Abstract In this study, the growth performance, carcass yield, relative organ weight, and thigh meat quality of quail fed with diets containing different amounts of nisin as an active ingredient were investigated. A total of 400 one-day-old Japanese quail chicks were used. The quail were divided into 4 groups with five replicates and were fed with diets without (control) or with nisin (150, 300, and 500Â mg/kg). The study lasted 35 d. At the end of the experiment, a total of 80 quail, 10 males and 10 females of each group, were randomly weighed and slaughtered. After slaughtering, carcass yield, relative liver, heart, gizzard, and proventriculus weights were recorded. Stress factors (Malondialdehyde (MDA), catalase (CAT), total antioxidant status (TAS), the total of oxidant status (TOS), and oxidative stress index (OSI)) were analysed in thigh meat. Increasing levels of nisin did not affect the growth performance of quail (PÂ >Â 0.05). In terms of slaughter weight, the slaughter weight of both males and females differed among the groups (PÂ <Â 0.05). While the highest value in males was observed in the control group, the highest value in females was observed in the N150 group. Only the relative liver weights of males and the relative proventriculus weights of females were statistically different (PÂ <Â 0.01) between treatments. With increasing nisin level, the weight of the liver increased in the males and the weight of the proventriculus in the females. The addition of nisin decreased MDA and OSI values in both males and females, as compared to the control group. Furthermore, CAT and TAS values were found to be significantly higher in the nisin supplemented group than in the control group. As a result, it is concluded that adding nisin to quail feed positively affects TAS, TOS, MDA and CAT values of thigh meat and can prevent the adverse effects that may occur due to stress.