EFFECTS OF ENZYME ADDITION TO CANOLA-MEAL IN PRAWN DIETS

Enhancement of nutritional value of canola meal by the addition of enz ymes was investigated in diets for juvenile Penaeus monodon ((X) over bar +/- SD; 0.96 +/- 0.09 g), with emphasis on liveweight gain and fee d conversion ratio (FCR). Six diets were prepared containing either no canola (squid meal based basal diet), basal + 20% canola (low canola diet), low canola + 0.25% enzyme mixture (Porzyme, Finnfeeds Internati onal), basal + 64% canola (high canola diet), high canola + 0.25% enzy me mixture or basal + 54% canola + 10% sucrose. All diets were fed ad libitum. Juvenile prawns (three prawns per tank) were fed diets for 42 days with five tank replications per diet. Liveweight gain and feed i ntake were measured. High canola diet gave significantly lower growth rates (1.79 +/- 0.42 g) (P < 0.05), and enzyme addition increased the liveweight gain from this diet by 28%, to a level similar to the basal (2.33 +/- 0.49 g) (P > 0.05). The low canola + enzyme diet also resul ted in higher liveweight gain (2.40 +/- 0.16 g) than the basal and low canola diets (2.29 +/- 0.27 g) but it was not significant. Addition o f the enzyme mixture to diets also gave a significant improvement in F CRs. The addition of sucrose to the canola based diet resulted in a si gnificantly higher liveweight gain (high canola + sucrose 2.01 +/- 0.2 2 g), but did not change the FCR. (C) 1997 Elsevier Science B.V.