Use of High Percentage of Soy Protein Concentrated as Fish MealSubstitute In Practical Diets for African Catfish, Clarias garierpinus(Burchell 1822):: Growth, Diet Utilization and Digestibility

摘要

The effects of replacing high percentages (50%, 75% or 100%) of dietary protein from fishmeal with soy protein concentrate on growth, diet utilization, and carcass composition of the African catfish, Clarias gariepinus, was evaluated. Supplemental methionine was added to the diet formulation in which soy protein concentrate replaced 100% of fishmeal protein. Diets were formulated (420 g crude protein/kg and 17.5 kJ gross energy/g dry diet) and fed to catfish fingerlings (13.1 plus or minus 0.5 g) to apparent satiation twice daily for 70 days. Replacement of 50% and 75% of fish meal protein with soy protein concentrate did not affect growth, feed utilization or carcass composition, which were similar (P > 0.05) to those fed with the control diet. At 100% replacement, growth and feed utilization were depressed and slightly inferior hematological characteristics were observed, compared with the other treatments. Liver histology of catfish fed any of the diets showed no alternations. Results indicate that 75% of fish meal protein in catfish diets can be replaced with soy protein concentrate and that catfish can effectively utilize supplemental methionine, thereby allowing up to 100% of the dietary protein from fish meal to be replaced by soy protein concentrate.