The effect of oral and injectable supplementation of selenium and vitamin E on performance and some blood parameters of growing Sanjabi lambs

Background and objectives: Several studies have been conducted regarding the importance of the availability of various minerals and vitamins for the growth and performance of livestock. Selenium and vitamin E are among the substances that have attracted the attention of researchers. Different dosses, appropriate time of consumption, and method of use are the aria that have been researched. Although the reports presented are not aligned and, in some cases, contradictions are observed. Therefore, in this study, the effect of oral and injectable supplementation of selenium and vitamin E on growth performance and some blood parameters of growing lambs was investigated.

Materials and methods:
Eighteen three-month-old lambs with an average weight of 18.6 ± 2.7 were kept randomly in three groups with six repetitions in individual cages for eight weeks. Experimental treatments included: control group (base diet without supplements), oral group (base diet plus 0.3 mg of selenium in the form of selenomethionine and 50 mg/kg of vitamin E in the form of alpha-tocopherol), injectable group (4 ml injectable supplement; each ml contains 0.5 mg of selenium in the form of sodium selenite and 50 mg of vitamin E in the form of alpha-tocopherol). The lambs were weighed every 15 days and, on the 1st, 30th, and 60th days of the experiment, blood was drawn from the Juglar vein

Results: There was no statistically significant difference between experimental groups in terms of daily feed consumption, final weight gain and feed conversion ratio. Blood concentrations of zinc, copper and iron were not affected by supplementation. Cholesterol, triglyceride, high, low and very low-density lipoprotein concentrations were not affected by the method of supplementation. The number of red blood cells was not affected, but the number of white blood cells in the injection group increased significantly compared to the control group on the 60th day of the experiment (P<0.05). In terms of the activities of alanine aminotransferase, aspartate aminotransferase and superoxide dismutase, no significant difference was observed between the experimental groups, but the activity of glutathione peroxidase on the 30th and 60th days of the experiment and the total antioxidant capacity on the 60h of the experiment in the group receiving oral supplements were more than other experimental groups (P<0.05). Malondialdehyde index decreased in the groups receiving selenium and vitamin E supplements compared to the control group (P<0.05).

Conclusion: The results of this experiment showed that the use of oral supplements of selenium and vitamin E improved the antioxidant capacity of lambs by both oral and injectable methods, and no significant difference was observed between the two methods. However, due to the convenience of the oral method and the reduction of stress caused by the injection and its non-invasive nature, it is recommended to prescribe an oral supplement. ‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬ ‬‬‬‬‬‬‬‬‬‬