水葫芦沼液对青菜生长及AsA-GSH循环影响的动态研究

以青菜为材料,研究了在青菜整个生长周期内,不同比例水葫芦沼液对青菜生长的影响及其体内AsA-GSH循环影响的动态变化。结果表明,使用不同比例沼液代替化肥对青菜的株高及生物量产生不同的影响,其中,以25%沼液替代化肥的处理效果最好,在不同的采样时期,其株高和生物量均显著大于对照,当沼液使用比例大于50%时,株高和生物量均随着沼液使用比例的增加而降低;处理后总量Vc、还原型抗坏血酸(AsA)和脱氢抗坏血酸(DHA)的变化趋势不同,25%沼液替代化肥处理45和60 d时,总量Vc与对照相比显著增加;AsA虽然有所增加(除了30 d时),但与对照差异不显著;DHA含量均显著大于对照。当沼液使用比例大于50%时,总量Vc、AsA和DHA与对照相比均显著降低;在AsA循环中的抗坏血酸过氧化物酶(APX)、抗坏血酸氧化酶(AAO)和脱氢抗坏血酸还原酶(DHAR)活性变化趋势相似,均随着处理时间增加呈先增加后降低的趋势,其中以25%沼液替代化肥处理30 d酶活性最高,而单脱氢抗坏血酸还原酶(MDHAR)活性则随着处理时间的增加而增加,以25%沼液替代化肥的处理效果最好;在还原型谷胱甘肽(GSH)循环中的氧化型谷胱甘肽(GSSG)和GSH含量随着处理时间的增加而增加,以25%沼液替代化肥的处理效果最好,与对照相比差异显著,而谷胱甘肽还原酶(GR)活性随着处理时间增加呈先增加后降低的趋势,其中以25%沼液替代化肥处理45 d酶活性最高。说明用适量的水葫芦沼液替代化肥对青菜进行处理,有助于植株的生长,同时增加了体内AsA-GSH代谢循环,提高了青菜的抗氧化防御能力。     

黄土丘陵区不同立地条件下紫花苜蓿地土壤水分动态变化

研究了定西市安家沟流域不同立地条件紫花苜蓿Medicago sativa土壤水分的变化。结果表明：阳坡土壤水分均小于阴坡土壤水分,紫花苜蓿在不同立地条件下土壤水分都发生了显著的变化,但其顺序为阴坡台地>阴坡坡地>阳坡台地>阳坡坡地。不同立地类型各土壤层次的月变化存在显著差异,阴坡台地和阴坡坡地第1茬（4-6月）的土壤水分极显著高于阳坡台地和阳坡坡地的土壤水分,二者间没有显著差异,而在7月后,阴坡台地极显著高于其他立地条件的土壤水分。不同立地条件下紫花苜蓿每层深度土层的土壤水分都发生了不同程度的变化,在整个垂直剖面上都在降低,40～100 cm土层土壤水分降低最多。     

野菊和神农香菊毛状体及叶片表面分泌物的比较

本研究以野菊(Dendranthema indicum)和神农香菊(D.indicumvar.aromaticum)为研究对象,对比分析了其叶片的表皮毛形态、密度以及叶片表面分泌物种类和含量。结果表明,其叶片表皮毛主要有两种类型,一类是没有分泌功能的T-形非腺毛,一类是具有分泌功能的头状腺毛。T-形非腺毛在上下表皮的密度差异不大,而头状腺毛差异较大,主要集中在叶片的下表皮。两种植物材料叶片表面分泌物里共分析出73种化合物,其中大部分为萜类及其衍生物,共有的化合物有18种;野菊和神农香菊中分别分析出48、43种化合物,分别占分泌物总相对含量的90.96%和84.33%。     

Assessment of Vein Diameter and Body Surface Temperature after High-Intensity Laser Therapy (HILT) on the Tarsal Joint in Healthy Horses

The aim of the study was to assess the influence of high-intensity laser therapy (HILT) on vein diameter and on body surface temperature changes in the tarsal joint area in a group of clinically healthy racehorses. The hypothesis of the study was that HILT increases vein diameter and body surface temperature in healthy tissue. The study involved 16 Thoroughbreds being subjected to ultrasonographic examination to assess changes of diameter of the cranial branch of the medial saphenous vein and thermographic examination to indicate temperature change of the dorsal surface of the tarsal joint, just before and immediately after HILT treatment. Vein diameter and mean surface temperature of the tarsal joint significantly increased after HILT treatment. In addition, the study was the first to describe the photothermal effect of HILT in healthy horses. More studies are necessary to specify the parameters of the procedure, that is, wavelength, energy density, or time of the procedure, depending on the patient’s individual characteristics and type of tissue.     

