APSS 2013 Proceedings - The University of Sydney

Aust. Poult. Sci. Symp. 2013.....24
ENZYME RESPONSE IS AFFECTED BY SUBSTRATE TYPE
Z.Z. ZHANG 1 , Y. FENG 1 , C.S. HUANG 1 , Z.Y. HUNG 1 and B.J. HOSKING 1
The variety of enzyme products available in the marketplace is considerable (PUBCRIS).
Individual products differ markedly in enzyme composition and activity for the same target
species regardless of ration (substrate)-type. This study demonstrates the effect of substratetype
on reducing sugar production from three enzyme mixtures with potential application in
poultry feeds.
Three substrate types (corn:soy (CS), wheat:soy (WS) and low-soy (LS) mixtures)
were prepared from grains and protein meals to reflect ingredient compositions common in
poultry feeds, c. 18% crude protein and 11.7 MJ/kg AME. CS and WS mixtures contained a
minimum grain content of 650g/kg. The LS mixture used (/kg) 600g grain as corn:wheat
(1:2), 50g soy bean meal and 150g canola meal. Samples were ground to pass a 0.25mm
screen and incubated in triplicate with xylanase alone (X, 2U/g), with a combination of
neutral protease and amylase mixture (NPA, 1U/g and 0.2U/g) and with each enzyme
combined (X+NPA). Reducing sugar production (RSP) was estimated at hourly intervals for
5 hours as described by Lü and Zhou (2011). Statistical analyses of absorbance values were
undertaken using a GLM procedure blocked for substrate type, enzyme inclusion and
incubation time (Minitab V14).
RSP as estimated from absorbance values was affected (P0.05) on the CS mixture. In contrast, responses to the NPA treatment
were greater on the CS mixture. The X+NPA treatment also showed highest RSP response
on the CS mixture.
Table 1 - Mean Reducing Sugar production is influenced by enzyme and substrate type.
Corn:Soy Non-Soy Wheat:Soy Enzyme
(main effect)
Xylanase alone 0.000a 0.040b 0.020c 0.020a
Neutral Protease + Amylase 0.265a 0.147b 0.172b 0.195b
Xylanase + Neutral Protease 0.214a 0.156b 0.178b 0.183b
+Amylase
Substrate (main effect) 0.160a 0.114b 0.124b 0.005
Pooled SEM: main effects, 0.005; substrate x enzyme terms, 0.008.
Inclusion of neutral protease and amylase increased the degradation of each rationtype
over the use of xylanase alone, as estimated by RSP. These results suggest that neutral
protease and amylase may be useful additions to enzyme formulations intended to stimulate
nutrient release from ingredients commonly used in poultry feeds. However, the RSP
technique does not reflect changes in the substrate that impact on nutrient absorption or gut
health (Jia et al., 2009) which may underestimate the value of xylanase in formulations for
younger birds.
PUBCRIS database; http://www.apvma.gov.au
Jia W, Slominski BA, Bruce HL, Blank G, Crow G, Jones O (2009) Poult.Sci., 88, 132-140.
Lü JL and Zhou PJ (2011) African Journal of Microbiology Research 5, 5757-5764.
1 Asiapac (Dongguan) Biotechnology Company, Songshan Lake Science and Technology Park, Guangdong,
PRC 53085. hosking@asiapac.cn
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