Effects of alkaline, hydrogen peroxide-treated fibres on nutrient digestibility, blood sugar and lipid profile in rats

Three diets containing different sources of dietary fibre, wheat bran, faba bean testas and rice hulls, were tested to determine the effects of alkaline, hydrogen peroxide (AHP)-treated fibre at 10% substitution level of dextrose corn flour on apparent digestibility, faecal characteristics, and levels of plasma glucose and lipid profile in rats. A fourth non-fibrous diet was used as a control. The results showed that, although AHP treatment of fibres resulted in reduction of their weight after washing, it caused an increase in their water absorption and in their swollen volume when mixed with an excess of water (up to three fold) as in the case of wheat bran. Rats consuming diets containing dietary fibres showed a significant loss of body weight but no significant effects on heart weight or liver weight were found. Faeces of rats fed on dietary fibre diets showed an increase in weight and volume, which resulted in reduction of faecal density. The consumption of the treated fibre significantly reduced total cholesterol, plasma triglycerides and blood sugar; wheat bran was the most effective followed by rice hulls and faba bean testas. On the other hand, it effected an increase in the plasma content of high-density lipoprotein HDL-C but this increase was only significant in rats fed with wheat bran. Alkaline hydrogen peroxide-treated fibres showed a great improvement in their absorbency, making them equal to or even better than untreated fibre in lowering blood lipids and sugar levels, in addition to their excellent effect on the physiological function of the intestinal tract.