Effects of phytase on enhancement of phosphorus utilization from plant materials in bybrid catfish [Clarias macrocephalus (Gunther) x Clarias gariepinus (Burchell)]

Abstract

Hybrid catfish of initial weight 5.57-5.72g were studied in 235-1 glass tanks filled with 1801 water and closed-recirculation system with 0.8 l/m flow rate was attached. Complete randomized design was employed in which there were three replications (20 fingerlings each) in each of nine treatments. The experimental period was 10 weeks. Formula 1 feed was the control in which fishmeal and soybean meal were used as protein source and was nutritionally suitable for catfish. In formulae 2-6 Feeds, only plant materials were used as feed components and sprayed phytase was aplied at 0,250,500,750 and 1,000 unit/kg feed. For formula 7-9 feeds, phosphorus from dicalcium phosphate (DCP) at 0.1,0.2 and 0.3% was supplemented. The results showed that the supplementation of 500 unit/kg feed as well as of 0.2% phosphorus were the most effective in improving the weight gain, specific growth rate and feed efficiency (FCR, PER and ANPU). The supplementation of phytase as well as of DCP elevated the bone as well as in the whole body while the blood parameters were not markedly affected.

Keywords

• phytase
• inorganic phosphate
• dicalcium phosphate
• phosphorus
• hybrid catfish
• Clarias macrocephalus (Gunther) x Clarias gariepinus (Burchell)