Adiposity,Plasma Insulin,Leptin, Lipids,and Oxidative Stress in Mature Light Breed Horses

Background

Increased blood insulin levels are associated with an increased risk of pasture‐associated laminitis in equids.

Objective

To determine the relationship between plasma insulin, leptin, and lipid levels, and measures of oxidative stress with adiposity in mature light breed horses.

Animals

300 randomly selected light breed horses, aged 4–20 years.

Methods

A random sample of horses (140 mares, 151 geldings, and 9 stallions) was drawn from the VMRCVM Equine Field Service practice client list. Evaluations occurred June 15 – August 15, 2006, with all sampling performed between 0600 and 1200 hours. Concentrate feed was withheld for at least 10 hours before sampling. Plasma was analyzed for insulin, glucose, leptin, triglycerides, nonesterified fatty acids, and measures of oxidative stress. Body condition score was determined as the average of 2 independent investigators.

Results

Overconditioned and obese horses had higher plasma insulin (P < .001) and leptin (P < .01) levels than optimally conditioned horses. Obese horses had higher triglyceride levels (P = .006) and lower red blood cell gluthathione peroxidase activities (P = .001) than optimally conditioned horses.

Conclusions and Clinical Importance

Maintaining horses at a BCS <7 might be important for decreasing the risk of pasture‐associated laminitis.     

Studies on the Response Time for Plasma Urea Nitrogen as a Rapid Measure for Dietary Protein Quality in Pigs

The optimal response time of plasma urea nitrogen (PUN) was investigated in slaughter pigs fed diets based on barley, wheat or casein as protein sources. Four blood samples were collected during the day from a catheter in the jugular vein: one sample was collected 0.5 h before morning feeding while the other three samples were collected 2, 4 and 6 h after the morning feeding. The effect from previously fed diets on the specific response from the test diet was investigated. However, only the diet fed on the previous day was found to influence the values of PUN before the morning feeding. The reported experiments included nine different diets fed to six pigs in six different feeding designs, all requiring 1 or 2 days for investigating the test diet. The diet used in the morning feeding also significantly influenced the concentration of PUN during the following 6 h. In general, a good agreement was found between the calculated biological value (BV) of the diet and the response of PUN. It was concluded that analysis of PUN can be used as a rapid response parameter for testing the protein quality of the diet and, consequently, this analysis may also be used as a rapid method for determining amino acid requirements in pigs.     

不同抗寒性冬小麦叶鞘质膜的稳定性表现

为了解叶鞘质膜稳定性与小麦抗寒性的关系,以返青率不同的4个冬小麦品种(系)为材料,研究寒地冬小麦越冬期叶鞘质膜稳定性变化及其影响因素。结果表明,低温下,冬小麦叶鞘相对电导率与自由水和总水分含量呈显著正相关,丙二醛含量与SOD和POD活性、AsA含量呈显著正相关;封冻后,抗寒性强的冬麦品种(系)的SOD活性和GSH含量显著高于抗寒性弱的品种(系)。在深度封冻期保持叶鞘质膜稳定性有助于增强冬小麦抗寒性。     

等离子体不同次数处理大豆种子对生物学性状·产量及产值的影响

[目的]研究等离子体不同次数处理大豆(Glycine max L.)种子对其生物学性状、产量及产值的影响,为等离子体处理大豆种子技术的应用提供理论依据。[方法]试验共设7个处理,处理1应用剂量1.0A×1次,处理2应用剂量1.0A×2次,处理3应用剂量1.0A×3次,处理4应用剂量1.0A×4次,处理5应用剂量1.0A×5次,处理6应用剂量1.0A×6次,处理7为对照(CK)。[结果]等离子体处理的大豆种子能明显提高苗期的根系数,并提高开花率、结荚率;各处理比对照增产23.0～315.0 kg/hm2,增幅达0.9%～12.6%,增值74.8～1 126.0元/hm2。处理2效果最好,与对照相比,增产、增幅、增值最高,分别为315.0 kg/hm2、12.6%、1 126.0元/hm2。[结论]等离子体处理大豆种子的最佳次数为2次,增产、增收效果显著,这可为大豆优质、高产、高效栽培技术的广泛应用提供有力的技术支撑。     

盐胁迫对甘蔗苗期生理的影响

为探讨不同甘蔗品种的耐盐特性,筛选适合盐碱地区种植的甘蔗品种,本试验利用盆栽粤糖93-159、粤糖86-368和新台糖22号3个品种,并施加0.034、0.068和0.102 mol/L 3个浓度的NaC l溶液对甘蔗进行胁迫处理。结果表明,随着NaC l胁迫浓度的增加,各品种都有不同程度的Na+含量增加,质膜透性增加,叶绿素含量降低,SOD酶活性降低的现象。而新台糖22号表现出比另2个品种Na+含量更高,质膜透性增加缓慢,叶绿素含量和SOD酶活性降低更缓慢的现象,表明新台糖22号比另2个品种具有更强的耐盐特性。     

