1995 Volume 61 Issue 6 Pages 915-920
A feeding experiment was conducted to investigate the effect of combined use of several alternative protein sources for fish meal in diets for fingerling rainbow trout Oncorhynchusmykiss. In the control diet, brown fish meal (BFM) was used as the sole protein source to provide 40% crude protein. In the test diets, 60 or 80% of the BFM protein in the control diet was isonitrogenously replaced by several combinations of soybean meal (SBM), meat meal (MM), malt protein flour (MPF), corn gluten meal (CGM), and dried brewer's yeast (DBY). These diets were fed to the fish with an initial mean weight of 9.4g for 6 weeks at 16°C.
Combinations of SBM and MPF, SBM and CGM, and MM and MPF at the 60% replacement level improved the weight gain, feed efficiency, and protein retention of the fish relative to the replacement of BFM by SBM or MM alone, and there were no significant differences in these values between the combination group and the control group. Combined use of SBM, MM and MPF at the 60% replacement level showed similar growth and feed performances to the above mentioned SBM and MPF, or MM and MPF diets, however, the performances at the 80% replacement level were inferior.Addition of DBY to the 80% replacement level diet improved the weight gain to the same level attained by the control group.
These results suggest that the combined use of two alternative sources such as SBM and MPF, SBM and CGM, and MM and MPF improve rearing performance of fingerling rainbow trout as cornpared with the use of SBM or MM alone, and that the combined use of SBM, MM, MPF, and DBY at a proper ratio can substitute the 80% of BFM protein.
