Influence of oligosaccharide extracts from pea and lupin seeds on caecal fermentation in rats

The influence of replacing cellulose in a casein diet with oligosaccharides from lupin and pea seeds (diets LOS and POS, respectively) on the metabolism of the caecum was investigated in an experiment on Wistar rats. The experimental diets contained 3.89 or 4.87 percent alpha-galactosides and 2.8 or 2.0 percent sucrose (LOS and POS, respectively). In rats receiving the diet with oligosaccharides, a greater weight of digesta and caecal tissue (especially in the LOS group), as well as a higher pH (range 7.15-7.37) and ammonia concentration (46-51 mg/100 g) in the caecal content were recorded, compared with the control group (7.03 and 24 mg/100 g, respectively). In rats fed diets with oligosaccharide extracts, the dry matter of caecal digesta was significantly lower and activities of bacterial beta- and alpha-galactosidase, alpha-glucosidase and beta-glucuronidase were significantly higher. The concentration of short-chain fatty acids in the caecum digesta was higher in rats given pea oligosaccharides (129.16 umol/g fresh digesta), than in rats fed with lupin-extract (98.55 umol/g) and rats fed the diet with cellulose (112.58 umol/g). Compared with cellulose, the total production of SCFAs in the caecum (expressed as umol/100 g BW) was significantly higher when the diet contained 4.87 percent alpha-galactosides from pea (POS-group) and insignificantly higher when the diet contained 3.89 percent of lupin alpha-galactosides (LOS-group).