Chemical composition, in vivo digestibility, N degradability and enzymatic intestinal digestibility of five protein supplements

The nutritive value of solvent extract palm kernel meal (SPKM), expeller palm kernel meal (EPKM), copra meal (CM), corn distillers dried grains (CDG) and corn gluten feed (CGF) were evaluated. Apparent in vivo digestibility was measured in rams using increasing levels of supplement studied. Dry matter (DM) and N degradability of feeds after 0, 12 and 16 h rumen incubation and enzymatic digestibility of rumen undegradable protein (UDP) were also determined. It was confirmed that supplements differ significantly in terms of digestibility (energetic value), N degradability and intestinal digestibility of UDP, the figures obtained being consistent with those found in the literature. The low energetic value of SPKM could limit its inclusion in high productive ruminant diets. Although CDG may be considered a good source of UDP, the intestinal digestibility of this fraction was low. Additionally, the relatively high unsaturated fat content of CDG might restrict its incorporation level in ruminant diets.