Phytase superdosing reduces anaemia and improves fish performance

During the third International Phytate Summit, Dr Eric Peatman from Auburn University revealed impressive results from catfish studies using high levels of phytase. Speaking about the results he said that they saw benefits with disease management that were unexpected.

Giving an overview of the US catfish industry, Dr Peatman described it as a ‘posterchild’ for where aquaculture is going in terms of diets without fishmeal.

With the use of fishmeal in aquaculture diets reducing, many producers are turning to more plant-based protein sources. These plant-based materials have an impact on the level of phytate in the diet and therefore part of the transition process involves addressing with enzymes some of the indigestible portions of the diet.

Whilst phytase in aquaculture diets isn’t new, high levels of phytase haven’t really been tried before. Dr Peatman explained how they first approached superdosing by looking at its health effects and minerals effects, rather than the traditional phosphorous release. Feed-related anaemia is increasingly prevalent in the US catfish industry and it is believed the reason for this is related to phytate’s ability to bind with iron in the diet and make it unavailable to the fish.

Dr Peatman explained how the results of the studies showed an impressive 90% increase in iron in the liver of the phytase-treated fish, which led to reduced anaemia and improved fish performance.

The International Phytate Summit, which took place in Miami in November 2016, brought together experts in animal nutrition to further our knowledge and understanding of phytate and identify advances in diet formulation. Dr Peatman was one of two aqua experts presenting at the summit; in addition Dr Gabriel Morales from the University of Buenos Aires explained how phytase superdosing can reduce the discharge of phosphorous into the water by 50%.