国产玉米DDGS猪有效能值预测方程的建立及其验证

With the rising of price of traditional feed ingredients, such as corn and soybean meal, corn distillers dried grains with solubles (DDGS) was widely used in the pig industry as a new alternative raw material. However, the different corn source and DDGS process technology are contributed to the high variation of nutrition value from different DDGS products, which results it is difficut to accurately evaluated the effective energy value of DDGS in practice. The stability and consistency of final feed products may interfered by wrong estimation of energy, which was detrimental to greater DDGS inclusion rate in swine feed. Furthermore, the net energy (NE) of DDGS was easy overestimated due to its high fiber and protein contents, which may result energy deficiency while relative high inclusion rate of DDGS was supplemented in growing-finishing diet. Data based on NRC, INRA(france net energy system) or empirical are introduced in formula for DDGS in practice while there is no observed value for reference in china. It's important to predict effective energy of corn DDGS through proximate nutrients. Therefore, our laboratory had investigated 16 ethanol plants to compare their processing which may be the reason of differences among corn DDGS products, and 25 different corn DDGS were collected and analyzed for the proximate nutrients.experiments will be conducted to measure digestible energy (DE), metabolizable energy (ME) and NE by balance study and with open-circuit respiratory calorimetry equipment respectively. Static data of corn DDGS, and the dynamic regression prediction equation of DE, ME and NE will be obtained. subsquently two typical low-fat and high-fat of DDGS samples were chose to formulated experiment diet based on ME system and NE system, the response of performance and carcass composition in growing-finishing pigs were determined to compare the different effective energy system. In conclusion, the study allows accurately prediction of effective energy and provides a theoretical basis and practical application.

随着玉米豆粕等饲料原料价格上涨，新型替代原料玉米DDGS在养猪业广泛使用。然而，受玉米产地及加工工艺等影响，产品间营养成分变异较大，极易高估其对净能的贡献，当配方中添加比例较高时出现能量缺乏，降低猪生长性能，从而影响实际应用。目前国内普遍参照NRC猪饲养标准、法国净能体系或经验值估算原料能值配制日粮。建立玉米DDGS对猪代谢能和净能的回归预测方程，通过测定原料常规成分，快速估测其实际能值并配制饲粮，对高效利用DDGS意义重大。本实验室实地调研国内16家酒精厂，已采集25种样品进行化学成分分析。拟进行消化代谢试验和呼吸测热净能测定，建立玉米DDGS化学成分与猪不同有效能体系的静态数据及动态回归预测方程。同时，选取2种典型低脂和高脂DDGS，通过生长肥育猪饲养试验对所建立预测方程进行验证，从而为玉米DDGS有效能值的准确预测及应用提供理论依据。

针对项目的研究目标，采集全国30个不同生产工艺的代表性玉米DDGS样品，围绕化学成分、猪消化代谢能和净能测定、体外仿生酶法预测、大猪和母猪饲养试验等四方面开展深入研究工作，并取得如下进展：[1] 不同DDGS的常规营养成分、氨基酸组成及色度变异较大，DDGS消化能和代谢能变异范围（DM）分别为：3,255 kcal/kg ~ 4,103 kcal/kg和2,955 kcal/kg ~ 3,899 kcal/kg，发现与其生产工艺密切相关；[2] 建立玉米DDGS化学成分与猪有效能静态数据的动态回归预测方程，全类、全油类和提油类消化能的最优方程（DM，kcal/kg）如下：全类方程DE = 1,874 – 21.35 × % NDF + 0.654 × % GE –99.84 × % CF；全油类方程DE = -643 – 94.52 × % CF + 1.136 × % GE –22.89 × % NDF；提油类方程DE = 4,338 – 36.75 × % NDF + 32.99 × % CP – 67.10 × % CF。净能最优预测方程为：NE（kcal/kg DM）= -740.49 - 43.82 ×% CF+ 161.98 ×% ash + 0.765 × DE（R2 = 1.00，RSD = 1.25）；[3] 体外仿生酶能值预测体内消化能值：DE（体内消化能；kcal/kg DM）= 497 + 1.07× IVDE （仿生酶能值；R2 = 0.88，P< 0.01）；[4] 生长肥育猪和妊娠母猪饲养试验发现，高油和低油玉米DDGS的猪代谢能预测方程比NRC（2012）更加准确，并促进猪的生长和屠宰性能。综上，玉米DDGS生产工艺不同造成其营养成分及有效能值变异大，可利用化学成分动态预测其有效能值，也可以通过体外仿生酶能值准确快速预测体内消化能。该研究完善猪饲料原料数据库，为准确快速配制猪饲料提供理论数据和方程，为玉米DDGS在猪营养领域的高效利用提供参考数据。项目执行期间，项目成员参加国际会议5人次，国内会议8人次；培养博士和硕士研究生共计7名；发表SCI文章38篇，中文文章3篇。