Chittin (Chitosan)

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Broiler chicken body weights, feed intakes, plasma lipid and small-intestinal bile acid concentrations in response to feeding of chitosan and pectin

One-day-old broiler chickens were fed on a control diet based on maize and maize starch or diets containing 30 g/kg of 89% deacetylated chitin (chitosan) or low-methoxyl (34% degree of esterification) pectin. Feeding of the chitosan diet to chickens significantly reduced body weights and feed intakes compared with animals fed on control or pectin diets on days 5 and 11 of the experiment. On day 12, significant reductions in total plasma cholesterol and HDL-cholesterol concentrations were observed among birds fed on the chitosan but not the pectin diet in relation to control-fed animals. A concomitant increase in the plasma HDL-cholesterol:total cholesterol ratio was observed among chitosan-fed chickens. The generally reduced concentrations of primary and total bile acids in the duodenum of birds fed on the fibre-containing diets on day 13 may have been an indication of a delay in the production and/or secretion of bile. Viscosity of the three broiler-chicken diets was measured after suspension in water, acidification and finally neutralization of the suspensions, in an attempt to simulate the effect of changes in pH and dilution of diets occurring in the gizzard and small intestine of chickens. Viscosity of the chitosan diet was significantly elevated after acidification and significantly reduced at neutralization in comparison with the control and pectin-containing diets suggesting that the hypolipidaemic influence of chitosan observed in the present study may be due to interruption of enterohepatic bile acid circulation rather than increased viscosity in the small intestine of chickens. The low viscosity of the pectin diet in vitro together with the absence of a hypocholesterolaemic effect of this diet when fed in vivo precludes any conclusion regarding the hypocholesterolaemic mechanism of pectin observed in earlier studies.

Razdan-A; Pettersson-D; Pettersson-J
Br-J-Nutr. 1997 Aug; 78(2): 283-91

Accelerating effect of chitosan intake on urinary calcium excretion by rats

The effect of chitosan on calcium (47Ca) metabolism was investigated in rats. The whole-body retention of 47Ca by rats fed on a 5% chitosan diet was significantly decreased when compared with that of rats fed on a cellulose diet, but showed no significant difference from that of rats fed on a fiber-free diet. Although there was no significant difference in the fecal excretion of 47Ca between the chitosan group and the cellulose or fiber-free group, the urinary excretion of 47Ca was significantly increased in the chitosan group when compared with the cellulose group. These results suggest that dietary chitosan would affect the calcium metabolism in animals.

Wada-M; Nishimura-Y; Watanabe-Y; Takita-T; Innami-S
Biosci-Biotechnol-Biochem. 1997 Jul; 61(7): 1206-8

The influence of high and low molecular weight chitosan on colonic cell proliferation and aberrant crypt foci development in CF1 mice

The effect of dietary chitosan, a fibre of animal origin, on the induction and development of colonic precursor lesions was determined in CF1 mice. Over a 2-wk pretreatment period, one group of mice was given azoxymethane (four injections of 5 mg/kg body weight) and the other was treated with saline. Subsequent to carcinogen or saline pretreatment mice were randomized into one of three dietary groups: (i) control AIN-76 diet; (ii) control AIN-76 diet with 2% low molecular weight chitosan (LMWC); or (iii) control AIN-76 diet with 2% high molecular weight chitosan (HMWC). Mice were maintained on this diet for 6 wk. Mice fed diet containing HMWC had significant reductions in the number of aberrant crypt foci, cell proliferation, crypt height and crypt circumference in the colonic epithelium (P < 0.05). In mice given diet supplemented with LMWC there was a trend towards reduced numbers of aberrant crypts, as well as decreased crypt height and circumference. The results of this study indicate that dietary chitosan reduces the incidence of early preneoplastic markers of colon carcinogenesis, as indicated by aberrant crypts and mitotic figures and altered crypt morphometrics in the murine colon. Molecular range and viscosity of the chitosan may influence the efficacy of this activity.

