The effects of three factors including concentrations of starch and serum proportion,the initial pH value of culture solution DMEM on the maximum population density of Balantidium coli were evaluated by L9(34) orthogonal design.The variance analysis of the experimental results showed that the initial pH was the primary factor,followed by concentrations of starch,and serum proportion had the weakest effect.The best medium for culture of B.coli in vitro was 40 mg/bottle of starch,serum proportion 150 mL/L in ...