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Effect of extrusion on in situ ruminal protein degradability and in vitro digestibility of undegraded protein from different feedstuffs
Author(s) -
Solanas Estela M,
Castrillo Carlos,
Jover Miguel,
de Vega Antonio
Publication year - 2008
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.3345
Subject(s) - rumen , legume , soybean meal , chemistry , zoology , extrusion , agronomy , food science , biology , fermentation , raw material , materials science , organic chemistry , metallurgy
BACKGROUND: The effect of extruding maize, barley, whole soybean (WSB), peas, lupins and soybean meal (SBM) on their in situ ruminal protein degradability and in vitro digestibility of the rumen undegraded protein (RUP) was studied. Two mixtures containing 0.75 WSB or lupins and 0.25 maize were also formulated. RESULTS: Extrusion of maize resulted in an increase of its effective protein degradability from 0.538 to 0.734 ( P < 0.001), whereas the opposite occurred with barley (from 0.854 to 0.797; P < 0.001). Extrusion increased the in vitro digestibility of the RUP of both cereals, increasing therefore the amount of barley crude protein (CP) digested in the intestines (PDI) from 62 to 176 g kg −1 CP ( P < 0.01), whereas maize resulted in lower (332 versus 229 g kg −1 CP; P < 0.01). Extrusion decreased ( P < 0.001) the protein degradability of the three legume seeds and increased ( P < 0.001) the in vitro digestibility of the RUP, resulting in a PDI increase ( P < 0.001), from 60 to 367 g kg −1 CP for peas, from 69 to 265 g kg −1 CP for WSB and from 107 to 205 g kg −1 CP for lupins. This effect was enhanced when WSB was extruded jointly with maize. The extrusion of SBM also resulted in an increase in the PDI from 296 to 384 g kg −1 CP ( P < 0.001). CONCLUSION: Extrusion decreases the rumen protein degradability of legume seeds, soybean meal and barley, and increases the digestibility of the RUP, resulting in an increase in the feed protein digested in intestine. The extrusion of soybean seeds together with maize enhances these effects. Copyright © 2008 Society of Chemical Industry