谷氨酸棒状杆菌全细胞催化合成Levan果聚糖条件优化分析

试验旨在探究微生物合成Levan果聚糖的新途径并优化其合成条件。利用转入果聚糖蔗糖转移酶基因的重组谷氨酸棒状杆菌进行全细胞催化合成Levan果聚糖,并采用响应面法以Levan果聚糖产量为响应值优化催化合成条件。首先设计Plackett-Burman试验从7个相关因素（蔗糖浓度、菌体浓度、转化时间、转化pH、PBS中Ca²⁺和Mg²⁺浓度、Levan果聚糖提取时的乙醇终浓度）中筛选出影响Levan果聚糖产量的3个主要因素（蔗糖浓度、乙醇终浓度和Ca²⁺浓度）;再用筛选出的3个最重要因素进行最陡爬坡试验逼近最大响应值区域;最后运用BBD响应面法优化确定3个主要因素之间的交互作用和最佳合成条件。结果显示,初始试验中Levan果聚糖平均产量为0.069 g/mL。经过响应面试验优化对利用重组谷氨酸棒状杆菌进行全细胞催化合成Levan果聚糖产量影响最大的因素为蔗糖浓度,其次为提取时的乙醇终浓度,最后是转化液中的Ca²⁺浓度。当蔗糖浓度为52.71%、乙醇终浓度为85.31%、Ca²⁺浓度为0.04 g/L时,利用重组谷氨酸棒状杆菌进行全细胞催化合成的Levan果聚糖产量平均值为0.238 g/mL,与模型预测最大值0.233 g/mL相近,转化率约为44%,转化率较初始试验提高了约1.9倍,产量亦较初始试验提高了约3.4倍。研究结果为Levan果聚糖工业化生产提供了依据,并为其在动物医学和营养方面的研究奠定基础。     

In situ provision of drinking water to grazing dairy cows improves milk production

AIMS: To determine the effect of providing water within the area grazed by dairy cows on milk yield and quality, compared to requiring cows to walk to a distant water trough, on a dairy farm in the Pampa region of Argentina during summer.

METHODS: Holstein dairy cows were allocated to two herds with similar parity, days in milk and milk production. They were grazed in one paddock that was divided in two, with a fixed water trough at one end. Cows were moved twice daily to grazing plots within the paddock. Control cows (n=66) could only access water from the fixed trough, whereas supplemented cows (n=67) also received water from a mobile trough within the grazing plot. Milk production of each cow, and water consumption of the two herds were measured daily over 62 days. Milk composition for each herd was determined weekly from Days 18 to 60 of the study, and grazing behaviour was observed between 08:00 and 16:00 hours on Days 11–15, 19–22 and 39–43.

RESULTS: Over the 62 days of the study, supplemented cows produced 1.39 (SE 0.11) L/cow/day more milk than Control cows (p=0.027). Estimated mean daily water intake was 50.4 (SE 2.1) L/cow/day for supplemented cows and 58.2 (SE 2.7) L/cow/day for Control cows (p=0.004). Percentage total solids in milk was higher for supplemented (12.5 (SE 0.06)%) than Control (12.4 (SE 0.04)%) cows (p=0.047). During the periods of behavioural observation, a higher percentage of cows in the water supplemented than the Control herd were observed in the grazing area (p=0.012).

CONCLUSIONS AND CLINICAL RELEVANCE: This preliminary study demonstrated that provision of water to dairy cows within the grazing plot was beneficial for milk production and composition, and may be associated with longer periods spent within the grazing area, during hot weather in the Pampa region of Argentina.     

Dietary cation and anion difference: Effects on milk production and body fluid distribution in lactating dairy goats under tropical conditions

This study aimed to determine the effect of dietary cation and anion difference (DCAD) on milk production and body fluid distribution in lactating dairy goats. Ten dairy goats were selected and divided into two groups, five animals each. Animals received either control DCAD (control, 22.81 mEq/100 g dry matter (DM)) or high DCAD (DCAD, 39.08 mEq/100 g DM). The results indicated that rectal temperature (Tr), respiration rate, milk yield and compositions did not differ between groups. But the percentage change of Tr from the DCAD group was lower than the control group between 09.00 and 13.00 hours. DM intake tended to increase in the DCAD group. Dairy goats in the DCAD group drank more water, but urinary excretion and plasma antidiuretic hormone concentration remained unchanged. Apparent water balance was higher from the DCAD group over 24 h. There was no effect of DCAD on plasma and blood volumes, but tended to increase in extracellular fluid and thereby increased total body water. The present results indicate that animals supplemented with high DCAD increase their total body water and apparent water balance. These results have contributed to the process of adaptation for evaporative cooling and would be useful in slowing down the elevation in Tr.     

Local evidence for tolerance of birdsfoot trefoil (lotus corniculatus) to acid soils

Abstract

The pattern of yield response of birdsfoot trefoil (Lotus corniculatus) cv. San Gabriel to soil amendment with lime and superphosphate on a virgin acid soil indicated that this legume is tolerant of local acid soils and moderately tolerant of low levels of extractable phosphorus.     

优质牦牛肉肉质的综合评价

2000-2002年对大通牛场40头6月龄不同性别的全哺乳牦牛的肉质进行了综合评价。对供试牦牛肌肉pH、嫩度、肌纤维细度、系水率、肉的贮存损失、肉的煮熟时间、熟肉率和烹饪损失率及肉色等进行了评价，分析了肌肉的化学成分，氨基酸及微量元素含量。结果表明该牦牛肉系水率强，肉的煮熟时间短，肉的贮存损失及烹饪损失较小，肌纤维较细，肉色深红。并具有蛋白质含量高，脂肪含量低及富含各种氨基酸的特点。