Antibiotic-free pig feed

The invention relates to antibiotic-free pig feed. The antibiotic-free pig feed comprises the following raw material components in percentage by weight: 60-70% of corn, 15-25% of soybean meal, 5-15% of wheat bran, 3-5% of a core material and 0.2-0.4% of a compound microbial ecological preparation, wherein the total weight percent is 100%, wherein the core material comprises the following raw material components: 2.5-5.5% of compound trace elements, 0.5-1.0% of multivitamins, 13.5-19.5% of amino acid, 69.5-81.5% of mineral substances, 0.3-0.8% of an antioxidant and 1.5-4.0% of mildew preventive, wherein the total weight is 100%; and the compound microbial ecological preparation comprises the following raw material components: 97.5-99.5% of probiotics and 0.5-2.5% of oligosaccharide, each gram of the probiotics contains (4.5-5)*10 lactic acid bacteria, (2.2-2.6)*10 bacilli and (3.0-3.4)*10 saccharomycetes, and the total weight is 100%. The antibiotic-free pig feed has the advantages that the active microbial ec