Effect of probiotic supplementation on growth and global gene expression in dairy cows

Use of probiotic supplements as a non-chemical approach to promote health has increased in animal production. The present study evaluated the effect of oral probiotic administration on growth and global gene expression profile in dairy cows. Lactating Holstein-Friesian cows received a daily dose (50 ml) of a commercial probiotic (containing Lactobacillus acidophilus, Saccharomyces cerevisiae, Enterococcus faecium, Aspergillus oryza and Bacillus subtilis) for 60 days. A microarray experiment was performed with blood collected at day-0 and day-60. Although probiotic supplementation had no effect on body weight, PCV and total protein concentration in plasma (P > 0.05), per cent lymphocyte count increased (P < 0.05), and per cent neutrophil count decreased (P < 0.05) in probiotic-treated animals. Gene expression analysis identified 10,859 differentially expressed genes, 1168 up-regulated and 9691 down-regulated genes, respectively, following probiotic treatment. Single experiment pathway analysis identified 87 bovine pathways impacted by probiotic treatment. These pathways included the Toll-like receptor (TLR), inflammation response and Wingless signalling pathways. Oral administration of probiotics to dairy cows had a systemic effect on global gene expression, such as on genes involved in immunity and homeostasis. The results of this study show that the utilization of probiotics in animal agriculture impacts genes important to dairy cow health and production.