Torzsas-TL; Kendall-CW; Sugano-M; Iwamoto-Y; Rao-AV
Food-Chem-Toxicol. 1996 Jan; 34(1): 73-7

Continuous and massive intake of chitosan affects mineral and fat-soluble vitamin status in rats fed on a high-fat diet

We investigated the effects of continuous and massive intake of chitosan with sodium ascorbate (AsN) on the mineral and the fat-soluble vitamin status in male Sprague-Dawley rats fed on a high-fat diet. The apparent fat digestibility in the chitosan-receiving group was significantly lower than that in the cellulose- or glucosamine-receiving group. Chitosan feeding for 2 weeks caused a decrease in mineral absorption and bone mineral content, and it was necessary to administer twice the amount of Ca in the AIN-76 formula, which was supplemented with AsN, to prevent such a decrease in the bone mineral content. Moreover, the ingestion of chitosan along with AsN led to a marked and rapid decrease in the serum vitamin E level, while such a loss in vitamin E was not observed for rats given glucosamine monomer instead of chitosan.

Deuchi-K; Kanauchi-O; Shizukuishi-M; Kobayashi-E
Biosci-Biotechnol-Biochem. 1995 Jul; 59(7): 1211-6

Effect of the viscosity or deacetylation degree of chitosan on fecal fat excreted from rats fed on a high-fat diet

Several chitosan preparations, either with a comparable degree of deacetylation but differing viscosity or with comparable viscosity but a differing degree of deacetylation, were examined for their effect on the fecal fat excreted from rats fed on a high-fat diet. As the viscosity or deacetylation degree of a chitosan preparation increased, the more its effect on the apparent fat digestibility by rats became conspicuous. A supplement of ascorbic acid to each chitosan diets resulted in a significant depression of fat digestion and absorption in the lumen. The chitosan intake caused a higher level of fat to be excreted in the feces of the corn oil-receiving rats than the lard-receiving ones, although the effect was strong with both diet groups.

Deuchi-K; Kanauchi-O; Imasato-Y; Kobayashi-E
Biosci-Biotechnol-Biochem. 1995 May; 59(5): 781-5

Effect of chitin and chitosan on nutrient digestibility and plasma lipid concentrations in broiler chickens

Broiler chickens were fed on a control diet based on maize and maize starch or diets containing chitin, or 94, 82 or 76% deacetylated chitin (chitosans) with different viscosities (360, 590 and 620 m Pa.s respectively) at an inclusion level of 30 g/kg. Animals had free access to feed and water for the whole experimental period. On days 10 and 18 of the experiment chickens given the control and chitin-containing diets weighed more, had consumed more feed and had lower feed conversion ratios (g feed/g weight gain) than chitosan-fed birds. Feeding of chitosan-containing diets generally reduced total plasma cholesterol and high-density-lipoprotein (HDL)-cholesterol concentrations and gave an increased HDL:total cholesterol ratio in comparison with chickens given the control and chitin-containing diets. However, no significant reductions in plasma triacylglycerol concentrations resulting from feeding of the chitosan-containing diets were observed. The reduction in total cholesterol concentration and increased HDL total cholesterol ratio were probably caused by enhanced reverse cholesterol transport in response to intestinal losses of dietary fats. The suggestion that dietary fat absorption was impeded by the chitosans was strengthened by the observation that ileal fat digestibility was reduced by 26% in comparison with control and chitin-fed animals. In a plasma triacylglycerol response study on day 21, feeding of 94 and 76%-chitosan-containing diets generally reduced postprandial triacylglycerol concentrations compared with chickens given the chitin-containing diet. Duodenal digestibilities of nutrients amongst chickens given the chitin-containing diet were generally lower than those of control and chitosan-fed birds indicating decreased intestinal transit time. The reduced caecal short-chain fatty acid concentrations of chickens given chitosan diets compared with the control diet illustrates the antimicrobial nature of chitosan. The fact that the three chitosan-containing diets affected the registered variables similarly indicated that the level of inclusion of chitosans in the diet exceeded the level at which the effect of the different viscosities could be significant.

