Protective Effect of Vitamin E on laying performance, antioxidant capacity, and immunity in laying hens challenged...

Vitamin E (VE) has proven to function as potent lipid-soluble antioxidant, a signaling molecule, and a regulator of the immune system. The objective of the study was to assess the protective effect of VE on laying performance, antioxidant capacity, and immunity in laying hens exposed to Salmonella Enteritidis (SE). A total of 80 32-week-old salmonella-free double negative Hy-Line brown laying hens were randomly assigned to 4 treatments with 20 replicates each (1 bird per replicate) according to a 2 × 2 factorial design with 2 VE supplementation levels [0 IU/kg (VE0) vs. 30 IU/kg (VE30)], and 2 challenge treatments [SE vs. physiological saline solution (PS)]. During the last 3 D of week 43 of age, birds were orally challenged with 1.0 mL suspension of 109 cfu/mL S. Enteritidis daily, whereas the birds of negative treatments (VE0) received the same volume of PS. The egg mass of VE0 treatment decreased (P < 0.05) in contrast to VE treatment after challenge. The serum concentrations of interleukins (IL-1β and IL-6) and malondialdehyde (MDA) levels of SE treatments increased (P < 0.05) at week 44 and week 46, respectively. In both VE30 treatments, the decrease (P < 0.05) in birds' mortality was associated with higher IgA, IgG, IgM concentrations at week 44, and higher IgA, IgM concentrations at week 46. There is an interaction (P < 0.05) between SE challenge and VE levels with regard to feed conversion, daily egg mass, and serum MDA, IgA, and IgM levels. It can be concluded that supplemental VE (30 IU/kg) in diets for laying hens may alleviate oxidative and immune stress due to SE challenge.