动物有机微量元素吸收机制及吸收研究方法的进展

本文综述了有机微量元素可能的吸收机制和微量元素吸收的研究方法 ,以便深入了解有机和无机元素在动物体内吸收和代谢的异同 ,为在畜牧业生产中科学、有效地应用微量元素添加剂提供理论依据     

Effect of Application Method on the Efficiency of Potassium Chloride in Wetland Rice on a Beidellitic Potassium Problem Soil

A greenhouse pot experiment evaluated the effect of incorporation and placement on the efficiency of KC1 in wetland rice on a K-problem soil with beidellitic clay mineralogy and high tendency to fix added K.
Placement turned out to be superior to incorporation by increasing significantly both grain and straw yields.

Zusammenfassung

Einfluß der Anwendungsmethode auf die Effizienz von Kaliumchlorid in Wasserreis auf einem beidellitischen Kali-Problem-Boden
In einem Gewächshaus-Gefäßexperiment wurde der Einfluß des Einmischens und der Plazierung auf die Effizienz von KC1 bei Naßreis in einem K-Problemboden mit beidel-litischem Ton, der eine starke Tendenz zur Fixierung von gedüngtem Kalium aufwies, untersucht. Die Plazierung erwies sich gegenüber einer Einmischung überlegen; dies galt signifikant sowohl für Korn- als auch Stroherträge.     

Effect of rootstocks on the leaf mineral content of citrus

Leaves from ‘Valencia’, ‘Hamlin’ and ‘Washington Navel’ oranges grown on ‘Rangpur’ lime, ‘Cleopatra’ mandarin, ‘Sour Orange’, ‘Troyer’ citrange and ‘Rough Lemon’ root-stocks were analzed for N, P, K, Ca, Na, Cl, Fe, Mn, Cu and Zn. Significant differences among rootstocks were obtained for K, Ca, $\text{Ca}\text{K}$, Na and Cl, but not for N, P, Fe, Mn, Zn and Cu. Scion leaves on ‘Cleopatra’ mandarin tended to be low in K and high in $\text{Ca}\text{K}$ and those on ‘Rangpur’ lime were high in K and low in Ca and $\text{Ca}\text{K}$. ‘Troyer’ citrange induced higher uptake of Na and Cl than all other rootstocks. ‘Washington Navel’ leaves contained more Fe, Zn, Cu and Mn, and less Na, than ‘Hamlin’ or ‘Valencia’ leaves. ‘Valencia’ leaves contained more Ca and less K than the other two cultivars. The nutritional status of the trees was slightly low in N, K and Mn, optimum in Fe, Zn and Cu, normal-to-high in P, and contained non-toxic levels of Na and Cl. The statistical interaction of root stock and scion was found non-significant.     

Effects of different strategies of mineral supplementation (marine algae alone or combined with rumen boluses) in organic dairy systems

This study was designed to evaluate the effect of marine algae supplementation alone or in combination with a regular mineral supplement (rumen boluses) to improve the mineral status in organic dairy cattle and their effect on the milk mineral composition, milk production, composition (% of fat and protein) and quality (SCC). Thirty‐two Holstein Friesian lactating cows were randomly selected and assigned to the algae (A), boluses (B), algae+boluses (AB) and control group (C). For the algae groups (A, AB), a supplement composed of Sea Lettuce (80%), Japanese Wireweed (17.5%) and Furbelows (2.5%) was formulated to be given to the cows at the rate of 100 g/animal per day (A1) for the length of 4 weeks. In the second half of the experiment (weeks 5–8), the algae mixture was reformulated and the proportion of Furbelows was increased from 2.5% to 5.0% with a subsequent decrease of Lettuce to 77.5% (A2). In the boluses group (B), each cow received 2 boluses after calving. Blood (serum) and milk samples were collected at 2 and 4 week intervals, respectively, and analysed for trace element concentrations by ICP‐MS. Information related to the milk composition and SCC during a 305‐day lactation for each animal were obtained from the Dairy Records Management System. The supplementation with algae, boluses or the combination of both treatments showed a statistically significant effect on the iodine (algae), selenium (boluses) and cobalt (algae+boluses) status of the animals. In milk, treatments had a statistical significant increase on iodine, and a tendency to increase selenium concentrations. The assayed algae mixture combined with another source of selenium could be an effective tool to improve the mineral status in serum and milk.     

Effects of low phosphorus supply on the availability of calcium and phosphorus,and musculoskeletal development of growing dogs of two different breeds

To investigate the impact of a selective reduction in dietary phosphorus (P) supply on healthy growing dogs, a total of 23 Beagles and 30 Foxhound crossbreds (FBI) were used in a feeding trial between 6 and 24 weeks of age. Sixteen Beagles and 19 FBI were fed with selectively reduced P concentrations (low phosphorus, LP). The remaining puppies received a completely balanced control diet (CON). With these diets, the P supply in the Beagles at the age of 12 weeks added up to 2.5 ± 0.6 (LP) and 9.8 ± 1.4 g P/kg DM (CON), and in the FBI 4.3 ± 0.9 (LP) and 13.0 ± 1.6 g P/kg DM (CON). Therefore, the LP Beagles received an average of 33 ± 11% of the recommended daily allowances (RDA) of P, the LP FBI 41 ± 11%. The calcium (Ca) concentration stayed unaltered and led to a Ca/P ratio above the recommended range of 1.3/1 to 2/1. The apparent digestibility (aD) of phosphorus was reduced in the LP Beagle; otherwise, the aD of both minerals was not affected by the P concentration of the diet. The renal excretion of P was reduced to zero in both LP groups while the renal calcium excretion increased significantly. Several of the puppies from both breeds showed impaired appetite, growth, skin and fur quality, and a few also clinically showed relevant signs of a disturbed musculoskeletal system after the LP feeding. A rapid loss of muscle strength and posture within hours led to severe deviation of the limb axis with hyperflexion of the joints but no radiological aberrations or signs of pain. Immediate transition of affected puppies to a balanced diet with sufficient phosphorus resulted in a complete recovery of the puppies in less than one month. The results demonstrate the importance of an adequate P supply on the healthy development of growing dogs.     

