Effect of cellulase, phytase and pectinase supplementation on growth performance and nutrient digestibility of rainbow trout (Oncorhynchus mykiss, Walbaum 1792) fry fed diets containing canola meal

This experiment was conducted to evaluate the effects of supplementing exogenous enzymes on growth, feed conversion ratio (FCR) and apparent nutrient digestibility in rainbow trout (Oncorhynchus mykiss) fry diets containing 32% canola meal. Five experimental diets (including a control diet containing no enzymes) were prepared as isonitrogenous (44% crude protein) and isocaloric (4000kcal DE kg(1)). The four other diets contained either cellulase, phytase, pectinase or an enzyme mix (a mixture of cellulase, phytase and pectinase in the same ratio). The feeding trial was conducted in triplicate for 12weeks in 15 tanks (100-L). At the beginning of the experiment 20 rainbow trout fry (initial weight 1.23g) were stocked into each tank. Mean water temperature in the rearing tanks was 11 degrees C and waterflow in each tankwas 6L min(-1). At the end of the experiment the growth parameters and FCR displayed no significant differences in enzyme supplementation (P>0.05). In addition, no differences were observed in dry matter, protein, or lipid digestibility with enzyme supplementation (P>0.05). The results of this study showed that the addition of pectinase, phytase, cellulase or an enzyme mix to a diet containing 32% canola meal had no effect on growth, feed efficiency or dry matter, protein, or lipid digestibility in rainbow trout fry.