The effect of low-glucosinolate rapeseed meal in diets with multi-enzyme supplement on performance and protein digestibility in broiler chicks M. Toghyani 1,3 , A. Mohammadsalehi 1 , A. Gheisari 2 and S.A. Tabeidian 1 1 Department of Animal Science, Islamic Azad University, Khorasgan (Isfahan) Branch 81595-158 Isfahan, Iran 2 Department of Animal Science, Isfahan Agricultural Research Centre 81785-199 Isfahan, Iran (Received 24 July 2008; revised version 19 November 2008; accepted 20 March 2009) ABSTRACT Three hundred and eighty-four day-old Ross broiler chicks were used in a completely randomized experimental design with 4×2 factorial arrangements using four rapeseed meal (RSM) levels with and without a multi-enzyme preparation. RSM levels included: A: control (without RSM); B: 5, 10 and 15%; C: 10, 15 and 20%; D: 15, 20 and 25% RSM in starter, grower and finisher periods, respectively. Body weight gain and feed conversion ratio in treatments B and C were similar to controls, but in treatment D, weight gain decreased and FCR increased (P<0.05). Feed intake of broilers was not affected by different levels of RSM (P>0.05). Enzyme supplementation had no significant effect (P>0.05) on growth performance but resulted in a significant increase in ileal digestibility of protein (P<0.05). Feeding high levels of RSM (Treatment D) significantly increased liver and gizzard weights and decreased abdominal fat (P<0.05). KEY WORDS: broiler, rapeseed meal, enzyme, performance, protein digestibility 3 Corresponding author: e-mail: toghiani@hotmail.com Journal of Animal and Feed Sciences, 18, 2009, 313–321