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.