Determination of intestinal digestibility of feeds by three-steps technique

Abstract

The objective of this work was to estimate the intestinal digestibility of rumen-undegradable protein (RUDP) of feeds by a three-steps procedure. The evaluated feeds were the soybean meal, wheat meal, soybean peel, meat flour and fish flour. Firstly, the feeds were incubated in rumen during 16 hours to determine the rumen-undegradable protein. The residue was submitted to the digestion with pepsin solution during 1 hour, and pancreatic solution during 24 hours at 38ºC. Soon after, those residues were analyzed for total nitrogen (TN). The estimate of RUDP ranged of 22.07% to 91.30% and the intestinal digestibility of RUDP ranged from 35.13% to 80.67%. The soybean peel and the meat flour presented better intestinal digestibility, and the wheat meal presented the lowest digestibility. Although some formulation systems of diets for ruminant consider the intestinal digestibility of dietary protein as being constant, the data obtained in this work suggest that there are variation among the different feeds.