涝峪苔草微量元素的季节变化

为了分析涝峪苔草不同生长季节的微量元素变化,对涝峪苔草在春、秋、冬三个季节的Mn、Zn、Fe、Cu、Mg等5种微量元素进行了研究。结果表明:被测样品干重在不同季节由高到低表现为,秋季＞春季＞冬季。季节的变化对涝峪苔草体内微量元素有着一定影响,从不同季节几种元素的含量来看,Mn的含量冬季高于春季和秋季,差异极显著(p＜0.01);Zn的含量冬季高于秋季和春季,差异不显著(p＞0.05);Fe的含量冬季高于春季和秋季,差异不显著(p＞0.05);Cu的含量春季高于秋季和冬季,差异显著(p＜0.05);Mg的含量冬季高于秋季和春季,差异显著(p＜0.05)。     

东北稻蟹中18种微量元素含量及健康风险评价

为探讨东北地区（黑龙江省、吉林省和辽宁省）稻田养殖河蟹的微量元素含量水平和食用安全性,于2017年9月在东北主要养殖区采集稻田养殖河蟹56份,利用电感耦合等离子体质谱法（ICP-MS）检测了河蟹体内18种微量元素的含量,并采用单因子污染指数（P_i）和每周可耐受摄入量（PTWI）、目标危害商值（THQ）法分别评价了其污染程度和食用安全性。结果表明：河蟹中检出的大多数微量元素含量远高于该地区池塘养殖的淡水鱼类;吉林省河蟹体内的Cr、Cd、U等10种微量元素含量与其他两省份相比存在显著性差异（P<0.05）;所有样品的Cu、Pb、Cd和Cr含量均未超出国家食品安全标准;5种重金属（Cu、Zn、Pb、Cd和Cr）的成人每周实际摄入量（AWI）低于食品添加剂联合专家委员会（JECFA）推荐的每周可耐受摄入量;5种重金属和其他4种有害微量元素（Ba、U、Ag和Be）的人体每日摄入量（EDI）低于美国环保署（USEPA）推荐的参考剂量（RfD）。研究表明食用东北稻田养殖河蟹摄入的微量元素对食用人群没有明显的健康风险。在检测的18种微量元素中,Ba、Pb和Cd对复合污染物风险指数（HI）贡献率较高,是主要的风险元素。     

不同品种枇杷果实微量元素分析及综合评价

本研究采用电感耦合等离子体质谱法（ICP-MS）测定23种枇杷果实中9种微量元素含量,并对果实的外观品质指标进行测定,运用主成分分析、聚类分析方法及结合SPSS 19.0统计软件对测定结果进行综合评价。结果表明：（1）不同品种枇杷果实中微量元素含量顺序均为：Mn>Zn>Fe>Cu>Ni>Co>Mo>Se>V。其中Mn、Fe和Zn 3种微量元素是枇杷果实中主要微量元素,主成分分析筛选出4个主因子,枇杷果肉中Mn、Co、Cu和Se是枇杷的特征微量元素,综合得分较高的前3个品种依次是‘新霄’、‘卓南1号’和‘少核大红袍’。（2）根据微量元素含量将枇杷分为3个类型,即高Zn、Fe含量类型,包括‘木鱼种’、‘小毛枇杷’等共计19个品种;高Cu含量类型,包括‘少核大红袍’和‘湖北二六’;高Mn、Co含量类型,包括‘卓南1号’和‘新霄’。（3）对果实中微量元素之间相关性分析发现,元素Mn和Co、Cu之间表现为极显著性相关,相关系数分别为0.852和0.538;此外元素V和Fe、Zn,元素Co和Cu之间表现出显著相关,元素Ni和Se表现为显著相关。同时对微量元素与果实品质之间做相关性分析表明,Fe与果肉中的可溶性固形物呈极显著相关;元素Cu与果实横径表现为极显著相关。综合分析表明,枇杷中富含Fe、Zn、Mn等有益微量元素,且含有特征微量元素Se。‘新霄’是23个品种中营养价值最高的品种。     

