Key Laboratory of Animal Nutrition and Feed Science in South China;
Ministry of Agriculture;
State Key Laboratory of Livestock and Poultry Breeding;
Guangdong Public Laboratory of Animal Breeding and Nutrition;
Guangdong Key Laboratory of Animal Breeding and Nutrition;
Institute of Animal Science;
Guangdong Academy of Agricultural Sciences;
Agro-Biological Gene Research Center;
Guangdong Academy of Agricultural Sciences;
Piglet; Protein level; Protein source; Microbial metabolites; Diarrhea;