Razdan-A; Pettersson-D
Br-J-Nutr. 1994 Aug; 72(2): 277-88

Some effects of chitosan on liver function in the rat

Chitosan, a natural product derived from chitin, possesses hypocholesterolemic properties similar to those of cholestyramine, but there has been no report concerning its effects on the equilibrium between dietary cholesterol and de novo cholesterol synthesis in the liver. In this work, we studied the effects of chitosan on plasma and liver cholesterol levels, liver weight, and the key regulatory enzyme of cholesterogenesis 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase in rats fed a sterol diet containing 1% cholesterol and 0.2% cholic acid. The animals given the sterol diet showed increases in plasma and liver cholesterol, which were lowered by 54% in plasma and 64% in liver by 5% chitosan, while cholestyramine completely blocked such increases. HMG-CoA reductase activity was considerably increased in the sterol-cholestyramine group, but was greatly decreased in both sterol and sterol-chitosan groups. There was no change in liver weight or appearance after treatment with chitosan, but cholesty ramine-treated animals manifested secondary effects from the treatment, including smaller yellowish livers. High mol wt chitosans [> 750 kilodaltons (kDa)] were found to be less effective as hypocholesterolemia than a 70-kDa preparation. Also, when the 70-kDa chitosan was used at 2.5%, 5%, and 7.5% of the total diet, its effectiveness was greatest at the higher concentrations; indeed, incorporation of 7.5% chitosan in the sterol diet for 3 weeks completely prevented any decrease in plasma high density lipoprotein cholesterol or increase in the plasma cholesterol level and liver weight. This formula greatly reduced the increase in liver cholesterol content due to the sterol diet, with values of 8.8 +/- 1.3 for the sterol-chitosan diet vs. 18.2 +/- 0.8 mg/g tissue for the sterol diet. The increased intake of sterols considerably lowered both HMG-CoA reductase activity (33-fold) and HMG-CoA reductase mRNA levels (3-fold) in rat liver, but in the sterol-chitosan group, HMG-CoA reductase activity was 7.7 times more elevated than in the sterol group, although it was still lower than the control value, whereas HMG-CoA reductase mRNA levels were normal. The results obtained did not differ significantly when rats were studied for 1, 3, or 6 weeks. These results taken collectively indicate that the 7.5% chitosan formula maintained adequate cholesterol homeostasis in rats, despite a greatly increased intake of cholesterol.

LeHoux-JG; Grondin-F
Endocrinology. 1993 Mar; 132(3): 1078-84

Effect of dietary chitin on cholesterol absorption and metabolism in rats

The effect of chitin at the level of 5% in the diet on cholesterol absorption and metabolism was studied in Wistar rats fed on diet containing beef tallow (7%) and cholesterol (1%). When compared with pair-fed controls, rats fed on diet containing chitin had: (1) similar weight gain and feed efficiency, (2) lower apparent protein digestibility, (3) equivalent liver steatosis, (4) reduced levels of liver triglycerides and cholesterol, (5) similar levels of serum and fecal cholesterol, (6) higher excretion of triglycerides in feces.

Zacour-AC; Silva-ME; Cecon-PR; Bambirra-EA; Vieira-EC
J-Nutr-Sci-Vitaminol-Tokyo. 1992 Dec; 38(6): 609-13

Effect of chitosan feeding on intestinal bile acid metabolism in rats

The effect of chitosan feeding (for 21 days) on intestinal bile acids was studied in male rats. Serum cholesterol levels in rats fed a commercial diet low in cholesterol were decreased by chitosan supplementation. Chitosan inhibited the transformation of cholesterol to coprostanol without causing a qualitative change in fecal excretion of these neutral sterols. Increased fiber consumption did not increase fecal excretion of bile acids, but caused a marked change in fecal bile acid composition. Lithocholic acid increased significantly, deoxycholic acid increased to a lesser extent, whereas hyodeoxycholic acid and the 6 beta-isomer and 5-epimeric 3 alpha-hydroxy-6-keto-cholanoic acid(s) decreased. The pH in the cecum and colon became elevated by chitosan feeding which affected the conversion of primary bile acids to secondary bile acids in the large intestine. In the cecum, chitosan feeding increased the concentration of alpha-,beta-, and omega-muricholic acids, and lithocholic acid. However, the levels of  hyodeoxycholic acid and its 6 beta-isomer, of monohydroxy-monoketo-cholanoic acids, and of 3 alpha, 6 xi, 7 xi-trihydroxy-cholanoic acid decreased. The data suggest that chitosan feeding affects the metabolism of intestinal bile acids in rats.

