GAA and creatine in aquafeeds
Creatine is an amino acid derivate commonly found in vertebrate muscle tissue. Creatine facilitates the recycling of adenosine triphosphate and thus contributes to the energy supply of the muscles as well as the brain. Creatine is used as a supplement for several reasons and its effects in humans, particularly in sports medicine, have been studied excessively. Also, creatine supplementation has been studied for its functions and benefits in terrestrial farm animals. Up to date, little is known about the use of creatine as a supplement in fish nutrition. Yet, due to its many physiological functions, creatine may serve as a valuable supplement in aquafeeds of farmed aquaculture species. Indeed, creatine plays a pivotal role in the fish’s muscle and may help to enhance performance of fish reared in aquaculture systems. With regard to swimming exercise, creatine may even amplify its metabolic effects. Upon supplementation, creatine stimulates muscle growth increasing body mass and it has the potential to improve feed utilisation particularly of plant-based diets. Also, creatine plays a part in osmoregulation when fish adapt to changes in salinity. Furthermore, it may improve product quality upon slaughter. Here, we compile what is known about the many functions of creatine as well as its physiological effects in fish in comparison to mammals. We also highlight its potential beneficial effects as a supplement in aquaculture and infer why creatine can help increase the sustainability of fish feeds.