Abstract: A four-day digestive trial was conducted at the 63±4 days of weaned rex rabbits . Twenty weaned rex rabbits were selected from the five groups with 4 of each group (two males and two females and average body weight 1150.5 g±124.0 g). Five treatments of dietary were provided with isoenergy and isonitrogen of 25% raw soybean(RSB), 25% processed soybean by chemical inactivator, 25% processed soybean by heating, 25% soybean meal and 13% raw soybean + 12% soybean meal respectively. Feces and urine were collected totally and feed intakes were recorded.The results indicated that 25% RSB group has significantly declined apparent nitrogen digestibility (P<0.05) and significantly increased fecal nitrogen content (P<0.05). It had no effect on nitrogen in urine. There was no significant difference among groups of processed soybeans by chemical inactivator and heating and 13% raw soybean in fecal nitrogen, nitrogen digestibility. There is no difference in apparent digestibility of dietary dry matter, organic matter, nitrogen-free extract, ether extract and crude fiber among five groups (P>0.05). 

Key words: soybean; trypsin inhibitors; rex rabbits; nitrogen balance; apparent digestibility