Short communicationDose of selenium in goat kids and its effect on the antigenic response to Mannheimia haemolytica and oxidative stress

- Selenium supplementation in goat kids improves the humoral immune response to Mannheimia haemolytica.
- Subcutaneous doses of 0.25 mg Se/kg of live weight (LW) or administration of quick-release intraruminal Se boluses (0.46 mg/kg LW) improve the erythrocyte Se concentration.
- Selenium promotes cellular modulated responses in order to improve redox status in goat kids.
- Oxidative stress levels measured by GSH content, CAT activity and MDA show differences during the first 14 days post-dosing with selenium.

Selenium (Se) prevents oxidative damage and stimulates the immune system. Currently, there are no data available evaluating the Se-induced antigenic response to Mannheimia haemolytica and oxidative stress in goat kids. Twenty-one 6-month-old male Alpine Goat kids (22.9 kg) were immunized against M. haemolytica and divided into 3 groups: Basal diet with no additional Se (CG); Se injected subcutaneously at 0.25 mg Se/kg live weight (LW) (SeSG); and Se administered as intraruminal bolus at 0.46 mg Se/kg LW (SeBG). Blood samples were taken from the animals in all groups at 0, 14, 28, 42 and 56 days post-dosing. Erythrocyte Se levels doubled in SeSG during days 14-28 post-dosing (130.6 ng/g Se) as compared to CG. During days 28-42 post-dosing, Se levels decreased (P < 0.05) in SeSG (106.9 ng/g Se) vs. CG and SeBG (86.2 ng/g Se and 81.7 ng/g Se, respectively). Glutathione (GSH) levels decreased in days 0-28 post-dosing (3.7E-4 nmols/mg of total protein) and then, remained stable up to day 56 (5.6E-4 nmols/mg of total protein). Catalase levels in the SeBG and SeSG (79.9 U) were higher (P < 0.05) than in the CG (56.3 U) by day 14 post-dosing. Malondialdehyde (MDA) levels on day 14 post-dosing increased 7-fold in the SeBG (1.28E-3 ng/mg of total protein). IgG levels increased in the groups treated with Se during days 28-42 post-dosing (1.4 nM) vs. the CG (0.10 nM) (P < 0.05). Treatment with Se improved the immunological response to M. haemolytica.