Rapeseed use in aquaculture

The main problem of the aquaculture sector is the provision of suitable and sufficient fish feed, because the most important protein source in aquaculture, the fish meal, is a limited resource. Due to their high nutritional value the rapeseed proteins have great potential as an alternative protein source for the fish nutrition. Therefore, the aim of this work is to develop a manufacturing process of high quality rapeseed protein concentrates, which can replace the limitedmarine resource. For this purpose, small pilot scale processing procedures were performed to produce a rapeseed protein concentrate (RPC). The meal for protein extraction was prepared by gentle meal processing. Rapeseed protein fractions were prepared by an aqueous extraction procedure. The obtained protein solution is further purified and then dried. The investigated rapeseed protein extraction process provides RPC with high nutritional value and low levels of antinutritional factors. From the nutritional point of view the produced RPC can be compared with the fishmeal. Its amino acid profile reflects the amino acid demands of fish. The obtained RPC was utilized for experimental setups of fish meal replacement in diets for rainbow trout, turbot, common carp and wels catfish. Experimental results from the conducted feeding trials demonstrate an enormous potential of RPC as protein source in aquafeeds. The highest fishmeal replacement level (up to 100%) was observed in the feeding trials with rainbow trout. Therefore, especially in the nutrition of rainbow trout, RPC was identified as an excellent fishmeal alternative.