Download Effects of pretreatment in all-plant feedstuff with microbial phytase on

Effects of pretreatment in all-plant feedstuff
with microbial phytase
on phosphorous utilization and growth
performance of Nile tilapia
Cao, Ling and James Diana
University of Michigan
Wang Weimin
Huazhong Agricultural University
Wuhan China
Yang Yi
Shanghai Ocean University
Shanghai China
Travel funding for this presentation was provided by
AquaFish
Collaborative Research
Support Program
AquaFish CRSP
USAID
The Aquaculture CRSP is funded in part by United States Agency for International
Development (USAID) Grant No. EPP-A-00-06-00012-00.
The opinions expressed herein are those of the authors and do not necessarily
reflect the views of the US Agency for International Development.
Outline

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Background
Experimental design
Results
Conclusions
Acknowledgement
1. Background

Decrease of annual fishmeal production
 Fishmeal substitution by plant proteins
 High concentration of phytate in plant proteins

Phytate and phytase enzyme
Phytate = phytin = phytic acid
Up to 80% of the total P content in plants may
be present in the form of phytate and is
practically not available for monogastric or
agastric aquatic animals.
Table 1. Phytate contents in plants or plant products (NRC, 1993)
 Phytase:
An enzyme specific to hydrolyze phytate,
naturally found in animals, plants and
microorganisms
Figure 1. Action of phytase (Baruah et al. 2004)
Table 3. Commercial information of microbial phytase
(Cao et al. 2007)
Table 4. Optimum dose of phytase addition in
diets of different fish species (Cao et al. 2007)
2. Experimental design

2.1 Pretreatment trial
Objectives:
＊ Find out the most efficient phytase dose for
treating plant ingredients
pH 5.5
Citric acid buffer
Phytase (5000 U/g)
Enzyme solution
(10 U/ml)
Mix with plant
ingredients
(W:V=1:1)
Sampling
Oven 55 ℃
5～6 h
Chlorine anion 100-200 mesh AG1-X4
（Bio-Rad Laboratory, USA）

2.2 Growth trial
Objectives:
＊Find out the optimum addition dosage for
growth performance of tilapia juveniles.
＊Determine the best replacing amount for
inorganic phosphorous by phytase.
3. Results
3.1 Pretreatment

Soybean meal
 Mix plant ingredients
3.2 Growth performance
4. Conclusion

The optimal dose of phytase for the pretreatment of
plant ingredients is 1,000 U kg -1, which can
efficiently convert phytate P to available P and
replace 50% of the inorganic P supplementation to the
diets for Nile tilapia juveniles without affecting their
growth performance, apparent digestibility
coefficients of both crude protein and phosphorous.
 The addition of phytase in the diets can reduce the
use of inorganic P, enhance the utilization of P in
plant ingredients, and thus minimize the P discharge
to the environment.