常态下景天科室内观赏植物释放负离子的研究

目的为景天科拟石莲花属植物规模化繁殖和生产提供依据。方法以景天科拟石莲花属植物雪莲种子、红边月影、女雏、花乃井和小蓝衣叶片以及3种播种基质(V_{泥炭土422#}∶V_珍珠岩=3∶2、V_{泥炭土680#}∶V_珍珠岩=3∶2和V_{本地红壤土}∶V_珍珠岩=3∶2)为试材,测定了3种基质的理化性质及其对红边月影、女雏、花乃井和小蓝衣叶插生根率、新芽直径以及对雪莲种子发芽率的影响。结果3种基质的容重、总孔隙度、通气孔隙度、持水孔隙度、有机质和有效氮磷钾元素均存在差异,pH值和EC值均符合拟石莲花属植物的生长要求。3种基质对拟石莲花属植物叶插生根率影响不显著(P>0.05),对新芽直径和种子发芽率影响显著(P<0.05),拟石莲花属植物物种间的叶插生根率和新芽直径存在显著(P<0.05)或极显著(P<0.01)差异,拟石莲花属植物物种和基质间存在互作效应。基质理化性质中,对拟石莲花属植物发芽率和生根率均为显著影响的共性因素为基质中有机质含量、氮元素含量和持水孔隙度,而对生长速度有极显著影响的因素为通气孔隙度。结论泥炭和珍珠岩复配较适宜作为拟石莲花属植物的叶插和播种繁殖基质,针对不同拟石莲花属植物品种筛选不同性质的泥炭,并且在不同生长期选用不同理化性质的基质,可获得更好的繁育效果。     

红鳞蒲桃苗木生长和生理生化特征对不同盐分和干旱胁迫的响应

以1年生红鳞蒲桃盆栽苗木为研究对象,设置不同盐胁迫浓度及干旱程度,研究盐旱交互作用对红鳞蒲桃苗木的高、地径生长和各项生理指标的影响。结果表明：干旱和盐胁迫都抑制了红鳞蒲桃的生长,盐胁迫的影响要大于干旱胁迫,高生长受到的限制大于地径生长,2 g/kg盐分浓度在水分充足条件下促进了地径生长。相对电导率和丙二醛含量均随着干旱和盐胁迫的增强而增大。不同盐分浓度下,干旱胁迫对相对电导率的影响趋势一致,不同盐分胁迫的影响差异不显著。高盐浓度下丙二醛含量的增加显著大于低盐浓度,表明盐胁迫对红鳞蒲桃的伤害更大;红鳞蒲桃的渗透调节物质在干旱和盐交互胁迫下有一定程度的提高。水分充足时,盐分浓度的变化没有对红鳞蒲桃的游离脯氨酸含量产生影响。随着胁迫的增加,渗透调节能力显著提高。低盐浓度下,抗氧化酶活性在水分充足时没有受到显著影响,高盐浓度下,随着干旱胁迫的加剧则显著提高。     

不同种源刨花润楠苗期生长及叶片性状变异的研究

以刨花润楠主要分布区的14个种源为研究对象,在广州增城开展种源试验,通过对14个种源的刨花润楠苗高、地径、叶面积、叶周长等性状进行观测,分析不同种源苗期性状的遗传变异规律。结果表明：3个生长性状种源间和种源内变异系数相当,其种源间和种源内生长性状变异均较丰富;8个叶片性状种源间的变异系数为17.52%～44.71%,不同种源间叶片性状亦变异明显;生长性状的种源遗传力均大于0.750,说明在一定程度上刨花润楠的苗高、地径等苗期生长性状受自身遗传控制,且不同种源间变异明显,种源选择潜力较大。刨花润楠苗期生长性状的地理及气候变异趋势不明显,表现出随机现象;苗木生长性状与叶片大小呈负相关,即叶片越大、叶柄越长,苗木生长有变慢的趋势;对种源苗期性状进行聚类,可将刨花润楠14个种源划分为5个类群;刨花润楠苗期生长及叶片性状有一定的地理趋势,但也有一定的随机性。以地径为标准对刨花润楠优良种源进行筛选,初步选出永春、兴安、昭平3个种源作为适宜广东地区造林的优势种源。     

人参提取液体外抑制IHNV作用效果研究

探究人参提取液体外抑制CCB细胞感染IHNV的能力,构建体外CCB细胞模型,运用RTCA技术和MTT法测得不同浓度人参提取液对IHNV抑制作用曲线,并从阻断病毒复制和杀灭病毒两方面讨论人参提取液作用效果。结果表明,4%人参提取液对IHNV具有明显抑制作用,能够在16 h内保护细胞不受IHNV病毒的侵染,其中2 h时对病毒灭活抑制率最高达到51.5%,1~12 h内对病毒复制有持续抑制作用。研究可为IHVN防治药物的研发提供新的思路及参考。     

饲粮中添加乳铁蛋白对早期断奶仔猪生长性能、肠道菌群及肠黏膜形态的影响

本试验旨在研究在饲粮中添加乳铁蛋白(lactoferrin,LF)对断奶仔猪生长性能、肠道菌群及肠黏膜形态的影响。试验选用96头体重相近的21日龄"杜×长×大"三元杂交断奶仔猪,随机分为4组,分别饲喂基础饲粮(对照组)、基础饲粮+250 mg/kg乳铁蛋白、基础饲粮+500 mg/kg乳铁蛋白和基础饲粮+750 mg/kg乳铁蛋白,每组4个重复,每个重复6头仔猪。正试期21 d。结果表明,与对照组和750 mg/kg乳铁蛋白组相比,饲粮中添加250和500 mg/kg乳铁蛋白可显著提高仔猪平均日增重(P<0.05);与对照组相比,不同水平乳铁蛋白可显著降低盲肠中大肠杆菌数量(P<0.05),其中添加500 mg/kg乳铁蛋白显著提高了盲肠、结肠中乳酸杆菌的数量(P<0.05),显著降低了结肠中大肠杆菌数量(P<0.05);添加250和500 mg/kg乳铁蛋白极显著提高了十二指肠、空肠、回肠的绒毛高度/隐窝深度比值(P<0.01)。结果提示,饲粮中添加乳铁蛋白可刺激肠道有益菌生长、降低有害菌增殖,从而改善肠道功能,具有提高仔猪生长性能的作用,本试验条件下乳铁蛋白的适宜添加量为250 mg/kg。     

