The relationship between guanidino acetic acid and dietary metabolizable energy level on broiler's performance

The aim of this work was to investigate the effects of 2 levels of guanidino acetic acid (GAA) in a commercial form (CreAMINO™ (CreAM)) (with vs. without), and 4 levels of metabolizable energy (ME) (75, 50 and 25 kcal/kg less than the control) on performance and carcass characteristics of broiler chickens. The eight dietary regiments were tested for 3 periods: starter (0-10 d), grower (11-22 d) and finisher (23-35 d) by utilizing a total of 200 male Ross 308 broiler chickens in a factorial arrangements of treatments (2×4), in which each experimental diet was fed to 5 replicate pens. The results revealed a positive effect for CreAM supplementation on feed conversion ratio 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 CreAM supplementation compared to unsupplemented group. During the grower period, a significant difference in FCR was observed due to ME level; birds converted feed more efficiently, as the level of dietary energy increased in a linear trend (P<0.01). When examining the cumulative period of the trial (0 to 35 days of age), two-way interactions were significant for FI and BWG. Birds receiving the control level of energy, 75 or 50 kcal/kg lower ME than the control, consumed less feed, when these diets were supplemented with CreAM. Birds, which received (25 kcal/kg) lower ME or the control energy levels, gained more weight, when these diets were supplemented with CreAM. In summary, guanidino acetic acid (GAA) in a commercial form (CreAMINO™), which was used in this trial, improved feed conversion ratio of broilers on each period, as well as for the cumulative period. On the other hand, ME level affected FCR but not in a linear trend, and the improvement, which was due to CreAM, depended on the ME level. It is recommended to lower the ME level by 50 kcal/kg and supplement diets with CreAM.