利用微波消解-火焰原子吸收法测定不同类型饲料中常量元素含量的可行性分析

为研究微波消解-火焰原子吸收法测定饲料中钾、钠、钙、镁、铁、锰、铜和锌8种元素含量的可行性分析,本实验采取微波消解法代替传统的干灰化法,加入氯化铯、硝酸镧作为消电离剂及掩蔽剂,各元素的质量浓度在一定范围内与吸光度值呈线性关系,而且线性相关系数(R2)均达到0.995以上,满足仪器的要求;曲线最低点可以做到0.10mg/L,最高点可以做到7.00mg/L;方法检出限为0.68~207mg/kg,方法重现性(RSD)均小于3%,质控样在质控范围内,通过对实际多种类样品的测定,结果的准确度和精密度均符合饲料国标要求。综上,微波消解-火焰原子吸收法是一种速度快、成本低的联合检测方式,可以用于不同类型的饲料中钾、钠、钙、镁、铁、锰、铜和锌8种元素含量的测定。     

不同品种嫩果椰水主要品质性状、矿质元素含量分析

以海南4个主栽椰子品种为试材,研究不同品种嫩果椰水基本性状间及椰水中的矿质元素(K、Ca、Na、Mg、Fe、Mn、Cu、Zn)含量间的差异。结果表明,嫩果椰子水的pH平均值为5.50～5.58;可溶性固形物含量为5.60%～7.75%;测定的8种矿质营养元素中,K含量最高,达355.93mg/kg,Na为32.70mg/kg,Ca为6.36mg/kg,Mn为2.67mg/kg。各品种间存在显著和极显著差异。3个矮种椰子品种均具有各自特点,均可作为嫩果椰子品种发展,可根据不同特色矮种椰子的观赏价值、生态价值、经济价值和营养价值,规模栽培矮种椰子,发展海南热带旅游观光农业。     

深县猪肉质及营养价值分析

本研究选择国外猪种杜洛克和中国地方猪深县猪体重 95 kg 的阉割公猪各 5 头,比较 2 个猪品种背最长肌之间肉质、氨基酸、脂肪酸和微量元素的差异。结果表明:杜洛克猪的肌内水分、肉色、大理石纹、滴水损失、粗蛋白质和脂肪含量低于深县猪(P<0.01);杜洛克猪背最长肌中谷氨酸、天冬氨酸、精氨酸、组氨酸、丝氨酸、脯氨酸、甘氨酸、苏氨酸、半光氨酸、丙氨酸、缬氨酸、苯丙氨酸、异亮氨酸、酪氨酸、亮氨酸、呈味氨基酸总量、必需氨基酸和总氨基酸含量低于深县猪(P<0.01);杜洛克猪背最长肌的饱和脂肪酸含量棕榈酸、豆蔻酸、硬脂酸和花生四烯酸多不饱和脂肪酸亚油酸和亚麻酸低于深县猪(P<0.01);单不饱和脂肪酸棕榈油酸含量低于深县猪(P<0.01),而油酸没有显著性差异;杜洛克猪背最长肌中微量元素钾、锶、铜、锌、硅和铬含量均低于深县猪(P<0.01),镍差异显著(P<0.05)。结果显示,中国地方猪深县猪在肉质及营养价值方面优于瘦肉型的杜洛克猪,为深县猪的品种资源保护和肉产品的开发利用提供依据。     

The biomechanical construction of the horse's body and activity patterns of three important muscles of the trunk in the walk,trot and canter

The activity patterns of trunk muscles are commonly neglected, in spite of their importance for maintaining body shape. Analysis of the biomechanics of the trunk under static conditions has led to predictions of the activity patterns. These hypotheses are tested experimentally by surface electromyography (EMG). Five horses, with and without a rider, were examined in the walk, trot and canter. Footfall was synchronised with EMG by an accelerometer. Averages of ten consecutive cycles were calculated and compared by statistical methods. The start and stop times of the muscle activities of 5–10 undisturbed EMG plots were determined and the averages and standard deviations calculated. In walking, muscle activities are minor. Electromyography (EMG) activity was increased in the m. rectus during the three‐limb support. When the bending moments assume their greatest values, for example while the horses' mass is accelerated upward (two times earth acceleration) in the diagonal support phases in trot and canter the m. rectus, connecting the sternum with the pubic bone is most active. The m. obl. externus is most active when the torsional and bending moments are greatest during the same support phases, but not bilaterally, because the forces exerted on one side by the (recorded) m. obl. externus are transmitted on the other side by the (not recorded) m. obl. internus. While the hindlegs touch the ground in the trot and canter, ground reaction forces tend to flex the hip joint and the lumbar spine. Therefore, the vertebral column needs to be stabilised by the ipsilateral m. longissimus dorsi, which in fact can be observed. As a whole, our EMG data confirm exactly what has been predicted by theoretical analysis.     

柑橘黄龙病对纽荷尔脐橙叶片营养元素及土壤微生物群落的影响

柑橘黄龙病(Citrus Huanglongbing, HLB)堪称柑橘的癌症,严重为害产业健康发展。本研究采用盆栽试验,通过ICP-MS、平板计数法及微平板法测定了不同染病时间的纽荷尔脐橙叶片的矿质营养元素含量、土壤微生物种群数量及微生物功能多样性。研究结果表明,在黄龙病侵染的纽荷尔脐橙病株中,叶片中显著性减少的矿质营养元素多与叶绿素合成及光合系统相关。而土壤微生物群落功能多样性的下降时间段与土壤纤维素分解菌的增加时间段相吻合,表明根系生态系统的破坏多发生于黄龙病侵染后的6-8个月。     

Comparison of two intravenous anesthetic infusion regimens for alfaxalone in cats

Objective

To compare the performance of an alfaxalone constant rate intravenous (IV) infusion versus a 3-step IV infusion, both following a loading dose, for the maintenance of a target plasma alfaxalone concentration of 7.6 mg L^–1 (effective plasma alfaxalone concentration for immobility in 99% of the population) in cats.

家蚕类mariner转座子相关序列分析

通过PCR克隆,从家蚕基因组中获得大小为975bp的DNA片段(登录号:EU352872),Blast搜寻结果显示,该片段DNA序列的52-449nt区域与野蚕mariner-like元件DNA(登录号:AB237562)的同源性达90%,推测为家蚕类mariner转座子相关序列,在乙酰胆碱酯酶基因的第5内含子、微卫星S1104-R序列、BmBRC-NZ3 mRNA终止码的下游序列、ErB·1基因的内含子均检测到家蚕类mariner元件相关序列的同源区,暗示家蚕类mariner元件在家蚕基因组中发生了多次转座,并在家蚕基因组的不同区域随着进化发生了歧化。     

苹果营养诊断新方法

应用营养元素在树体内的移动原理,比较同一新梢不同部位叶片营养元素含量的差异,判断营养元素是否发生迁移,进而诊断营养的丰缺状况。通过对10多个生产园的取样分析,对这一诊断方法的可行性进行了初步探索。结果表明,对易流动营养元素来说,此法有较好的适用性。     

有机微量元素的研究应用进展

有机微量元素是发展较快的第三代新型微量元素添加剂,具有生物利用率高、化学结构稳定、增强免疫力、吸收率高利于环保,是当前国内外研制和开发的热点。本文综述了有机微量元素的生化特性、功能作用、吸收机理、生产应用和研究进展。