Fukada-Y; Kimura-K; Ayaki-Y
Lipids. 1991 May; 26(5): 395-9

Interaction of bile acids, phospholipids, cholesterol and triglyceride with dietary fibers in the small intestine of rats

Certain dietary fibers have been reported to lower plasma cholesterol by binding bile acids and reducing their recycling through the enterohepatic circulation. In addition, certain fibers may delay the digestion and absorption of fat. In the present study, the interaction of bile acids with guar gum (GG), konjac mannan (KM) and chitosan (CH) was determined. Rats were fed during a 20-min period a test meal containing either 5% cellulose (CE), GG, KM or CH and also containing 14C-labeled triolein and 3H-labeled cholesterol. The group fed CE served as control, since CE does not bind bile acids or phospholipids in vivo. Two hours after presentation of the test meal, rats were killed and the stomach and small and large intestine removed. All four groups ate the same amount of the test meal, about 1.9 g. The aqueous phase of the small intestinal contents was separated by ultracentrifugation, and the amount (mumol) of bile acids and phospholipids in the total intestinal contents and in the aqueous phase was estimated. The ratio of bile acids in the aqueous phase to that in total intestinal contents was significantly higher in the GG and KM groups and significantly lower in the CH group than that in the CE group, demonstrating that the bile acids are bound or trapped by each of these fiber sources. Only CH appeared to bind phospholipids, reducing the proportion in the aqueous phase compared to that in the CE group.(ABSTRACT TRUNCATED AT 250 WORDS)

Ebihara-K; Schneeman-BO
J-Nutr. 1989 Aug; 119(8): 1100-6

Hypocholesterolemic action of chitosans with different viscosity in rats

The relationship between hypocholesterolemic efficacy and average molecular weight of chitosan was studied in rats fed a cholesterol-enriched (0.5%) diet. Several chitosan preparations with a comparable degree of deacetylation but differing widely in average molecular weight, as demonstrated by viscosity, almost completely prevented the rise of serum cholesterol at the 5% dietary level. At the 2% level, chitosans with viscosities at both extremes exerted a comparable cholesterol-lowering action. The glucosamine oligomer composed mainly of three to five aminosugar residues was not effective. The results indicate that the hypocholesterolemic action of chitosans is independent of their molecular weight within the tested viscosity range.

Sugano-M; Watanabe-S; Kishi-A; Izume-M; Ohtakara-A
Lipids. 1988 Mar; 23(3): 187-91

A comparison of the lipid-lowering and intestinal morphological effects of cholestyramine, chitosan, and oat gum in rats

Cholestyramine, chitosan, and oat gum are lipid-lowering compounds. Cholestyramine use in humans may contribute to colonic adenocarcinoma; chitosan and oat gum are being studied in the rat to determine their potential for human use. To compare these compounds, we fed three groups of 10 male Sprague-Dawley rats one of the substances at 5% of diet with 1% cholesterol and 0.2% cholic acid; two other groups were fed cellulose with and without 1% cholesterol and 0.2% cholic acid. All groups had similar food intake and weight gains. Cholesterol feeding increased total liver lipids almost 3-fold and liver cholesterol concentration almost 10-fold. Cholestyramine, oat gum, and chitosan all significantly lowered liver cholesterol with cholestyramine feeding yielding levels identical to the noncholesterol-fed basal group. Chitosan and oat gum lowered liver cholesterol moderately. Cholestyramine and chitosan both significantly lowered serum cholesterol compared to the cellulose group. Oat gum was less effective. Hemoglobin and serum iron were similar in all groups except the oat gum group, which had decreased serum iron. Histological examination of small and large bowel with morphometry revealed statistically significant increases in both proximal and distal small bowel and distal large bowel mucosal thickness in the cholestyramine-fed group. No changes were noted in the proximal large bowel. Neither chitosan nor oat gum produced mucosal change other than an increase in the distal small bowel with the oat gum diet. Chitosan may have lipid-lowering effects similar to those of cholestyramine without the deleterious changes in intestinal mucosa.

