The invention relates to a method for preparing a mixed-type 
nucleotide feed additive from 
yeast cells and applications of the 
feed additive, which belong to the technical field of the preparation of 
nucleotide feed additives from 
yeast cells. The method comprises the steps: using 
yeast cells as raw materials and combining a homogenization method and a salt method to break yeast 
cell walls ; separating the yeast 
cell walls, 
protein and other insoluble substances by 
centrifugation and fractional isoelectric 
crystallization; specially collecting 
RNA precipitates at special isoelectric points to obtain wet and crude 
nucleic acid with the purity of 70 percent; dissolving the wet and crude 
nucleic acid in water, using high-activity 
phosphodiesterase from malt roots to carry out a high-efficiency directional enzymatic reaction; directly spraying, 
drying and crushing the solution after the enzymatic reaction to obtain the mixed-type 
nucleotide feed additive product comprising the 
protein content lower than 10 percent and four monosomic nucleotides (AMP, GMP, CMP and UMP) larger than 60 percent. After the feed additive is applied to 
animal feed, the 
intestinal absorption function of animals can be notably improved, the growth of the animals is stimulated, and the immune function, the antiviral capability and the anti-stress capability of the animals are improved.