Comparison of Different Levels of Vitamin Premix on Meat Lipid Oxidation in Floor and Battery Cage Broiler Raising Systems

A total of 1260 male broiler chicks (Ross 308) were allocated to 7 treatment groups (different levels and access time to vitamin premix (VP)) at 29 to 42 days of age, in floor system (Experiment 1) and battery cage system (Experiment 2). The oxidative stability was evaluated by thiobarbituric acid reactive substances (TBARS) on the thigh yield that were storage for 180 days in -20˚C. Results of experiment 1 showed that VP reduction and withdrawal from 29 d of age did not impair body weight, feed intake and feed conversion ratio during the final period of treatments (29-42d).Results of experiment 2 showed that there were no significant differences in the birds’ performance with reduction or withdrawal of VP from diets in 29-35 days among the experimental groups, but in 36-42 days of age, the performance of the group of birds fed with diet without VP (T1) was significantly lower than other groups. The results of experiment 2 showed that the performance of birds fed with diet without VP was significantly lower than other treatments in 36-42 days of age. The results of TBARS values in experiment 1 for thigh meat samples of birds slaughtered at 42 days of age showed that TBARS values of treatments without VP were significantly higher than other treatments. However in experiment 2, TBARS values of treatments without VP and with 33% VP were significantly higher than other treatments for birds slaughtered at 42 days of age. Finally, the results of this study demonstrate firstly that it is not possible to withdraw but it can be possible to reduce VP in finisher broiler's diets without negative effects on performance and meat quality during the time of freezing in both methods of rearing. Secondly, it is possible to reduce the VP levels in diet of broilers reared in floor system more than battery cage system