Effect of phytase enzyme on the growth performance of Clarias gariepinus fingerlings
A 56 day feeding trial experiment was conducted using Clarias gariepinus fingerlings of 10g mean weight fed four different iso-nitrogenous diets with 40% crude protein level. The experiment evaluated the relative effects of phytase enzyme inclusions in plant protein supplement (Soybean meal, T1) and animal protein supplement (Fish meal, T3). The other two diets, plant protein base (T2) and animal protein base (T4) had no phytase enzymes. Results of growth indices showed significant differences (P<0.05) among the treatments. The best growth and feed conversion efficiency were obtained with Diet T3 fish meal with phytase inclusion which had the highest mean weight gain (MWG) of 6.109, specific growth rate (SGR) of 0.0085%, protein efficiency ratio (PER) of 0.060, apparent net protein utilization, (ANPU) of 59.80 and the lowest feed conversion ratio (FCR), of 2.65. Based on these results, diet T3, (fishmeal with phytase inclusion) was best. However, diet T1 - soybean meal with phytase inclusion is recommended to fish farmers based on relative economic advantage as a cheap protein supplement than fish meal.
Key words: Diet performance, phytase, ingredient substitution, growth, Clarias gariepinus.