Jennings-CD; Boleyn-K; Bridges-SR; Wood-PJ; Anderson-JW
Proc-Soc-Exp-Biol-Med. 1988 Oct; 189(1): 13-20

Effects of fibre on digestibility and passage time in callithricidae

The effects of fibre in a pelleted diet on food intake, digestibility of crude fibre, dry matter and energy, on passage time and consistency of faeces were studied in 2 species of Callithricidae, Callithrix jacchus and Saguinus fuscicollis. Coarse cellulose, microcellulose, wheat bran and shrimp meal (chitin = crude fibre) were tested in diets containing 2,4 and 6% total crude fibre, respectively. Digestibility and passage time were determined by inclusion of 0.5% Cr2O3 in the diet. Both celluloses had little influence on the digestibility of energy and dry matter. Digestibility of crude fibre was very low. Wheat bran led to evident depression of energy and dry matter digestibility. High digestibility of crude fibre occurred at the higher levels of inclusion in the diet. Shrimp meal was highly digested with little influence on digestibility of energy and dry matter, indicating considerable degradation of chitin. Wheat bran showed a marked effect, while microcellulose had no effect on passage time, consistency and volume of faeces.

Krombach-F; Flurer-C; Zucker-H
Lab-Anim. 1984 Jul; 18(3): 275-9

Effect of krill chitin on performance, nitrogen balance and histology of rats

Pastuszewska-B; Szewielow-A; Byrka-H
Z-Tierphysiol-Tierernahr-Futtermittelkd. 1983 Mar; 49(3): 163-71

A novel use of chitosan as a hypocholesterolemic agent in rats.

A series of experiments with male rats clearly demonstrated the hypocholesterolemic activity of dietary chitosan. On feeding a high cholesterol diet for 20 days, addition of 2 to 5% chitosan resulted in a significant reduction, by 25 to 30%, of plasma cholesterol without influencing food intake and growth. The concentration of liver cholesterol and triglyceride also decreased significantly. Plasma, but not liver cholesterol-lowering effect, was roughly comparable with that of cholestyramine. Chitosan at the 10% level further reduced plasma cholesterol, but depressed growth. Also, finer chitosan particles tended to restrain growth even at the 2% level. In rats fed a cholesterol-free diet containing 0.5% chitosan for 81 days, the concentration of serum cholesterol was the same with that of the corresponding control, but relatively more cholesterol existed as high-density lipiproteins and less as very low-density lipoproteins. Dietary chitosan increased fecal excretion of cholesterol, both exogenous and endogenous, while that of bile acids remained unchanged. There was no constipation or diarrhea. A proper supplementation of chitosan to the diet seemed to be effective in lowering plasma cholesterol.

Sugano-M; Fujikawa-T; Hiratsuji-Y; Nakashima-K; Fukuda-N; Hasegawa-Y
Am-J-Clin-Nutr. 1980 Apr; 33(4): 787-93

Effects of chitosan--a coagulating agent for food processing wastes--in the diets of rats on growth and liver and blood composition

Effects of feeding free chitosan to rats at graded levels up to 15 percent of the diet for eight weeks was investigated. Animals receiving diets containing 5 percent or less of chitosan grew well at comparable rates. Progressive growth reduction occurred when chitosan was increased to 10 and 15 percent of the diet and enlargement of liver and kidneys was observed only in animals receiving the highest level of dietary chitosan. Liver moisture, protein, lipid, ash, and nucleic acids; blood hemoglobin and packed cell volume; and serum total protein, albumin, ceruloplasmin and transferrin were determined. Values for these components of liver and blood were altered significantly in the animals receiving the highest level of chitosan when compared to control animals. However, in animals receiving 5 percent or less of dietary chitosan none of these measures of tissue composition was different from controls, except for liver protein concentration of rats fed the 5 percent of chitosan diet. Animal feeds containing coagulated by-products are not expected to contain over 0.2% chitosan in the total diet. No adverse effects have been observed at this level in rat feeding studies. Therefore the tolerance level for dietary chitosan appears to be well above the levels expected to be in animal feeds containing by-products recovered from food processing wastes by coagulation with chitosan.

