A total of 240 weaned piglets (Duroc×Landrace×
Yorkshire, 28 days old) with similar body weight (9.01±0.22 kg body weight) were randomly allocated to four treatments with 6 pens per treatment and 10 piglets per pen. The temperature of the pig shed was 20 to 22°C and the relative humidity was 50 to 70%. The pigs were fed ad lib. and had free access to water. The body weight and feed intake of pigs were measured weekly on pen basis. Diarrhea was monitored daily throughout the experiment. This trial was conducted for 28 days in accordance with laws and regulations that control experiments and procedures in live animals in China, as overseen by the Chinese Animal Research Authority.