High-fat diet promotes the effect of fructo-oligosaccharides on the colonic luminal environment, including alkaline phosphatase activity in rats.

We recently reported that fermentable nondigestible carbohydrates such as oligosaccharides, commonly increase colonic alkaline phosphatase (ALP) activity and the gene expression of Alpi-1, coding for rat intestinal alkaline phosphatase-I isozyme in rats and that the effect of oligosaccharides on colonic ALP activity is affected by the quality of dietary fats. We hypothesized that the amount of dietary fat would modulate the effect of oligosaccharides on colonic ALP and luminal environment in rats. In experiment 1, male Sprague-Dawley rats were fed a low-fat (LF, 5% lard) or high-fat (HF, 30% lard) diet with or without 4% fructo-oligosaccharides (FOS). In experiment 2, they were fed a 2.5%, 7%, 20%, or 40% fat (lard) diet with 4% FOS for 2 weeks. Dietary FOS in the HF diet (HF-FOS) significantly increased ALP activity in the colon and cecal digesta and colonic expression of Alpi-1, but not in the LF diet with FOS groups (LF-FOS). In comparison to the LF-FOS group, the increases in fecal mucins, Lactobacillus ratio, as well as cecal n-butyrate, and the decrease in fecal Clostridium coccoides, were more pronounced in the HF-FOS group. Compared with the 2.5% or 7% fat + FOS diet, the 20% fat + FOS diet significantly increased colonic ALP activity, Alpi-1 expression, and fecal mucins. These factors did not differ significantly between 20% and 40% fat + FOS diets. To exert the maximum effect of FOS on the colonic luminal environment, including ALP activity in rats, significantly more fat may be required than that contained present a LF diet.

Consumption of lily bulb modulates fecal ratios of firmicutes and bacteroidetes phyla in rats fed a high-fat diet.

It has been recently suggested a high ratio of fecal Firmicutes and reduction in the Bacteroidetes in obese animals. This study investigated the effect of dietary lily bulb (LB) on fecal Firmicutes and Bacteroidetes in rats fed a high-fat (HF) diet. In experiment 1, rats were fed an HF diet with or without 7% raw (R) or steamed (S) LB. In experiment 2, rats were fed the HF diet with or without 7% RLB, 0.9% ethanol extract of LB, or 6.1% ethanol extract residue of LB. In experiment 1, fecal Firmicutes was reduced and Bacteroidetes was increased in both the RLB and SLB groups. In experiment 2, the fecal Firmicutes/Bacteroidetes ratio was not affected by the ethanol extract or ethanol extract residue of LB. These results suggest that LB in its entirety modulates colonic microflora, regardless of heat treatment.