氮肥基追施比例对芝麻产量和氮素吸收、分配的影响

【目的】研究实现芝麻高产、提高氮肥利用效率、减少氮肥残留的氮肥最佳基追比例。【方法】采用盆栽试验,供试芝麻品种为‘郑太芝1号’,设置4个氮肥基追比例处理,氮肥底施与初花期追施比例分别为1∶0(N1∶0)、2∶1(N2∶1)、1∶2(N1∶2)、0∶1(N0∶1)。利用15N示踪技术,每盆施含有15N标记的总氮0.9g,分析各处理芝麻产量及氮素的吸收、分配特征。【结果】不同处理相比,N2∶1处理单株产量最高,N1∶2处理次之,N2∶1与N1∶0、N0∶1处理差异达显著水平。在初花期,N2∶1处理,芝麻单株生物量和植株总吸氮量均最高,不施基肥的N0∶1处理最低;各处理植株对肥料氮的吸收表现为N1∶0>N2∶1>N1∶2,对土壤氮的吸收以N2∶1最高;肥料氮和土壤氮在各器官中的分配均为叶>茎>根。在成熟期,N2∶1处理的单株总生物量最大,单株籽粒吸氮量和总吸氮量也最高,N1∶0处理最低,两者差异达显著水平;植株对肥料氮和土壤氮的吸收比例为23.7%~29.1%和70.9%~76.3%;对肥料氮和土壤氮的吸收均为籽粒>叶片>茎>蒴皮>根,籽粒吸氮量明显高于其它器官,籽粒占总吸氮量的33.0%~44.3%。N2∶1处理氮肥利用率最高,为32.5%,N2∶1、N1∶2、N0∶1处理间差异不显著,但均与N1∶0(17.8%)差异达显著水平。不同处理芝麻收获后土壤15N回收率以N2∶1处理的最低(16.2%),N0∶1处理的最高(31.3%)。【结论】在本试验条件下,氮肥底施与初花期追施比例为2∶1时,芝麻产量和生物量以及氮肥利用率最高,氮肥土壤残留量最少,是最佳氮肥基追施比例。     

陕西关中地区肉牛产地同位素溯源技术初探

为应用牛组织中C、N同位素组成的区域分布和同位素指标溯源肉牛产地,本文利用同位素比率质谱仪(IRMS)对陕西关中不同区县来源的牛尾毛样品的1δ3C和1δ5N值进行检测,通过聚类分析,研究陕西关中地区肉牛组织中同位素组成的区域分布情况。结果表明,杨凌区、眉县牛尾毛样品聚为一类;乾县、永寿县样品聚为一类;麟游县样品聚为一类;扶风县、岐山县和凤翔县分类不十分明显,分散在上述3类中。说明陕西关中不同地区肉牛组织中同位素组成存在差异,利用它们可进行肉牛地域的小范围溯源。     

槐叶萍生物体微量元素含量特征研究

为了解京杭运河台儿庄段槐叶萍生物体中微量元素的含量特征,运用非色散原子荧光光度计和火焰原子吸收分光光度计测定了槐叶萍生物体不同部位中微量元素的含量。结果显示:Fe、Mn、Zn、Ni、Cu、Se 6种微量元素在槐叶萍花芽、叶、根与茎中含量差异极显著(P≤0.01),其中槐叶萍中微量元素Fe含量最高,Se的含量最低;与同科植物体比较,京杭运河台儿庄段槐叶萍生物体中微量元素Fe、Mn含量处于中等水平,Zn、Cu含量处于下游水平。     

Spatial and temporal variation in otolith chemistry and its relationship with water chemistry: Stock discrimination of Sperata aor

