Table 5.

Effect of guanidinoacetic acid (GAA) supplementation on breast meat creatine–phosphocreatine system of male broilers subjected to chronic cyclic heat stress in the finisher phase at day 26 and 39.¹

Item	Dietary treatment			Pooled SEM	P-value
Supplemental GAA, g/kg	0.0	0.6	1.2		Model	Linear	Quadratic
ATP, μmol/g DM
Day 26	26	27	26	0.6	0.703	0.898	0.410
Day 39	29	29	28	0.5	0.472	0.387	0.388
PCr, μmol/g DM
Day 26	49	55	65	3.0	0.085	0.029	0.748
Day 39	85b	95a,b	99a	2.2	0.016	0.005	0.532
Free Cr, μmol/g DM
Day 26	111	128	129	3.9	0.097	0.056	0.310
Day 39	45b	57a	61a	1.9	0.001	<0.001	0.245
Total Cr, μmol/g DM
Day 26	160b	183a	194a	3.9	<0.001	<0.001	0.357
Day 39	130b	151a	160a	3.4	<0.001	<0.001	0.274
PCr:ATP
Day 26	1.9	2.1	2.6	0.13	0.080	0.033	0.488
Day 39	3.0b	3.3a,b	3.7a	0.9	0.008	0.002	0.785

^a,bMeans within a row lacking a common superscript letter differ (P <0.05).

Abbreviations: ATP, adenosine triphosphate; Cr, creatine; GAA, guanidinoacetic acid; PCr, phosphocreatine.

¹Broilers were fed a corn–soybean starter diet from day 0 to 10, a grower diet from day 10 to 25, and a finisher diet from day 25 to 39. Values are means of 12 replicate chickens.