Comparative Study of the Digestibility of Forage Cellulose and Hemicellulose in Ruminants and Nonruminants1

Feed digestibility and mineral balance of the diet of young mice kept in mouse cages inside or outside an isolator, using varied concentrations of sodium phytate.

“…Refined celluloses are chemically processed and differ markedly from natural cellulose in physical properties (16). Thus, refined celluloses are relatively unfermentative (17), In rats, Keys et al (18) found a much lower digestibility of cellulose than of hemicellulose when alfalfa was the fiber source. The comparison between this study and our previous experiment (15) showed that digestibility of purified cellulose, i.e., cellophane spangles, was about 13% and much less than that of crude fiber (about 20%) in the practical diet.…”

Comparative investigations on digestion in grazing (Ceratotherium simum) and browsing (Diceros bicornis) rhinoceroses

“…in the form of increased saliva production) might therefore not have an advantageous effect in browsers. A considerable soluble fiber fraction will also occur in grazing hindgut fermenting species, since a significant fraction of dietary hemicelluloseswhich are generally found to be particularly prominent in grasses (Robbins 1993;) -is probably turned soluble in the proximal sections of the gut (Keys et al 1969;Parra 1978); in addition, hemicellulose might have a lesser effect on the viscosity of the digesta compared to pectins. Thus the fiber composition of the diet might have facilitated an adaptation to a higher fluid flow through the GIT, which improves washing of soluble, absorbable nutrients out of the digesta plug towards the absorptive gut surface (Lentle et al 1996).…”

Effect of fermentable carbohydrates on volatile fatty acids, ammonia and mineral absorption in the rat caecum

“…!gmeyer, 1974). Volatile fatty acid measurement by glc has been previously described Demign6, 1974, 1976 (Keys, Van Soest and Young, 1969 Whatever the substrates (with possible differences in caecal flora), the VFA are the main end-products of bacterial fermentation. The total VFA concentrations vary between rather narrow limits (90 to 150 mM), but the size of the caecum differs markedly with the diets.…”