Abstract
The protein levels of casein diet (CA), soy protein diet (SP) and protein mixture diet (PM, mixture in equal portions of casein and soy protein as a protein source) were 10%, respectively.
1. Similar tendencies on feed intake, body weight gain, feed efficiency and N efficiency were obtained from the three groups.
2. The apparent N digestibility and ratio of N retention were CA>PM>SP. The differences of mean values between CA and SP on the apparent N digestibility and between CA and other two groups on the ratio of N retention were significant.
3. The apparent Ca digestibility, and the quantity and the ratio of Ca retention were SP>CA>PM. Significant differences of mean values were found between CA and PM on the apparent Ca digestibility and the ratio of Ca retention, and between SP and PM on the quantity of Ca retention.
4. The quantity of Mg retention was SP>PM>CA, and the difference of mean velues from SP to CA was significant.
5. The apparent P digestibility and the quantity of P retention were SP>CA>PM. Significant differences of mean values were found between SP and PM on the apparent P digestibility, and be tween PM and other two groups on the quantity of P retention. The ratio of P retention was CA>SP>PM, and the difference of mean values from CA to PM was significant.
6. In the femur and the tibia with fibula, the P content in the bones, and Ca and P % in the moisture and fat-free bones were SP>PM>CA. A significant difference was found between SP and CA.
