Three experiments were conducted to examine the effects of a commercial
enzyme preparation on chicks performance and digestibilities of nonstarch
polysaccharides (NSP),
raffinose (R),
stachyose (S), and total
oligosaccharides (O) in diets containing whole and dehulled lupin and
ethanol-extracted dehulled lupin meal.
Ethanol extract was also used to produce a rich
oligosaccharide fraction. In the first experiment, the dehulling treatment and the addition of
enzyme to the diet improved (P < 0.05)
weight gain (24 and 15%), feed-to-gain ratio (13 and 9%), dry matter retention (32 and 8%), apparent
protein digestibility (6 and 3%) and ileal digestibilities of
raffinose (19 and 119%),
stachyose (85 and 204%), and total
oligosaccharides (68 and 178%), respectively. In addition,
enzyme treatment improved (P < 0.05) excreta digestibility values for NSP (from -1.7 to 5.5%), R (from 64.6 to 92.6%), S (from 48.8 to 82.4%), and O (from 55.8 to 83.5%). In the second experiment, extraction of the
ethanol soluble components from dehulled lupin decreased (P < 0.0001)
weight gain (51%), and increased (P < 0.0001) feed consumption (34%), feed-to-gain ratio (32%), relative gizzard weight (14%), and the relative ceca length (20%). The addition of the isolated fraction of oligosacharides to the corn-extracted lupin diet (7.5 and 15%) yielded performance values similar to those obtained with the unextracted dehulled lupin. The addition of
enzymes to the diets significantly improved the
weight gain (11%) and feed to gain ratio (6%), and decreased relative gizzard weight (12%) and relative ceca length (7%). Ileal digestibilities of R, S, and O were considerably lower than corresponding excreta digestibilities. The excreta digestibility of NSP and excreta and ileal digestibilities of R, S, and O were lower (P < 0.05) in chicks fed the lupin diet containing the high concentration of extract compared with those fed the same diet containing the lower concentration of extract.
Enzymes, when added to the diets, increased (P < 0.05) the digestibilities of R, S, and O with the relative effects being much greater for ileal than excreta samples. In the third experiment, the
ethanol extract (7.5 and 15%) added to a corn-soybean diet improved
weight gain, feed consumption, and feed-to-gain ratio by 19, 13, and 6%, respectively. Ileal digestibilities of R, S, and O were low (< 45%), especially in chicks fed the diets containing the high amount of added
oligosaccharide fraction. There was no effect of
enzyme addition on the performance parameters. However, supplemental dietary
enzymes improved (P < 0.05) ileal and excreta digestibilities of
oligosaccharides from 15.6 and 68.6% to 52.3 and 84.8%, respectively. In summary, dehulling greatly improved the nutritional value of lupin, while removal of the
ethanol soluble materials, including
raffinose and
stachyose considerably decreased its value. The
oligosaccharide fraction does not seem to have an antinutritive effect and the addition of
enzymes increased the digestibilities of NSP,
raffinose, and
stachyose but did not significantly improve chick performance.