Alternative protein sources for the aquaculture industry poised to accelerate By John Bowzer, Ph.D., Research Scientist, Archer Daniels Midland Company (ADM). Aquaculture is one of the fastest growing animal production sectors, and currently contributes more seafood to human consumption than wild-caught fisheries. The growth in the industry, along with the intensification of production practices, has increased the use of commercial aquafeeds for nearly all species. Fish meal has been a staple ingredient in commercial aquafeeds, but concerns over volatile price, stagnant supply, and sustainability of harvested fish are driving research and development of alternative proteins. Those concerns, coupled with an increasing global population and per capita consumption of seafood, highlights a need for alternative proteins to support the continued growth of the aquaculture industry. However, finding suitable alternatives to high-quality fish meal is difficult due to its exceptional palatability, high protein content, favorable amino acid profile, and good digestibility that supports growth performance and health. Advances in feed formulations continue to decrease fish meal inclusion levels in the diets of many species, but these reductions are
offset by increases in overall production and use of commercial aquafeeds in omnivorous species. Even though diets of omnivorous species contain minimal fish meal, total global production of these species is large and therefore requires large volumes of fish meal to support it (Naylor et al. 2009). Aquaculture already consumes the majority of fish meal, which also limits the opportunity to take larger shares from other industries. Cost-effective alternative proteins will need to play a bigger role in feed formulations for the industry to sustain current growth projections, but they must also maintain growth performance and health of the animals.
Alternative proteins Emerging alternative proteins include single-cell proteins (e.g., fungi, yeast, algae, and bacteria), animal byproducts, fishery byproducts, insect meals, and plant proteins. However, antinutritional factors, poor digestibility, unfavorable amino acid profiles, large variations in quality, poor palatability,
limited or irregular availability, government policies, and cost constraints can diminish the inclusion level of these various alternative protein sources. Additionally, tolerance to alternative proteins varies by species and life stage, requiring an assortment of options to suit specific applications. For example, many plant proteins are cost-effective alternatives, but they typically are deficient in some essential amino acids (e.g., lysine and methionine), high in fiber, and contain anti-nutritional factors which affect performance in some species (Ayadi et al. 2012). On the other hand, animal proteins tend to have more desirable amino acid profiles, but large variability in quality and government policies can reduce their inclusion. Fishery byproducts are an attractive alternative, but high ash content along with concerns of a steady supply to support processing plants are major constraints (Naylor et al. 2009). Single -cell proteins have a high protein content and similar amino acid profiles to fish meal, but cost constraints, palatability, and limited