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Corn distiller’s dried grains as protein source for European catfish

An abundant but underutilized ingredient may be used as a suitable partial replacement to the more expensive traditional grains in European catfish (Silurus glanis) diet. 

Corn distillers’ dried grains with soluble (DDGS), a bioethanol by-product, can replace up to 30 per cent of soybean and wheat in the fish diet without compromising the growth performance and nutrient utilization, said Zsuzsanna J. Sandor et al. in the study conducted in Hungary to evaluate the suitability of DDGS as a protein source for the fish.

Corn DDGS is obtained after fermentation of corn by enzymes and yeast which produces bioethanol as major product. It is a suitable ingredient for fish due to its relatively high level of energy, protein, amino acid, non-phytate phosphorus and yeast protein and fat contents. The composition, however, varies between processing plants and among the grain used.

Two experiments were conducted to evaluate the suitability of corn DDGS as a protein source for European catfish. Limited knowledge on these had previously created “major challenges” for its successful use in aquafeeds.

In the first experiment, in vivo digestibility was assessed to determine apparent digestibility co-efficients for protein, lipid, phosphorus and amino acids available in DDGS. The second experiment involved an eight-week nutritional trial with growth performance, nutrient utilization, feed conversion and diet digestibility.

European catfish has traits that make it popular in Central and Eastern European aquaculture: fast growth, robustness, stress tolerance and high market value. Identifying an alternative and sustainable ingredient to its feed would lead an even better environment. 

“Fish meal was successfully replaced with soybean and rendered animal protein by but replacing the soybean is getting more attention in European feed production. Utilization of agriculture and food industry by products became a current emergent topic,” the authors said.

 Currently, less than two per cent of global DDGS supply is used in aquaculture feeds. Demand for corn DDGS for aquafeed may increase though because of expansion of the aquaculture industry.

 The study, “Potential of corn distiller’s dried grains with solubles (DDGS) in the diet of European catfish (Silurus glanis),” was published in Aquacuture Reports.