Effect of dietary supplementation with unprocessed and ethanol-extracted apple pomaces on caecal fermentation, antioxidant and blood biomarkers in rats

Abstract

The present 4-week study on growing Wistar rats was aimed at assessing the potential advantages of dietary supplementation with apple pomace containing both fibre and polyphenols, which enables nutritional exploitation of the physiological traits of both compounds. A total of twenty-four rats, assigned to the control (C), group fed with a diet supplemented with 14 % of processed apple pomace (A) and group fed with a diet supplemented with 15 % unprocessed apple pomace (AP) groups, were fed the following iso-fibrous diets: control, ethanol-extracted and unprocessed apple pomaces (low and high level of dietary polyphenols, i.e. 0·002 and 0·018 %, respectively). To measure the animal response, parameters describing the caecal fermentation, antioxidative status and lipoprotein profile of rats were assessed. Both dietary apple pomaces were found to significantly (P# 0·05) decrease caecal pH and ammonia concentration, microbial b-glucuronidase activity as well as to increase caecal SCFA concentration in comparison to the control diet. The unprocessed pomace did not suppress caecal fermentation. Unlike the extracted one, the dietary apple pomace rich in polyphenols significantly (P#0·05 v. C group) increased erythrocyte superoxide dismutase activity and serum antioxidant capacity of lipid-soluble substances and significantly (P#0·05 v. C group) decreased amounts of thiobarbituric acid-reactive substances in liver tissue. Moreover, the 4-week administration of the AP diet to rats evoked a significant decrease in serum glucose concentration (P# 0·05 v. C and A groups).In conclusion, the results demonstrated that the polyphenol-rich fibre complexes from apple pomace exerted positive effects on gastrointestinal physiology and antioxidant status of rats.

Effect of diets varying in the type of dietary fibre and its combination with polyphenols on gut function, microbial activity and antioxidant status in rats

“…Previous studies conducted in our laboratory as well as those by other researchers revealed that inclusion of dietary fructans, apple pomace and polyphenolic fraction from chicory and apple significantly decreased activity of β-glucuronidase released from bacterial cells into the large gut environment (Bouhnik et al, 2007;Juśkiewicz et al, 2011Juśkiewicz et al, , 2012. Among all experimental preparations, pectin was the only one associated with markedly increased activity of β-glucuronidase.…”

“…After centrifugation at 4800 g for 5 min, the supernatant was collected and the residue was re-extracted twice with 3 ml of the same solvent to gain about 10 ml pooled extracts. The ethanolic extracts, containing most of the soluble polyphenols, were analysed by a Dionex HPLC coupled with a Gemini 5-mm C18 110A column (250 × 4.6 mm; Phenomenex Synergi; Torrance, CA; USA), as described previously by Juśkiewicz et al (2012).…”

Effects of Dietary Addition of a Low-Pectin Apple Fibre Preparation on Rats

“…Ghibu et al [2013] have shown that a high-fructose diet (60% of the diet) can be used as a model to induce oxidative stress in rats. Also, Zagrodzki et al [2007] have shown that the diet high in fructose signifi cantly changes the antioxidant defence status of rats, which may be counteracted by the ad- Maffei et al [2007] have suggested that the consumption of whole apple provides a useful dietary source of active scavengers to protect cells and tissues from oxidative stress, whereas Juśkiewicz et al [2012] have demonstrated that the polyphenol-rich fi bre complexes from apple pomace exert positive effects on the antioxidant status of rats. In the present experiment, the parameters of antioxidant status did not change after AFP administration to a high-fructose diet.…”

“…were measured spectrophotometrically using the rate of -or o-nitrophenol release from the respective nitrophenyl-glycosides and expressed as μmol product formed per h per g of the digesta [Juśkiewicz et al, 2012].…”

“…reduce blood cholesterol concentration and postprandial glycaemia [Anderson & Hanna, 1999]. Moreover, dietary fi bre is found in apples together with polyphenols which are able to improve the antioxidant status of the organism and can help protect it against chronic diseases related to oxidative stress [Maffei et al, 2007; Bonarska- Kujawa et al, 2012;Juśkiewicz et al, 2012].…”