Effect of dietary chitosans with different viscosity on plasma lipids and lipid peroxidation in rats fed on a diet enriched with cholesterol

To investigate the effect of dietary chitosan on lipid metabolism, male SD (Sprague-Dawley) rats were fed a cholesterol-enriched diet containing 5% ce llulose (CE), 5% chitosan (CCS; high viscosity), or 5% chitosan (FCS; low v iscosity) for 4 weeks. The two types of chitosan with a comparable degree o f deacetylation had a different molecular weight and intrinsic viscosity. S ignificantly (p < 0.05) lower plasma total cholesterol, LDL-cholesterol and VLDL-cholesterol concentrations were observed in the rats fed on the chito san diets. In addition, chitosan significantly increased the fecal choleste rol and triglyceride contents. Although no significant difference in body w eight was found among the dietary groups, the rats fed on the chitosan diet s had lower relative liver weight when compared with those fed on the cellu lose diet. Both of the chitosan groups had significantly lower liver total lipid and total cholesterol contents compared to the cellulose group, altho ugh the FCS group was less effective. The plasma and liver thiobarbituric a cid reactive substances (TBAR) values were similar in the CE and PCS groups , while the CCS group had increased liver TBAR values. Although a significa nt increase in liver glucose-6-phosphate dehydrogenase activity was observe d in the CCS group, no significant change was found in the FCS group. The o bserved influence of chitosans with different viscosity on the plasma lipid level, liver lipids and lipid peroxidation suggests that, while the hypoch olesterolemic action of chitosans with different viscosity was similar, cha nges in the liver lipids and liver peroxidation status depended on their mo lecular weight when the deacetylation degree was comparable.