Landes-DR; Bough-WA
Bull-Environ-Contam-Toxicol. 1976 May; 15(5): 555-63

Dietary fibers modulate indices of intestinal immune function in rats

To explore the immunological roles of dietary fiber, male 4-wk-old Sprague-Dawley rats were fed for 2 wk cellulose (water-insoluble), konjak mannan (water-soluble), pectin (water-soluble) or chitosan (acid-soluble) at 5 g/100 g diet. Serum IgE concentrations in rats fed konjak mannan, pectin and chitosan were significantly lower than in those fed cellulose (mean +/- SEM: 5.0 +/- 1.1, 3.6 +/- 1.3, 3.0 +/- 1.2 and 9.6 +/- 1.9 microg/L, respectively). Rats fed pectin had significantly higher serum IgA and IgG concentrations (358 +/- 38 and 424 +/- 36 mg/L for IgA and IgG, respectively) than those fed cellulose (240 +/- 31 and 337 +/- 25 mg/L) or chitosan (176 +/- 22 and 379 +/- 23 mg/L), while the IgM concentration did not differ among the groups. Concentrations of IgA, IgG and IgM in mesenteric lymph node (MLN) lymphocytes generally were greater, while IgE concentration was lower, in rats fed pectin and chitosan than in those fed cellulose. The proportion of CD4+ T-cells in MLN lymphocytes was also dietary fiber-dependent, and the CD4+/CD8+ ratio was significantly higher in the pectin fed group than in all other groups. Under certain experimental conditions, MLN lymphocytes from rats fed pectin had markedly greater interferon-gamma concentration than cells from other groups, while the effect on tumor necrosis factor-alpha concentration was less marked. Thus, dietary fiber may have an immunoregulatory effect on the intestinal immune system of rats.

Lim-BO; Yamada-K; Nonaka-M; Kuramoto-Y; Hung-P; Sugano-M
J-Nutr. 1997 May; 127(5): 663-7

Effects of chitin and chitosan particles on BALB/c mice by oral and parenteral administration

Chitin and chitosan were administered orally and parenterally into mice and their toxicity was investigated. When 5 mg of chitin were injected intraperitoneally every 2 weeks over a 12-week period, the mice were apparently normal, but histologically, many macrophages with hyperplasia were observed in the mesenterium and foreign-body giant-cell-type polykaryocytes were observed in the spleen. The polykaryocytes were also observed in the spleen of the mice injected subcutaneously with 5 mg of chitin, but no other changes were observed. When 5 mg of chitosan were injected intraperitoneally, the body weights of the mice decreased significantly and inactivity was observed in the fifth week. Histologically, many macrophages with hyperplasia were observed in the mesenterium. Subcutaneous injection of 5 mg of chitosan did not evoke the general and cellular abnormalities. Oral administration of 5% chitosan via a casein diet caused mouse body weights to decrease and also decreased the number of Bifidobacterium and Lactobacillus in normal flora of the intestinal tract. These results indicate that special care should be taken in the clinical use of chitin and chitosan over a long time period.

