et al. (1995) examined winter and spring -
glucan data from seven European countries
in data (from nine papers) that covered a
12-year period. -Glucan content varied
from 1.0 to 5.6%, with an annual mean of
3.56%. The largest range in -glucan
percentage for Spain in 1987 and 1988
was 3%. Between countries, there were
no clear seasonal trends in -glucan con-
tent. Although seasonal differences were
evident, there was no consistent pattern.
This work shows the importance of being
able to measure the NSP content of all feed
samples in a rapid, accurate and economic
way. If the NSP content of each feed
sample was known, enzyme inclusion
levels could be adjusted to maximize NSP
degradation.
The Future of Feed Enzymes
Future feed enzyme research should
continue the process of refining enzyme
formulations and application techniques
and the development of rapid, cheap and
reliable assays for measuring enzyme
activity and anti-nutritional compounds.
Improvements in these four areas will see
the value of feed enzymes in animal
nutrition continue to rise.
Although feed enzyme research with
poultry and pigs has been extensive, there
is still potential to identify and refine
protease activities which will break down
the anti-nutritive compounds found in raw
legume seeds. If compounds such as
trypsin inhibitors, lectins, etc. can be
broken down by enzymes and heat treat-
ment is not required, then the availability
of amino acids in these legumes will be
improved.
The amount of research required to
develop the feed enzyme industry for
ruminants to the same degree as the pig
and poultry industries is large. More work
is required to develop optimum combina-
tions of enzyme activities dependent on
diet composition. Application and feeding
protocols for direct-fed feed enzymes are
also needed in ruminant diets.
The aquaculture industry has much to
gain from research on feed enzymes con-
ducted with pigs and poultry. Little work
has been done with carbohydrases which
will become increasingly important as the
amount of non-fish meal protein in aqua-
culture diets increases. More research is
required to determine the factors that
influence the efficiency of phytase in
aquaculture diets.
The amounts of NSP and other anti-
nutritive factors change with each feedstuff
and even with each consignment of the
same feed. There is therefore a need to
measure the concentration of these factors
and know how to alter feed enzyme
formulations to maximize improvement in
animal production. Research to develop
simple assays for anti-nutritive factors and
even feed enzyme activities is required if
we are to understand why some experi-
ments produce greater improvements in
animal response than others. The sustain-
ability of feeding animals diets based on
ingredients that can be used for human
food will be improved if feed enzyme
technology is used to maximize utilization.Feed Enzymes 421References
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