Interday variation and effect of transportation on indirect blood pressure measurements,plasma endothelin-1 and serum cortisol in Standardbred and Icelandic horses

Background

Systemic hypertension is a prominent feature in humans with metabolic syndrome (MS) and this is partly caused by an enhanced endothelin-1 (ET-1) mediated vasoconstriction. There are indications that systemic hypertension might be a feature in equine metabolic syndrome (EMS) but if ET-1 is involved in the development of hypertension in horses is not known. Increased levels of cortisol have also been found in humans with MS but there are no reports of this in horses. Before blood pressure, plasma ET-1 and serum cortisol can be evaluated in horses with EMS, it is necessary to investigate the interday variation of these parameters on clinically healthy horses. The aims of the present study were therefore to evaluate the interday variation and influence of transportation on systemic blood pressure, plasma ET-1 and serum cortisol in healthy Standardbred and Icelandic horses, and to detect potential breed differences.

Methods

Nine horses of each breed were included in the study. Blood pressure was measured and blood samples were collected between 6 and 9 am on two separate days. Eight of the horses (four of each breed) were transported to a new stable were they stayed overnight. The next morning, the sampling procedure was repeated.

Results

The interday variation was higher for plasma ET-1 (37%) than for indirect pressure measurements (8-21%) and serum cortisol (18%). There were no differences in systemic blood pressure between the two breeds. The Icelandic horses had significantly lower serum cortisol and significantly higher plasma ET-1 concentrations compared to the Standardbred horses. Plasma ET-1 was significantly elevated after transportation, but systemic blood pressure and serum cortisol did not differ from the values obtained in the home environment.

Conclusions

Indirect blood pressure, plasma ET-1 and serum cortisol are of interest as markers for cardiovascular dysfunction in horses with EMS. The elevated plasma ET-1 concentrations recorded after transportation was likely caused by a stress response. This needs to be considered when evaluating plasma ET-1 in horses after transportation. The differences detected in plasma ET-1 and serum cortisol between the two breeds might be related to differences in genetic setup, training status as well as management conditions.     

小白菜体内硝酸盐积累与其细胞膜上H+-ATPase的关系

【目的】研究硝酸盐在小白菜叶柄和叶片中分布的差异及其与细胞膜H+-ATPase的关系。【方法】采用两相法分离了小白菜品种‘上海青’叶柄和叶片细胞膜,并测定了与硝酸盐在细胞膜上共运输相关的H+-ATPase的活性。【结果】细胞膜纯度达到90%以上。离体条件下,叶柄细胞膜H+-ATPase的水解活性显著高于叶片。将H+-ATPase在20℃及30℃时测定所得的Vmax代入Arrhenius 方程计算后发现,叶柄H+-ATPase的活化能也高于叶片。Western Blot结果说明,叶柄细胞膜H+-ATPase酶浓度要显著高于叶片H+-ATPase。此外,叶柄细胞膜上H+-ATPase的Km值显著高于叶片,且叶柄H+-ATPase最佳pH在6.6,而叶片在pH在 6.4至6.6之间。【结论】叶柄H+-ATPase的活性高于叶片是因为其单位细胞膜上的H+-ATPase酶分子数量大于叶片。叶柄中硝酸盐含量高,且与其细胞膜H+-ATPase活性呈正相关关系。因此叶柄细胞膜H+-ATPase活性高很可能是增强硝酸盐吸收的一个重要原因。     

射频等离子体对小麦种子萌发的影响

为了系统、深入的了解等离子体对作物影响的作用机理,采用射频等离子体处理小麦种子,测定了不同强度等离子体处理后的种子活力、萌发过程中淀粉酶活性、呼吸速率以及幼苗的根系活力的变化。结果表明,较低强度等离子体处理(80～200W)能提高小麦萌发过程中淀粉酶活性和呼吸强度,促进碳水化合物的转化和运输,使小麦种子的发芽率、发芽势和发芽指数分别提高30.0%、107.7%和53.5%。80～200W等离子体也能够提高小麦幼苗根系活力、促进根系发育,其中以160W等离子体作用效果最强,使根系活力提高39.65%、侧根数增加19.81%、根长增加7.85%。等离子体强度过高(240W)则表现出一定的抑制效应。