Wheat grain quality under increasing atmospheric CO2 concentrations in a semi-arid cropping system

We investigated wheat (Triticum aestivum) grain quality under Free Air CO₂ Enrichment (FACE) of 550 ± 10% CO₂ μmol mol⁻¹. In each of two full growing seasons (2008 and 2009), two times of sowing were compared, with late sowing designed to mimic high temperature during grain filling. Grain samples were subjected to a range of physical, nutritional and rheological quality assessments. Elevated CO₂ increased thousand grain weight (8%) and grain diameter (5%). Flour protein concentration was reduced by 11% at e[CO₂], with the highest reduction being observed at the late time of sowing in 2009, (15%). Most of the grain mineral concentrations decreased under e[CO₂] - Ca (11%), Mg (7%), P (11%) and S (7%), Fe (10%), Zn (17%), Na (19%), while total uptake of these nutrients per unit ground area increased. Rheological properties of the flour were altered by e[CO₂] and bread volume reduced by 7%. Phytate concentration in grains tended to decrease (17%) at e[CO₂] while grain fructan concentration remained unchanged. The data suggest that rising atmospheric [CO₂] will reduce the nutritional and rheological quality of wheat grain, but at high temperature, e[CO₂] effects may be moderated. Reduced phytate concentrations at e[CO₂] may improve bioavailability of Fe and Zn in wheat grain.     

苎麻营养成分分析及瘤胃降解特性研究

为系统的研究苎麻的营养价值及其在山羊瘤胃中的降解特性,利用化学分析等方法检测了7个茬次苎麻的粗蛋白(CP)、氨基酸(AA)组成、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)等营养成分、单宁等抗营养成分的含量,并采用3只装有永久瘤胃瘘管的波尔山羊为试验动物,对苎麻的部分营养成分的降解率和降解参数进行测定。结果表明,7个茬次苎麻的CP含量均较高且品质较好,CP平均值达到了19.57%,而且呈现出随着茬次的增加,CP含量有所下降的趋势,但是第7茬和第6茬相比CP含量略有升高。AA总和平均值达到了16.40%,占CP平均值含量的83.80%,赖氨酸(Lys)的平均含量达到了0.84%,苏氨酸(Thr)的平均含量达到了0.82%。抗营养因子方面,单宁可能是苎麻最主要的抗营养因子,平均值达到了0.67%。苎麻的干物质(DM)、CP、有机物(OM)、NDF和ADF的降解率均随着瘤胃消化时间的延长而不断提高,有效降解率分别达到了47.00%,35.53%,44.29%,57.68%和38.59%。由此得出,苎麻的营养价值较高,主要体现在CP含量高且品质较好,主要营养成分的瘤胃降解率均较高,可以作为反刍动物优良的粗饲料资源加以开发利用。     

基施硒肥对蚕豆籽粒硒含量、营养成分及抗氧化性的影响

为探明硒对蚕豆籽粒产量、硒含量、营养物质含量及抗氧化性的影响,以"崇礼蚕豆"和"凤豆6号"2个品种为试验材料,采用盆栽试验研究5个土壤施硒水平(Na2SeO3,以Se计0、3.1、6.2、12.4和24.8mg/kg)对硒在蚕豆籽粒中的富集规律、营养物质含量及1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除力的影响。结果表明:在本试验条件下,适宜硒浓度能够提高蚕豆籽粒产量,而高浓度硒则降低蚕豆产量;施硒能够显著提高蚕豆籽粒硒含量(崇礼蚕豆和凤豆6号分别较对照提高21.3~35.8和4.97~7.60倍),籽粒硒含量与施硒浓度之间呈对数关系;硒同时可以影响籽粒中粗蛋白、粗纤维、粗灰分和单宁等物质的含量,而对总碳水化合物及植酸含量的影响并不显著;施硒可以显著提高籽粒提取物DPPH自由基清除力;硒对籽粒中物质含量和抗氧化性的影响在蚕豆品种间也存在一定的差异。因此,合理施硒具有增加硒含量和改善蚕豆营养品质的双重效益,低浓度硒处理(3.1mg/kg)便适于富硒蚕豆的开发。     

植物蛋白原料抗营养因子及其消除方法的研究进展

鱼粉是渔用饲料的主要蛋白源,但是目前正面临着短缺的问题,因此,寻找合适的鱼粉替代物显得尤为迫切。植物蛋白作为鱼粉替代品有很多的优点,目前已经得到了广泛的应用,但同时也存在着一些问题。植物蛋白含有一定种类和一定量的抗营养因子,因此在应用之前必须采用合适的方法进行处理以消除抗营养因子,否则会影响使用效果。本文对目前主要的三种处理方法(物理法、生物法和化学法)进行综述。     

Contribution of microbial phytases to the improvement of plant growth and nutrition: A review

Phytases belong to the class of phosphohydrolases that begin the step-wise hydrolysis of phosphates from phytates. Phytates are a derivative of myo-inositol, which is the primary storage form of organic phosphorus in plant cells. Phytase has been used globally to diminish phosphorus pollution and to enhance nutrition in monogastrics. In this review, the classification, sources, and diversity of microbial phytases, and their practical applications, as well as supplementation of the soil with transgenic and wild types of microbial strains, which can release phytase to enhance phosphorus availability for plant uptake and reduce the need for fertilizers, are discussed. The overexpressed microbial phytases in transgenic plants enhance the growth capacity of co-cultivated plants and can therefore be employed in agricultural and biotechnological practices, such as intercropping. The introduction of phytases into the soil for improved plant growth and enhanced crop yield can be accomplished without extra cost. A diverse group of photoautotrophic microalgae can synthesize phytase and will likely be useful in many human food and animal industries.     

灌木类植物抗营养成分的研究

我国的灌木资源十分丰富,且其营养价值很高,但这类饲料资源的开发利用还存在着一定的局限性。对灌木类植物含有的抗营养成分——酚类物质的抗营养作用进行了初步的探讨。     

鱼虾饵料中内源性抗营养因子及解除

介绍了鱼虾饵料中存在的能削弱和破坏营养生理功能的硫胺素酶，胰蛋白酶抑制因子，棉酚环丙烯脂肪酸，维生素Ｂ６拮抗物，肌醇六磷酸，吡咯烷生物碱，芥子甙，单宁，血球凝集剂等抗营养机理，提出采用物理，化学，生物育种等方面加以解除。