تاثير سطوح مختلف پروتئين و ترئونين بر عملكرد و فعاليت سيستم ايمني جوجه هاي گوشتي

چكيده انگليسي :

The Effect of Different Protein and Threonine Levels on Performance and Immune Responses of Broiler Chickens Mohammad Ali Abbasi Mohammad4659@yahoo com Date of submission 2012 2 5 Department of Animal Science Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisors A H Samie asamie48@cc iut ac ir A H Mahdavi mahdavi@cc iut ac irAbstractThis study was carried out to evaluate the effects of different levels of crude protein CP and threonine Thr on performance carcass traits humoral immunity and intestinal morphology of broiler chicks A total of 432male broiler chicks Ross 308 were randomly allocated in a factorial arrangement 3 3 based on acompletely randomized design consisting 9 treatments with 4 replicates and 12 birds per replicate treatmentsincluded 3 levels of CP 100 95 and 90 of broiler Ross 308 recommendations and 3 levels of dietary Thr 100 110 and 120 of broiler Ross 308 specifications Chicks recived starter 1 12 days grower 13 24days and finisher 25 42 days diets Weight gain feed intake and feed conversion ratio were determinedover 3 age periods On day 16 all birds were challenged by injection route with a commercial Newcastlevaccine Then on day 28 two birds from each replicate were chosen at random and blood samples werecollected from the brachial vein and antibody titer against Newcastle disease viruse were performed byHemagglutination halter test Also at 23 and 33 days of age two birds from each pen were immunizedintramuscularly into each thigh with 0 5 mL of 7 SRBC Sheep Red Blood Cell suspension to determineprimary and secondary humoral antibody responses Heparinized blood was collected from the birds at 6 dayafter first and 12 day after second immunizations with SRBC to evulate antibody titers against SRBC On day45 two chicks were randomly killed from each replicate to determine the effects of dietary treatments onintestinal cell morphology At the end of experiment two birds from each replicate were slaughtered andcarcass drumsticks breast pancreas abdominal fat as well as lymphoid organs including spleen and bursa offabricius were weighted and expressed as a percentage of live body weight Experimental data were analyzedusing the GLM procedure of SAS software This study showed that the reduction of dietary CP decreasedrelative carcase yield and relative weights of abdominal fat and pancreas However reducing CP up to 10 had no effect on the relative weight of drumsticks and breast but after addition of second level of Thr theseeconomic traits increased significantly PB0 05 Reducing dietary CP decreased primary P 0 16 andsecondary P 0 13 immune responses against SRBC however after addition of 110 of recommended Thr these responses raised P 0 05 Although after reduction of dietary CP level the jejunal villus height cryptdepth and goblet cell numbers decreased significantly but administration of diets with 110 of Thrrequirement could compensate these alterations by enhancing the intestinal absorptive surface area and gobletcell numbers After starting period reduction of dietary CP up to 90 of recommended CP level had nosuppressive effect on broiler growth performance however the best result obtained when diets administratedwith 110 of recommended Thr The present results indicated that reduction of dietary CP up to 10 afterstarting period had no inadvisable effect on growth performance however the best results obtained whendiets supplemented with 110 of recommended Thr Key wordsBroiler chicks Threonine Performance Humoral immunity Mucosal morphology

عباسي، محمدعلي

تاثير سطوح مختلف پروتئين و ترئونين بر عملكرد و فعاليت سيستم ايمني جوجه هاي گوشتي

ايمني همومورال , بافت شناسي مخاط