Starch and fibre intake and glucose postprandial response of dogs

ABSTRACT: Fibre has been studied to reduce the postprandial glucose response of dogs, but the results are inconsistent. Starch intake, however, was not properly considered in the published studies. The effects of starch and fibre intake on the postprandial glucose response were studied in non-obese adult dogs. Cellulose (CEL), carboxymethylcellulose (CMC), pea fibre (PE) and sugarcane fibre (SCF) were combined to form six diets with starch contents ranging from 33% to 42%: SCF+CEL and PE+CEL diets, both with high insoluble fibre (IF=22%) and low soluble fibre (SF=2.5%) content; SCF+CMC and PE+CMC diets with high SF (SF=4.5%; IF=19%) content; and CMC and CEL diets with low dietary fibre (14%) content. The diets were fed in two amounts, providing an intake of 9.5g or 12.5g of starch (kg0.75)-1 day-1, totaling 12 treatments. Each diet was fed to six dogs conditioned to consume all of the daily food in 10min. Their plasma glucose levels were measured before and during 480min after food intake. Results of fibre and starch intake and their interactions were compared by repeated measures ANOVA and the Tukey test (P0.05). High-dose starch intake, however, induced a higher glycaemia at 180 and 240min after the meal and a greater maximal glycaemia and greater area under the glucose curve (P<0.05). A range in insoluble and soluble fibre intake does not change postprandial glucose response, and the amount of starch intake is a main factor for the postprandial glucose response of healthy non-obese dogs

Influence of long-term feeding of different purified dietary fibers on the volatile fatty acid (VFA) profile, pH and fiber-degrading activity of the cecal contents in rats

The aim of this study was to investigate the effect of four weeks ingestion of 10% fiber diets (cellulose, lignocellulose, pectin or guar gum) and fiber free diets on volatile fatty acid (VFA) concentration, pH, and in vitro fiber-degrading activity of the cecal contents of female Sprague Dawley rats. The pH was significantly lower (p<0.05) on guar gum (6.1) and pectin (6.4) than on the other diets (7.2\u20137.6). The cecal concentration of VFAs was similar among groups, ranging from 62.5\ub112 for cellulose to 93.8\ub112 \u3bcg/g for pectin. Guar gum produced significantly more propionic acid than all the other groups, with a relative acetic-propionic-butyric-other acids ratio of 53-29-9-9, compared with 57-22-13-8 for pectin, 50-20-12-18 for cellulose, 51-21-15-13 for lignocellulose and 61-19-9-11 for fiber free. The in vitro fermentation showed a marked increase in guar (+210%) and pectin (+90%) fermentability when incubated with inocula from adapted rats, supporting the hypothesis of a change in the in vivo metabolic activity of the fecal microflora after long term feeding of these fibers