长期饲喂高锌日粮对断奶仔猪免疫机能的影响

试验选用60头23日龄±1日龄临床检查健康的"杜×长×大"三元杂交断奶仔猪,按体重和性别随机分成3组,每组20头,分别饲喂基础日粮、基础日粮 3000mg/kg氧化锌、基础日粮 500mg/kg蛋氨酸锌,测定断奶仔猪免疫机能的变化。结果显示,在断奶后0d～21d饲喂高锌日粮能显著提高仔猪白细胞吞噬率和T淋巴细胞转化率,增加血清免疫球蛋白水平;而在断奶后42d、70d,仔猪白细胞吞噬率、T淋巴细胞转化和血清IgG、IgA水平显著下降。     

Influence of Graded Levels of Organic Zinc on Growth Performance and Carcass Traits of Broilers

This study investigated the effect of graded levels of organic Zn (Bioplex Zn) on growth performance and carcass traits of broilers fed diets containing organic Se (Sel-Plex). Dietary treatments consisted of adding 0, 15, 30, 45, or 60 ppm organic Zn to a basal diet containing 60 ppm Zn from an inorganic source. Feed and water were provided ad libitum. Body weight, feed intake, feed conversion, and carcass traits were evaluated. Carcass evaluation was also performed on the last day of the experimental period. Body weight, feed intake, feed conversion, and weights of individual meat cuts were not statistically influenced by increasing organic Zn levels in the diet. However, a significant increase in skin tearing strength was observed in response to increasing levels of dietary organic Zn. Zinc plays a role in epithelial cell layers and collagen synthesis, thus affecting susceptibility of skin to tearing. These data indicated that organic Zn does not affect growth performance of broilers but increases resistance of skin to tearing, therefore improving carcass quality.     

Cu^2＋、Zn^2＋复合条件下Cd^2＋在陕西5种土壤中的吸附

通过平衡吸附的方法,研究了Cd2＋在单一及与Cu2＋、Zn2＋复合条件下,在陕西塿土、黄绵土、黑垆土、黄褐土、砂土5种土壤中的吸附特征,并通过多重相关分析探讨了其吸附机制。结果表明,在20、30℃条件下,Cd2＋在各供试土样中吸附等温线总体上呈H或L型等温线形式,黑垆土对Cd2＋总是吸附最强,而砂土的吸附总是最弱;Cd2＋吸附的温度效应呈现升温负效应特征,塿土土样中,Cu2＋的共存对其温度效应影响较大,而在其他4种土样中Zn2＋的共存具有较大影响;Cu2＋、Zn2＋的共存均降低了Cd2＋的吸附量,具有显著的拮抗作用;Freundlich模型是描述Cd2＋吸附等温线最佳模型。相关分析结果表明,Cd2＋在土壤中的吸附主要以电性引力吸附为主,Cu2＋的共存主要和其与土壤有机质之间的络和吸附等化学吸附作用有关,因此其对Cd2＋以化学竞争性吸附的影响相对较弱,而Zn2＋共存吸附与Cd2＋吸附机制类似,因此表现出Zn2＋共存对Cd2＋吸附影响较大的特点。     

编码棉花胞质铜锌超氧物歧化酶基因的克隆与表达分析

 【目的】克隆编码棉花胞质铜锌超氧化物岐化酶基因并分析其表达特性。【方法】采用 RACE 技术克隆基因，Northern blotting 检测基因的表达谱；采用氮蓝四唑（NBT）光下还原法测定不同生育期的酶活性。【结果】获得了棉花胞质铜锌超氧化物岐化酶基因cDNA 全长序列（GenBank 注册号：DQ445093）；该基因cDNA全长共682 bp，开放阅读框456 bp，编码152个氨基酸。分子结构预测结果：酶蛋白理论分子量约为15.03 kD，理论等电点为6.09，与其它植物的蛋白质氨基酸序列同源性在82%～87%之间。Southern blotting显示不同棉种该基因的拷贝数基本一致，均属于低拷贝基因。Northern blotting显示该基因在不同的组织、不同的生育期表达量不同；酶活性测定显示盛花期最高。【结论】棉花胞质铜锌超氧化物岐化酶基因在陆地棉中属于低拷贝数基因；在整个生育期中mRNA的含量呈规律性动态变化，前期较低，后期较高，在盛花期达到顶峰；变化曲线与不同时期的酶活性变化一致；不同器官的基因表达检测结果显示：基因在根中表达量最高，叶片次之，花中的表达最低。     

军曹鱼幼鱼日粮锌最适添加量的研究

试验选用234尾军曹鱼随机分为6个处理,每处理设3个重复,每重复13尾鱼,采用单因素浓度梯度法研究军曹鱼幼鱼商品饲料中锌的最适添加量。在基础日粮(锌含量为75.47mg/kg)中分别添加锌0、30、70、110、150和190mg/kg,制成6种试验日粮,分别投喂军曹鱼幼鱼6周。试验结果表明,基础日粮组鱼成活率、饲料系数、特定生长率、血清碱性磷酸酶(AKP)活性、肌肉和血清锌含量与添加锌组无显著差异(P>0.05)。添加锌组骨骼和肝脏锌含量与基础日粮组差异显著(P<0.05),表现为随锌添加的增加而上升的趋势。以成活率和特定生长率为评价指标,军曹鱼商品日粮中的锌含量可以满足其正常生长需求,不需要额外添加锌。     

