Thử nghiệm bổ sung Phytase (từ Bacillus subtilis Ba 58) trong khẩu phần thức ăn lên sự tăng trưởng và hiệu quả sử dụng thức ăn cá tra (Pangasianodon hypophthalmus)

The effects of phytase supplementation (Bacillus subtilis Ba 58 in the lab) in diets on growth, feed  utilization  and  phosphorus  content  of  tra  fish  (Pangasianodon  hypophthalmus). The experiment  includes  four  isonitrogenous  (33,3%  crude  protein)  were  prepared  with  graded levels of supplemental phytase (500 U/kg, 1000 U/kg and 1500 U/kg) and controls (no added phytase) in diets and was repeated 4 times for 12 weeks. At the end of the experiment, the results  showed  that  fish  fed  with  feed  supplemented  phytase  improved  final  body  weight, weight gain and specific growth rate and higher phosphor fish compared to controls (P <0.05). Furthermore,  the  addition  of  phytase  reduce  the  amount  of  phosphorus  discharged  into environment from catfish.  In particular, the phytase supplementation  with   1500 U/kg feed gained the best results.