Abstract
This work aimed to investigate the effects on performance and carcass characteristics of broiler chickens of 2 levels of guanidino acetic acid (GAA) in a commercial form (CreAMINO (R)) and 4 levels of metabolisable energy. The eight dietary regimens were tested for starter (0-10 d), grower (11-22 d) and finisher (23-35 d) periods on a total of 200 male ROSS 308 broiler chickens in a factorial arrangements of treatments (2 4), with experimental diet fed to 5 replicate pens with 4 birds each. The results revealed a positive effect for CreAMINO (R) supplementation on feed conversion ratio (FCR) for the starter, grower, finisher and cumulative periods (P<0.05, 0.05, 0.01 and 0.001, respectively); feed conversion was significantly improved in the treatment with CreAMINO (R) supplementation vs unsupplemented group. During the grower period, a significant difference in FCR was observed for metabolisable energy (ME) level (P<0.01). When examining the cumulative period of the trial (0 to 35 days of age), two-way interaction was significant for feed intake and body weight gain. Birds receiving the control level of energy, 75 or 50 kcal/kg lower ME than the control, consumed less feed when supplemented with CreAMINO (R). Birds receiving 25 kcal/kg lower ME or the control energy levels gained more weight when supplemented with CreAMINO (R). In summary, GAA (as CreAMINO) improved FCR of broilers in each period as well as cumulatively, while ME level also affected FCR. CreAMINO (R) supplementatio to reduced-energy diets showed FCR improvements, while the best performance was detected for the diet with 50 kcal/kg lower ME.