本试验旨在通过探讨单胃动物仿生消化系统测定鸭饲料酶水解物能值(EHGE)的可加性,进一步检验仿生消化方法的可行性.采用单因素完全随机设计,共12个处理,其中处理1~4分别为玉米、大豆粕、棉籽粕、小麦麸饲粮,处理5~12为以上2种或2种以上的饲料原料按不同比例组合制备的8种饲粮.每个处理5个重复,每个重复1根消化管.通过仿生消化系统测定各处理的干物质消化率(DMD)和EHGE,并根据饲粮中饲料原料的比例及其DMD和EHGE分别计算饲粮的DMD和EHGE.结果表明,8个饲粮DMD实测值的平均值显著高于计算值的平均值(分别为70.15%和69.48%,P=0.000 9),但从DMD的计算值对实测值的线性回归看,模型的决定系数为0.993 3(P<0.05),截距与0无显著性差异(截距=1.77,P=0.468 3),斜率与1无显著性差异(截距=0.98,P=0.647 4).DMD实测值的方差和变异系数分别显著低于计算值的方差和变异系数(P=0.000 2和P=0.001 0).在计算值的方差对实测值方差的线性回归,计算值变异系数对实测值变异系数的线性回归上,模型的决定系数分别为0.020 8(P>0.05)和0.115 7(P>0.05).8个饲粮EHGE实测值的平均值与计算值的平均值无显著性差异(分别为13.21和13.21 MJ/kg,P=0.965 3).从EHGE的计算值对实测值的线性回归看,模型的决定系数为0.991 0(P<0.05),截距与0无显著性差异(截距=0.04,P=0.941 9),斜率与1无显著性差异(截距=1.00,P=0.940 0).EHGE实测值的方差平均值与计算值的方差平均值无显著差异(P=0.681 1),而实测值变异系数的平均值与计算值的变异系数平均值有显著性差异(P=0.003 6).在计算值的方差对实测值方差的线性回归,计算值变异系数对实测值变异系数的线性回归上,模型的决定系数分别为0.200 0(P>0.05)和0.080 5(P>0.05).综合上述结果,仿生消化法测定玉米、大豆粕、棉籽粕、小麦麸的DMD和EHGE在饲粮中具有可加性,然而测试数据的方差与变异系数不具有可加性.

Additivity of enzyme hydrolysate gross energy (EHGE) of feedstuffs determined using computer-controlled simulated digestion system was investigated to validate the method for in vitro digestion. Twelve treatments consisted of 4 feedstuffs and 8 diets were used in a single factorial completely randomized arrangement. Treatments 1 to 4 were corn, soybean meal, cottonseed meal and wheat bran diets, respectively. Treatments 5 to 12 were 8 diets formulated with 2, 3 or 4 feedstuffs at different concentration. Each treatment contained 5 replicates with 1 digestion tube per replicate. The dry matter digestibility (DMD) and EHGE of each treatment were determined using computer-controlled simulated digestion system. The calculated DMD and EHGE of treatments 5 to 12 were estimated according to the determined DMD and EHGE of individual ingredients and their concentrations in the diets, respectively. The results showed as follows: the mean of determined DMD was greater than that of calculated values of 8 diets (70.15% and 69.48% for determined and calculated values, respectively; P=0.000 9). However, the regression of determined values on calculated values for DMD revealed that the coefficient of determination was 0.993 3 (P<0.05), and the intercept did not differ from 0 (intercept=1.77, P=0.468 3) and slope did not differ from 1 (slope=0.98, P=0.647 4). The variance and coefficient of variation (CV) of determined values were less than those of calculated values for DMD (P=0.000 2 and P=0.001 0 for variance and CV, respectively). The regression of observed values on calculated values for variance and CV of DMD showed that the coefficients of determination were 0.020 8 (P>0.05) and 0.115 7 (P>0.05), respectively. No significant difference was observed between the determined values and calculated values for EHGE (13.21 and 13.21 MJ/kg for determined and calculated values, respectively; P=0.965 3). The regression of determined values on calculated values for EHGE revealed that the coefficient of determination was 0.991 0 (P<0.05), and the intercept did not differ from 0 (intercept=0.04, P=0.941 9) and slope did not differ from 1 (slope=1.00, P=0.940 0). The differences between observed values and calculated values were not significant for variance (P=0.681 1), however, significant for CV (P=0.003 6). The regression of observed values on calculated values for variance and CV of DMD showed that the coefficients of determination were 0.020 0 (P>0.05) and 0.080 5 (P>0.05), respectively. In conclusion, the values in corn, soybean meal, cottonseed meal and wheat bran are additive for DMD and EHGE in a complete diet, respectively. However, the values for variance and CV are not additive, respectively.