Selenium and copper interaction at supra-nutritional level affecting blood parameters including immune response against P. multocida antigen in Murrah buffalo (Bubalus bubalis) calves

Minerals play important role in the diet of an animal. Bio-availability of minerals largely gets affected by absolute as well as the relative amount of each mineral present in the diet of an animal. Copper and selenium are two such an essential elements affect utilization of each other in the gastrointestinal tract. The present study elucidates the utilization of copper and selenium at supra-nutritional levels (higher than nutritional requirements). Male Murrah buffalo (Bubalus bubalis) calves (n = 10, 8-9 months, 111.7 ± 12.55 kg body weight) were divided equally into two groups and fed either a standard (Control) diet or the same diet supplemented with 0.3 ppm selenium (Se) and 10 ppm copper (Cu) (Treatment). Supplementation was made using liquid solutions of two inorganic mineral sources after mixing in the concentrate mixture and study lasts for a period of 80 days. Blood samples were collected just before starting supplementation (designated as 0 day of study) and at day 40 and 80 after starting supplementation. Blood samples were subjected to haematological parameters, plasma minerals and various oxidative stress-related parameters were determined with the cell-mediated and humoral immune response against antigen P. multocida (P52 strain). Supra-nutritional Se with Cu had higher blood monocytes (P < 0.05) and plasma selenium (P < 0.01) levels, while other hematological parameters and plasma minerals (except zinc, which was lower (P = 0.025) at day 80 in the treatment group) remained unaffected. Among markers for oxidative stress in blood, levels of lipid peroxidation were lesser (P < 0.01), at day 80 and overall mean values of the enzyme glutathione peroxidase and catalase were higher (P < 0.05) in the supra-nutritional group against control values. The overall mean activity of other oxidative stress markers including reduced glutathione, ceruloplasmin as well as the concentration of α tocopherol, retinol, and β carotene remained unaffected due to supra-nutritional Se and Cu. Although cell-mediated immune response remained comparable (P > 0.05) between groups, higher (P < 0.05) overall mean antibody titer values, as well as the values at day 80, was reported in supra-nutritional Se + Cu group. The study concluded that supra-nutritional Se with Cu in the ration of growing Murrah buffalo calves was helpful to reduce the oxidative stress and to enhance the humoral immune response. Simultaneously, higher plasma Se level and number of monocytes in blood highlighted the additional role of selenium and copper in a ration of growing buffalo calves as compared to its normal recommended dose.