Creatine: A valuable supplement in aquafeeds?

Abstract

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.

Dietary glycine supplementation enhances syntheses of creatine and glutathione by tissues of hybrid striped bass (Morone saxatilis ♀ × Morone chrysops ♂) fed soybean meal-based diets

“…In an aqueous environment, fish swim almost constantly, which requires a relatively large amount of energy for muscle movement. The synthesis of creatine from glycine in the skeletal muscle of fish may promote more efficient coupling with local energy metabolism for physiological functions (e.g., constant swimming [ 32 ]) when compared with terrestrial mammals and birds, because guanidinoacetate is formed and further converted into creatine in the same muscle fiber. Because activities of creatine-synthesizing enzymes in HSB were upregulated by the dietary intake of glycine, it is crucial that diets must provide sufficient glycine to support creatine synthesis in fish.…”

“…This ensures the maintenance of whole-body homeostasis that is essential for life in animals including fish. Furthermore, by serving as a component of a major energy buffer system, creatine is crucial for supporting fish-specific burst swimming [ 32 ]. Thus, compared with terrestrial farmed animals, creatine may play a more important role in the growth and survival of fish.…”

Impact of the rearing environment on the metabolism of shrimps and tracing the origins and species of shrimps using specific metabolites

“…Creatine improves the circulation of adenosine triphosphate, which contributes to the supply of energy to the brain and muscles. 17 It has been found that adding creatine to plant feed can improve growth performance and promote growth. [18][19][20] In solutions at relatively low pH and high temperature, creatine is rapidly degraded to creatinine, whereas in the alimentary tract of aquatic products, degradation is greatly reduced or stopped.…”

Methionine: An Indispensable Amino Acid in Cellular Metabolism and Health of Atlantic Salmon

“…Creatine is synthetized in two steps, catalyzed by L-arginine glycine amidinotransferase and guanidinoacetate N-methyltransferase in kidney and liver, respectively [36]. Carnitine is synthetized from peptide bound trimethyllysine, that after being hydrolyzed, are transformed to butyrobetaine and transported to the liver for hydroxylation to carnitine [16].…”