No abstract

Two experiments were conducted to determine the digestible energy (DE) and metabolizable energy (ME) content of 19 rice bran samples and to develop prediction equations for DE and ME based on their chemical composition. The 19 rice bran samples came from different rice varieties, processing methods and regions. The basal diet was formulated using corn and soybean meal (74.43% corn and 22.91% soybean meal and 2.66% vitamins and minerals). The 19 experimental diets based on a mixture of corn, soybean meal and 29.2% of each source of rice bran, respectively. In Exp. 1, 108 growing barrows (32.1±4.2 kg) were allotted to 1 of 18 treatments according to a completely randomized design with 6 pigs per treatment. The treatment 1 was the control group which was fed with basal diet. The treatments 2 to 18 were fed with experimental diets. In Exp. 2, two additional rice bran samples were measured to verify the prediction equations developed in Exp. 1. A control diet and two rice bran diets were fed to 18 growing barrows (34.6±3.5 kg). The control and experimental diets formulations were the same as diets in Exp. 1. The results showed that the DE ranged from 14.48 to 16.85 (mean 15.84) MJ/kg of dry matter while the ME ranged from 12.49 to 15.84 (mean 14.31) MJ/kg of dry matter. The predicted values of DE and ME of the two additional samples in Exp. 2 were very close to the measured values.

The present study was performed to estimate genetic parameters for growth and fur quality traits in Chinese silver blue mink. Recordings of body weight (BW), body length (BL), guard hair length (GL), underwool length (UL) and the rate of guard hair and underwool length from 1678 silver blue minks (280 male and 1398 female) spanning six generations were obtained from Dalian Ming Wei Marten Industry Company. Genetic parameters were estimated using a multitrait animal model with year and sex as fixed effects. The heritability estimates for BW, BL, GL, UL and RATE were 0.41, 0.53, 0.53, 0.52 and 0.52, respectively. The genetic trends were estimated by regressing breeding value on year. The genetic trends for body weight and body length were close to zero, and positive. The genetic changes for GL, UL and nap were negative and parallel. Our results herein form a practical basis for designing optimal breeding schemes in silver blue mink.