The influence of replacing fish meal partially in the diet with soybean meal on growth and body composition of juvenile tin foil barb (Barbodes altus)

Juvenile Barbodes altus (0.90 +/- 0.02 g body weight) were fed 42% crude protein diets in which dietary protein was supplied by brown fish meal (FM) (60% crude protein) or an isonitrogenous mixture of soybean (defatted, with hulls, 44% crude protein) and PM. Diet 1 was a control diet containing 73% FM (100% fish meal protein (FP)) as a protein source and without any soybean meal (SP). Diets 2-4 contained 27%, 37%, and 52% SBM with FM (ratios of FP to soybean meal protein (SBM) were 3:1, 2:1, and 1:1, respectively). Fish fed the diet containing FP/SP ratio of 1:1 had significantly (P < 0.05) lower weight gain and feed efficiency than fish fed with the other diets. There was no significant difference in body weights of fish fed with the other three diets. When compared to the control (Diet 1), fish fed with the other three diets did not show any significant difference in body protein content. However, body fat content was significantly higher in fish fed with the control diet than the fish fed with diets containing FP/SP ratios of 2:1 and 1:1. Whole-body ash content was significantly lower in fish fed with a diet containing fish-protein/soy-protein ratio of 1:1 than in those fed the other diets. The results of the present study indicate that SBM may be included in the diet up to 37% as a substitute fbr FM, replacing about 33% of FP. (C) 2000 Elsevier Science B.V. All rights reserved.