Radiocesium interception potential (RIP) of smectite and kaolin reference minerals containing illite (micaceous mineral) as impurity

Cesium-137 (¹³⁷Cs) is strongly adsorbed on clay minerals, especially on illite. The adsorption of Cs⁺ on reference clay minerals, however, has not been fully investigated in relation to the presence of illite. The objective of this study was to clarify the effect of impurities (i.e., illite and vermiculite), present in reference smectite group minerals and kaolin minerals, on the retention of Cs⁺. The clay mineralogy of the reference minerals was characterized by X-ray diffraction (XRD). The radiocesium interception potential (RIP) was measured as an index of the Cs⁺ retention ability of clays. The content of illite in clay was represented by the total potassium (K) content given that illite is a major source of K in the clay fraction. The content of vermiculite in clay was represented by the Cs fixation capacity induced by Cs saturation followed by heating of samples at 110°C. Metabentonite and beidellite gave extremely high RIP values compared with other smectite group minerals, although a peak for illite (at 1.0 nm) was not observed in XRD analysis. The reference smectite and kaolin minerals showed a range of RIP values, even though their RIP values are theoretically zero. The RIP values had a significant positive correlation with the total K content of all the reference clay minerals (r_s = 0.621*). This indicated that the retention ability for ¹³⁷Cs depended more on the content of illite, as impurity, rather than the type of bulk mineral. Hence, the contribution of illite to the magnitude of the RIP was elucidated by the combination of measurement of total K content and XRD analysis.     

水分非饱和条件下土壤矿物界面有毒有机物转化机制研究进展

土壤矿物作为土壤重要活性组分，可驱动土壤有毒有机物化学转化，降低污染风险。以往土壤矿物与有毒有机物界面行为研究主要集中于水环境或矿物悬浊液体系，然而实际环境中土壤及其矿物常处于干燥、湿润等水分非饱和状态。近年来，水分非饱和条件下土壤矿物界面有毒有机物转化及机制已成为研究热点，相关研究获得一系列新发现。低含水量铁锰矿物、黏土矿物和金属离子饱和黏土矿物能驱动多环芳烃、抗生素等疏水性有毒有机物化学转化。水分非饱和环境会减弱矿物界面水分子与有毒有机物竞争活性位点，并使矿物发生脱水、向高活性结构转变。此外，土壤矿物水分状态也会影响有毒有机物转化产物，水分非饱和环境更有利于持久性自由基和卤代二噁英等中间产物的形成和稳定。以往研究认为，电子转移反应是土壤矿物界面有毒有机物转化机制，随着检测技术与理论计算的发展，自由基催化和水解作用机制逐渐被发现，相关机制研究精准至矿物晶型和晶面层面。虽然水分非饱和条件下土壤矿物界面有毒有机物转化及机制已逐渐清晰，但其研究广度和深度有待进一步拓宽和加深。建议未来在实际水分非饱和土壤和矿物中开展有毒有机物转化研究，深入探究还原转化过程，研发原位反应装置及检测方法，尝试从微纳米尺度和分子水平解析有毒有机物在矿物界面转化机制。     

陕西省3种北极狐饲料中矿物质元素的含量分析

随机抽取陕西境内 3家养狐场哺乳期北极狐饲料 ,对其中的Ca、P、K、Mg、Fe、Cu、Zn、Mn、Co、Se 1 0种矿物质元素的含量进行了检测。结果表明 ,在 3种饲料样品中Ca、Mg、Mn、Co、Se的含量都明显偏高 ,Cu、Zn基本符合要求。另外 ,P在A样中含量较高 ,C样中基本符合要求 ,而B样中略低 ;但部分元素如Ca与P、Cu与Zn、Zn与Ca、P与Cu等之间的比例严重失调。     

饲料中添加不同水平锰对生长育肥猪增重和组织中矿物元素沉积的影响

选用施格×三江白猪杂交一代幼猪25头,随机分成5组(分别为1,2,3,4,5组),每组5头,分圈饲养.在含锰27～31ppm的玉米-豆粕型实用无鱼粉日粮中分别添加锰(以MnSO_4·5H_2O形式)0ppm,20ppm.40ppm,80ppm,160ppm,依次饲喂各组试验猪.应用最优非线性回归方法及通径分析方法探讨了30～90kg阶段生长肥育猪日粮中添加不同水平锰对增重和组织中几种矿物元素(钙、磷、镁、锌、铁、铜)沉积的影响.结果表明,日粮锰在27～191ppm范围内对30～90kg生长育肥猪的生长发育无不良影响.日平均采食量(ADF)变化不显著(P>0.05);第2组(日粮锰含量为47～51ppm)猪的平均日增重(ADG)、饲料效率(G/F)较其他组高(P<0.01或0.05);锰对增重具有直接促进作用(P_1=0.2687),但含量不宜过高(Σrijpy=-1.1470).铜沉积的升高,是引起增重的原因之一(P_7=0.4207,Σrijpyi=0.5286).被毛作为评定锰营养状态的指标是可取的.锰沉积与其他几种矿物元素沉积的关系非常复杂,建立了有关的回归模型.