PERFORMANCE OF Clarias gariepinus FED NATIONAL INSTITUTE FOR FRESHWATER FISHERIES RESEARCH (NIFFR) FEED SUPPLEMENTED WITH NUTRASE XYLANASE

Abstract

Eight weeks feeding experiment was conducted to evaluate xylanase inclusion into un-extruded and extruded diets of
Clarias gariepinus fingerlings in a 2 x 3 factorial design. Triplicated groups of 10 fingerlings with mean weight of
5.3 g ± 0.5 were used at National Institute for Freshwater Fisheries Research, New Bussa, Niger State, Nigeria.
There were significant differences (P < 0.05) in final weight, specific growth rate and weight gain of the fish. The
fish that fed on the diets produced by cold pelleting supplemented with either yeast or xylanase were not
significantly different (P > 0.05) in growth, but were significantly lower than those on diet with enzyme produced by
extrusion (P < 0.05). However the groups that fed on diets with xylanase had higher mean weight gain, 20.76 versus
22.39 g fish-1 for yeast and xylanase respectively. There was a reduction in cost per kg of feed with xylanase
supplementation compared to yeast as an additive. It was observed that xylanase resulted in better performance
which could be due to its effect on the B,1- 4 bonds to expose and reduce the polymers of nutrients that might have
been bound up in the cell wall for the available endogenous enzyme. It was concluded that xylanase
supplementation in diets of C. gariepinus results in significantly (P < 0.05) higher performance. It will be necessary
to carry out further studies on this species.