Studies on the Characterisation and Utilisation of a New Phytase-Producing Bacterium Isolated from the Rumen of Cattle
Five phytase-producing bacterial strains isolated from the rumen of cattle were identified to be a new bacterial species based on their morphological, physiological, biochemical and molecular characters. The new species is named Mitsuokella jalaludinii. Mitsuokella jalaludinii hydrolysed sodium p...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2001
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/7955/1/IB_2001_4_.pdf |
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| Summary: | Five phytase-producing bacterial strains isolated from the rumen of cattle were
identified to be a new bacterial species based on their morphological, physiological,
biochemical and molecular characters. The new species is named Mitsuokella
jalaludinii. Mitsuokella jalaludinii hydrolysed sodium phytate rapidly and the
phytase production was strongly induced by phytate present in the medium. Rice
bran (RB) and soybean milk (SM) were found to be the best carbon and nitrogen
sources, respectively, for phytase production by M. jalaludinii. Phosphate at a level
of 0.05 - 0.5% in RB -SM medium had no effect on phytase production. Glucose
added to RB-SM medium had a negative effect on phytase production of M
jalaludinii. The optimum temperature and optimum initial pH for phytase
production of M jalaludinii were 3 9 °C and about 7.0, respectively.
The activity of M jalaludinii phytase was highest at 55 - 60°C and pH 4.0 -
5.0. It was specific to phytate as a substrate, significantly stimulated by Ba2+, Mn2+,
and Ca2+ and significantly inhibited by Zn2+, Cu2+, Fe2+ and Fe3+. The metal ion
chelators and phosphate were not the inhibitors of M jalaludinii phytase activity. Acute pathogenicity tests indicated that M jalaludinii was non-pathogenic to
chickens and mice. Supplementation of M jalaludinii culture to corn soybean meal
feed for chickens significantly increased P released from the feed in vitro and P,
DM and CP digestibilities in vivo. About 70% of in vivo response in P digestibility
and 90% of in vivo response in DM and CP digestibilities or AME value could be
predicted by the P released in vitro. Mitsuokellajalaludinii phytase was most active
in the crop of broiler chickens and was inactivated in the stomach.
Supplementation of either fresh active M jalaludinii culture (AMJC) or freezedried
active M jalaludinii culture (FD-AMJC) or Natuphos® phytase to 10w-aP diet
significantly improved the feed intake, body weight gain and feed conversion ratio
of broilers. The digestibilities of DM, CP, P , Ca, and Cu and the AME value of diet
were significantly increased by the supplementation of AMJC. S upplementation of
AMJC or FD-AMJC or Natuphos® phytase to 10w-aP diet significantly increased
the tibia ash content and serum P concentration but significantly reduced Mn
concentration in tibia ash of broiler chickens. Chicks receiving FD-AMJC had
better (P<0.05) feed conversion rate as compared to those receiving Natuphos®
phytase. FD-AMJC supplementation to 1 0w-aP diet significantly (P<O.OS) increased
the AME value of diet and the digestibilities of DM, CP, P, Ca and Cu ( 1 1 to 1 3 -
day-old and 1 8 to 20-day-old chicks) but Natuphos® phytase supplementation only
significantly improved the digestibilities of DM, P ( 1 1 to 1 3 -day-old and ] 8 to 20-
day-old chicks) and Ca ( 1 1 to 1 3 -day-old chicks). Chicks receiving 10w-aP diet
added with AMJC or FD-AMJC or Natuphos® phytase had similar (P>0 .05)
performance as those receiving normal-aP diet but excreted less (P<0.05)
phosphorus. |
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