Demand for safe and healthy fish for human consumption has been growing. From scientists to aquaculture producers, people are looking for ways to increase the yield of fish farms. In the United States, the aquaculture sector now has a new tool. In January, the Association of American Feed Control Officials (AAFCO) added aquafeeds to the list of approved uses for manufactured taurine. The Food and Drug Administration (FDA) has an agreement with the AAFCO to assist with the scientific process. As a result, AAFCO's approval resulted in FDA endorsement in February.
Manufactured taurine had already been approved for use in baby food, sports drinks, dog food and chicken feed. Following testing, it has now been approved for the use in cat and fish feeds.
Many animals and humans can make this amino acid, but it is an essential component in the diets of others, such as cats and carnivorous fish. In cats, a lack of taurine in the diet can cause blindness, as well as problems with digestion and heart function. In carnivorous fish, like salmon and trout, a lack of taurine causes less obvious problems and scientists continue to study the effects, but vision and sense of smell might be impacted.
Dr Ron Johnson is the program manager for the Aquaculture Research Program at the National Oceanic and Atmospheric Administration (NOAA) Northwest Fisheries Science Center in Seattle. He heads a team which looks in to alternative ingredients for aquafeeds.
The focus on synthetic taurine was due to the fact that those fish diets that use a mixture of corn and soybean meal are missing a number of ingredients essential to carnivorous fish species and therefore require the addition of fishmeal. Each farm-raised carnivorous fish should be expected to eat its own weight in fish before being processed.
A one-to-one ratio isn't sustainable with the current fish market, Johnson said. Having alternatives to fishmeal and fish oil means farmers can save money and utilize more options.
Similar types of taurine are approved for use in the European Union, Canada and Japan. The process takes longer in the US because the FDA has to approve use for each type of animal individually. As a result, US aquaculture producers have lacked a tool that is available to many seafood producers in other parts of the world.
“We're behind on this,” Johnson said. “Some traditional alternatives…they're missing the essential nutrients fish need, [such as long-chain fatty acids].”
The NOAA and the United States Department of Agriculture, USDA, identified taurine as a key ingredient for fish feed in 2011.
Johnson's group studied coldwater sablefish and how the different combinations of plant-based fish meal impacted them. The sablefish worked well because they are non-discriminate feeders and grow quickly, Johnson said.
Last spring, Johnson and three other scientists presented a petition to the AAFCO. Scientists reviewed the information presented to them. In January, the AAFCO re-wrote the definition of taurine.
Dr Rick Barrows, from Aquatic Feed Technologies LLC, said the approval should help aquaculture in the US to thrive.
“This will allow the aquaculture industry to grow. It allows for the formulation of a variety of different types of fish feeds,” Barrows said.
He said that the approval of this alternative taurine will reduce the amount of animal protein needed in feed formulations and increase the amount of proteins available from other sources – including plants, insects and bacteria.
“It provides another tool for the nutritionists to formulate a balanced diet for the fish,” Barrows said.
He added that synthetic taurine was in fact previously used in the US, before the FDA decided to remove its approval from fish food. “It's not a logic thing. We couldn't use algae in fish feeds but we can use it in baby formula,” Barrows said.
Synthetic taurine is chemically identical to naturally occurring taurine, and the version used for Johnson’s study was sourced from the company NuSci Institute & Corp, based in Walnut, California. When contacted about the material used in the taurine, they said the information is not available for the public. However, according to Rick Barrows, manufactured taurine tends to be a mixture of plant, insect and bacteria taurine.
Barrows believes that some feed producers started the process to use synthetic taurine in their formulations the day after its inclusion in aquafeeds was approved. A US-produced aquafeed containing the manufactured taurine should be available soon.
Johnson said approving synthetic taurine will be a benefit to the aquaculture industry, but his group will continue to study diets with low fishmeal content and how these might impact a range of cultured species.