The Effects Of The Dietary Microbial Phytase Supplementation In Juvenile Olive Flounder, Paralichthys olivaceus And Juvenile Korean Rockfish, Sebastes schlegeli Fed Soybean Meal-Based Diets

  • Gwangyeol Yu (Department of Aquaculture, Pukyong National University) ;
  • Kyungmin Han (Department of Aquaculture, Pukyong National University) ;
  • Park, Semin (Department of Aquaculture, Pukyong National University) ;
  • Sungchul C. Bai (Department of Aquaculture, Pukyong National University)
  • 발행 : 2003.10.01

초록

This study was conducted to determine the effects of the dietary microbial phytase (P) supplementation on growth performance and bioavailability of phosphorus in juvenile olive flounder, Paralichthys olivaceus and juvenile Korean rockfish, Sebastes schlegeli fed soybean meal-based diets. Nine experimental diets were formulated to be isonitrogenous and isocalolic to contain 50.0%crude protein (CP) and 16.7kJ, 48.6% crude protein (CP) and 16.0kJ available energy/g without the dietary phytase supplementation for olive flounder and Korean rockfish, respectively : 100% fish meal (FM); 70% FM + 30% soybean meal (SM); 70% FM + 30% SM + Phytase(P) 1000U/kg diet; 70% FM + 30% SM + P 2000U/kg diet; 70% FM + 30% SM with phytase-treated (Ptre) P 1000U/kg diet; 60% FM + 40% SM; 60% FM + 40% SM + P 1000U/kg diet; 60% FM + 40% SM + P 2000U/kg diet; 60% PM + 40% SM with Ptre P 1000U/kg diet. After two weeks of the conditioning period, triplicate groups of 25 fish initially averaging 6.15$\pm$0.04g, was randomly distributed into the aquarium for olive flounder, and 20 fish initially averaging 7.25$\pm$0.04g was randomly distributed into the aquarium for Korean rockfish. After 8 weeks feeding trials, there was no significant difference on weight gain fish fed between 100% FM and 70% FM+30%SM with Ptre P 1000U in olive flounder and Korean rockfish. Apparent phosphorus digestibility fish fed phytase supplemental diets were significantly higher than those of fish fed phytase non-supplemental diets in olive flounder and Korean rockfish. Therefore, these results indicated that pre-treated soybean meal with phytase 1000U could replace fishmeal up to 30% for the maximum growth of juvenile olive flounder and Korean rockfish. Phytase supplementation could improve apparent digestibility of phosphorus in olive flounder and Korean rockfish fed soybean meal based diets.

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