Three experiments (EXP) were carried on; in two of them the focus was performance and the third consisted in a metabolism study. The first EXP used 384 male Cobb 500 strain chicks and was conducted from one to 20 days of age. The second EXP was conducted with the same birds after all of them were homogenized, from 21 to 34 days, using 256 broilers. The metabolism assay utilized 32 broilers and was carried on from 21 to 34 days. Acidulated soybean soapstock (ASS) and soybean oil (SO) included in four levels (2; 3; 4 and 5%) were compared, forming eight treatments with four replication each, arranged in a 2x4 factorial. Performance, diet coefficient of metabolism of dry matter (CMDM), of crude fat (CMCF) and of gross energy (CMCE) and also the contents of triglycerides and blood serum cholesterol on the 34th day were evaluated. There was no interaction between oil type and inclusion levels for any response. Increasing oil level in the diet higher body weight (P<0.01) and better feed conversion (FC) (P<0.01) were observed. Only in the first performance EXP, but not in the EXP from 21 to 34 days, reduction in feed intake (P<0.01) by adding oil was observed. In the metabolism assay, birds receiving ASS presented better CMDM (P<0.01), related to SO. Increasing in oil level improved CMDM (P<0.01) and CMCF (P<0.01) of the diets. Higher levels of triglycerides were noticed in the blood serum of birds receaving higher levels of oil (P<0.01). The ASS showed RE of 93 and 90% in the performance EXP from 1 to 20 and 21 to 34 days, respectively, based on FC and of 95%, compared to SO, based on regression analysis between oil level added (X) and CMCF (Y), determined in the metabolism assay. ASS is a good energetic source for broiler diets, presenting energetic value a bit lower of the SO.
fat sources; included level; metabolism; performance
