Effect of guar gum on glucose and water absorption from isolated loops of jejunum in conscious growing pigs

Abstract

I . Four pigs initially of 30 kg live weight were surgically prepared with two re-entrant cannulas in the jejunum 1.0 m apart which allowed an isolated loop to be formed through which solutions were perfused. Wr-EDTA was used as a marker for measuring net secretion or absorption.2. A new Ringer solution was made, the ionic content of which resembled more closely that found in the jejunum of pigs given similar diets, than Krebs-Ringer solution.3. The absorption of glucose and water from Krebs-Ringer and new Ringer solutions was compared. 4.The effect of guar gum on the absorption of glucose and water from solutions of glucose and maltose was studied.5. There was a trend (not significant) for greater absorption of glucose and water from the new Ringer solution than from the Krebs-Ringer solution.6. Guar gum significantly reduced the net absorption of glucose from glucose or maltose solutions from 74.2 to 41.4% (P i 0401) and 71.1 to 35.0% (P < 0.001) respectively. 7.Guar gum significantly reduced the net absorption of water from the glucose solution from 42.7 to 8.3% (P < 0.01) and from the maltose solution from 49.2 to 5.1% (P < 0@01).8. The lack of differences between the absorption of glucose from solutions of glucose or maltose suggested that maltase (EC 3.2.1.20) activity was not inhibited to the extent that this limited the rate of glucose absorption.The beneficial effects of guar gum on glucose tolerance in normal (Jenkins et al. 1977) and diabetic (Jenkins et al. 1976) man are well established. The principal effect of adding guar gum to the diet is a decrease in postprandial hyperglycaemia. However, its mode of action remains unclear. Several hypotheses have been proposed to explain its action within the gut. These include a reduced rate of emptying of the stomach, altered motility in the stomach and small intestine, poorer mixing of digesta and enzymes in the gut lumen, slower hydrolysis of dietary components by brush-border enzymes in the small intestine and a reduction in the rate of absorption across the epithelial cell membrane (Low et al.

Effects of mannan level and β-mannanase supplementation on growth performance, apparent total tract digestibility and blood metabolites of growing pigs

“…The produced volatile fatty acids during fermentation of dietary NSP, play a role to be used as an energy resource instead of blood glucose (Rerat, 1996). In the current study, high mannan level did not change blood glucose, however, some other studies reported that the high mannan level in the diets reduce the absorption of glucose (Rainbird et al, 1984;Yoon et al, 2010). The ability of glucomannan to lower blood glucose appears related to its viscous and soluble nature (Vuksan et al, 1999).…”

“…Dietary supplementation of β-mannanase may improve glucose absorption by hydrolyzing β-mannan, thus partly explaining the observed growth response to β-mannanase. Rainbird et al (1984) noticed that supplementing β-mannanase resulted in a decrease in glucose and water absorption in pigs. Present findings are consistent with data reported by Yoon et al (2010) and Kim et al (2013) who observed increase in blood glucose concentrations but no effects on the total cholesterol and triacylglycerides in pigs fed diets supplemented with β-mannanase.…”

Influences on Gum Feeding in Primates

“…In addition to benefits from consuming gums later in the day there are also potential costs of consuming them earlier. As Power (1991) noted, they can delay glucose absorption in the small intestine (Blackburn and Johnson 1981;Tsai and Peng 1981;Johnson et al 1984;Rainbird et al 1984) and slow both gastric emptying and small intestinal passage (Blackburn and Johnson, 1981;Johnson et al 1984;Nash 1986;Power and Oftedal 1996).…”

Gut transit and carbohydrate uptake

“…Differences in the rate of digestion of starches in vivo were also seen by RCrat et al (1979), who found that glucose derived from wheat starch reached the hepatic portal vein of pigs more rapidly than that from barley. Under normal conditions the supply of brush-border disaccharidases for completing starch digestion appears to be sufficient: even when a large amount of guar gum was present in pigs in studies by Rainbird et al (1984) no reduction in the rate of maltose hydrolysis was seen.…”

“…These results emphasize the dangers of interpreting movements of digesta as an indication of movements of nutrients. Guar gum reduced the rate of absorption of glucose from the jejunum in vitro (Johnson & Gee, 1981) and in vivo (Rainbird et al 1984); the reasons for this finding appear not to be a reduction in small intestinal contact area (Blackburn etal. 1984a), but seem to relate to reduced diffusion or convection of glucose to the epithelial cell surface (Blackburn et al 1984b).…”