Study On Evaluating The Net Energy Of Rapeseed Meal(SOL.) For Ducks

The Net energy(NE)of feed ingredients for poultry can be evaluated by respiratory calorimetry method or comparative slaughting method.However,most of the laboratory evaluation take too much of time and require a lot of labor and capital.Besides,the energy of feed ingredients can be predicted by models established by chemical composition and Near Infrared Reflectance Spectroscopy(NIRS)analysis technique.Nowadays,the NE data or research of rapeseed meal for duck was not clear.Therefore,the present study was conducted to evaluate the net energy of rapeseed meal for Cherry Valley Duck and establish models for predicting net NE of rapeseed meal using chemical composition and NIRS.First,conduct an animal experiments which NE and AME were evaluated.A factorial analysis procedure was used to estimate net energy of rapeseed meal that combines net energy for maintenance(NEm)and production(NEp).Formal trial period is 7-14 days,a total of 760 Cherry Valley Duck with an average weight of(130.48±3.01)g were selected,20 ducks With the body weight close to average of the experimental were slaughtered at the beginning of the experiment(called baseline)to determine the initial body energy.Based on rapeseed quality grading standards(First Grade:crude protein ?40%,crude fiber<14.0%,crude ash<8.0%;Second Grade:crude protein ?37%,crude fiber<14.0%.crude ash<8.0%;Third Grade:protein ?33%,crude fiber<14.0%.crude ash<8.0%).for the experiment 31 rapeseed meal samples with a variety content of chemical compositions were collected,Each Rapeseed meal were incorporated into a modified basal(corn-soybean meal)diets which formulated the Basal diet 2 for determination of rapeseed meal net energy for production(NEp)which was calculated using the comparative slaughter technique.NEp test diets(Ptd)were formulated with 850 g/kg of the modified corn-soybean meal diet and 150 g/kg of rapeseed.Each rapeseed meal was provided to 20 ducks housed in cages with four ducks per repetition and five replications.At the end of experiment all ducks were slaughtered,and performance were determined.NEm was estimated by fasting heat production(FHP).The FHP was measured by establishing regression equation and extrapolating HP measured at five feeding levels including ad libitum and restricted feeding by 15%,25%,35%,45%to zero ME intake.Then 36 rapeseed meals were measured for their CP,EE,CF,NDF,ADF.Correlation and multiple linear stepwise regression analyses were conducted to establish the models for predicting NE of rapeseed meal by chemical compositions.After spectra were collected,NIRS models for predicting NE of rapeseed meal were established using partial least square regression(PLS)by the OPUS software ver.5.5.Results showed that Differences in the chemical composition of 31 different sources of Rapeseed meal,The gross energy(GE)of 31 kinds rapeseed range is 16.09?19.02 MJ/Kg,crude protein(CP),dry matter(DM),crude fat(EE),crude fiber(CF),neutral detergent fiber(NDF)and acid detergent fiber(ADF)content ranges of 35.05?46.33%,88.39?91.97%,0.423?3.03%,11.72?17.82%,25.02?50.32%,14.46?19.38%,the Rapeseed meal of First Grade?second grade and third grade was 15?10 and 6 respectively.the NEm of Cherry Valley Duck was 0.557MJ/kgW0.75·d,the variations in nutrients were large between different sources of the com samples,and AME of rapeseed meal on Cherry Valley Duck were(9.97±2.97)MJ/kg DM.The NE of rapeseed meal were(5.59±0.69)MJ/kg DM,which contributed(0.57±0.05)of the apparent metabolizable energy.The correlation coefficient of NE and AME,rapeseed meal,CP,EE,CF,NDF and ADF were 0.786,0.645,-0.218,-0.012,-0.708 and-0.601,respectively.The best prediction model established by chemical composition was NE=0.612AME+0.012EE-0.028NDF-0.052ADF+1.1623,in which R2 and RSD were 0.901 and 0.06 MJ/kg,respectively.In NIRS model,The analysis showed that The rapeseed NE for NIRS prediction model content is as follows:Best spectral interval 7508.2?4246.7 cm-1;internal validation optimal spectral region is 6101.9?5446.2 cm-1,4610.2?4246.7 cm-1 optimum principal component of dimension 5,calibration and external validation optimal spectral region is 7295.6?6098.1 cm-1;5450.1?4240.7 cm-1,the optimum principal component dimension is 6,the coefficient of determination of internal cross-validation(R2cv),coefficient of determination of calibration(R2cal)and coefficient of determination of external validation(R2val)were 80.32%?82.42%? 81.01%,respectively;the root mean square error of internal cross-validation(RMSECV),the root mean square error of calibration(RMSEE)and the root mean square error of external validation(RMSEP)were 0.186 MJ/kg?0.174 MJ/kg ? 0.180 MJ/kg respectivelyIn conclusion,the NE of rapeseed meal on Cherry Valley Duck were(5.59±0,69)MJ/kg DM,and the chemical composition of rapeseed with a correlation between the NE.it is feasible to establish NE prediction model of rapeseed meal using its chemical composition and NIRS.