TY  - THES
T1  - Evaluation of locally produced microbial phytases and their by-products as additives in broiler nutrition
A1  - Khin, San Mu
LA  - English
YR  - 2011
UL  - http://discoverylib.upm.edu.my/discovery/Record/oai:psasir.upm.edu.my:84988
AB  - Phosphorus (P) is a critical and expensive mineral in poultry nutrition. It is an
essentially important mineral for the development of skeletal system and metabolism
of broiler chickens. Two-thirds of P provided in typical broiler feed ingredients such
as corn and soybean meal is bound to phytic acid. Phytic acid is of low availability to
monogastric animals. such as poultry and pigs. due to the lack of phytate hydrolyzing
enzyme, phytase. The addition of microbial phytase is an effective way to release a
portion of phosphorus bound to the phytate in maize and soybean meal, thereby
increasing improving P availability and reducing P excretion into the environment,
Five experiments were conducted to evaluate the potential of locally produced
microbial phytases as additive in broiler nutrition. In the first experiment. two locally
produced microbial phytases (ASUIA279 and ASUIA271) were evaluated for their
efficiency in improving growth performance. bone and serum mineralization. and phosphorus utilization of broiler chickens fed on corn and soybean meal based diet in
a three-week study. The addition of 1000 units/kg feed of ASUIA279 phytase to the
phosphorus deficient diet significantly increased (P< 0.05) body weight gain, tibia ash
and phosphorus content, serum phosphorus concentration and phosphorus utilization
at 21 days of age.
The second experiment was conducted to evaluate the efficacy of ASUIA279 phytase
at graded levels (500, 1000 and 1500 units/kg diet) on performances of broiler
chickens fed corn soybean meal based diet in a 42-day study. Except for feed
conversion ratio (FCR) and serum minerals (calcium and phosphorus), the
improvement (P<0.05) in weight gain and feed intake. bone ash and bone P, and
phosphorus retention were observed in the birds when phosphorus deficient diet was
supplemented with phytase (1000 and 1500 units/kg feed) But the improvements
were significantly (P<O.05) lower than the results observed with the adequate P diet.
Five hundred units/kg feed of phytase supplementation improved only growth
performance of broiler chicken in comparison with negative control diet.
The third experiment was conducted to investigate the efficacy of phytase at graded
dietary levels of non phytate phosphorus on performance of broiler chickens.
Without considering interaction effect, both phytase supplementation and, dietary
levels of non phytate phosphorus gave significant (P<().05) effects on all parameters
(growth performance, bone and serum mineralization. nutrient utilization) except
serum calcium level. Dietary levels of 0.251% non phytate phosphorus gave the lower
performance (P<0.05) than dietary level of 0.33% and 0.45% non phytate
phosphorus. Interaction between phytase and dietary levels of non phytate phosphorus showed that supplementation of phytase gave significant improvement
(P<0.05) in body weight at dietary levels of 0.25 and 0.33% non phytate phosphorus,
feed conversion ratio at dietary levels of 0.33% nPP and bone P content and P
retention at dietary levels 0.25 and 0.33 % nPP. But dietary levels of 0.33% non
phytate P with phytase supplementation gave better response than dietary levels of
0.25 (Yt) nPP and these results were comparable with the results obtained by the
dietary levels of reference diet (nPP 0.45%). Supplementation of phytase at dietary
levels of 0.45% nPP did not give additional positive response in all measurements.
Experiment 4 was conducted to study the effects of centrifuged phytase and
uncentrifuged phytase in rice bran media of ASUIA279 at 1000 units/kg feed on
broiler chickens fed corn-soybean diet. Both centrifuged and uncentrifuged phytase
supplementation gave significant improvement (P<O.05) in growth performance of
broiler chickens (body weight gain and FCR) in comparison with negative control
diet. The effect by centrifuged phytase supplementation was significantly (P<0.05)
better than that of normal phosphorus adequate diet. However. bone mineralization,
nutrient retention and excretion (P, Ca. and crude protein) were only significantly
improved (P<0.05) by supplementation of centrifuged phytase.
In experiment 5, the effects of fermented rice bran, a bio-converted byproduct of
phytase production on performance of broiler chickens were evaluated in comparison
with untreated rice bran. The contents of crude protein and crude fat were increased
in the fermented rice bran and phytate P content was reduced as compared to
untreated rice bran. Inclusion of 1(Jolt) untreated rice bran or fermented rice bran in
corn soybean meal based diet did gave the same effects on performances of broiler chicken except for total P retention and can reduce feed cost. The addition of 10%
fermented rice bran in the corn soybean meal diet produced better bone
mineralization and P retention in comparison with untreated rice bran.
These studies indicated that the locally produced microbial phytase. ASUIA279 has
the potential to be used in commercial poultry operations. The fermented rice bran.
byproduct of phytase production can be utilized as chicken feed without giving
detrimental effects.
KW  - Phytases
KW  - Broilers (Chickens) - Nutrition
ER  -