VARIABILITY IN NUTRITIONAL VALUE OF FISH FLOUR
Corrected protein efficiency ratio (P.E.R.) values for various samples of fish flour were found to vary from 1.51 to 2.76. Coefficients of apparent protein digestibility were similar for all flours tested, but the lysine in the sample which gave the lowest P.E.R. was less available by rat bio-assay than that in the other samples. Although the variation in nutritional value could not be ascribed to differences in the total lysine, methionine, and cystine contents of the samples, reduced amounts of lysine and methionine were released by pancreatic digestion of the flour which gave the lowest P.E.R. value. It was suggested that the reduced utilization of the amino acids in this sample may have resulted, in part, from a reduction in their rates of release in vivo. It was concluded that although fish flour may vary widely in nutritional value, properly prepared samples provide high quality protein for use in human or animal diets.