This experiment was conducted to study the effects of guanidinoacetic acid(GAA) supplementation on growth performance,haematological indice,organ indices,tissue homocysteine contents and histomorphology,and to systematically evaluate the tolerance of Arbor Acres(AA) broilers to GAA.A total of 540 oneday-old AA male broilers were randomly divided into five groups with six replicates and eighteen broilers per replicate.Broilers were fed the same basal diet supplemented with 0(control),800,1 600,4 000 and8 000...