Comparison between enzymatic procedure and CNCPS proposed method to estimate rumen degradable and intestinal digestible protein of soybean seed processed with two different methods

This experiment was conducted to compare between in vitro enzymatic procedure and the use of nitrogen fractions for estimate rumen degradable protein and post-ruminal digestibility of rumen undegradable protein of raw, roasted and extruded soybean seed. Relative to the control, roasting and extruding decreased A and B1 fractions of nitrogen and soluble nitrogen of soybean seed but resulted in an increase of B2, B3 and C (except for extruding method) fractions. The lowest rumen degradable and post-ruminal digestible protein was observed in roasted soybean seed. Results showed that heat processing led to change in protein fractions and decreased ruminal protein degradability of soybean seed. In addition, our findings showed there was a high correlation between enzymatic-laboratory procedure and proposed method with cornel net carbohydrate and protein system for predict amount of rumen degradable (r2=0.93) and post-ruminal digestible (r2=0.96) protein. It appears that extruding processing with a decrease in C fraction of nitrogen and increase in post ruminal digestibility of rumen undegradable protein of soybean is the better method for enhancing escaping protein of soybean seed. In addition, the use of nitrogen fractions could be appropriate methods for enzymatic procedure to determine rumen degradable and post ruminal digestible protein of soybean seed.