تأثیر فیتاز میکروبی بر عملکرد، کیفیت لاشه و محتوی فسفر و کلسیم استخوان درشت نی جوجه های گوشتی

A 2×2×2 factorial arrangement with control group was conducted to study the effect of different levels of microbial phytase, metabolizable energy and available phosphorus on performance, carcass characteristics and phosphorus and calcium content of tibia in broiler chicks. In this experiment, 1260 Ross 308 male broiler chicks allocated to 9 treatments in a factorial arrangement, with 2 levels of microbial phytase (0 and 500 FTU), 2 levels of metabolizable energy (recommended level and 80 kcal lower than recommended levels), 2 levels of available phosphorus (50 and 75% of recommended levels) with control group (without enzyme and recommended level of available phosphorus), with 4 replications and 35 chicks in each replicate in a completely randomized design (CRD). Use of microbial phytase had significant effect on feed intake, body weight gain in whole period of the experiment (P<0.05). Differences of energy levels had significant effect on feed intake, body weight gain and feed conversion ratio (P<0.05). There were significant differences between treatments for available phosphorus levels for feed intake (3299.5 Vs. 3714.4 g), body weight gain (1531.5 Vs. 1974.6 g), feed conversion ratio (2.17 Vs. 1.91), breast (33.02 Vs. 33.69) and thigh (35.4 Vs. 36.3) percentage, tibia ash (41.69 Vs. 43.66%) phosphorus (7.96 Vs. 8.35%) and calcium (14.65 Vs. 15.81%) content of tibia (P<0.05). Interaction of energy and phosphorus was significant on feed intake, body weight gain, feed conversion ratio and phosphorus percentage of tibia (P<0.05). Results of this experiment showed that use of 500 FTU microbial phytase, with 80 kcal/kg ME lower than recommended levels and 75% recommended available phosphorus level had the best result on performance in broiler chicks.