ABSTRACT
Eighteen growing lambs averaged 3 months old and 16.92±1.23 kg body weight were used to assess the dose-response of vitamin E and Selenium (Se) injection on growth performance, hemato-biochemical indices, thyroid hormones, immune and antioxidant status. Lambs were randomly allocated into 3 equal groups (6 lambs each). The 1st group served as control and injected with 1.0 ml/head of sterile saline solution (0.9 % NaCl). The 2nd (T1) and the 3rd (T2) groups received vitamin E and Se injection at rate 0.5 ml/head (contained 3.57 IU vitamin E + 0.03 mg Se/head/day) and 1.0 ml/head (contained 7.14 IU vitamin E + 0.06 mg Se/head/day), respectively. The injection solution was administered biweekly and continued for 12 weeks. The results show that lambs received T2 had heavier (P<0.05) final body weight (FBW) than the control and T1. Average daily gain (ADG) was improved (P<0.05) for lambs received T1 and T2 vs. control. There was a significant (P<0.05) increase in FBW and ADG of lambs received T2 compared with those of T1. No significant differences in dry matter intake for lambs of T1 and T2 vs. control, while averages of feed conversion ratio were improved (P<0.05) for lambs received T2 compared to T1 and control. Lambs of T2 had higher (P<0.05) concentration of blood Hb and PCV % than those of T1 and control. The increase (P<0.05) in RBCs count was dose-dependent for lambs received T1 and T2. Leucocytes count and lymphocytes (%) increased (P<0.01) for lambs received T1 and T2 vs. control. Moreover, lambs of T2 had higher (P<0.05) concentrations of serum total protein and globulin than those of T1 and control. Serum cholesterol concentration decreased (P<0.05) for lambs received T1 and T2 vs. control. Also, lambs received T1 and T2 had higher (P<0.05) serum immunoglobulin G concentrations than the control. Serum triiodothyronine (T3) levels and T3:T4 ratio increased (P<0.05) for lambs received T1 and T2 vs. control. In addition, the results showed that serum total antioxidant capacity increased (P<0.01) for lambs received T1 and T2 vs. control. Lambs received T2 had higher (P<0.05) serum superoxide dismutase activity than those of control and T1. There were dose-dependent increases (P<0.05) in serum glutathione peroxidase activity for lambs received T1 and T2 vs. control. No significant differences in neutrophils, eosinophils,basophils, monocytes (%), serum levels of glucose, albumin, AST enzyme and T4 hormone due to injection of vitamin E and Se. These results show that injection of vitamin E and Se could exert dose-dependent beneficial effects on growing lambs which improve their growth performance concomitant with favourable signs for physiological responses, enhancing their immune function and antioxidant status.