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Background and Objective:
One of the primary purposes for including
enzyme supplements in animal feed has been to reduce viscosity of
digesta contributed by non-starch polysaccharides in cereals and to
provide more nutrients to animals by breaking down feed constituents
that can not be digested by the animal’s own enzymes. It is now
recognized that these enzymes may also play an important role in
influencing the growth of various bacteria that colonize the
gastrointestinal tract of animals.
The purpose of this investigation was to evaluate
the effects of various enzyme preparations on poultry feed ingredients
with respect to growth enhancement and or inhibition of various
pathogenic and probiotic bacteria (Listeria monocytogenes,
Enterococcus faecalis, Enterococcus gallinarum, Esherichia
coli, Salmonella typhimurium, Salmonella pullorum, Clostridium
perfringenes, Lactobacillus brevis, Bifidobacterium pullorum,
Bifidobacterium gallinarum, Bifidobacterium animalis,
Lactobacillus rhamnosis, Lactobacillus acidophilus and
Campylobacter jejuni).
Also, an in vivo feeding trial using
chickens was performed to evaluate the effects of enzyme
supplementation on the growth dynamics of various intrinsic bacterial
populations ( Escherichia coli, enterococci, aerobic and
anaerobic spore formers).
Results of this investigation indicated that
inclusion of xylanase in a wheat based diet resulted in a
significant decrease of E. coli in the caecal digesta of
chickens. Enterococci, and spore former levels, however, remained
unchanged. The addition of glucanases and multi-carbohydrases to
barley and corn based diets, respectively also did not alter the
levels of any of the bacterial populations investigated.
Growth levels of the pathogenic and probiotic
bacteria on various substrates (β-glucan raffinose, guar gum and xylan)
with enzyme supplementation appeared higher for most species.
Overall, however, no clear pattern could be established in regards to
growth promotion of probiotic bacteria and or inhibition of pathogens
based on the substrate-enzyme combinations used in this investigation.
Acknowledgements:
This
project was made possible due to funding from the Governments of
Manitoba and Canada through the Canada-Manitoba Agri-Food Research
and Development Initiative (ARDI); the Poultry Industry Council; and
Canadian Bio-Systems.
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