The effects of increase in threonine to lysine ratio on performance,blood parameters and humoral immune responses of male broiler chickens challenged with salmonella [Salmonella’ya maruz kalan erkek broyler piliçlerde threonine-lysine oranındaki artışın performans,kan parametreleri ve humoral ımmun tepki üzerine etkileri]

The aim of this study was to assess the effect of threonine to lysine (thr/lys) ideal ratio for optimum performance,blood parameters and immunity of broiler chicks. supplemental threonine (equal or 25% more than breed’s threonine/lysine ratio requirement) was added to a control,threonine deficient and high crude fiber diet,then fed to 288 one-day-old male ross 308 broiler chicks (three treatments and eight replications per treatment). on day 11 and 21 of age,infectious bursal disease virus and infectious bronchitis virus vaccines were orally administered individually,respectively. then,21 days after each administration,blood antibody titers against viruses were measured. on day 32 of age,four birds in each treatment group were infected orally with equal numbers of salmonella paratyphi a (5×104 cfu/bird). as a result of this study,challenging with salmonella led to increase in mortality rate and increase in thr/lys ratio could not decrease it. increase in thr/lys ratio decreased feed intake and weight gain of ensemble challenged and non-challenged groups,however improved feed conversion ratio of challenged group in finisher period. feed consumption cost increased by salmonellosis and increase in thr/lys ratio could not improve salmonellosis based economic loss. salmonellosis increased serum urea,uric acid and ast and decreased serum glucose and cholesterol and increase in thr/lys ratio did not alleviate triglyceride. increase in thr/lys ratio improved non-significantly humoral immune response in the challenged and non-challenged groups. these findings indicate that higher thr/lys ratio in infected birds improved production performance,however could not be an economical lucrative medicative agent. © 2016,veteriner fakultesi dergisi. all rights reserved.