Are processed animal by-products a sustainable source of fish feeds?
AQUASOJA identified several agri-food by-products as potential fishmeal and fish oil replacements to be used by the aquafeed industry. Results will be presented at Aquaculture Europe 2019.
The agri-food industry generates large amounts of by-products that, after proper processing, can become valid fishmeal and fish oil substitutes. The need for locally-available, affordable, sustainable and nutritious ingredients for aquafeeds derives from the low availability and high price of fishmeal and fish oil.
A research conducted in European seabass by Soja de Portugal, CIIMAR and the University of Porto evaluated several agri-food by-products as potential fishmeal and fish oil replacements to be used by the aquafeed industry.
Researchers found that wheat germ, fish by-product peptides, β-lactoglobulin, poultry by-product meal, steam hydrolyzed feather meal and enzymatically hydrolyzed feather meal were protein sources well-digested by European seabass.
Replacing up to 76% of fishmeal with steam hydrolyzed feather meal did not negatively affect growth performance, nutrient gain, immune status and muscle EPA and DHA levels. Its inclusion improved the phosphorus apparent digestibility coefficient, significantly decreasing its emissions into the environment.
Replacing fish oil without impairing feed intake, growth performance and nutrient utilization was possible up to 100% when using poultry fat or up to 75% when using the poultry fat and mammal fat mix, indicating that poultry fat would be a better alternative lipid source than mammal fats in seabass diets. With up to 75% of fish oil being replaced by either poultry fat or the poultry fat and mammal fat mix, seabass muscle still provided the recommended levels of EPA and DHA for human consumption and showed a potential to improve the consumer’s coronary heart health.
Researchers said that using these locally generated by-products as aquafeed feedstuffs, aquaculture sustainability can be increased by reducing the use of fishmeal and fish oil. They will also contribute to a functional circular economy by reintroducing such by-products into valued production chains.
For more details download the thesis Processed animal by-products as sustainable ingredients in diets for European seabass (Dicentrarchus labrax) by Inés Campos.
Some of these findings will be presented on October 9 at Aquaculture Europe 2019 in the session PS17 Nutrition: Animal ingredients in aquafeed.