不同种植地全株青贮玉米蛋白质营养价值及瘤胃降解特性与其分子结构之间的关系

本试验旨在探究不同种植地对全株青贮玉米蛋白质分子结构的影响及其与蛋白质营养价值、瘤胃降解特性之间的相关关系。本试验采用常规化学分析方法、美国康奈尔大学净碳水化合物-净蛋白质体系(CNCPS)、尼龙袋技术对不同种植地的全株青贮玉米营养价值进行评定,并结合傅里叶变换红外光谱(FTIR)技术对青贮玉米蛋白质分子结构进行研究,进而探求蛋白质分子结构与蛋白质营养价值之间的相关关系。结果表明:1)不同种植地全株青贮玉米蛋白质化学成分存在显著差异(P<0.05);CNCPS蛋白质组分中非蛋白氮、中速降解蛋白、慢速降解蛋白、不可利用蛋白含量存在显著差异(P<0.05);干物质及粗蛋白质有效降解率也存在显著差异(P<0.05)。2)通过FTIR扫描后发现,不同种植地对全株青贮玉米蛋白质分子结构中酰胺Ⅰ带的峰高、峰面积,酰胺Ⅱ带的峰高、峰面积,酰胺Ⅰ带与Ⅱ带的总峰面积、峰面积比、峰高比,α-螺旋、β-折叠峰高均有显著影响(P<0.05)。3)酰胺Ⅰ带峰高、峰面积,酰胺Ⅱ带峰高、峰面积,酰胺Ⅰ带与Ⅱ带峰高比、峰面积比以及α-螺旋峰高均可以作为预测因子对全株青贮玉米蛋白质营养价值及瘤胃降解参数进行预测。其中,青贮玉米蛋白质分子结构对粗蛋白质(R^2=0.81)、酸性洗涤不溶蛋白(R^2=0.88)、不可利用蛋白(R^2=0.85)及粗蛋白质快速降解部分(R^2=0.69)拟合最好。综上所述,不同种植地对全株青贮玉米蛋白质成分、CNCPS组分、干物质和粗蛋白质瘤胃降解参数及蛋白质分子结构均有影响。并且,蛋白质分子结构与蛋白质营养价值之间存在明显的相关关系,可以借助青贮玉米蛋白质红外光谱参数对其蛋白质营养价值进行预测。

Preliminary Study on Planting Direction of Flood Land at Different Altitudes——a Case Study in Xiaojiang Valley, Yunnan

Flood land, with abundant light, heat, and water resource, is an important potential land resource to resolve the situation of the limited arable land in mountain areas in Xiaojiang Valley, Dongchuan, Yunnan. It will have a great significance on the development of local characteristic agriculture and the settlement of poor moun- tain immigrants that how to develop and protect the flood land in a scientific, effec- tive and sustainable way. In this paper, flood land of Xiaojiang Valley is divided into three zones （higher zone is 1 600-1 300 m, medium zone is 1 300-1 000 m, low- er zone is 1 000-700 m） according to different elevations. Through field survey, in situ measurement, sampling analysis and ＂3S＂ technology, the area and soil nutri- ent characteristics of flood land at different altitudes are tested and analyzed sys- tematically. And also according to the climatic characteristics in different elevations of flood land, the research analyzed and investigated the growing conditions of flood land in different elevations in Xiaojiang Valley, and then discussed how to develop and cultivate reasonably and effectively in flood land. All the work is intended to provide beneficial reference for the development and cultivation of flood land in mountain areas.