An investigation by the Agronomy School of University of Buenos Aires (FAUBA) shows that use of enzymes in fish feed improves the efficiency of nitrogen and phosphorus retention in fish, thereby reducing the discharge of these nutrients to the aquatic environment.

As the level of vegetable protein increases in fish feed, there is increasing concern about anti-nutritional factors such as phytate or phytic acid, a form of phosphorus that is not bioavailable to the fish, adversely affecting growth potential and also increasing its discharge into the aquatic environment.

This issue prompted researchers from FAUBA to develop nutritional strategies using environmentally-friendly functional diets.

\"Our strategy from the nutritional point of view is to find a way to release the native phosphorus that is naturally present in seeds, using enzyme additives and inducing changes in the fish gastrointestinal environment, which makes it possible to increase the absorption and retention of nutrients,\" said Dr. Gabriel Morales, Professor of Aquaculture in FAUBA and researcher at CONICET.

For testing, the team uses a digestive modelling system in vitro that makes it possible to more closely observe the specific enzyme-substrate interactions.

\"This evaluation system is complemented with in vivo trials developed on a pilot scale in fish tanks installed in college. Subsequently, we test optimized diets under production conditions in trout fattening cages installed in the reservoir Alicurá, province of Neuquen,\" explains the researcher.

According to Dr. Morales, the use of enzymatic additives, such as the phytase, in fish feed has a double positive effect. On the one hand, it significantly improves the use of native phosphorus reserves that is present in the seeds, increasing the bioavailability of the nutrient and significantly reducing its discharge into waterways. On the other hand, the enzyme promotes the breakdown of phytate-protein complexes, also naturally present in plant ingredients, which is also reflected in increased bioavailability, higher protein retention in fish and lower discharge of the nutrient into the environment.

Source: FIS.com. Read the full article here.