The effect of high-molecular-weight guar gum on net apparent glucose absorption and net apparent insulin and gastric inhibitory polypeptide production in the growing pig: relationship to rheological changes in jejunal digesta

Abstract

The present study was designed to determine the quantitative effects of starchy meals containing guar gum on rates of net apparent glucose absorption and net apparent insulin and gastric inhibitory polypeptide (GIP) production in growing pigs. The effects of these meals on the viscosity of jejunal digesta were also examined and correlated to changes in glucose absorption. Four growing pigs were each given either a low-fat semi-purified diet (control) or the same diet supplemented with a high-molecularweight par gum at concentrations in the diet of 20 or 40g/kg. Blood samples were removed simultaneously via indwelling catheters from the mesenteric artery and the hepatic portal vein. Samples of jejunal digesta were removed via a T-piece cannula and used immediately for viscosity measurements at 39'. The 'zero-shear' viscosity of each sample was then calculated. Blood-flow measurements were made using an ultrasonic flow probe fitted to the hepatic portal vein. All measurements were made at intervals of 10 or 30 min during a 4 h postprandial period. Meals containing guar gum significantly increased (P < 0.05) the viscosity of jejunal digesta, an effect that was strongly dependent on the concentration of guar gum in the original diet. No significant differences in blood-flow rates were found between the control and guar-containing diets. Both concentrations of guar gum significantly reduced (P < 0.05) glucose absorption and insulin and GIP secretion rates over the 4 h postprandial period. An inverse relationship between the rate of glucose absorption and the 'zero-shear' viscosity of jejunal digesta was found. This study also provides direct evidence for the important role played by the enteroinsular axis in modifying the glycaemic response to a meal containing guar gum.

Non-starch polysaccharides extracted from seaweed can modulate intestinal absorption of glucose and insulin response in the pig

“…Glucose absorbed 1 h (1) 2 h 5 h 8 h moles moles moles moles % starch (2) Group 1 response relationship can be found [11]. This can be explained first by dilution of secretions in the digestive tract, and second by the effect of pH and ionic conditions prevailing in the gut.…”

“…Similar physiological responses have been demonstrated in humans and pigs consuming seaweed fibres [1,19]. Moreover, in the pig, it is possible to monitor glucose and insulin concentration changes directly in the portal vein draining the viscera, and to quantify intestinal absorption when portal blood-flow-rate is also measured [11,24]. In addition, the experimental design used allowed a paired comparison of the effect of seaweed fibre vs. cellulose supplementation in the same animals.…”

“…This study was performed in the pig, which is increasingly used in biomedical research [31], especially for gastrointestinal studies. Moreover, in the present case as well as in a previous study on guar gum [11] using the pig model, quantitative data on glucose absorption and insulin response was obtained, and related to the physico-chemical properties of digesta.…”

“…The present data suggest that viscosity is also a major factor in the case of algal polysaccharides, as the three fibre extracts tested differed greatly in that respect, and the effects observed were correlated with their intrinsic viscosity. As already emphasised by [4] and [11], changes in the viscosity of digesta are difficult to predict from the viscosity of the fibre ingredients, and no dose-pancreatic amylase activity [3]. It is thus suggested that LD supplementation does not act by inhibiting starch hydrolysis.…”

Influência de frações da parede celular de levedura (Saccharomyces cerevisiae) sobre os índices séricos de glicose e lipídios, microbiota intestinal e produção de ácidos graxos voláteis (AGV) de cadeias curtas de ratos em crescimento

“…Alguns estudos in vivo relatam que a suplementação com fibras viscosas diminui a resposta glicêmica frente a uma ingestão elevada de hidratos de carbono 10,16,20,32,62 . A causa deste efeito, segundo os autores, pode estar na ação dos polissacarídeos viscosos sobre as propriedades físicas do conteúdo intestinal, porém este mecanismo fisiológico não está totalmente esclarecido, já que existem outros fatores que podem contribuir para este fenômeno, tais como: o atraso no esvaziamento gástrico, que segundo alguns autores seria o principal fator na modificação da movimentação intestinal; a redução na velocidade de difusão da glicose nas células da mucosa e, por último, o aumento da viscosidade do conteúdo intestinal e a diminuição do acesso da enzima alfa-amilase a seu substrato.…”