Dietary supplementation of Eucalyptus leaves enhances eggshell quality and immune response in two varieties of Japanese quails under tropical condition.

The effect of dietary supplementation of Eucalyptus leaves (EL) powder on productive performance and immune response in 2 varieties of Japanese quail was investigated. A total of 180 twelve-week-old laying Japanese quails from 2 color varieties (gray and white) were randomly assigned and distributed according to a completely randomized design in a 3 × 2 factorial arrangement (dietary treatment × variety) forming 6 subgroups (30 each). EL were mixed with the diet in 3 levels (0, 0.1, and 0.2%). Each hen was individually housed in a wire cage of laying batteries and kept in an open house under hot environmental temperature. Productive traits were determined for an experimental period of 6 wk. Egg quality, carcass traits, blood parameters, and immune response were also determined. The results indicated that the productive traits were not significantly affected by EL supplementation. Shell quality and broken eggs significantly improved in quails fed a diet containing EL compared with those in the control. The quails fed a diet supplemented with 0.1% EL exhibited significantly higher cellular mediated and humoral immune responses than those in the other treatment groups. Glutathione peroxidase activity tended to be significantly increased by the dietary administration of EL at the level of 0.2%. Concerning quail varieties, it could be noticed that the gray quails exhibited higher productive performance, shell quality, and cellular immunity than the white counterparts. It could be concluded that supplementing a diet with 0.1 EL as a natural feed additive greatly enhances eggshell quality and immunocompetence and reduces number of broken eggs of Japanese quails raised under high environmental temperature.