The effect of dietary fibers on the digestive tract mass, diamine oxidase (DAO) ... liquid diet (ED) or ED containing 3g/lOO ml of dietary fiber either a mixture of.
NutritionResearch,W. 18,No. 5. pp. 883491.1998 Copyright0 1998Elsevia ScienceInc. printedin theUSA. All ri&ts resaved 0271~5317/98 $19.00+ .OO ELSEVIER
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COMPARATIVE EFFECT OF WATER-SOLUBLE AND -INSOLUBLE DIETARY ON BOWEL FUNCTION IN RATS FED A LIQUID ELEMENTAL DIET
FIBER
Kiyoshi Ebihara, PhD and Yoshihisa Nakamoto, BS Department of Biological Resources, Faculty of Agriculture, Ehime University, Matsuyama 790-0905, Japan
The effect of dietary fibers on the digestive tract mass, diamine oxidase (DAO) activities in the small intestine and plasma and pool of ammonia and organic acids such as acetic, propionic, butyric, lactic and succinic acid in the cecum in rats fed a liquid formula diet was compared. Rats were fed an elemental liquid diet (ED) or ED containing 3g/lOO ml of dietary fiber either a mixture of crystal cellulose and carboxymethyl cellulose sodium salt (CC), sugar-beet pectin (BP) or hydrolyzed xyloglucan (HXG) for 14 days. The mass of colon plus rectum was higher in rats fed CC, but not in rats fed BP and HXG than in rats fed ED. Cecal tissue mass was higher in rats fed BP and HXG, but not in rats fed CC, than in rats fed ED. Cecal contents and cecal pH were higher and lower in rats fed CC, BP and HXG than in rats fed ED. DA0 activities in the small intestine and plasma were higher in CC than in rats fed ED. Cecal ammonia were lower in rats fed CC, BP and HXG than in rats fed ED. Production of organic acids was similar between rats fed ED and CC except for acetic acid that was much lower in also improved in rats fed CC. combination of water -soluble and diet would have more beneficial soluble dietary fiber alone. 0 1998 Ehwier Science Inc.
rats fed CC. Diarrhea and loose feces were The results suggest that the addition of a -insoluble dietary fiber to a liquid formula effects on the bowel function than water-
KEY WORDS: Liquid diet, Dietary fiber, Rats
Bowel function,
Cecal organic
acids,
Liquid formula diets are used in pre- and post-operative bowel preparations to provide complete nutrition orally and in treatment of some diseases such as inflammatory bowel disease and irritable bowel syndrome. Constipation and Correspondence: Kiyoshi Ebihara, Department of Biological Resources, Faculty of Agriculture, Ehime University, Matsuyama 790-0905
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K. EBIHARA and Y. NAKAMOTO
diarrhea are potentially serious problems experienced in chronic care patients who are fed exclusively on liquid formula diets. Several studies have showed that addition of dietary fiber (DF) to liquid formula diets alleviates constipation ( 1) and diarrhea (2,3). As a consequence of this perceived beneficial effect, a number of DF enriched liquid enteral diets have been introduced which have found widespread clinical usage. DF-enriched liquid formula diets are marketed in Japan, in the United States and in Europe. In order to facilitate the administration of diets through fine bore nasogastric feeding tubes, DF had to be fine and soluble in The addition of DF to liquid formula diets increases viscosity, which in turn, water. make it harder to administer the diets through fine bore nasogastric feeding tubes. Therefore, hydrolyzed
water- soluble DF with low viscosity such as polydextrose and partially However, physiological guar gum were used as DF source in Japan.
effects of DF are affected by their physical nature such as whether they are coarse Short-chain fatty or fine, soluble in water or not and more fermentable or less. acids (SCFA), which are a major product of DF fermentation, are the predominant anions in the colonic lumen and are thought to have a major impact on luminal and mucosal metabolism. The fermentation of cellulose is less extensive than that of noncellulolytic polysaccharides such as hemicellulose, pectin and guar gum. The purpose of this study was to compare the effect of water-soluble and -insoluble DF added to a liquid elemental diet on the functional changes in the small intestine and colon and on cecal organic acids.
