USE OF LUPIN FLOUR AS A REPLACEMENT FOR FULL-FAT SOY IN DIETS FOR RAINBOW-TROUT (ONCORHYNCHUS-MYKISS)

A 12-week feeding study was conducted to determine if either whole or dehulled lupin flour could be used as an economical replacement for full-fat soybean meal (FFSM) in a ration for rainbow trout (Oncorhynchus mykiss) and to determine if it was necessary to replace the soybean oil lost when FFSM was omitted from the ration. The ressults of the trial indicated that lupin can be used as a substitute for FFSM without the soy oil supplements used in a previous study. Total percentage weight gains of fish fed the diets containing soy, lupin, or lupin with added oil for 12 weeks all fell within the range 170-180. In addition, in fish fed the diets containing the higher-protein lupin, growth was at least equal to and up to 15% greater than that shown by the fish fed the soy diets. This interpretation of the data would indicate that the economics of using lupin (at the quoted prices) favors its use over FFSM in the test ration and that the dehulled (higher-protein) lupin may be even more desirable for use in feeds for salmonids.