Promotion and Inhibition of Ruminal Epithelium Growth by Butyric Acid and Insulin-Like Growth Factor-1 (IGF-1) in Dairy Goats

Isolated ruminal epithelia from caudal blind sacs of dairy goats were incubated with butyrate and insulin-like growth factor-1 (IGF-1) at different concentrations. Proportions of ruminal epithelium in different phases of the cell division cycle were determined by flow cytometric analysis. The proportion of epithelial cells in S phase and G₂-M phase (P_S&G2-M) increased significantly (P<0.01) whereas the proportion of epithelial cells in G₀-G₁ phase (P_G0-G1) decreased after incubation with IGF-1. P_S&G2-M decreased whereas P_G0-G1 increased markedly (P<0.01) after incubation with sodium butyrate. P_S&G2-M incubated with IGF-1 and butyrate sodium together increased more than that incubated with IGF-1 alone; P_G0-G1, however, decreased significantly (P<0.01). Our results indicate that IGF-1 enhances whereas sodium butyrate inhibits the proliferation of rumen epithelial cells. Furthermore, butyrate and IGF-1, together, have a synergic effect on the proliferation of rumen epithelium.