Raspberry pomace alters cecal microbial activity and reduces secondary bile acids in rats fed a high-fat diet

The profile of bile acids (BA) largely depends on the enzymatic activity of the microbiota, but this can be modulated by the dietary addition of biologically active compounds, e.g., polyphenols and polyunsaturated fatty acids. The aim of this study was to examine the effect of dietary raspberry pomace as a rich source of biologically active compounds on microbial activity and the BA profile in the caecum of rats fed a high-fat diet. Wistar rats were fed the standard diet AIN-93, a high-fat diet or a modified high-fat diet enriched with 7% different types of processed raspberry pomaces produced by standard grinding and fine grinding, with or without seeds. Rats fed the high-fat diet for eight weeks showed some disorders in liver function and cecal BA, as manifested by an increased concentration of cholesterol, total BA in the liver and cholic, deoxycholic, and β-muricholic acids in the cecal digesta. In general, irrespective of the type of raspberry pomace, these dietary preparations decreased liver cholesterol, hepatic fibroblast growth factor receptor 4, peroxisome proliferator-activated receptor alpha, cecal ammonia and favorable changed BA profile in the cecum. However, among all dietary pomaces, the finely ground preparation containing seeds had the greatest beneficial effect on the caecum by modulating bacterial activity and reducing the levels of secondary BA

Effect of faba bean seeds with different content of proanthocyanidins on growth of rats, caecal enzyme activity and metabolism indices

Rats were fed for 6 weeks with diets containing seeds or their fractions (cotyledons and hulls) of two types of faba bean: colour-flowered varieties (dark seeds) and white-flowered strain (light seeds). Compared to dark seeds, the light seeds contained more crude protein (29.68% vs. 26.96) and less fibre (CF: 7.79 vs. 8.54% and DF: 24.74 vs. 28.93%). The light seeds contained also more a-galactosides (3.88%) than the dark seeds (3.37%). Amino acid composition, e.g. the content of lysine, methionine and cystine in the seeds and cotyledons of different types of faba bean was similar. The content of total polyphenols in light seeds of white flowered faba bean (2.79 g kg -1) was about five times lower than in dark seeds of colour-flowered varieties (10.95 g kg -1). Proanthocyanidins (condensed tannins) consist about 65% of the content of total polyphenols in dark seeds and about 1% of polyphenols in light seeds. The content of proanthocyanidins in the diet (about 2.7 g kg -1) significantly lowered the body weight gain of rats and protein efficiency ratio (PER). Proanthocyanidins decreased also the activity of ß-glucuronidase in the caecal digesta, without affecting the activity of a- and ß-glucosidase and a- and ß-galactosidase. Different proanthocyanidin content in the diet had no effect on the content of glucose, triglycerides and total cholesterol in the serum and activity of selected enzymes: aspartate aminotransferase, alanine transferase, superoxide dismutase and glutathione peroxidase.</sup

Physiological effects of dietary inulin, xylitol and β-galactosyl-derivatives of sugar alcohols in rat

Rats were fed for 4 weeks with diets containing 5% sucrose or the following preparations: inulin, xylitol or b-galactosyl-derivatives of polyol (b-galactosyl-xylitol, -sorbitol, -erythritol). Except for b-galactosyl-erythritol, all preparations caused an enlargement of caecum weight (tissue: 0.41-0.51, digesta: 1.28-1.80 g/100 g BW), compared to the control group (0.28 and 1.00, respectively). The control caecal pH was close to 7.0, while in the experimental groups it ranged from 6.45 (xylitol) to 6.84 (b-galactosyl-erythritol). The caecal ammonia concentration was the lowest in the inulin group (0.45 mg g-1) and the highest in ß-galactosyl-sorbitol group (0.62). All preparations decreased the b-glucuronidase activity in the caecal digesta (0.59-0.81 U g-1) compared to rats fed sucrose-diet (1.00). The highest concentration of SCFAs in the caecum was in inulin and b-galactosyl-erythritol groups (68.57 and 68.36 µmol g-1), and the lowest one - with xylitol (52.41). The total production of SCFAs in the caecum (µmol/100 g BW) was the lowest in the control group (64.8)

Physiological influence of chokeberry phenolics in model diet

Seven groups of Wistar rats (8 males in each) were fed for 4 weeks diets with chokeberry products. Chokeberry juice was added every day to diets at a dose of 1.5, 3 and 6 ml per rat (corresponding to the intake of about 0.5, 1 and 2 l of juice by an adult person) or diets were supplemented with polyphenolics extract to reach the same level of phenolics. The addition of juice or extract did not affect food intake and body gain. Chokeberry juice increased stomach pH from 3.44 (control group) to 3.69–3.85, and ileal pH from 6.16 to 6.23–6.46. Alkalisation of digesta was less distinct with diets containing polyphenolics extract. Both chokeberry products decreased the concentration of caecal ammonia, especially at medium and high doses. The highest dose of chokeberry juice increased microbial α-glucosidase, decreased β-glucosidase and had no effect on β-glucuronidase activities in the caecal digesta. To compare with the control group, the highest dose of chokeberry juice and extract numerically decreased triglycerides (from 265 to 211 and 219 mg dl−1, respectively) and significantly decreased total cholesterol level in the serum (from 133 to 118 and 114 mg dl−1, respectively) and increased content of butyrate in short-chain fatty acids sum of caecal digesta. Indices of the antioxidant status of rats were similar in all treatments. Physiological results of applying relatively low amount of phenolic extract in the diet were similar as when applying high doses of chokeberry juice

Metabolic response of the gastrointestinal tract and serum parameters of rabbits to diets containing chicory flour rich in inulin

A 36-day experiment carried out on 54-day-old rabbits addressed the analysis of physiological properties of diets supplemented with chicory roots flour. Twenty-four rabbits were allocated in individual cages to three treatments, in which they were fed each diet with the chicory flour at 0, 25 and 50 g/kg (control, ChF (2.5) and ChF(5) groups respectively). The chicory preparation administered at a higher dose, lowered ileal pH and viscosity, and evoked increased hydration of ileal and caecal digesta, compared to the control treatment (p <= 0.05). The ChF(2.5) group was characterized by the highest increase in the bulk of digesta and concentration of protein in the caecum (p < 0.05 vs. control). The lowest colonic pH was found in the ChF(5) group (p <= 0.05 vs. control). Compared to the control group, both chicory treatments effectively (p <= 0.05) diminished the activity of the potentially harmful bacterial enzymes beta-glucosidase and beta-glucuronidase in the caecal and colonic digesta. The ChF(2.5) group was characterized by a significantly higher volatile fatty acids (VFA) pool size in the caecum, whereas rabbits fed the ChF(5)diet had the highest colonic VFA pool size (p <= 0.05 vs. control). The lowest level of triglycerides and total cholesterol, at concurrently the highest proportion of high-density lipoprotein (HDL) fraction in the HDL/totai cholesterol profile, were recorded in the plasma of rabbits fed the ChF(5) diet. In conclusion, the chicory flour rich in inulin, exerted positive effects on the rabbit gastrointestinal tract physiology and would be a potential source of functional feed additivesVytauto Didžiojo universitetasŽemės ūkio akademij