Effects of supranutritional selenium supplementation during different trimesters of pregnancy on humoral immunity in beef cattle at parturition

Authors: HALL, JEAN - Oregon State University; BOBE, GERD - Oregon State University; VORACHEK, WILLIAM - Oregon State University; KLOPFENSTEIN, JOSEPH - Oregon State University; THOMPSON, IAN - Oregon State University; ZURITA CRUZ, CINDY - Oregon State University; DOLAN, BRIAN - Oregon State University; JIN, LING - Oregon State University; Davis, Thomas

Submitted to: Biological Trace Element Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2024
Publication Date: 12/20/2024
Citation: Hall, J.A., Bobe, G., Vorachek, W.R., Klopfenstein, J.J., Thompson, I.O., Zurita Cruz, C.L., Dolan, B.P., Jin, L., Davis, T.Z. 2024. Effects of supranutritional selenium supplementation during different trimesters of pregnancy on humoral immunity in beef cattle at parturition. Biological Trace Element Research. 203:3709-3723. https://doi.org/10.1007/s12011-024-04457-1.
DOI: https://doi.org/10.1007/s12011-024-04457-1

Interpretive Summary: For several decades, selenium (Se) has been recognized as an essential trace element for cattle health. In the northwest region of the United States the concentrations of Se in soils is very low, and thus, forages grown on these soils have insufficient So to maintain optimum health and immune function in cattle consuming them. Because of the high prevalence of Se deficiency in livestock in the US (cattle, sheep, goats, horses, and swine), the FDA established safe and efficacious recommendations for Se supplementation. The purpose of this research was to determine the time in gestation that would be most effective to dose Se to increase humoral immunity. We have shown in this report that supranutritional Se-yeast supplementation of pregnant cows during the second half of gestation improves humoral immune status, specifically virus neutralization titers for bovine respiratory syncytial virus, as well as complement-mediated bacterial killing in cows at parturition. Knowing how timing of supranutritional Se supplementation during pregnancy best supports humoral immunity at parturition may help prevent diseases that are prevalent during the periparturient period, such as clinical mastitis. This information may also influence decision making for guidelines on Se supplementation by the FDA.

Technical Abstract: Background: Selenium (Se) is an essential micronutrient required by all mammals. Supranutritional Se supplementation may improve immune responses in beef cattle. Immunity is compromised in beef cattle during the periparturient period. Objective: To determine the best time during pregnancy to supplement beef cows with Se to optimize humoral immunity at parturition. Animals: Multiparous cattle (n=80), black Angus and Angus cross, were used in the study. Procedures: All cows had ad libitum access to a mineral supplement containing 120 mg/kg Se (US UDA regulations) from Na selenite. In addition, all cows except controls (CTR) received Se supplementation of 105 mg Se/week from Se-yeast boluses administered once weekly during their specific treatment trimester (TR1, TR2, or TR3) for 13 weeks. This dosage was supranutritional equaling five times the upper range of US FDA Se administration regulations. Blood was collected at parturition from all cows. Laboratory analyses studied to assess humoral immunity included measuring IBR, BVD types 1 and 2, PI3, and BRSV serum neutralization titers post vaccination, assessing total IgM and antigen-specific IgM concentrations, and determining complement-mediated bacterial killing percentages. Results: Supranutritional Se-yeast supplementation increased whole blood (WB) Se concentrations regardless of trimester of supplementation (all P < 0.0001). Supplementation during TR2 and TR3 was more effective in increasing WB-Se concentrations at parturition than during TR1 or CTR (all P < 0.0001). TR2 (but not TR1; TR3 was not assessed) cows had higher serum neutralization titers for BRSV than CRT cows (P = 0.03). Total serum and Vibrio coralliilyticus specific IgM concentrations were highly correlated (r = 0.78; P < 0.0001). Compared with CTR cows, TR1, TR2, and TR3 cows had similar total IgM concentrations (all P = 0.19) and similar Vibrio coralliilyticus specific IgM concentrations (all P = 0.47). Complement-mediated bacterial killing percentages were greater in TR2 and TR3 cows (> 99.6%) compared with TR1 (93.9%) and CTR (89.3%) cows. Se-TR groups had higher killing percentages than CTR cows (all P < 0.05%). Conclusions and Clinical Relevance: Supranutritional Se-yeast supplementation of pregnant cows during TR2 and TR3 is associated with higher serum neutralization titers for some viral antigens, as well as enhanced complement-mediated bacterial killing in cows at parturition. These findings suggest that Se supplementation during later trimesters of pregnancy may help combat infectious disease challenges during the periparturient period in beef cattle.