Dietary fibre in dogs diet: comparisons between cellulose, pectin, guar gum, and between two incorporation rates of guar gum

The aim of the present experiments was to investigate the effects of adding dietary fibre (DF) to the diets of healthy dogs. In a first study, four young adult Beagle dogs were used in a 4 x 4 Latin square design. They were offered either a control diet (FF1) based on minced meat and cooked rice or the same diet supplemented with cellulose (CEL), pectin (PEC) or guar gum (GG) at an incorporation rate of 3.4% on dry matter basis. Gastric emptying rate, measured by sequential radiographs during the 12 h after the meal tended to be lowered when GG was added. The intestinal absorption of xylose measured on fasted animals was not affected by GG and DEC but was significantly delayed with CEL (p < 0.05). The GG and DEC decreased the dry matter content of the faeces (p < 0.001 and p < 0.01, respectively). The incorporation of DF reduced the digestibility of the different nutrients, the differences being significant with CEL for dry matter (p < 0.05), with GG for protein and ether extract (p < 0.05) and with PEC for protein (p < 0.001). There were no effects of DF supplementation on plasma glucose, insulin a-amino nitrogen, urea and triglycerides concentrations measured before the meal. PEC induced higher post-prandial insulin concentration (p < 0.05) expressed as area under the curve. The post prandial rise of plasma alpha amino nitrogen and urea concentrations were significantly reduced with GG (p < 0.05 and p < 0.01, respectively). The GG induced lower concentrations of plasma cholesterol both in non-fed or fed animals (p < 0.05). In the second study six adult Beagle dogs were used in two combined 3 x 3 Latin square design. They were offered either a control diet (FF2) based on minced meat and steam-treated rice or a diet supplemented with 3.5% and 7% GG on a dry matter basis. The increasing levels of GG decreased the dry matter content of the faeces and increased the protein content (p < 0.001). A dose-level lowering-effect on the different nutrients digestibility and on plasma concentrations of insulin cc-amino-nitrogen and urea (p < 0.01 or p < 0.001) was also observed. Inclusion of 7% GG decreased pre-and postprandial plasma cholesterol concentrations (p < 0.01).