Animals and diets. Male Wistar rats (Japan SLC, Hamamatsu, Japan) with an initial weight of approximately 80 g were used in the experiment. They were housed in individual cages with screen bottoms of stainless steel in a room maintained at 23 + 1°C with a 12-h 1ight:dark (light, 0700-1900h). Rats were acclimated by feeding a commercial solid diet (MF@; Oriental Yeast Co., Osaka, Japan) for 7 days. After acclimation, rats were divided into 4 groups of 6 rats approximately equal body weight (147 +4 g). Rats were fed an elemental liquid diet (ED) or ED containing 3g/lOO ml of dietary fiber either a mixture of crystal cellulose and carbowmethyl cellulose sodium salt (CC), sugar-beet pectin (BP) or hydrolyzed ED(Elental@, Roussel Morishita Co. Ltd., Osaka) xyloglucan (HXG) for 14 days. consisted of 4.7 g amino acids, 0.16 g lipid (soy bean oil), 2 1.2 g carbohydrate (dextrin), vitamins and minerals in 100 ml. Rats drank experimental liquid diets from calibrated feeding bottles with fitted sippers. CC is a commercial preparation named “Avicel RC-591” (Asahi Chemical Industry Co., Ltd., Tokyo, Japan), which is a mixture of crystal cellulose (average particle diameter=10 cc) and carboxymethyl cellulose sodium salt in the ratio of 89: 11 (weight). BP (Classic RU30 1, Herbstreith & Fox KG, Neuenbiirg, Germany) was gifted from Dainippon Pharmaceutical Co. Ltd. HXG is a commercial preparation named “Glyroid” (Dainippon (Osaka, Japan). Pharmaceutical Co., Ltd., Osaka, Japan), which is prepared from tamarind seed polysaccharide and consists of xyloglucan hepatosaccharide, octasaccharide and nonasaccharide. Body weight and food intake were recorded daily in the morning, and then the condition of feces of each rat was observed.
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DIETARY FIBER AND LIQUID DIET
Sampling
and
were sacrificed
analytical
under
sodium
procedures. pentobarbital
At the end of experiment, all rats (50 mg/kg body mass, Nembutal, Abbot
Blood was collected from the Laboratories, North Chicago, Ill) anesthesia. abdominal aorta in a blood collection tube (Vacutainefl, Becton Dickinson, Franklin Plasma was separated by centrifugation at 1400 x g for 15 min at 4°C Lakes, NJ). The ileo-cecal and ceco-colonic junctions were and stored at -50°C until analyzed. ligated and the digestive tract was removed. The small intestine (the ligament of Treitz to the ileo-cecal junction) and was flushed with ice-cold saline (9 g/L NaCl), blotted on filter paper and length and weight were measured. The colon plus rectum was opened longitudinally, rinsed with ice-cold saline and length and weight were measured. Mucosal scraping of proximal ileum (7-17 cm from ileo-cecal junction) was homogenized in 10 ml of phosphate buffer (0.1 M, pH7.2) followed by centrifuging at 10,000 x g for 20 min. enzyme and protein assay.
An aliquot
of the supernatant
was used for
Activities of intestinal and plasma diamine oxidase (DAO) were assayed according to Hosoda et al. (4) using cadaverine (Wako Pure Chemical Industries, Ltd., Osaka, Japan) as substrate, One unit of DA0 activity is defined as the amount of enzyme that Alkaline phosphatase (ALP) was measured will produce 1 pmol Hz02 per min. according to Kind and King method (5) using disodium phenyl phosphate as substrate. One unit of ALP activity is defined as the amount of enzyme that will produce 1 pmol pnitrophenol per min. Maltase activity was assayed by the method of Takahashi et al. (6) and protein was measured by the method of Lowry et al. (7). The ileo-cecal and ceco-colonic junctions were ligated and the cecum was removed. The cecum was first weighed with contents (total cecal weight). The contents were drained from the ceco-colonic junction into a 50-mL vial, mixed well The cecal wall was flushed clean with ice-cold saline, blotted on and used analyses. Cecal pH was measured with a compact filter paper and weighed (cecal wall weight). pH meter using a sampling sheet (Model C-l, Horiba, Tokyo, Japan; calibrated at Cecal ammonia was determined spectrophotometrically in deproteinized (4 20°C). mL of 0.25 mol/L sulfuric acid and 50 g/L sodium tungstate dihydrate, 50 mg contents) supernatant (1500 x g, 10 min) of cecal contents (8). Cecal organic acids (acetic, propionic, n-butyric, measured by HPLC (LC-1OA; Shimadzu, Kyoto, Japan)
succinic (9).
