Creatine, (CREA) a central constituent in energy metabolism, is obtained from dietary animal protein or de novo synthesis from GAA, explained Joris Michiels of the University of Ghent, Belgium, and co-authors at University College Ghent, Institute for Agricultural and Fisheries Research in Melle, Katholieke Universiteit Leuven and Evonik Degussa GmbH.

In the introduction to the paper published recently in Poultry Science, they proposed a hypothesis that, especially in all–vegetable diets, supplemental CREA or GAA may restore the CREA availability in tissues, and hence, improve performance.

In their study, 768 day–old male Ross 308 broilers were assigned to one of four diets: negative control, all-vegetable corn-soybean-based; negative control supplemented with either 0.6 or 1.2g of GAA per kilogram of feed; and positive control (60, 30, and 30g per kg of fish meal in the starter, grower and finisher diets, respectively).

Each treatment was replicated in six pens of 32 birds each. At the end of the grower period (day 26), two birds per pen were euthanised for metabolic measurements. Four broilers per pen were selected at slaughter age (day 39) to determine carcass characteristics and meat quality.

Compared with the negative control, GAA supplementation resulted in an improved gain:feed ratio (P<0.05) and average daily gain (P<0.05; + 2.7 and + 2.2 per cent for GAA at 0.6 and 1.2g per kg, respectively), throughout the entire period.

Breast meat yield was higher for the GAA diets than the negative control birds (P<0.05; 30.6 versus 29.4 per cent) and was comparable with that of the positive control birds (30.2 per cent).

With regard to meat quality, lower ultimate pH values, higher cooking and press fluid losses, and higher colour L* values were observed for the GAA diets than the negative control diet (P<0.05). These effects were small, however.

In breast meat, the GAA levels were lower in GAA-fed birds than the control birds and CREA levels were higher (P<0.01).

The diets did not affect plasma metabolic traits, except that plasma insulin-like growth factor I concentrations were almost twice as high in animals fed 1.2g per kg of GAA than all other treatments.

GAA included in all-vegetable diets improved animal performance for the whole rearing period and increased breast meat yield, concluded Michiels and co-authors.

Reference

Michiels, J., L. Maertens, J. Buyse, A. Lemme, M. Rademacher, N.A. Dierick and S. De Smet. 2012. Supplementation of guanidinoacetic acid to broiler diets: Effects on performance, carcass characteristics, meat quality, and energy metabolism. Poult. Sci. 91(2):402-412. doi: 10.3382/ps.2011-01585

Further Reading

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March 2012