添加酸马奶源乳酸杆菌对犊牛肠道菌群和短链脂肪酸含量的影响

选取刚出生的健康荷斯坦犊牛20头,随机分为酸马奶组、正常组、腹泻组和抗生素组,每组5头。除正常组外,其他3组在相同哺乳的基础上均口服100 mL致病性E.coli O1菌悬液(2.5×10¹¹ CFU/mL)建立腹泻模型,抗生素组添加环丙沙星0.5 mg/kg,试验期15 d。结果表明：酸马奶组犊牛肠道微生物丰富度与多样性显著高于其他3组(P<0.05)。酸马奶源乳酸杆菌干预后显著提高了肠道内厚壁菌门、普雷沃氏菌科、毛螺菌科未确定菌属和拟普雷沃菌属的相对丰度,降低了拟杆菌门、变形菌门、梭杆菌门、放线菌门的相对丰度;酸马奶组犊牛粪便中乙酸、丙酸和丁酸含量显著高于其他3组(P<0.05)。由此可见,犊牛日粮中添加酸马奶源乳酸杆菌可显著提高肠道微生物多样性,增加肠道中有益菌的丰度,降低有害菌的丰度,并显著提高其粪便中乙酸、丙酸和丁酸的含量。     

林分密度对毛乌素沙地樟子松人工林林分结构和林下植被的影响

[目的]研究不同密度下,樟子松人工林林分结构和林下物种多样性的变化,以期为毛乌素沙地以樟子松为建群种的植物固沙模式提供理论依据。[方法]以毛乌素沙地榆林地区5种不同密度25a生樟子松人工林为研究对象,采用样方调查和测试分析法,探究樟子松人工林林分结构和林下物种多样性随林分密度的变化特征。[结果]樟子松人工林密度与平均胸径呈幂函数递减关系,与高径比呈显著的线性正相关关系。樟子松人工林林下共出现植物8科13属16种。草本以禾本科的狗尾草为优势种,草本丰富度、多样性指数随着密度的不断减小,表现出明显的增加趋势。林分密度与物种丰富度指数、多样性指数呈显著的负相关关系,Shannon多样性指数对密度变化最为敏感。[结论]毛乌素沙地樟子松人工林的林分密度与林分结构、林下物种多样性的相关关系十分显著,可以将林下物种多样性指数作为衡量林分密度是否合理的参考指标。     

Successful sterlet, Acipenser ruthenus L., propagation with synthetic LH-RH hormone

Abstract. The synthetic LH-RH (luliberine) has proved to be successful in inducing the ovulation of sterlet, Acipenser ruthenus L. Three dosages of LH-RH 50, along with carp pituitary, and 100 and 300 μg/kg of body weight were administered, and 100 and 300 μg of LH-RH/kg body weight were found to be successful in ovulation. Spawners were kept at low temperature (9–12°C). Forty-two hours after treatment the eggs entered ovulation in the ovary and became suitable for stripping. The ripening ratio for spawners varied between 75 and 83%. The eggs that could be obtained by opening the abdominal wall were fertilized with milt diluted with pond water to avoid polyspermism. The fertility of the stripped eggs was 89–90%. Despite a reduced number of subjects (12 treated, 2 control females), as a result of the favourable fertilization percentage, approximately 55 000 fingerlings were reared in tanks to approximately 5–7cm in size.     

乌珠穆沁羊生长分化因子11基因外显子1序列CpG位点的甲基化模式分析

为了探讨乌珠穆沁羊生长分化因子11 (growth differentiation factor 11,GDF11)基因外显子1的甲基化模式,本研究采用亚硫酸氢盐测序PCR (BSP)的方法对普通乌珠穆沁羊和多脊椎乌珠穆沁羊GDF11基因外显子1的甲基化水平进行检测,通过检测发现普通乌珠穆沁羊GDF11基因外显子1的平均甲基化率为0.123,多脊椎乌珠穆沁羊的平均甲基化率为0.569,差异显著性检验表明这两组数据间差异极显著(P<0.01),即多脊椎乌珠穆沁羊GDF11基因外显子1中的CpG甲基化率极显著高于普通乌珠穆沁羊(P<0.01).通过分析GDF11基因外显子1的13个CpGs位点发现,多脊椎乌珠穆沁羊CpG_11和CpG_13位点的甲基化率值最高,达到90%,推测这两个位点的甲基化可能与乌珠穆沁羊的脊椎数增加有关,是导致多脊椎发生的主要原因.     

