Ingestion and excretion of nitrogen and phosphorus by beef cattle under contrasting grazing intensities

There is increased global interest in the environmental impacts of farming, including the need to prevent the contamination of soil, water and air with excessive amounts of nitrogen (N) and phosphorus (P) in grazed systems. Reduction in grazing intensity has frequently been recommended to meet biodiversity and production goals in sustainable grazing systems. The objective of this experiment was to measure N and P ingestion and excretion by beef cattle grazing semi‐natural pastures at two grazing intensities (Moderate or Lenient). The cattle grazing at Moderate grazing intensity had significantly more defaecations each day than those grazing at Lenient intensity (9·5 vs. 7·5) and tended to have more urinations (7·0 vs. 5·8). For the Moderate and Lenient treatments, respectively, 113 vs. 76 g N d^?1 was excreted compared with 136 vs. 94 g N d^?1 ingested; 12 vs. 8 g P d^?1 was excreted compared with 13 vs. 10 g P d^?1 ingested and urine N comprised 0·51 and 0·52 of the total N excreted each day. In improved, intensively managed grassland systems, urine N comprises a much higher proportion (approximately 0·70–0·85) of the daily total N excreted. The lower level found here is likely to impact on potential volatilization, denitrification and leaching losses, and these aspects should be examined further to see the extent to which semi‐improved grasslands containing increased plant diversity compared with improved grasslands can deliver higher resource protection, as well as enhanced grassland faunal diversity and abundance.     

固相萃取-UPLC-MS/MS快速测定猪尿中的苯乙醇胺A

建立了-种固相萃取-超高效液相色谱-串联质谱法（SPE—UPLC—MS／MS）快速测定猪尿中苯乙醇胺A的方法。猪尿样品以莱克多巴胺-D,为内标,尿液经酸化后离心,上清液经OasisMCX固相萃取柱净化,超高效液相色谱-串联质谱法测定。苯乙醇胺A监测离子为m／z345〉150和m／z 345〉327。结果表明在0．2～5μg／L范围内苯乙醇胺A呈良好的线性关系,高中低浓度绝对回收率在80—110％,精密度小于15％,最低定量限0．2μg／L。本方法快速、简便,适于猪尿中苯乙醇胺A的残留测定。     

C-reactive protein as an indicator of inflammatory responses to experimentally induced cystitis in dogs

The aim of this study was to demonstrate and assess C-reactive protein (CRP) changes in dogs with induced bacterial cystitis with or without antibiotics. We also evaluated availability of CRP levels to serve as an indicator for monitoring or diagnosing bacterial cystitis. Serial CRP concentrations in dogs with induced bacterial cystitis were higher than those of controls (p < 0.001). CRP concentrations peaked on day 7 and gradually decreased thereafter. In the treatment group, CRP concentrations decreased after medication compared to the untreated group (p = 0.032). CRP levels had a linear correlation with urine white blood cell counts among all groups (r = 0.837, p < 0.001, n = 140). Compared to the negative urine culture group, dogs with positive urine culture results had higher CRP concentrations (median 43.8 mg/L vs. 5.9 mg/L; p < 0.001). Area under the receiver operating characteristic curve was 0.955; when cut-off value was 12.2 mg/L, CRP measurements were found to have a sensitivity of 92.3% and specificity of 86.4%. This result indicates that rapid increases of CRP occurred after inducing bacterial cystitis and CRP may be a useful indicator for monitoring or diagnosing canine bacterial cystitis together with sediment urinalysis and urine bacterial culture.     

《诸病源候论》辨治糖尿病肾脏疾病分析

《诸病源候论》为我国第一部中医病因证候学专著,本文立足于《诸病源候论》对糖尿病肾病相关证候的病因病机、治疗原则,分析其主要病机为肾脏气、阴两虚,治疗当以补气滋阴为主,此书为我国现代中医研究糖尿病肾脏疾病提供了理论依据。     

PCR对猪全血、血清、尿液和粪便中PCV2的检测

根据已发表的基因序列 ,选取 PCV2保守的基因片段 ,利用计算机软件设计的一对引物对某猪场的 7只患病仔猪的全血、血清、尿液、和粪便进行 PCR扩增 ,再对扩增产物酶切鉴定 ,并将 PCR产物连接到 p MD1 8-T载体上 ,然后转化到大肠杆菌 DH5α感受态细胞中 ,抽提重组质粒 ,对重组质粒 PCVp MD1 8进行 PCR、酶切鉴定及测序。结果表明 :全血、血清、尿、粪便阳性率分别为 85.7% (6/7)、71 .4% (5/7)、42 .9%(3 /7)、2 8.6% (2 /7)。通过比较 ,全血的阳性率最高 ,其次为血清     

