Creatine in Animal Feeds – 10 Key Facts
Guanidinoacetic acid (GAA) as a source of creatine
1. Creatine is a naturally occurring component in the body of animals and is a critical component in energy metabolism.
2. In contrast to other nutrients, creatine is stored in the muscle and directly reloads ATP for energy supply to the muscle. This is particularly important during periods of high energy demand and prevents the formation of reactive oxygen substances which have a negative effect on performance.
3. Therefore, creatine is of primary importance in places with high energy need, such as skeletal muscle, heart, brain, sperm and immune cells.
4. Despite its importance, it is estimated that only 66% of the daily creatine requirement can be synthesised by the animal while the remainder is required from the diet.
5. While creatine is a natural constituent in meat or fish, creatine does not readily withstand heat treatment during rendering and therefore may be lacking in conventional animal diets. In vegetarian rations, creatine supply is further reduced, and this deficit of creatine may reduce performance accordingly.
6. Guanidinoacetic acid (GAA) is the direct endogenous precursor of creatine in all vertebrates. The body can produce GAA from the amino acids, glycine and arginine (figure 1.) or it can be provided via feed (Creamino® is what we know).
7. Creatine is produced from GAA acquiring a methyl group from the transmethylation cycle via S-Adenosyl Methionine (SAM), (Figure 1.).
8. In muscle, creatinine is formed from creatine by an irreversible non-enzymatic dehydration and loss of phosphate. This constant loss of creatine is proportional to muscle mass and must be replaced by resynthesis of creatine. Without constant replacement of creatine, muscle mass is reduced.
9. It has been estimated that creatine synthesis is responsible for 33% of the body’s demand for methyl groups (from betaine, choline or methionine).
10. Therefore there is a direct link to adequate methyl donors (betaine is the best source) supply and creatine production.