During the last three decades, world aquaculture production increased more than tenfold, reaching 73.8 million tons in 2014 (FAO 2016). Globally, fish currently represent about 16.6 percent of animal protein supply and 6.5 percent of all protein for human consumption. It is predicted that aquaculture will provide the most reliable and sustainable supply of seafood (i.e., marine-derived food) in the future (Hixson, 2014). However, there are a number of difficult issues associated with producing an aquaculture feed ingredient that is permitted for use in the United States.
Historically, a new feed ingredient may be approved for use via three routes: (1) a food (i.e., feed) additive petition for approval by FDA; (2) a new ingredient definition petition submitted for approval by the American Association of Feed Control Officials (AAFCO) and; (3) the Generally Recognized As Safe (GRAS) process. Regardless of the route, the safety of feed of a feed ingredient must be demonstrated either by the history of use prior to 1958 (in GRAS process) or by scientific procedures (in all three routes). Because the FDA food additive petition route is very cumbersome and lengthy and, because the AAFCO definition route is not compliant with federal law, therefore, in this article, the author will focus on GRAS. The FDA’s final rule on GRAS (including the Center of Veterinary Medicine (CVM)) on how to determine the GRAS status of a feed ingredient was finalized in August, 2016 (Federal Register 81:54960, August 17, 2016).
To demonstrate safety, toxicity tests are required for a GRAS to show that the feed ingredient is safe for the target animal. These tests may include, but are not necessarily limited to: (1) a demonstration of the biochemical fate of a substance; (2) a repeated-dose study, such as a 90-day toxicity study; (3) a possible test for reproductive effects and, (4) most always, tests for genotoxicity and mutagenicity. However, special circumstances must be considered when applying these aforementioned tests in aquaculture.
First, extra stability studies may be required to assess the stability of the ingredient in the feed because, after all, aquaculture diets are consumed in the water not as dry substances in a rodent feeder. Particularly troublesome circumstances are presented by the slow-feeding or bottom-feeding aquaculture species, where the diet pellet must retain its form and nutrient content until the pellet is consumed. For example, it is possible for water-soluble nutrients to dissolve out of the pellet before consumption, preventing the aquaculture animals from accessing all the required nutrients (FDA, 2016).
Second, special consideration should be taken for adequate nutrition. That is, aquaculture fish are often fed the same diet formula for long periods of their life and the diet must provide appropriate amounts of all the nutrients the animal requires and, in a form that animal can consume and utilize; otherwise a nutrient deficiency may occur and mistakenly be interpreted as a toxic effect (FDA, 2016). Therefore, a feed ingredient intended for use in aquaculture would need to demonstrate that it is stable and would not change the other nutrients or their utilization by the animal. For example, it is a common practice to use terrestrial plant meal to replace fish meal in aquaculture diets to reduce cost. However, terrestrial plant meal is often deficient in one or more essential amino acids and if a diet is inadequate in any essential amino acid, the target (i.e., test) species cannot properly develop and mature. Although the composition of macronutrients in the diet could be formulated similar to fish meal, a full replacement of fish meal with terrestrial plant ingredients (e.g., soybean meal) in fish diets may lead to malnutrition symptoms in fish such as reduction in feed intake, digestion, absorption, and growth and feces with high nutrient content (Marine Harvest, 2016). Although not direct toxic reactions, the symptoms of malnutrition caused by formulation changes would be considered adverse effects of a feed ingredient during a safety assessment. Further, the adverse effects from malnutrition are often more profound in aquaculture fish than common farmed animals (e.g., swine and chicken), because fish are often more efficient in feed conversion compared to farmed animals (Marine Harvest, 2016). Therefore, a feeding study in fish to demonstrate the maximum level at which the new feed ingredient can replace the traditional ingredient must do so without seriously affecting development, maturation and net performance.
Third, contamination of fish tissues with organic and inorganic contaminants has been a pervasive environment and public health issue (Hixson, 2014). From a human health perspective, concerns regarding relatively high levels of Persistent Organic Pollutants (POPs) and inorganic contaminants (e.g., heavy metals) in farmed fish have raised questions to consumers regarding health risks. Although the accumulation of environmental contaminants in fish may come from different sources (e.g., polluted water in the pond), a major source of the contaminants in aquaculture is the feed. For the manufacturers, it is essential to test and strictly control levels of environmental contaminants in a feed ingredient, in particular when it is intended to use in aquaculture (e.g., fish oils and fish meals). In a safety assessment, it is often required to ensure that the feed ingredient would not introduce environmental contaminants into the fish diets because even small amounts of contaminants could accumulate in fish flesh and result in health concerns for human consumption. Therefore, residue studies are often required to show the residual concentrations of ingredients (including contaminant residues) that may be present in the tissue of fish are safe for human consumption.
The importance of regulating feed and feed safety in aquaculture has been recognized all over the world. Before launching your product in the US market, think about the stability and the intended use level, as well as environmental contaminant residues in the feed ingredients. The FDA’s final rule for GRAS poses special emphasis on the safety for target animal as well as the safety of animal product for human consumption. The manufacturer must show that the use of new feed ingredient in aquaculture is safe, reasonable, and within acceptable limits. For more information, consult the references provided below or contact Burdock Group.
 AAFCO is a private organization consisting of feed control officials from the various US states whose objective is to harmonize state regulations among the various states. However, AAFCO decisions are not a substitute for federal regulations and only have the power of regulations in those states adopting the AAFCO ingredient definition; further, adoption is not universal among the various states.
FAO, 2016 The state of world fisheries and aquaculture 2016. http://www.fao.org/3/a-i5555e.pdf (site visited February 28, 2016)
FDA, 2016. Final Rule for Substance Generally Recognized as Safe. https://www.federalregister.gov/documents/2016/08/17/2016-19164/substances-generally-recognized-as-safe (site visited February 28, 2016)
Hixson, S.M., 2014. Fish nutrition and current issues in aquaculture: the balance in providing safe and nutritious seafood, in an environmentally sustainable manner. Journal of Aquaculture Research & Development, 5(3), 1.
Marine Harvest, 2016. Salmon Farming Industry Handbook 2016. 1-94.