THE EFFECT OF EXOGENOUS ENZYME ON THE GROWTH PERFORMANCE OF Clarias gariepinus FINGERLINGS

The continuous increase in the price of fishmeal, coupled with its scarcity has made the development of aquafeed with reduced or zero inclusion of fishmeal in the diet a major focus. The diet must however, not impede with the growth performance, feed utilization and fish health. Among the alternative ingredients, plant ingredients have been widely studied. Most of which contain several antinutritional factors such as phytate, saponins, non-starch polysaccharides, lectins, glucosinolates, phytoestrogens and phytosterols that are not inactivated by heat or feed processing and may interfere with feed utilization and fish health.

The use of exogenous feed enzymes will allow the dietary incorporation of plant ingredients and reduce feed cost. Presently, the potentials of exogenous enzymes to improve macronutrients in fish is limited to few studies.

This study was conducted for six weeks to determine the optimum level of Fullzyme® (a multi enzyme) inclusion in the diet for Clarias gariepinus fingerlings based on growth performance. Four treatments each with three replications were used, the control diet (A) was formulated to contain 42 g/kg crude protein from fishmeal and plant ingredients. The other diets were made like the control but supplemented with 0.25 mg/kg, 0.50 mg/kg or 0.75 mg/kg of commercial enzyme mix: Fullzyme® in diets B, C and D respectively. Feed was supplied at a rate of 5% of the fish body weight. The weight gain and SGR in fish fed diet B was significantly (P<0.05) higher than fish in the other treatment groups. Protein efficiency ratio was not significantly (P>0.05) different among the dietary treatment groups. The results of this trial suggest that exogenous enzyme (Fullzyme®) was effective and improve the growth performance of C. gariepinus fingerlings at the inclusion level of 0.25 mg/kg.