To provide a compounding agent for fodder comprising safe ingredients derived from natural sources, more effectively preventing diarrhea of animals and improving healthy conditions of animals through regulation of intestinal environment, and a fodder compounded with the same.

The compounding agent for fodder contains mannose and/or manno-oligosaccharide and a viable cell agent as effective ingredients and, in addition, preferably contains a vegetable drug and/or a sterilized microbe. Preferably, the vegetable drug is one or more species selected from a group consisting of Lycii folium, malt, Eriobotryae folium, Panax ginseng, Zizyphi fructus, Dioscoreae rhizoma, Polygonatum sibiricum Red, Lonicerae flos, Kimihide gama, Japanese pumpkin seeds, Plantago seeds, persimmon leaves, Eucommia ulmoides Oliv. leaves, Gardenia jasminoides ellis, Echinaceae and common chickweed. Preferably, the sterilized microbe is crushed yeast cells or sterilized lactobacteria cells.