凯氏定氮法与杜马斯燃烧法检测三氯乙酸沉淀大豆和小麦蛋白中蛋白氮含量研究

目的检验尿素干扰下三氯乙酸沉淀分离大豆和小麦蛋白质的效果。方法本研究以牛奶、大豆蛋白、小麦水溶性组分为参试样品,分别在去离子水、尿素溶液2种溶液体系下分散样品,参考国家标准采用三氯乙酸沉淀蛋白氮,2种蛋白检测方法(凯氏定氮法、杜马斯燃烧法)检测氮含量,并计算氮检测回收率评估三氯乙酸对大豆蛋白、小麦水溶性组分等植物性蛋白的适用性。结果去离子水(无外源氮)分散的上清液经三氯乙酸沉淀,凯氏定氮法和杜马斯燃烧法检测牛奶的回收率分别为114%、101%,大豆的回收率分别为96%、98%,小麦的回收率分别为104%、105%。尿素溶液(有外源氮)分散的上清液经三氯乙酸沉淀,牛奶的回收率分别为99%、94%,大豆的回收率分别为95%、92%,小麦的回收率分别为101%、92%。结论有无尿素干扰时,三氯乙酸均可以沉淀大豆蛋白、小麦水溶性组分中蛋白氮,并可以采用凯氏定氮法、杜马斯燃烧法检测,回收率较好。

哈蟆油非水溶性成分抗疲劳保健功能研究

[目的]研究哈蟆油(OVIDVCTUS RANAE)非水溶性成分的抗疲劳作用。[方法]以低、中、高(0.25、0.5、1.0 g/kg)3个剂量的哈蟆油非水溶性成分连续灌胃小鼠30 d,空白对照组给予等量的蒸馏水,测定小鼠负重游泳时间、血清尿素、肝糖原和血乳酸含量。[结果]哈蟆油非水溶性成分中剂量组小鼠的游泳时间明显长于对照组(P<0.05);各剂量组小鼠肝糖原含量均明显高于对照组(P<0.05);中、高剂量组小鼠运动后的血乳酸曲线下面积均小于对照组(P<0.05);各剂量组小鼠运动后血清尿素氮含量无明显改变。[结论]哈蟆油非水溶性成分具有抗疲劳作用。

哈蟆油非水溶性成分酶解物的抗疲劳作用

目的:研究哈蟆油非水溶性成分酶解物抗疲劳生物活性。方法:采用碱性蛋白酶酶解法制备哈蟆油非水溶性成分酶解物。以哈蟆油非水溶性成分酶解物高、中、低(0.6g/kg,0.3g/kg,0.15g/kg)3个剂量组对小鼠进行连续灌胃给药30天,空白对照组给予等体积蒸馏水,分别观察小鼠负重游泳时间、血清尿素氮含量、肝糖原含量、血乳酸含量等指标的变化。结果:中剂量组小鼠负重游泳时间与对照组比较时间显著延长(P<0.05),低剂量组肝糖原与对照组比较含量显著增加(P<0.05),各剂量组血乳酸曲线下面积与对照组比较显著减小(P<0.01),各剂量组血清尿素氮与对照组比较含量均无显著下降(P>0.05)。结论:哈蟆油非水溶性成分酶解物具有明显抗疲劳作用。

哈蟆油非水溶性成分酶解前后降血脂功效比较研究

目的比较哈蟆油非水溶性成分酶解前后对饮食性高脂血症大鼠的降血脂作用。方法通过给正常大鼠饲喂高脂饲料,建立高脂大鼠模型,将实验大鼠随机分为基础饲料对照组、高脂模型组、非水溶性成分(低、中、高剂量)组及其酶解物(低、中、高剂量)组,测定各组大鼠的总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)等含量。结果 TC含量,酶解前仅高剂量组降低且具有显著性意义,酶解后各剂量组均降低且具有显著性意义;TG含量,酶解前后各剂量组均降低且具有显著性意义;HDL-C含量,酶解前后各剂量组均无显著性变化。结论哈蟆油非水溶性成分酶解前后均具有辅助降血脂作用,且酶解后作用进一步加强。

哈蟆油非水溶性成分酶解前后耐缺氧活性研究

比较研究哈蟆油非水溶性成分酶解前后的耐缺氧作用。设立哈蟆油非水溶性成分及其酶解物的低、中、高剂量组和空白对照组,连续灌胃30 d。测定小鼠的常压耐缺氧时间、亚硝酸钠中毒存活时间、急性脑缺血性缺氧存活时间。结果表明:与对照组比较,酶解前各剂量组的常压耐缺氧时间、亚硝酸钠中毒存活时间、急性脑缺血性缺氧存活时间均无显著性差异;酶解后各剂量组常压耐缺氧时间具有显著性差异,中、高剂量组亚硝酸钠中毒存活时间具有显著性差异,中剂量组急性脑缺血性缺氧存活时间具有显著性差异。哈蟆油非水溶性成分无耐缺氧作用,酶解后产物具有显著的耐缺氧作用。

Impact of Feedlot on Soil Phosphorus Concentration

Raising cattle in feedlots is becoming more common in Argentina, but there is little information available about the effects of this practice on soil phosphorus (P) dynamics. In this study, concentrations of water and Bray -1 extractable soil P were quantified in a feedlot (upper and lower slope positions in the feedlot pen), runoff area and pasture during 2006 - 2008. The feedlot showed higher P concentrations in all P forms, soluble reactive P, soluble nonreactive, total soluble P, and Bray-P1 when compared to runoff area and pasture. Most of the total soluble P was soluble reactive P from the soil in the feedlot and the runoff area, while soluble nonreactive P predominated in the pasture. Concentrations of total soluble P were elevated in the feedlot at the soil surface, ranging on average from 158.71 to 245.86 mg?P?kg?1, and had a rapid decrease within the first 20 cm and remained relatively low, about 25.53 - 27.33 mg?P?kg?1. The evidence that total soluble P concentration in the feedlot was significantly (p < 0.05) higher than that registered in the pasture at 20 - 40 and 40 - 60 cm soil depth suggests a potential transfer of P through the soil from the surface. Although the feedlot had a moderate increase of 23.05 to 24.55 mg?P?kg?1 from the background concentration, it may represent a long-term source of increased nutrient loading to groundwater. Soil extractable Bray-1 P in the top 0 - 2.5 cm fluctuated from 659.26 to 45.36 mg?P?kg?1 in the feedlot and pasture, respectively. The relationship between soil P extracted by test and TSP was linear, and correlation coefficient was r2 = 0.95.