Selenium Biofortified Alfalfa Hay Supplemented to Dairy Heifers During the Peripartum Affects the Antioxidant Function of Albumin but Has Little Impact on Metabolic and Immune Function

Abstract

Background: the peripartum is the most critical period in dairy cows with high incidence of diseases due to immune dysfunctions, often paired with systemic inflammation and oxidative stress. Selenium is a trace mineral that plays an important role in anti-oxidative function and immune response. We hypothesize that supplementing dairy cows with a relatively small amount of Se-biofortified hay during the last 40 days of pregnancy and early lactation improves performance, metabolism, oxidative status, and immune response.Methods: ten Jersey and 8 Holstein pregnant dairy heifers were divided into two groups and supplemented with 1 kg/100 kg BW of Se-biofortified (Sel; n=9; 3.2 ppm Se) or non-biofortified (Ctr; n=9; 0.4 ppm Se) alfalfa hay from 40 days prior- to 2 weeks post-partum. Heifers were monitored daily for feed intake, activity, and milk yield, and weekly for BW and BCS. Milk samples were assessed for components and fatty acid profile. Blood samples were collected regularly to assess metabolic, oxidative, and inflammatory biomarkers, and to evaluate leukocytes phagocytosis and differential through flow cytometry.Results: supplementation of Se biofortified hay did not affect feed intake, milk yield, BW, BCS, milk components, and any of the parameters measured on leukocytes but increased the hematocrit. Animal receiving Se biofortified hay had larger concentration of plasma albumin and a tendency for larger blood urea, indicating a possible better liver status, especially post-partum. None of the parameters measured in plasma related to the oxidative status were affected, except the concentration of advanced oxidation protein products that was greater in Sel vs. Ctr. The concentration of advanced oxidation protein products was negatively correlated with parameters related to inflammation but positively associated to plasma albumin suggesting a possible improved anti-oxidative function of circulating albumin by Se-biofortified hay supplementation.Conclusions: feeding Se-biofortified hay during pregnancy in dairy heifers had little effect on metabolic, inflammatory, and oxidative status parameters with no effect on performance or immune response. Supplementation with Se-biofortified hay increased plasma level of albumin, possibly as consequence of improved liver function, promoting the antioxidant role of albumin as indicated by increased AOPP.