Tanaka-Y; Tanioka-S; Tanaka-M; Tanigawa-T; Kitamura-Y; Minami-S; Okamoto-Y; Miyashita-M; Nanno-M
Biomaterials. 1997 Apr; 18(8): 591-5

Human enzymatic activities related to the therapeutic administration of chitin derivatives

Three cases are presented where modified chitins have been extensively administered to volunteers, as dressings for wounded soft and bone tissues, as anticholesterolemic dietary foods, and in the controlled delivery of anti-inflammatory drugs. The interactions of the modified chitins with human enzymes is critically examined. In the context of drug carrier resorption and wound healing, chitooligomers and monomers, generated by lysozyme, N-acetylglucosaminidase and human chitinase, activate macrophages and stimulate fibroblasts, respectively; the effects are production of smooth, vascularized and physiologically normal tissues. In the dietary food area, lipase, amylase, 3-hydroxy-3-methylglutaryl CoA reductase, glucokinase and the enzymes of prostaglandin synthesis are involved in the oral administration of chitosan: lipid adsorption is depressed mainly because of the physical form of the chitosan-lipid aggregates, which are unsuitable as substrates. When chitosan is used as a drug carrier, chitosan-drug complexes are present. The uniqueness of chitosan among polysaccharides is underlined in terms of susceptibility to enzymatic depolymerization, cationicity, supply of cell-activating oligomers, and supply of N-acetylglucosamine for rebuilding of other biopolymers. Advances in molecular recognition and biocompatibility are also presented.

Cell-Mol-Life-Sci. 1997 Feb; 53(2): 131-40

Influence of dietary fiber on the bioavailability of zinc in rats

Young male albino rats were fed ad libitum semipurified diet supplemented with or without 5% of purified dietary fiber (cellulose, agar-agar, pectin, chitin or chitosan) for 31 days. Each test diet was carefully prepared in order to contain zinc at the level of 8 ppm from zinc acetate. In rats fed diets containing 5% of dietary fiber except chitosan, food consumption was higher than the control. The body weight gain of rats fed diets containing cellulose, pectin or chitin was higher than the control. However, food intake and body weight gain of rats fed the diet containing 5% of chitosan were definitely lower than not only the other fiber including diet groups but also the control group. When dietary fiber was added at 5% level to diet, zinc absorption was not changed to a considerable degree. But, the apparent zinc absorption of rats fed the agar-agar diet was 70%. On the other hand, zinc absorption in the pectin diet group was about 10% higher than the control. The total amount of zinc in tibia or femur of rats fed non-fiber diets was a little higher than that of rats fed fiber diets.

Kondo-H; Osada-A
Biomed-Environ-Sci. 1996 Sep; 9(2-3): 204-8

Hypolipidaemic, gastrointestinal and related responses of broiler chickens to chitosans of different viscosity

Broiler chickens (1-d-old) were fed ad libitum on a control diet based on maize and maize starch or diets containing low-, medium- or high-viscosity chitosans at an inclusion level of 15 g/kg. Body weights and feed intakes of chickens given chitosan-containing diets were generally depressed in comparison with those of control-fed animals on days 11 and 18 of the experiment. On days 12 and 19, feeding the low-viscosity-chitosan diet reduced plasma triacylglycerol and total plasma cholesterol concentrations in relation to chickens receiving the control diet, while the medium- and high-viscosity-chitosan-containing diets reduced total plasma cholesterol and elevated, although not significantly, plasma HDL-cholesterol concentrations compared with those of control-fed animals. Chitosan feeding generally improved plasma HDL-cholesterol:total cholesterol ratio in comparison with control feeding, which was attributed to the general reductions in plasma cholesterol concentrations rather than increases in plasma HDL-cholesterol concentrations. Feeding the high-viscosity-chitosan-containing diet significantly reduced the ileal digestibility of crude protein (N x 6.25) and crude fat compared with chickens given the control diet. The reduction in ileal crude fat digestibility was greatest among chickens receiving the high-viscosity-chitosan-containing diet and chitosan-containing diets reduced ileal fat digestibility by 8% on average compared with that of control-fed birds. However, increasing the viscosity of the chitosan fraction could not be correlated with increases in terminal ileal digesta viscosity and, therefore, it could not be established that increased ileal lumen viscosity alone contributed to reductions in body weight, feed intake and plasma cholesterol concentrations. However, the fact that ileal digestibility of fat was reduced by feeding chitosan to chickens suggests the action of other hypolipidaemic mechanisms.

Razdan-A; Pettersson-D
Br-J-Nutr. 1996 Sep; 76(3): 387-97

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