Effects of Acremonium terricola culture on performance, milk composition, rumen fermentation and immune functions in dairy cows

The effects of Acremonium terricola culture (ATC) on performance, rumen fermentation and microbiota, and antioxidant and immune functions in dairy cows were investigated in two experiments. In Experiment 1, thirty multiparous Holstein dairy cows were blocked for day in milk, somatic cell counts and milk production and were randomly assigned to 1 of 3 treatments in an 8-week trial: a basal diet plus 0, 15 or 30 g/d ATC. The result of supplementing dairy cows with ATC was a linear increase in the apparent digestibility of dry matter, crude protein, acid detergent fiber and neutral detergent fiber, milk production, 4% fat-corrected milk, energy-corrected milk, feed efficiency, milk fat and lactose yields, and milk fat percentage, but a linear decrease in the milk somatic cell count. In Experiment 2, five late-lactating dairy cows were fed the basal diet from d 1 to 14 (pre-trial period). From d 15 to 35 (trial period), the same cows were fed 30 g/d ATC. Supplementation with ATC was stopped from d 36 to 42 (post-trial period). Feed, rumen and blood samples were collected on d 13, 14, 34, 35, 41 and 42. Compared with the pre- and post-periods, the ruminal pH and molar proportion of butyrate decreased during the trial period. Additionally, the ammonia nitrogen and total volatile fatty acid concentrations as well as the molar proportion of acetate were increased. For most of the rumen bacteria that were measured, the relative expression level increased during the trial period, but that of Fibrobacter succinogenes decreased. Moreover, ATC significantly increased the total antioxidant capacity as well as the activities of glutathione peroxidase and total superoxide dismutase during the trial period. The concentrations of blood glucose and immunoglobulins A, M, and G also increased in the plasma. By contrast, ATC resulted in a significant reduction in the plasma concentrations of aspartate transaminase, non-esterified fatty acids, beta-hydroxybutyric acid, interleukin-1, interleukin-6, tumor necrosis factor-α and malondialdehyde. These results show that feeding ATC can increase performance, improve rumen fermentation, and increase antioxidant and immune functions in dairy cows, when fed up to 30 g/d.