3 Promising Alternative Feeds for Aquaculture
· Fishmeal and fish oil production cannot sustain the growing aquaculture industry, which is forecasted to grow dramatically over the next 2 decades.
· Advances in plant-based products make for promising alternative feeds.
· Ultimately, based on current science, alternative feed ingredients are going to need to work together to make up a larger percentage of future aquaculture feeds.
In aquaculture, traditionally, you must kill fish to grow fish — but for how much longer? Historically, aquaculture has been tied to fishmeal and fish oil production, but alternative feed ingredients are becoming more popular. A diet that most closely simulates the natural diet for most aquaculture species, fishmeal and fish oil contain an optimal mix of essential nutrients: easily digestible protein and vital nutrients like omega-3 fatty acids. Currently, to make most fishmeal and fish oil, small forage fish like anchovies and sardines are ground up and dried. Fishmeal is then fed to higher-value seafood species like salmon and shrimp. According to Rick Barrows, founder of Aquatic Feed Technologies and USDA feed researcher, this is a major issue for the future of the aquaculture industry: “There is just not enough of the current fish-based ingredients available to match the expansion of aquaculture as the human population grows.”
Fortunately, there are a lot of companies working to address this growing problem by developing alternatives to fishmeal and fish oil. Currently, the top alternative feed ingredients replicate the nutritional profile of traditional fishmeal without compromising growth rates or animal health. However, over the past three decades, levels of fishmeal and fish oil in aquaculture feeds have decreased significantly. In 2000, over 10 ounces of wild fish were caught for every pound of farmed seafood. In 2015, less than 4 ounces of wild fish was caught to grow every pound of farmed seafood. This is largely due to volatile and increasing fishmeal costs; over the past 20 years, fishmeal has seen a 110% price increase.
Additionally, sustainability initiatives backed by government and environmental advocates seek to reduce levels of key fish inputs for the feed industry. Ultimately, at current growth rates, demand for seafood from aquaculture is going to outpace fishmeal production. For this reason, alternative feeds are going to grow as a percentage of feed formulas.
Here are three promising ingredients in aquaculture feeds that may supplement (or even replace) the use of fishmeal:
1. Advanced Plant-Based Products
Plant-based ingredients have long been included in many aquaculture feeds. Advances in digestibility, protein content, and omega-3 levels are driving plant-based products to be a leading alternative to fishmeal. A current leader in plant-based feed ingredients are advanced soy products like fermented soy and soybean protein concentrate (SPC). These products reduce anti-nutritional factors in soy, improving their digestibility. A large portion of fishmeal in aquaculture feeds can be replaced by advanced soy products. Moreover, some companies like startup Midwest Ag Enterprises have seen positive results by entirely replacing fishmeal with advanced soy proteins in shrimp diets.
Not only can advanced soy products replicate many of the nutritional requirements of fish and crustaceans, they can generally be widely sourced and are comparably inexpensive. “We are already using soy successfully in almost all aquaculture diets and expect that we will see this inclusion rate increase, particularly with the use of soy products such as the advanced soy proteins”, writes Lukas Manomaitis, Aquaculture Program Technical Contractor for the U.S. Soybean Export Council.
Other plant-based products show promise to replace fish oil in aquaculture feeds, like developing canola oil rich in omega-3s . Fish oil, the world’s least expensive source of omega-3 fatty acids, is challenged by a new class of plant-based oils. Agricultural giant Cargill is developing a canola oil high in EPA/DHA omega-3 fatty acids. In salmon feeding trials, Cargill reports they were able to completely replace fish oil in feed with oil from their EPA/DHA canola.
Algae is the bottom of the food chain for marine animals, making it a potential natural replacement for fishmeal and fish oil. Algae like seaweed and spirulina (a type of blue-green algae) are an excellent source of amino acids and omega-3 and omega-6 fatty acids. The inclusion of algae in aquaculture feeds has shown significant improvements to growth rates, overall animal health, improved color, and disease resistance in multiple species. Moreover, algae is an excellent feed for juvenile fish and crustaceans.
The current downside of algae is the relative cost of high-quality material. While substituting a large portion of fishmeal by algae is possible and perhaps even beneficial to animal health and growth rates, algae remains only economically viable as a supplement to existing protein sources. Refined spirulina is currently significantly more expensive than fishmeal. Despite the high cost, the inclusion of algae in feeds (even as a small percentage) leads to better animal health and nutrition. For that reason, algae remains one of the best alternative feed ingredients.
3. Insect Protein
Most wild fish and crustaceans eat marine insects as a part of their natural diet. Several insect species have shown promise to become economically viable alternatives to fishmeal. Insect protein sources like cricket meal, mealworm meal, and black soldier fly larvae meal are novel feed ingredients that may augment aquaculture feeds. Current tests have shown their inclusion rate in aquaculture feeds is currently effective up to 30%.
Startups like Enviroflight seek to leverage the most promising insect meal: black soldier fly larvae (BSFL). BSFL is promising because it is a hearty, omnivorous insect that can turn common organic waste into protein. While currently uncompetitive with fishmeal, demand for insect protein is increasing and producers are scaling up production in an attempt to reduce the cost of insect meal.
Feed is the largest input cost for most aquaculture operations. Aquaculture growth is increasing price of fishmeal and fish oil, which is driving demand for other advanced ingredients. Current alternative feed ingredients are complimentary; feeds that include several ingredients are more balanced and reduce the anti-nutritional factors of each separate ingredient and lead to better growth rates and animal health. Currently, vegetable-based sources like soy dominate the fishmeal replacement market. There is room, however, for certain novel ingredients, such as algae- and insect-based feeds to gain a larger share of feed ratios in aquaculture.
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