effects of probiotic and organic acids on performance, some blood parameters and serum antibody titer against viral vaccines in broilers

to consider the effect of probiotic and organic acids on performance, carcass characteristics, blood parameters and immune response of broilers, a completely randomized design test was done with four treatments and four replicate for each reatment. two hundred and forty one day-old mixed sex broilers (ross breed) were divided into four treatments with 15 chicks per each replicate (pen). treatments were contain of: 1- basal diet without additive (control); 2- basal diet plus % 0.1 protexin; 3- basal diet plus % 0.3 salkil; 4- basal diet plus % 0.1 protexin and % 0.3 salkil. the diets were fed to broilers at 42 days and water and feed were fed ad-libitum. range of feed intake and gain of each replicate were weighted weekly and took blood in two steps to determine antibody titer from wing vein of birds. the result of this experiment showed during the whole period of experiment, using protexin and salkil had significantly effect on performance and characteristics such as percent of carcass, breast, thigh, gizzard and small intestine. contemporaneously usage of protexin and salkil coused the best feed conversion ratio (fcr) among all experimental diets and made the most effect on the weighting percent of carcass and digestive organs. also among all treatments, diet with protexin had significantly effects on the reduction of cholesterol and triglycerid of serum. percent of heterophyls in birds that had used protexin and salkil diet, had significant reduction, in contrast, percent of lymphocytes were higher in them. the highest antibody titer of newcastle and gambro was in the diet consist of protexin and salkil and the most antibody titer of bronchitis was in protexin diet. as a general it can be resulted that with manipulation of gut microorganisms and creating suitable microbial balance in this organ, we can improve desirably performance and immune response of bird with separately or contemporaneously usage of protexin and salkil.