Fly Frass Forms Fabulous Fish Food

People gotta eat, and with the world population projected to reach nearly 10 billion in the next few decades, we’ll need to produce a lot more food. Fish farming – aquaculture – is one way of doing that.

ARS researchers have worked with American catfish farmers to develop a feed supplement that not only increases the weight of their fish – meaning there’s more of it to eat – it also helps keep the fish healthier and is environmentally sustainable. The feed, called “frass,” is high in protein and chitin, a compound that helps fish better withstand pathogens by triggering their immune systems.

Frass is the byproduct of farming insects that are non-pathogenic and do not pose a risk for human, animal, or plant health. In this case, black soldier fly larvae are raised on organic waste products until they reach a specific age. Larvae are then processed into protein meal and oil for biofuel. As with raising other “livestock,” larvae leave their own waste – including exoskeletons and residual feed. When processed, frass resembles a crumbly soil and is loaded with nutrients.

More information can be found in our Down on the Farm article.