Effects of additional cassava pulp meal and fibrolytic enzymes in Nile tilapia (Oreochromis niloticus L.) diets on digestibility and growth performance

Abstract

Study on the effects of additional cassava pulp meal as carbohydrate source and adding fibrolytic enzymes in Nile tilapia diets were investigated. An experiment was focused on carbohydrate digestibility of carbohydrate in diets and growth performance of Nile tilapia. Five isonitrogenous diets was supplemented with 8% cassava pulp meal. The dietary treatments were basal diet (T1; control, no enzyme), T2; control diet added 24,000 U / kg of xylanase, T3; control diet added 10 U/kg of cellulase, T4; control diet added 750 U/kg of mannanase and T5; control diet added cellulase: mannanase 5U : 375U. Five experimental diets were performed for 90 days growth performance and feed utilization of fish were evaluated with average initial weight of fish was 45.81±1.95 - 51.66 ±3.48 g/fish. Results of carbohydrate digestibility showed that control diets and fibrolytic enzymes supplemented diet were not significantly different (P>0.05). Growth parameters, feed conversion ratio and survival rate were not significantly different (P>0.05), the average daily gain, specific growth rates, feed conversion ratio and survival rate were ranged 0.41- 0.50 g/day, 0.65-0.95  %/day, 1.46-2.19 and 91.67-100 %, respectively. Results from this study revealed that dietary supplementation of fibrolytic enzymes have no effect on carbohydrate digestibility,growth performance and feed utilization. Therefore, cassava pulp meal could be used as carbohydrate source replacement for broken rice at the level 8 % without fibrolytic enzymes supplementation.