Long‐whiskered catfish, Sperata aor (Hamilton 1822), is commercially important in food, ornamental and sport fisheries. The fish is mainly caught from the wild populations because its aquaculture practices are not commercialised. Inland fishery in the Ganga basin is mostly unorganised; hence, no published report is available on the trend of S. aor production from the selected habitat. In India, S. aor has been categorised vulnerable mainly due to natural and anthropogenic threats. Otolith chemistry shows variation with changing physico‐chemical conditions of the fish habitat. Therefore, the present study was conducted with the objective to analyse spatio‐temporal variations in water chemistry in relation to environmental factors; relationship between water and otolith chemistry; and spatio‐temporal variations in otolith chemistry to discriminate the stocks of S. aor inhabiting the River Ganga. Most of the element: Ca ratios in water samples did not show significant correlations with environmental factors, viz. temperature and conductivity. Only few element: Ca concentrations in otoliths were positively correlated to their corresponding ratios in the ambient water. In the selected study area, the S. aor populations were discriminated into four stocks possibly because of heterogeneous water chemistry at the sampling sites, and physical barriers. In the present study, otolith chemistry showed relatively low temporal variability as compared to spatial variability; thus, the classification accuracy of individuals to their original populations remained consistent over the selected time period. The findings could be useful in devising scientifically sound management strategies and/or any conservation plans for the vulnerable S. aor populations inhabiting the River Ganga.     

Random-effects linear model application to herd-level assessment of bovine hepatic trace mineral concentrations

To evaluate the utility of random-effects linear modeling for herd-level evaluation of trace mineral status, we performed a retrospective analysis of the results for trace mineral testing of bovine liver samples submitted to the Michigan State University Veterinary Diagnostic Laboratory between 2011 and 2017. Our aim was to examine random-effects models for their potential utility in improving interpretation with minimal sample numbers. The database consisted of 1,658 animals distributed among 121 herds. Minerals were assayed by inductively coupled plasma–mass spectroscopy, and included cobalt, copper, iron, molybdenum, manganese, selenium, and zinc. Intraclass correlation coefficients for each mineral were significantly different (p < 0.001) from zero and ranged from 0.38 for manganese to 0.82 for selenium, indicating that the strength of herd effects, which are presumably related to diet, vary greatly by mineral. Analysis of the distribution and standard errors of best linear unbiased predictor (BLUP) values suggested that testing 5–10 animals per herd could place herds within 10 percentile units across the population of herds with 70–95% confidence, the confidence level varying among minerals. Herd means were generally similar to BLUPs, suggesting that means could be reasonably compared to BLUPs with respect to the distributions reported here. However, caution in interpreting means relative to BLUPs should be exercised when animal numbers are small, the standard errors of the means are large, and/or the values are near the extremes of the distribution.     

饲粮组成对牛乳中乳蛋白及乳脂肪合成与调控机理影响的研究进展

牛乳中的营养物质对人类健康有着相当大的益处,乳蛋白和乳脂肪作为牛乳营养品质的物质基础,还与奶牛生产性能息息相关,受到人们的广泛关注。本文从牛乳中基本营养物质的种类和功能出发,重点介绍了饲粮组成的改变及添加植物提取物、微量元素、微生态制剂等对乳蛋白及乳脂肪合成与调控机理的影响,为科学合理地调整饲粮营养组成,提高牛乳中乳蛋白率和乳脂率提供理论依据。     

微量元素对黑麦草产量和品质的影响

在N、P、K肥料的基础上,采用Fe、Cu、Zn、Mn、B、Mo 6种微肥对黑麦草Lolium multiflorum进行叶面喷施,研究不同用量对黑麦草产量和品质的影响。试验表明：喷施Fe 0.05%、Cu 0.07%、Zn 0.40%、Mn 0.10%、B 0.60% 和Mo 0.20%与对照组相比增产差异显著（P＜0.05）。适度的Fe、Cu、Mn、B和Mo能提高黑麦草的粗蛋白、粗纤维和粗灰分含量,粗蛋白提高3.72%～6.67%,无氮浸出物含量呈降低趋势,喷施Zn肥降低了粗蛋白含量,喷施B肥提高了粗脂肪含量。黑麦草中Cu、B、Mo的含量随喷肥量的提高而增加,喷施Cu 0.1%、B 1%和Mo 0.3%时,黑麦草中的含量最高,与对照组差异显著（P＜0.05）。喷施Zn 0.40%、Mn 0.1%、Fe 0.05%时牧草中相应的微量元素最高,与对照组差异显著（P＜0.05）。