International Research Journal of Applied and Basic Sciences © 2012 Available online at www.irjabs.com ISSN 2251-838X / Vol, 3 (S): 2785-2793 Science Explorer Publications Effects of Guar meal with and without -mannanas enzyme on performance and immune response of broiler chicks Mohammad Akbari Gharaei 1 ; Behrouz Dastar 1 ; Alireza Hesabi Nameghi 2 ; Gholamreza Hashemi Tabar 3 and Mahmoud Shams Shargh 1 1 . Department of Animal Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. 2. Department of Animal Sciences, Agricultural and Natural Resources Research Center of Khorasan, Mashhad, Iran. 3 .Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran. 4. Department of Animal Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. *Correspondence Author email: makbari9@yahoo.com ABSTRACT: This experiment was conducted to study the effects of guar meal (0, 3, 6 and 9 %) and -mannanase enzyme (0 and 0.05 %) on performance, immune response and ileal viscosity in broiler chicks. Ross male broiler chicks (480 birds) allocated to 8 treatments with five replications (12 chicks in each pen) and reared on floor pen for 42 day. Immunity was assessed as antibody production to Infectious Bronchitis Virus (IBV) and Sheep Red Blood Cell (SRBC). On 10 day, chickens were inoculated intramuscular with 0.5 ml of 5 % SRBC. The injection with SRBC was repeated 12 d later. The data were analyzed as 4×2 factorial arrangement in a completely randomized design. Daily weight gain and body weight (42d.) significantly reduced and FCR increased in chicks fed diets containing 9 % guar meal. Feed intake was lower in chicks fed 9 % guar meal than other groups only at starter period. The ileal viscosity increase by elevating amounts of guar meal in chick diets at 21 and 42 day, as well as -manannase enzyme supplementation relatively decrease the ileal viscosity. Antibody titers for primary and secondary responses to SRBC was highest in chicks receiving 3 % guar meal diet and was lowest in chicks receiving 9 % guar meal diet. Humoral immunologic response showed that antibody titer to IBV significantly increased in all chicks receiving guar meal diets. In spite of a trend to improve FCR and bodyweight gain with - mannanase supplementation, feed intake was not affected by enzyme supplementation. The greatest positive effect of enzyme supplementation was related to improve immune responses. The results of this experiment showed that use of guar meal up to 6 % not only have no negative effect on performance but also improve immune response in broiler chicks. The supplementation of - mannanase enzyme to guar meal diets improves performance and immune response in broiler chicks. Keywords: -mannanas, Broiler chicks, Guar meal, Immune response, Viscosity. INTRODUCTION Guar (Cyamopsis tetragonoloba), a drought-tolerant legume, is primary used in the gum industry because its seeds contain high amounts of guar gum. Guar gum is derived from the seeds of guar plant; it is a natural nonionic branched polymer with -D-mannopyranosyl units linked 1–4 with single membered a-D- galactopyranosyl units occurring as side branches. Guar gum has been used in many areas such as thickening agent, ion exchange resin, suspending agent, pharmaceuticals and paper (Wang and Wang, 2009). To produce gum, guar seeds are split, yielding both a high protein germ fraction and a lower protein husk fraction as by- products. These two fractions are usually recombined to create guar meal with a crude protein level of 35 to 47.5 % depending on the relative concentration of the two fractions (Ambegaokar, et al., 1969).