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Scientists warn that global fish stocks are on the verge of collapse due to the effects of climate change and overfishing, fueling concerns of increased malnutrition.  This not only translates into less fish for human consumption but, ironically, impacts aquaculture as commercial fish feed contains a large amount of fishmeal.

In an effort to identify a protein-rich replacement for fishmeal, researchers from Karatina University and the University of Eldoret in Kenya and the University of Arizona explored the use of amaranth (Amaranthus hybridus) leaves, which contain 17.5–30.3 percent dry matter as protein, of which 5 percent is lysine.  Specifically, they replaced fishmeal with amaranth leaf protein concentrate (ALPC) for the production of Nile tilapia (Oreochromis niloticus). Through their research, it was determined that up to 80 percent of fishmeal could be replaced with ALPC without compromising growth performance and nutrient utilization.

The scientists also identified various limitations with amaranth, including lower levels of certain amino acids that can limit fish growth performance.  Another obstacle would be the ability to process amaranth leaves into ALPC at the farmer level. 

These results demonstrate that while it is possible to substitute a large portion of fishmeal with ALPC, the amaranth product cannot completely replace it.

Related to this topic, ECHO’s Amaranth Tech Note is available, as well as an ECHO Asia Notes article on Farm-Generated Fish Feed.

The full research report is available online at: http://www.sciencedirect.com/science/article/pii/S2352513416301168

Let us know in the comments if you have any experience using amaranth leaves in this way.