The Use of Varying Levels of Pepsin for Pepsin Digestion Studies with Animal Proteins , ,

Abstract

Nine meat and bone meals were digested with a .002%, .02%, and .2% pepsin-HCl solution and six feather meals were digested with .002%, .2%, and 2% pepsin-HCl for a 16-hr period. An acid blank value for the meals was determined from digestible nitrogen with .075 N HC1. The meat and bone meals ranged from 90.03% to 94.09% pepsin digestible nitrogen (PDN) under the standard AOAC (1975) procedure with .2% pepsin and not subtracting the HC1 digestible nitrogen from the total digestible nitrogen. The same meat and bone meals digested with .002% pepsin and correcting the value with an acid blank ranged from 60 to 81.95 PDN. Feather meals digested with .2% pepsin ranged from 66.15 to 79.92 PDN (corrected with acid blank) compared to 12.5 to 34.93 PDN for feather meals digested with .002% pepsin. The decreased quantity of pepsin-HCl solution increases the sensitivity of the test and increases digestibility difference between the meat and bone and feather meals.