Farm Animal Metabolism and Nutrition

Chapter 19

Feed Enzymes

D.I. Officer

NSW Agriculture, Agricultural Research and Advisory Station,

Grafton, NSW, Australia

Introduction

Early enzyme preparations included in
animal diets were not formulated as animal
feed additives but were produced for
industrial or human food uses. Between
the late 1980s and mid 1990s, enzyme
products changed with the formulation of
feed enzyme supplements specifically for
animal diets. Over this period, feed
enzyme supplementation has increased
dramatically all over the world, but pre-
dominantly in pig and poultry diets. Also
in recent years, renewed research interest
into the potential value of feed enzymes
has occurred in the fields of ruminant
nutrition and aquaculture. The reliability
of enzyme supplementation has improved
over time, especially with respect to heat
stability during pelleting and the matching
of enzyme activity to anti-nutritive com-
ponents in the feed.
The importance of matching enzyme
activity and feed composition has become
evident as our understanding of the
chemistry of non-starch polysaccharides
and other feed components has improved.
To provide any benefit to the animal, feed
enzymes must target specific feed com-

ponents which are otherwise harmful or of

little or no value. In doing so, a wider

range of ingredients may be used in diet

formulation without compromising on diet

cost or animal performance. For example,

feed enzymes are used to increase the

amount of nutrients available from

vegetable proteins so that they can be

substituted for fish meal or other high-

quality and expensive animal protein

sources. Feed enzymes can also be used to

substitute a previously unacceptable energy

source for another (e.g. barley for wheat in

broilers).

One of the benefits from increasing the

efficiency with which nutrients are

obtained from a feed ingredient is the

reduction in faecal nutrient level.

Reductions in nutrient excretion produced

by enzyme supplementation are especially

important where faeces are being applied

to land with restrictions on nutrient

application and for aquaculture where

there is the potential to maintain or

improve water quality after feeding.

Feed enzymes are also increasingly seen

as ‘environmentally responsible’ alternatives

to some hormone growth promotants and

antibiotics. This is because they currently

© CAB International2000. Farm Animal Metabolism and Nutrition

(ed. J.P.F. D’Mello) 405