A comparison of the effects of dietary cellulose and fermentable galacto-oligosaccharide, in a rat model of colorectal carcinogenesis: fermentable fibre confers greater protection than non-fermentable fibre in both high and low fat backgrounds

Abstract

The objective of this experiment was to compare the effects of diets with either a non-fermentable fibre source (cellulose) or a fermentable fibre source [galacto-oligosaccharide (GOS)], combined with different levels of dietary fat, on the development of colorectal cancer. Male Wistar rats were fed AIN76-based diets with either a low or high level of cellulose, or a low or high level of GOS, for 9 months. The fat content of the diets was low, medium or high. All rats were treated with 1,2-dimethylhydrazine to induce colorectal tumours. Generally, the tumour incidence increased with increasing fat content in the diet. Despite marked faeces bulking, dietary cellulose either had no effect or an enhancing effect on the formation of colorectal tumours in general, although the development of carcinomas was decreased. GOS appeared to be highly protective against the development of colorectal tumours, as was demonstrated by an inhibitory effect on tumour incidence, multiplicity and size, regardless of the fat content of the diet. Neither fibre source influenced the bromodeoxyuridine labelling index determined in colon crypts or tumours. In animals fed high-GOS diets, the caecal content was significantly increased in weight and significantly decreased in pH. It was concluded that tumorigenesis was enhanced by increased fat content of the diet, and that the diets containing fermentable GOS conferred a greater protection against colorectal cancer than did the diets containing non-fermentable cellulose.

Effect of Dietary L-arabinose on the Intestinal Microbiota and Metabolism of Dietary Daidzein in Adult Mice

“…The amount of faeces was significantly lower in the AR group than in the CO group (p<0.01). Daily faeces production was reportedly greater in rats fed a diet containing a higher cellulose concentration than in rats fed a diet containing a lower cellulose concentration [31]. Significant increases in faecal weights of rats fed cellulose diets have also been reported [32].…”

Potential of probiotics, prebiotics and synbiotics for management of colorectal cancer

“…GOS also significantly inhibited the development of DMH-or AOMinduced colorectal tumors. 97,98 In human volunteer studies, administration of 10 g trans-GOS increased the bifidobacterial count and modified the fermentative activity of colonic flora. 99 Consumption of inulin, FOS and GOS caused a laxative effect upon reaching the large intestine where they underwent fermentation, stimulated microbial growth resulting in increased bacterial mass, fecal bulking and peristalsis.…”

Fructooligosaccharide associated with celecoxib reduces the number of aberrant crypt foci in the colon of rats

“…Thus, the rat strain may explain such a discrepancy. In Wistar rats, a moderate intake in galactooligosaccharide fibres (8.88%) was found without an effect on the development of colonic tumours [49]. The major finding of our study is that the association of celecoxib to butyrate-producing fibres leads to a strong reduction in the number of ACF.…”