Chemical Composition and Digestibility of Fiber Fractions of Certain By-Product Feedstuffs Fed to Ruminants

Abstract
These experiments were conducted to study chemical composition of five by-product feedstuffs and their fiber fractions to determine the components that make up their indigestible residue. Corn fiber (CF), coarse corn fiber (CCF), oat hulls (OH), soybean hulls (SH) and cottonseed hulls (CSH) were chemically fractionated into eight components: original by-product, chloroform-methanol (CHCl3:CH3 0H)-extracted material, NDF, lignin-carbohydrate complex (LCC), alkali-extracted residue (AER), holocellulose, hemicelluloses and cellulose. The three by-products containing sufficient amounts of LCC (CF, CCF and OH) were fractionated using washed ruminal cell suspensions into a by-product residue (BR) and a by-product filtrate (BF). The primary alkali-labile phenolic monomers detected in both the chemically and biologically isolated fractions were p-coumaric acid (PCA) and ferulic acid (FA). Monosaccharides detected were xylose, arabinose and glucose. In vitro DM disappearance (IVDMD) of original by-products varied greatly, with values ranging from 31.9% for OH to 85.6% for CF. The IVDMD of the AER of the monocot by-products was greater (P < .05) than that of the original by-product (92.3 vs 85.6% for CF; 93.1 vs 81.8% for CCF; 69.4 vs 31.9% for OH). Alkali extraction did not improve digestibility of dicot by-products. Isolated LCC were very soluble in McDougall's buffer; thus, IVDMD of LCC was unrealistically high. Data are interpreted to indicate that the residues isolated using biological fractionation are different in composition from the chemically isolated residues. Copyright © 1988. American Society of Animal Science . Copyright 1988 by American Society of Animal Science

This publication has 0 references indexed in Scilit: