This research was aimed at evaluating the effects of enzyme and symbiotic inclusion in broilers diets bred in conventional and alternative systems on performance, carcass yield, cuts, abdominal fat and economic return these additives in both breeding systems. 720 one-day old male Cobb chicks were distributed in randomized blocks design according to a 2x3 factorial, two breeding systems: conventional (with growth promoter) and alternative (no growth promoter) and three additives: no additive (NA), symbiotic (SY) and symbiotic + enzyme (SYE), with four replicates of 30 broilers each. At 42 days old, the production factor (PF) was lower in NA broiler chickens (324) as broiler chickens supplemented with SY (334) and SYE (337). Broiler bred in conventional system showed higher PF (338) as broilers bred in alternative system (325). In alternative breeding system, the feed conversion was better in SY broilers (1.77) as SYE (1.82) and NA (1.85) broilers. The SY and SYE use improve the performance of broiler chickens at 42 days old and it doesn’t affect carcass yield, cuts, and abdominal fat, in conventional or alternative system; moreover these additives increase production costs in both systems. Alternative system provide higher economic return, despite of lower production factor.
carcass yield; growth promoter; performance; poultry
