The need to reduce reliance of aquaculture industries on fish based protein resources has long been recognized as an important issue. Notably the Fisheries Research and Development Corporation have given this issue such importance it is rated among their 9 key challenges to address in the 2000 – 2005 Research and Development Plan. Substantial work has already been undertaken to address this challenge over the past 10 years. Notably, recent developments have seen the increased adoption of some grain based alternatives being used by the aquaculture feed manufacturing industries. Lupin kernel meal use by this sector in particular is a prominent success story.
As the aquaculture feed industries begin to increase their use of alternative protein resources, such as lupin kernel meals, it becomes increasingly important to develop quality assurance (QA) assessment criteria for specific feed ingredients. The nature of these criteria will vary depending on the end use of the product. An improved understanding of the nutritional value and functional properties of the ingredients is also required to maximize the use of these ingredients by these industries and to begin the QA criteria development process.
Presently the extruded fin-fish feed sector (primarily salmonid feeds) is the largest aquaculture user of value-added grain products in Australia. However, it is apparent that further development of market confidence, through resolution of some of the nutritional value assessment and processing issues, is required for some additional aquaculture sectors (e.g. prawns) to encourage routine use of these products and work addressing these issues is planned in this proposal.
Furthermore, exploration of new product possibilities has already begun in the GRDC project with the development of a series of very promising lupin protein concentrates. However, further evaluation of the potential and constraints for the use of these new and innovative products within aquaculture feeds is needed and additional evaluation in Atlantic salmon and prawns is required.
Final report
This program represents a major collaborative initiative between the Grains and Fisheries Research and Development Corporations. It has engaged seven different research providers and three industrial collaborators in achieving its outcomes. Numerous findings were encountered through this program, which are collated in this report.
Key among those findings is:
- The dehulling of lupins significantly improves their nutritional value to fish. A linear increase in digestible energy value was observed, while a curvilinear response in digestible protein value was observed. This finding shows that there is significant nutritional benefit to the fish in optimizing the dehulling efficiency of lupins, but in terms of protein value that a minor contamination with hulls is unlikely to significantly reduce the protein value.
- Considerable variability in the digestible protein and energy value of the lupin kernel meals was observed. It was shown that this variability could be assessed as a function of grain composition.
- Considerable variability in the composition of lupin kernel meals was observed among the 76 samples evaluated for digestibility. As protein increased in each lupin kernel meal a reciprocal decrease in NSP was observed.