1:l (v/v), for -
and L-lactic
acids)
were
Statistical analysis. Values are given as the means&EM and, where appropriate, significance of the difference between mean values was determined by Values of P analysis of variance coupled with Duncan’s multiple range test (10). ~0.05 were considered significant.
Rats quantity.
Rats fed ED had loose feces in lower fed BP had severe diarrhea. Rats fed HXG had loose feces in higher quantity. In rats fed CC, diarrhea
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K. EBIHARA and Y. NAKAMOTO
and loose feces were completely
improved.
Body mass gain, food intake and intestinal weight and length of rats at sacrifice expressed per 100 g body mass are shown in Table 1. Body mass gain of rats fed BP was significantly lower than those of rats fed CC and HXG. Food intake of rats fed BP was significantly lower than those of rats fed W, CC and HXG. The weight of small intestine of rats fed CC and HXG were slightly higher than that of rats fed W. The weight of cecal wall of rats fed BP and HXG were significantly higher than that of rats fed W. The weight of colon plus rectum of rats fed CC was significantly higher than that of rats fed ED. No differences were observed for the lengths of small intestine and colon plus rectum. As shown in Table 2, the activity of DA0 in the lower ileum was significantly higher in rats fed CC, but not in rats fed BP and HXG, than in rats fed W. The activity of ALP in the lower ileum was significantly higher in rats fed CC and HXG,but not in rats fed BP, than in rats fed W. No differences were observed for maltase activity in the lower ileum and plasma ALP activity. Plasma DA0 activity was significantly higher in rats fed CC and HXG, but not in rats fed BP, than in rats fed W.
The wet weight and pH value of cecal contents and total organic acids in cecal Cecal contents were 2, 3.6 and 4.6 times greater contents were shown in Table 3. in rats fed CC, BP and HXGthan in rats fed W, respectively. Those of rats fed BPand
TABLEI Body Weight Gain, Food Intake, Intestinal Length and Organ Weight of Rats fed a Liquid Elemental Diets with or without Dietary Fiber Diets ED Body mass gain (g/2 weeks) Food intake (ml/2 weeks) Feed efficiency Organ weight (g/100 g b.w.) Small intestine Cecal wall Colon + rectum Organ length (cm/100 g b.w.) Small intestine Colon + rectum
57 * 2* 922 * 21a
cc 65 * 6b 875 * 23ab
BP 50 * 2= 741 * 1%
2.10 * 0.02ab 0.26 * 0.02a 0.33 * 0.02a
2.27 * 0.06b 2.00 * 0.07a 0.36 * O.OSab 0.42 * 0.02b 0.33 * 0.02a 0.48 f: 0.03b
38.8 * 1.2 6.3 * 0.5
39.1 * 1.7 7.6 * 0.6
43.9 * 2.3= 6.6 * 0.3a
HXG 63 * St’ 835 t32b
2.23+ 0.08b 0.78 t 0.06~ 0.39 ??0.02a 41.0 * 1.6 7.5 * 0.4
Means * SEM (n=6) not sharing a common superscript letter within the same row were significantly different at p-&OS. 1 Rats received a liquid elemental diet (ED) or ED containing 3g/lOO ml of dietary fiber either a mixture of crystal cellulose and carboxymethyl cellulose sodium salt (CC), sugar-beet pectin (BP) or hydrolyzed xyloglucan (HXG) for 14 days.
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DIETARY FIBER AND LIQUID DIET TABLE 2 Diamine Oxidase (DAO), Alkaline Phosphatase (ALP) and Maltase Activities of Rats fed a Liquid Elemental Diets with or without Dietary Fiber1 Diets
Ileum mucosa (Wmg protein) DA0 ALP Maltase Plasma (U/ml)
DA0 ALP Means* SEM (n=6) not sharing significantly different at p
