Effects of Bupleurum extract on blood metabolism, antioxidant status and immune function in heat-stressed dairy cows

Abstract This experiment was conducted to evaluate the effects of Bupleurum extract (BE) on blood metabolites, antioxidant status, and immune function in dairy cows under heat stress. Forty lactating Holstein cows were randomly assigned to 1 of 4 treatments. The treatments consisted of 0, 0.25, 0.5, and 1.0 g of BE kg −1 dry matter. Supplementation with BE decreased ( P P >0.05) on blood glucose (GLU), nonesterified fatty acid (NEFA), total triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C). Compared with control cows, cows fed BE had higher ( P P >0.05) on total antioxidant capacity (T-AOC) or malondialdehyde (MDA) levels. The immunoglobulin (Ig) A and G contents increased ( P −1 . Interleukin (IL)-2 and IL-4 levels were higher ( P −1 , and IL-6 was significantly elevated ( P −1 . There were no treatment effects ( P >0.05) on the CD4 + and CD8 + T lymphocyte ratios, CD4 + /CD8 + ratio, or tumor necrosis factor-α (TNF-α) level among the groups. These findings suggest that BE supplementation may improve protein metabolism, in addition to enhancing antioxidant activity and immune function in heat-stressed dairy cows.