekstrakt lišća smanjuje aktivnost samo β-glukuronidaze. Prehrana nije utjecala na koncentraciju i sastav masnih kiselina, osim što je hrana s dodatkom ekstrakta korijena bitno smanjila koncentraciju acetata u slijepom crijevu. Dodatkom ekstrakata kore i lišća hrani bogatoj fruktozom znatno se povećala antioksidativna aktivnost seruma. Studija je pokazala da dijelovi cikorije i njezine prerađevine mogu poslužiti kao izvor vrijednih sastojaka koji poboljšavaju fiziološku aktivnost inulina

Methodological aspects of determination of the physiological effects

Candidate prebiotics available for human consumption and animal nutrition represented a numerous and diverse group of substances with different amount of bifidogenic oligosaccharides (20-90% of dry matter). The application of prebiotic preparation caused a decrease in the energy value of diets, however the body weight gain of an animal remained unchanged with increased diet intake. One of the effects of oligosaccharide addition to a diet is an increase in the amount of digesta in the gastrointestinal tract, including caecum, which in turn lowers concentration of major products of oligosaccharide fermentation - short-chain fatty acids in fresh caecal digesta. Therefore, total SCFA pool in the whole caecum (converted into 100 g of body weight of rats) is a better indicator of the intensity of oligosaccharide fermentation in the large bowel. The content of probiotic preparations in a diet differentiates the activity of microbial enzymes (mainly α-and β-lactosidase as well α- and β-glucosidase) in the caecal digesta

Nutritional properties of tubers of conventionally bred and transgenic lines of potato resistant to necrotic strain of Potato virus Y (PVYN)

The potential effect of genetic modification on nutritional properties of potatoes transformed to improve resistance to a necrotic strain of Potato virus Y was determined in a rat experiment. Autoclaved tubers from four transgenic lines were included to a diet in the amount of 40% and compared with the conventional cv. Irga. The experiment lasted 3 weeks and special attention was paid to nutritional properties of diets, caecal metabolism and serum indices. Genetic modification of potato had no negative effect on the chemical composition and nutritional properties of tubers, ecosystem of the caecum, activity of serum enzymes and non-specific defence mechanism of the rats. Obtained results indicate that transgenic potato with improved resistance to PVYN: line R1F (truncated gene coding for PVYN polymerase in sense orientation), R2P (truncated gene coding for PVYN polymerase in antisense orientation), and NTR1.16 (non-translated regions of PVYN genome in sense orientation) are substantial and nutritional equivalence to the non-transgenic cultivar. Tubers of transgenic line NTR2.27 (non-translated regions of PVYN genome in antisense orientation) increased the bulk of caecal digesta and the production of SCFA as compared to tubers of the conventional cultivar and the other transgenic clones. Taking into account some deviations, it seems reasonable to undertake a long-term feeding study to confirm the nutritional properties of tubers of transgenic lines

A High-Fat Diet Differentially Affects the Gut Metabolism and Blood Lipids of Rats Depending on the Type of Dietary Fat and Carbohydrate

The aim of this model study was to investigate how selected gut functions and serum lipid profile in rats on high-fat diets differed according to the type of fat (saturated vs. unsaturated) and carbohydrate (simple vs. complex). The experiment was conducted using 32 male Wistar rats distributed into 4 groups of 8 animals each. For 4 weeks, the animals were fed group-specific diets that were either rich in lard or soybean oil (16% of the diet) as the source of saturated or unsaturated fatty acids, respectively; further, each lard- and soybean oil-rich diet contained either fructose or corn starch (45.3% of the diet) as the source of simple or complex carbohydrates, respectively. Both dietary factors contributed to changes in the caecal short-chain fatty acid concentrations, especially to the butyrate concentration, which was higher in rats fed lard- and corn starch-rich diets compared to soybean oil- and fructose-rich diets, respectively. The lowest butyrate concentration was observed in rats fed the soybean oil- and fructose-rich diet. On the other hand, the lard- and fructose-rich diet vs. the other dietary combinations significantly increased serum total cholesterol concentration, to more than two times serum triglyceride concentration and to more than five times the atherogenic index. In conclusion, a high-fat diet rich in fructose can unfavorably affect gut metabolism when unsaturated fats are predominant in the diet or the blood lipids when a diet is rich in saturated fats

Effects of Lactofermented Beetroot Juice Alone or with N-nitroso-N-methylurea on Selected Metabolic Parameters, Composition of the Microbiota Adhering to the Gut Epithelium and Antioxidant Status of Rats

An objective of this work was to assess the biological activity of beetroot juice (Chrobry variety, Beta vulgaris L. ssp. vulgaris), which was lactofermented by probiotic bacteria Lactobacillus brevis 0944 and Lactobacillus paracasei 0920. The oxidative status of blood serum, kidneys, and liver of rats consuming the fermented beetroot juice were determined. The experimental rats were divided into four groups on diet type: Basal diet, basal diet supplemented with fermented beetroot juice, basal diet and N-nitroso-N-methylurea treatment, and basal diet supplemented with fermented beetroot juice and N-nitroso-N-methylurea treatment. Mutagen N-nitroso-N-methylurea, which was added to diet in order to induce aberrant oxidative and biochemical processes and disadvantageous changes in the count and metabolic activity of the gut epithelium microbiota. The nutritional in vivo study showed that supplementing the diet of the rats with the lactofermented beetroot juice reduced the level of ammonia by 17% in the group treated with N-nitroso-N-methylurea. Furthermore, the positive modulation of the gut microflora and its metabolic activity was observed in groups of rats fed with the diet supplemented with the fermented beetroot juice. A concomitant decrease in the b-glucuronidase activity was a consequence of the gut epithelium microbiota modulation. The antioxidant capacity of blood serum aqueous fraction was increased by about 69% in the group of rats treated N-nitroso-N-methylurea mixed with the fermented beetroot juice and N-nitroso-N-methylurea versus to the N-nitroso-N-methylurea treatment, whereas the antioxidant parameters of the blood serum lipid fraction, kidneys, and liver remained unchanged

Ellagitannins and Flavan-3-ols from Raspberry Pomace Modulate Caecal Fermentation Processes and Plasma Lipid Parameters in Rats

Raspberry pomace is a source of polyphenols, which nutritional and health promoting properties are not sufficiently known. The aim of this 8-weeks study was to scrutinize if raspberry extracts (REs) with different ellagitannins to flavan-3-ols ratios might favorably affect the caecal fermentation processes and blood lipid profile in rats. Forty male Wistar rats were fed with a standard diet or its modification with two types of REs (E1 and E2) characterized by different ratios of ellagitannins to flavan-3-ols (7.7 and 3.1 for E1 and E2, respectively) and added to a diet at two dosages of polyphenolic compounds (0.15 and 0.30% of a diet; L and H treatments, respectively). Irrespective of polyphenols dietary level, both REs reduced the activity of bacterial β-glucuronidase, increased production of butyric acid in the caecum and reduced triacylglycerols in blood plasma. The E1 treatment at both dosages caused more effective reduction in the concentration of ammonia and elevated acetate level in the caecal digesta than E2. On the other hand, only the E2 treatment lowered value of the atherogenic index when compared with control group. When comparing dosages of REs, a higher one was more potent to reduce the activity of bacterial β-glucosidase, β-, α-galactosidase and lowered value of the HDL profile in plasma. To conclude, REs may favorably modulate the activity of the caecal microbiota and blood lipid profile in rats; however, the intensity of these effects may be related to the dosages of dietary polyphenols and to their profile, e.g., ellagitannins to flavan-3-ols ratio