高钙与高蛋白日粮诱发鸡痛风

将120只35日龄健康蛋仔鸡随机分为3组：对照组饲喂基础日粮，高钙组(HC)在饲喂基础日粮的同时添加石粉(含钙3．80％)，高钙高蛋白组(HCHP)在饲喂基础日粮的同时添加石粉和豆粕(含钙3．55％，粗蛋白24．58％)，进行30d的饲养试验。结果显示：HC组鸡出现普遍的肾脏损害，但未见尿酸盐在内脏器官的沉积；HCHP组鸡出现尿酸盐在内脏器官表面广泛沉积，发生典型的内脏型痛风。与对照组相比，HC组血清无机磷和钾显著降低，血清尿酸和钠显著升高；HCHP组血清尿酸极显著升高，血清钙显著升高；HC和HCHP组尿液中钠及钾浓度均显著降低，无机磷浓度均显著升高；HC组24h尿液中镁排出量显著升高，HCHP组24h尿液中镁与钾排出量显著升高，HC和HCHP组24h尿液中尿酸、钙和无机磷排出量极显著升高，而钠排出量极显著降低。     

Influence of urine pH on accurate urinary protein determination in Sprague-Dawley rats

BACKGROUND: Rat urinary protein concentration is commonly measured during safety assessment studies to evaluate potential drug-induced nephrotoxicity. It has been reported that impregnated reagent test strips (dipsticks) can yield false-positive urinary protein results for alkaline urine samples. OBJECTIVE: The objective of this study was to determine if urinary dipsticks accurately assess protein concentrations, especially in alkaline rat urine. METHODS: Ten male Sprague-Dawley rats were treated with 2% sodium bicarbonate and 2% ammonium chloride to alkalinize and acidify the urine, respectively. Urine pH was measured in treated and control rats using a pH meter and urinary dipsticks with the Clinitek 500. Quantitative urinary protein results were compared to urinary dipstick protein evaluations obtained with the Clinitek 500 and sulfosalicylic acid precipitation test methods. RESULTS: The urinary dipstick pH measurement had a very high correlation (r = .98) with the pH meter technique. Samples with alkaline pH (>or=7.5) analyzed for protein by dipstick analysis were in complete agreement 34.7% of the time with the quantitative technique, which was very similar to the 39.3% agreement for samples with neutral and acidic pH (urine dipstick method does not lead to gross overestimation of urinary protein concentration in alkaline urine and provides a rapid and reasonably accurate way of determining the presence or absence of urinary protein in rats.     

改性沸石吸附柱去除和回收脱磷尿液废水中氨氮试验研究

经鸟粪石沉淀法回收尿液中磷后的废水中仍含有高浓度的氨氮,若直接排放,不仅会造成水体污染,也导致氮资源浪费。本文在5％HCl浸提,400℃焙烧,结合微波处理改性沸石以提高氨氮吸附能力的基础上,研究了改性沸石吸附柱高度（H）、吸附柱串联数量（N）以及水力停留时间（T）对脱磷尿液废水中氨氮去除效果的影响,评价了HCl溶液、NaCl溶液及其组合对吸附氨氮饱和的沸石的再生效果。结果表明：HCl-焙烧-微波改性沸石对氨氮的平衡吸附量为17．9mg·g-1,是天然沸石对氨氮平衡吸附量（6．9mg·g^-1）的2．6倍。当柱高H=35cm,水力停留时间亚2．0h,吸附柱串联个数N=3时,改性沸石对脱磷尿液废水中氨氮的去除效果最佳。当吸附柱内氨氮负荷小于6370mg时,吸附柱出水中氨氮浓度低于30mg·L-1。10％HCI＋5g·L-1 NaCl混合液作为沸石再生剂时,氨氮洗脱率达到88．3％,再生沸石的平衡吸附量可达16．4mg·g-1,为改性沸石的91．6％。可见,改性沸石吸附柱可有效去除脱磷尿液废、水中氨氮,同时10％HCI＋5g·L-1 NaCl混合溶液能够有效实现沸石再生和氨氮回收。研究结果为脱磷尿液废水中氨氮处理与回收中试试验奠定了基础。