A new, nonproprietary mix, according to Barrows, was needed to replace a decades-old formula that wasn’t adapted to today’s fish-feed processing technology. That technology, known as “extrusion processing,” heats and cooks fish feeds, shaping them into firm pellets that are either sold “as is” or perhaps crushed into smaller bits suited for the tiny mouths of very young fish.

Though extrusion processing has many advantages over previous methods, the heating can damage some vitamins. The formula that Barrows developed takes this into account, compensating appropriately for estimated losses.

He combed scientific journal articles and other published literature from around the globe to find the best available data on these losses, then used that information to determine the best quantity of each affected vitamin to use in the new premixed formula. It’s just one of many steps that went into the 2 years of research and development that resulted in the science-based product dubbed “ARS-702.”

Barrows went public with the formula—which specifies the type and amount of each nutrient—in 2007. Two major manufacturers of vitamins now make the mix which, in turn, has been added by feedmakers to more than 650,000 pounds of fish feeds.

Feedback indicates that the mix has helped invigorate finfish as varied as rainbow trout, walleye, and the endangered Rio Grande silvery minnow.

Barrows, who is with the ARS Small Grains and Potato Germplasm Research Unit, developed the vitamin mix in collaboration with ARS teammate and fish physiologist Gibson Gaylord and Ron Hardy, director of the Aquaculture Research Institute at the University of Idaho.