Mv. Vranjes et al., INFLUENCE OF PROCESSING ON DIETARY ENZYME EFFECT AND NUTRITIVE-VALUE OF DIETS FOR LAYING HENS, Canadian journal of animal science, 75(3), 1995, pp. 453-460
Two experiments were carried out to examine the influence of a Trichod
erma viride enzyme complex [cellulase, endo-beta-(1:3)(1:4)-glucanase,
xylanase] on nutrient utilization and production parameters of laying
hens. In exp. 1, the influence of extrusion (110 degrees C, 20 s) and
dietary enzyme addition on the nutritive value of the diet was tested
. Dietary treatments were as follows: M and MR, unprocessed feed, plus
or minus enzyme; E, feed extruded without enzyme; ER(-1), feed extrud
ed with enzyme; ER-2, enzyme added after extrusion. Diets were fed in
mash form. Partial inactivation of the enzyme took place as indicated
by a significant difference in energy use in groups ER-1 and ER-2 (73
vs. 75%). According to the enzyme-affected changes of the feed extract
viscosity, 65% of the enzyme initial efficacy were lost as a result o
f extrusion. Nevertheless, the addition of enzyme before extrusion (ER
-1) was not without effect, as birds fed the ER-1 diet had improved en
ergy (73 vs. 71%) and fat utilization (89 vs. 85%) as compared with th
ose fed the extruded unsupplemented diet (E). Extrusion decreased feed
AME content by 0.3 MJ kg(-1). A significant interaction between proce
ssing and enzyme for energy and fat utilization indicated a greater be
neficial effect of enzyme in extruded feed. Experiment 2 was arranged
in a same way as exp. 1, with the exception that pelleting (70 degrees
C) replaced the extrusion process. Feed extract viscosity measurement
s revealed that pelleting reduced initial enzyme efficacy by 52%. Desp
ite this, enzyme improved nutrient utilization in unprocessed and pell
eted diet to the same extent, and no further improvements were observe
d by supplementation of the feed after processing. Pelleting itself di
d not affect nutritive value of the feed.