Replacement of dietary fishmeal for canola meal on the growth performance, digestibility, digestive enzyme activities and hemato immunological responses in pacu, Piaractus brachypomus (Cuvier, 1818)

Abstract

Introduction: Fish powder is one of the most important ingredients in aquatic diets.
Materials & Methods: A 63-day trial was conducted to examine the effect of different levels (10, 20, 30, 40, 50 and 100%) of fishmeal replacement for canola meal in the diet of pacu fish (Piaractus brachypomus, 45.12±1.36 g) on growth performance, survival rate, apparent digestibility coefficient of diets, activities of digestive and hepatic enzymes and hemato-immunological responses.
Result: The highest level of the final weight and specific growth rate and the lowest food conversion ratio were achieved in pacu fish fed with 40% canola meal. Significant decreasing trends were achieved in the serum levels of total cholesterol, triglyceride, and low-density lipoprotein of pacu fish fed with increasing the contents of canola meal (p<0.05). Based on the growth indices, the maximum tolerable contents of dietary glucosinolate and phytate in the pacu fish were 4.90-5.22 μmol g-1 and 6.12-6.52 g kg-1, respectively. The activities of amylase, lipase, and trypsin in pacu fish increased according to enhance CM substitution levels (p<0.05).
Conclusion: According to the broken line technique, the highest specific growth rate (1.91% body weight day-1) was observed in pacu fish fed with 40.2% CM.