Expression of receptor tyrosine kinases VEGFR-1 (FLT-1), VEGFR-2 (KDR), EGFR-1, PDGFRa and c-Met in canine primary brain tumours

Inhibition of tumour growth and angiogenesis by targeting key growth factor receptors is a promising therapeutic strategy for central nervous system tumours. Characterization of these growth factor receptors in canine primary brain tumours has not been done. Using quantitative real‐time TaqMan polymerase chain reaction (PCR), we evaluated the expression of messenger RNA (mRNA) for five tyrosine kinase growth factor receptors (vascular endothelial growth factor receptor [VEGFR]‐1, VEGFR‐2, endothelial growth factor receptor [EGFR]‐1, platelet‐derived growth factor receptor a [PDGFRa], and c‐Met) relative to normal cerebral cortex in 66 spontaneous canine primary brain tumours. Increased expression of VEGFR‐1 and VEGFR‐2 mRNA was greatest in grade IV astrocytomas (glioblastoma multiforme) and grade III (anaplastic) oligodendrogliomas. EGFR‐1 mRNA expression was more consistently increased than the other receptors in all tumour types, while increased PDGFRa mRNA expression was mostly restricted to oligodendrogliomas. The similarities in increased expression of these tyrosine kinase growth factor receptors in these canine tumours, as compared to data from their human counterparts, suggest that common molecular mechanisms may be present.     

Effect of ruminal dosing of mechanical stimulating brush on rumination time, ruminal passage rate and rumen fermentation status in Holstein steers fed a concentrate diet

This experiment was conducted to determine the effect of ruminal dosing of a mechanical stimulating brush on rumination time, ruminal passage rate and rumen fermentation status in steers fed a concentrate diet at maintenance level. Animals were dosed three Rumen Faibu (RF) per head through the rumen fistulae (RF treatment) and not dosed (control) in a change‐over design. The organic cell wall content of the concentrate diet was 12.7% of dry matter. Daily time spent on rumination was very short in both treatments with 24 min in RF treatment and 15 min in control. The turnover rate of ruminal fluid in RF treatment was higher than that in control. There were no differences in ruminal pH and total volatile fatty acid concentration between RF treatment and control. Acetic and butyric acid concentrations were not different between the treatments. Propionic acid concentration tended to be higher in the animals on RF treatment than in control animals. The RF dosing in Holstein steers fed a low fiber diet did not affect the rumination time, but increased rumen digesta passage rate and ruminal propionic acid production.     

奶牛主要植物性蛋白质饲料蛋白质和纤维物质瘤胃降解率的研究

选用3头安装永久性瘤胃瘘管的健康荷斯坦产奶牛为试验动物,选取8种北方地区奶牛常用蛋白质饲料原料为试验样品,每个样品设3个重复,用尼龙袋法分别测定各个样品的粗蛋白质(CP)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)在瘤胃内的动态降解率和有效降解率。结果表明:(1)所选8种蛋白质饲料原料中葵花粕的粗蛋白质(CP)有效降解率均高于其他粗饲料,达到61.17%以上,酒精粕的粗蛋白质(CP)有效降解率最低,仅为19.03%。(2)在饲喂基础上,玉米蛋白粉所含的瘤胃降解蛋白质(RDP)的比例最高,达到30.99%以上,而酒精粕所含的比例最低,仅为5.52%。(3)豆粕所含的中性洗涤纤维(NDF)的有效降解率最高,达到50.74%以上,而菜籽粕的最低,仅为11.06%。(4)玉米蛋白粉所含的酸性洗涤纤维(ADF)的有效降解率最高,达到59.23%以上,而酒精粕的最低,仅为11.27%。     

Describing the growth and molt of modern domestic turkey (Meleagris gallopavo) primary wing feathers

The use of feathers as noninvasive physiological measurements of biomarkers in poultry research is expanding. Feather molting patterns and growth rates, however, are not well described in domestic poultry. These parameters could influence the measurement of these biomarkers. Therefore, the objective of this study was to describe the juvenile primary feather molting patterns and feather growth rates for domestic turkeys. The 10 primary wing feathers of 48 female turkeys were measured weekly from week 1 (0 d of age) to week 20. Feathers were manually measured, and the presence or absence of each primary feather was recorded weekly. Generalized linear mixed models were used to investigate if feather growth differed between the primary feathers. The molting of the juvenile primary feathers followed a typical descending pattern starting with P1 (5 wk of age), while P9 and P10 had not molted by the end of the study (20 wk of age). The average feather growth rate was 2.4 cm/wk, although there was a significant difference between the 10 primary feathers (P < 0.0001, 2.1 to 2.8 cm/wk). Over time, feather growth followed a pattern where the growth rate reaches a peak and then declines until the feather is molted. The results of this study provide a critical update of patterns of molting and feather growth in primary wing feathers of modern turkeys. This can have implications for the interpretation of physiological biomarkers, such as the longitudinal deposition of corticosterone, in the feathers of domestic turkeys.