ARS | Publication request: Apparent digestibility of macro-nutrients and phosphorus in plant-derived ingredients for Atlantic salmon, Salmo salar and Arctic charr, Salvelinus alpinus

Submitted to: Aquaculture Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 30, 2011
Publication Date: N/A

Interpretive Summary: Worldwide fishmeal production had reached a maximum sustained level while demand has been increasing. Alternative protein sources for aquafeeds from more environmentally friendly sources, such are waste products from other industries (microalgae from carbon capture projects), need to be found. Scientists at the National Cold Water Marine Aquaculture Center in Franklin, ME evaluated the digestibility of sun dried algae, barley protein concentrate, a bacterial fermentation product, corn gluten meal, canola protein concentrate, soybean meal and soy protein concentrate with Atlantic salmon and Arctic charr. Barley protein concentrate and corn gluten meal had high digestibility in both species and appear to be good candidates as alternative protein sources for salmon and charr. Algae digestibility Algae had the highest organic matter digestibility value for arctic charr and shows some promise as a feed ingredient.

Technical Abstract: The inclusion of alternative protein sources in aquafeed needs to be increased in order to reduce reliance on fishmeal and to enhance salmonid culture sustainability. Many studies have examined terrestrial plant meals and protein concentrates as alternative sources of protein. Recently the focus has turned to aquatic protists and plants as well as waste products from other industries, such as breweries. Atlantic salmon, Salmo salar, and Arctic charr, Salvelinus alpinus, were fed canola meal, soybean meal, corn gluten meal, soy protein concentrate, barley protein concentrate, and solar dried algae. The fish were then manually stripped and the fecal material collected and dried. Protein, ash, and dry matter were analyzed to determine digestibility of the diets. The barley protein concentrate had the highest apparent protein digestibility values for both species (96.3% for Atlantic salmon and 85.1% for arctic charr), followed by corn gluten meal. Algae had the highest organic matter digestibility value for arctic charr (80.1%) while corn gluten meal had the highest organic matter digestibility value for Atlantic salmon (88.4%). Both corn gluten and barley protein concentrate appear good candidates as alternative protein sources and feeding trials with both species.