Supplemental guanidino acetic acid affects energy metabolism of broilers

The semi-essential nutrient creatine is an important molecule in the cellular energy metabolism for short term energy storage. Energy from surplus adenosine tri-phosphate (ATP) can quickly be overtaken by creatine and vice versa. Supplemental guanidino acetic acid (GAA) is a natural precursor of creatine and might be used as creatine source. Either no (negative control), 0.20, 0.40, or 0.60 g/kg GAA were added to pure vegetable basal starter, grower, and finisher diets and fed to 3120 male broilers (six pens with 130 birds per treatment) for 41 days. GAA supplementation significantly improved feed conversion ratio (0.40 g/kg GAA; p<0.05). At day 41 five birds per pen were slaughtered and breast meat samples were collected for biochemical evaluation. The muscle creatine content gradually increased from 3986 (negative control) to 4560 mg/kg breast meat (0.60 g/kg GAA; p<0.05). In contrast, the muscle GAA content stepwise decreased with increasing GAA supplementation (from 24 to 4 g/kg, p<0.05). One hour post mortem the muscle ATP content was increased up to 0.40 g/kg dietary GAA compared to the control whereas the ADP content was rather unaffected. The muscle AMP and IMP levels gradually declined with increasing dietary GAA up to 0.60 g/kg. Results indicate that supplemental GAA improves the cellular energy metabolism.