Effects of different sources of Zn on performance and liver enzymes of broiler ‎chicks

A 360 Ross 308 broilers were used in a completely randomized design with 6 treatments and 4 replicates with the objective of comparing the effects of different sources of zinc on growth performance and some liver enzymes. The experimental treatments were: 1) negative control (non-supplemented), 2) positive control with 80mg/kg zinc sulfate, 3) hydroxychloride Zn (80mg/kg), 4) zinc sulfate (60mg/kg) + Zn-Met (20mg/kg), 5) zinc sulfate (40mg/kg) + zinc oxide (40mg/kg) and 6) zinc sulfate (30mg/kg) + zinc oxide (30mg/kg) + Zn-Met (20mg/kg). After 42 days, relative weight of bursa of Fabricius  (except for treatment 4) and thymus (except for treatment 3) were decreased significantly compared with the  negative control group (P<0.05). The hydroxychloride Zn source improved feed intake, compared to positive control group and daily weight gain compared to treatments 1, 2 and 4 (P<0.05). The inclusion of zinc oxide in treatments 5 and 6 increased alkaline phosphatase activity in plasma compared to treatments 3 and 4 (P<0.05). But, there were no differences in plasma AST, ALT, and LDH levels among the zinc different sources. These findings show that hydroxychloride Zn have comparable effects with zinc of inorganic and combination of organic with inorganic sources in broiler chickens.