معصومه توکلی - گروه علوم دامی، واحد رشت، دانشگاه آزاد اسلامی، رشت، ایران
مهرداد بویه - گروه علوم دامی، واحد رشت، دانشگاه آزاد اسلامی، رشت، ایران
علیرضا صیداوی - گروه علوم دامی ، واحد رشت ، دانشگاه آزاد اسلامی رشت، ایران

Description of the subject. Increasing the concentrations of blood glucose lead to decreased appetite and decreased concentration of stimulant in the hunger center of the bird's hypothalamus and consequently decreased feed intake. High intakes of vitamin C may alter blood glucose concentration, although the evdienec is contradictory. Objectives. The aim of this study was to evaluate the effects of three different levels of vitamin C (۰, ۲۰۰ and ۴۰۰ mg/kg DM) on performance, carcass and digestive organ characteristics, blood plasma components, liver enzymes, immune system, and cecal microbial flora of broilers. Method. The study had a completely randomized design with ۳ treatments and ۴ replicates of ۱۰ chickens per pen. The study lasted ۴۲ days and started with ۱۲۰ one-day-old male chickens of commercial Ross ۳۰۸ strain. Tmt measn were compared using Duncan's multiple-range test. Results. Chicks fed a diet containing ۲۰۰ mg/kg vitamin C had the highest feed intake and weight gain as well as the best feed conversion ratio, the lowest cost per kilogram of live body and the best European production factor. The effect of vitamin C was significant on live body weight, featherless weight, full abdomen carcass weight, empty abdomen carcass weight, relative crop weight and relative breast weight (p <۰.۰۵) and the highest increase was related to the level of ۲۰۰ mg/kg vitamin C. On the other hand, the use of different levels of vitamin C on blood parameters and liver enzymes of broilers was not significant (P≥۰.۰۵). In addition, the percentage of neutrophils and lymphocytes was significant (p <۰.۰۵) and the highest percentage of neutrophils was also for using the level of ۲۰۰ mg/kg vitamin C. Comparing the mean results of antibody titers against SRBC did not show a significant difference (P≥۰.۰۵), except for ۳۵ days of age, which was significant (P <۰.۰۵). Numerically, the highest antibody titer was related to the level of ۲۰۰ mg/kg vitamin C. So, based on the results of the present study, the use of ۲۰۰ mg/kg vitamin C to supplement the diet of Ross ۳۰۸ strain broiler chickens is recommended. Conclusions. Although vitamin C was not very effective on blood parameters, it improved the immune system and reduced the fat content of the ventricular area, thereby improving the quality of carcass meat. Therefore, according to the results of this experiment, it is recommended to use ۲۰۰ mg/kg vitamin C in diet as an antioxidant compound and a cheap promoter of growth.

Chick, Ascorbic acid, Immunity, performance