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.