火焰原子吸收光谱法测定奶粉中锌的含量

采用原子吸收光谱法测定多种品牌奶粉中锌的含量,对干法消化奶粉所用混合酸的组成、比例等试验条件进行了研究,其最佳样品处理条件为:硝酸-高氯酸(4+1)作为溶解用酸,1 mol/L盐酸作为定容用酸,测定结果的相对标准偏差小于2%.     

苜蓿草粉比例对豁鹅蛋黄铁锌含量的影响

本试验采用3×3因子设计,将日粮苜蓿草粉比例设为10%、20%、30%三个水平、蛋白质设为15.83%、14.01%、12.74%三个水平。选用180只12月龄健康产蛋豁鹅,随机分为9组,每组20只,试验期20d。研究日粮苜蓿草粉比例和蛋白水平及二者交互作用对豁眼鹅蛋黄铁锌含量的影响。结果表明,苜蓿草粉比例增加使蛋黄铁含量呈降低趋势,而日粮蛋白质水平对蛋黄铁含量无显著影响;日粮苜蓿草粉比例和蛋白质水平的交互作用对蛋黄铁含量无显著影响（P〉0.05）。苜蓿草粉比例增加使蛋黄锌含量呈增加趋势,而日粮蛋白质水平     

高锌日粮对断奶应激仔猪血清激素水平的影响

选用100头(26±2)日龄"杜长大"三元杂交断奶仔猪,按体重和性别随机分成5组,每组20头,分别饲喂基础日粮、基础日粮 2 000 mg·kg-1氧化锌、基础日粮 3 000 mg·kg-1氧化锌和基础日粮 250 mg·kg-1蛋氨酸锌、基础日粮 500 mg·kg-1蛋氨酸锌.试验期14 d.断奶后于前腔静脉采血,测定部分血清激素水平.结果表明,断奶应激仔猪血清生长激素(GH)、胰岛素(INS)、胰岛素样生长因子-Ⅰ(IGF-I)和三碘甲腺原氨酸(T3)水平显著下降,血清皮质醇水平显著升高.日粮添加高剂量锌,显著提高断奶仔猪血清GH、INS、IGF-I和T3水平.实验证实,高锌日粮能抑制仔猪断奶应激,调节仔猪促生长激素轴.     

Turf Response to Superferrite Fertilizer in Contrasting Soil Types

Abstract

Superferrite is marketed as a turf fertilizer in the United States, but there is limited information on its effectiveness or potential risks due to high zinc (Zn) and lead (Pb) contents. A greenhouse study was conducted where hybrid bermudagrass and tall fescue, growing in a calcareous clay or acid sandy soil, and creeping bentgrass, growing in a putting green root zone mix, were fertilized with 0, 50, 100, and 150% the recommended rate of Superferrite fertilizer (73.4 g m^?2). Bermudagrass and tall fescue clipping weights increased with Superferrite rate but root mass was not affected. Tissue iron (Fe) concentrations were mostly unaffected by Superferrite, but total Fe uptake, tissue Zn, and total Zn uptake increased with Superferrite rate. Increased yields were probably due to increasing nitrogen (N) applications rather than Fe or Zn. Small increases in Pb uptake with Superferrite applications suggest that Superferrite Pb had low bioavailability to turf.     

Bioaccumulation and interrelationship of manganese and zinc in horse mussel Modiolus modiolus fromEastern Canada

ABSTRACT:   Bioaccumulation and distribution of Mn and Zn in the total softtissues, digestive glands, residuals and adductor muscles of thehorse mussel Modiolus modiolus from three sites, includingindustrialized and non-industrialized locations in Eastern Canada,were investigated. Extremely high digestive gland metal concentrationswere found in individual mussels, as high as 1819 µg/gMn wet weight and 1964 µg/g Zn wet weight,with mean values from 358 to 404 µg/gMn and from 399 to 614 µg/g Zn for thecollection sites. High Mn to Zn interrelationships were observed inall types of tissues and at all sites. Between different tissues,Zn was interrelated by linear relationships, and Mn was best describedby power curve relationships for all tissue types. In the totalsoft tissue, Mn and Zn interrelations were fitted to power regressioncurves with different slopes between the three study sites. Thisindicated that horse mussel was exposed to different metal levels inthe environments and could be useful for monitoring these metals.The uptake of both metals at extremely high concentrations, thelack of regulation and the occurrence of interactions all suggest thatMn and Zn may play a biological role in horse mussels. Zn and Mninteractions, surprisingly, were not disrupted at the very highconcentrations of either metal, which proves that the mechanism ofmetal interactions does not involve a detoxification role.