The effect of guar gum and level and source of dietary fat on glucose tolerance in growing pigs.

Six growing pigs (30-75 kg) were fed on semi-purified diets containing either 30 g maize oil/kg diet (LFM), 30 g soya-bean oil-tallow mixture (1:1, w/w)/kg diet (LFST) or 160 g soya-bean oil-tallow mixture (1:1, w/w)/kg diet (HFST) without and with the addition of guar gum (40 g/kg diet). Plasma glucose and insulin concentrations following twice daily feeding at 09.00 and 21.00 h were measured, during 24 h periods, in blood sampled from a permanent indwelling vena cava catheter. The source and level of dietary fat had no significant effect on pre-prandial plasma glucose or insulin concentrations except for insulin with diet LFST in the morning (P less than 0.05). Addition of guar gum to the diets had no significant effect on pre-prandial plasma glucose and insulin levels. The peak post-prandial plasma glucose and insulin levels were not significantly affected by dietary fat. The addition of guar gum, however, significantly reduced (P less than 0.05) the peak post-prandial plasma glucose concentration with diets LFM and LFST and also the peak plasma insulin concentration for all diets except for diet HFST in the morning. The time taken to reach the peak post-prandial plasma glucose and insulin concentrations was not significantly affected by dietary fat but it was increased by the addition of guar gum, although the differences were not always significant.