An international team of researchers recently concluded a life cycle assessment of current and emerging protein ingredients for aquafeeds in an effort to evaluate the nutritional value, scalability, and environmental performance of each ingredient.
“Our goal was to illuminate potential ways forward for the rapidly growing global aquaculture sector in terms of satisfying multiple objectives related to fish nutrition, profitability, feasibility, and resource and environmental performance,” said Nathan Pelletier, lead author on the study and Endowed Chair in Bio-economy Sustainability Management, Egg Industry Chair in Sustainability at the University of British Columbia - Okaganan.
The study examined a representative subset of aquafeed protein ingredients from different sources, including Peruvian anchoveta meal (a large scale and energy efficient reduction fishery), BC herring byproduct meal (a smaller-scale, less energy efficient fishery), soybean meal and soy protein concentrate from both the United States and Brazil (each with different production conditions and environmental implications), U.S. poultry by-product meal and feather meal (each with different nutritional attributes and energy intensities), krill meal (with unique nutritional attributes and an energy intensive fishery), and black soldier fly meal (an emerging protein source).
Although soy protein concentrate and feather meal have the highest protein levels of the non-fishmeal sources, the study cautions that additional research is needed to identify “semi-essential” nutrients in fishmeal that may need to be replaced or supplemented when utilizing only non-fishmeal proteins.
In addition to nutritional values, production impacts of each ingredient were considered in terms of land use, energy use, and acidifying, eutrophying, and greenhouse gas emissions throughout the supply chain.
The environmental performance profiles of the ingredients vary widely. Overall, U.S. soybean meal and Peruvian anchoveta meal perform quite well across most impact categories relative to the other feed inputs. U.S. soybean meal has the lowest estimated carbon footprint, followed closely by Peruvian anchoveta.
In terms of scalability, the study projected that limited supply and increasing demand will cause fishmeal prices to continue rising beyond 2025, incentivizing the substitution or augmentation of other protein sources. Feather meal and poultry by-products ranked highest in terms of scalability due to the expected expansion of poultry meat production by 1.8% per year to 2050.
The market price of soybean meal, which has remained substantially lower than fishmeal, is also favorable for scalability in higher value aquaculture species, although the varying cost of inputs for growing soybeans is uncertain. Because the majority of soybean meal is used in other animal agriculture, increased use of soy in aquaculture must be supported by either diversion of use from other sectors or through global expansion of production.
Soy protein concentrate plays a small but increasing role in aquaculture feeds, especially for high value carnivorous species. However, its higher price can exclude it from many lower value aquaculture species and make it less favorable for scalability as a general aquafeed ingredient.
The study concluded that it is unlikely that a single protein source will scale up to meet all demand for protein from aquaculture feeds. Access to a multitude of alternative protein sources, coupled with an improved understanding of how to formulate diets to balance tradeoffs between animal nutrition, profit, resource intensity, and environmental impact, will increase the resiliency of the global aquaculture industry.
Dane Klinger, a co-author on the study and Aquaculture Innovation Fellow at Conservation International, cautioned that this analysis should be seen only as a preliminary treatment of this subject area.
“We considered a small subset of commercially important aquaculture species, protein feed inputs, and resource use and emissions of potential concern,” he said.
“On the basis of these considerations, we nonetheless underscore that decision making that seeks to satisfy multiple objectives must necessarily confront multiple trade-offs that span nutritional, economic, and environmental concerns.”
Read the entire study in Environmental Science & Technology
