6Collington G K, Parker D S, Armstrong D G. The influence of inclusion of either an antibiotic or a probiotic in the diet on the development of digestive enzyme activity in the pig [J]. British Journal of Nutrition, 1990, 64 : 59-70.
7Jin L Z, Ho Y W, Abdullah N, et al. Growth performance intestinal microbial populations, and serum cholesterol of broil ers fed diets containing Lactobacillus cultures [J]. Poultry Sci ence,1998, 77:1259 -1265.
8Jin L Z, Ho Y W, Abdullah N. Digestive and bacterial enzyme activities in broilers fed diets supplemented with lactobacillus cultures [J]. Poultry Science,2000, 79 : 886-891.