Attribution of explanatory factors for change in soil organic carbon density in the native grasslands of Inner Mongolia,China

The variation in soil organic carbon density(SOCD) has been widely documented at various spatial and temporal scales. However, an accurate method for examining the attribution of explanatory factors for change in SOCD is still lacking. This study aims to attribute and quantify the key climatic factors, anthropogenic activities, and soil properties associated with SOCD change in the native grasslands of Inner Mongolia, China, by comparing data between the 1960s and the 2010s. In 2007 and 2011, we resampled 142 soil profiles which were originally sampled during 1963–1964 in the native grasslands of Inner Mongolia. SOCD was determined in A horizon(eluvial horizon) of the soil. We selected the explanatory factors based on a random forest method, and explored the relationships between SOCD change and each of the explanatory factors using a linear mixed model. Our results indicated that the change in SOCD varied from the east to the west of Inner Mongolia, and SOCD was 18% lower in the 2010s than in the 1960s. The lower SOCD in the 2010s may primarily be attributed to the increasing in mean annual water surface evaporation, which explained approximately 10% and 50% of the total variation and explainable variation in the change in SOCD, respectively. The sand content of the soil is also a significant explanatory factor for the decrease in SOCD, which explained about 4% and 21% of the total variation and explainable variation in the change in SOCD, respectively. Furthermore, the collection of quantitative information on grazing frequency and duration may also help to improve our understanding of the anthropogenic factors that govern the change in SOCD.     

沙尘暴应激对荷斯坦牛红、白细胞及红细胞黏附免疫功能的影响

在春夏之交沙尘暴多发季节,为初步了解沙尘暴对奶牛的影响,在沙尘暴期间和前后随机抽取6头荷斯坦牛,用经典红、白细胞计数、白细胞分类计数及红细胞黏附免疫功能检测方法,检测红、白细胞数及红细胞黏附免疫功能的变化。结果表明。沙尘暴期间红、白细胞总数有所增高;中性粒细胞极显著增多;淋巴细胞却显著下降;C3bR和ICR的受体花环率略有减少。说明沙尘暴所导致的环境低氧使奶牛增加红细胞数以应付缺氧的环境;中性粒细胞为吞噬沙尘颗粒清除异物极显著提高,而具有特异性免疫作用的淋巴细胞却显著下降;同时红细胞黏附免疫功能也有所下降。可见沙尘暴使炎症细胞聚集,特异性免疫细胞显著下降,很可能导致炎症发生。     

乙酸木质素基聚氨酯硬泡的制备与性能

将乙酸制浆法废液中的木质素进行提取和精制,采用红外光谱(FTIR)、31P-NMR谱和凝胶渗透色谱(GPC)对其结构进行表征,并利用乙酸木质素、聚醚多元醇和甲苯二异氰酸酯在发泡剂和催化剂的条件下合成聚氨酯硬泡。采用TG、DSC和压缩测试对聚氨酯硬泡的热学和力学性能进行研究,并用扫描电子显微镜观察聚氨酯硬泡的泡孔结构。结果表明:乙酸木质素作为多羟基聚合物,可以部分代替聚醚多元醇和异氰酸酯发生反应制备聚氨酯材料;当乙酸木质素添加量为5%时,聚氨酯硬泡的压缩强度达到1.325MPa,比未添加木质素的泡沫高出约63%,此时的压缩模量也达到0.181MPa;随着乙酸木质素添加量增加,乙酸木质素基聚氨酯硬泡的最快分解温度下降,而玻璃化转变温度没有明显升高;乙酸木质素基聚氨酯硬泡泡孔平整均匀。     

Choanephora blight and alternaria leaf spot of Amaranth in Tanzania

A leaf blight incited by Choanephora cucurbitarum and a leaf spot incited by Alternaria amaranthi on cultivated amaranth, Amaranthus cruentus , are described. This is a new host record for C. cucurbitarum , and A. amaranthi is a new record for Tanzania. Additional hosts of C. cucurbitarum are listed.     

Four Cases of Congenital Malformation of the Heart in a Litter of Eleven Dogs

Abstract—Four cases of congenital malformation of the heart in a litter of eleven dogs are reported. In one case the only defect to be found was a patent ductus arteriosus. In the other three cases there was an unusual malformation of the tricuspid valve giving rise to pronounced stenosis. These three dogs had a right to left shunt on the atrial level and in one dog it was possible to demonstrate that the main vascular supply to the lungs was through the bronchial artery. The litter was the result of inbreeding and this could be the reason for the familial incidence of the malformations. Résumé—Quatre cas de malformations congénitales du coeur, dans une portée de onze chiens, sont rapportés. Dans un cas seulement, le seul défaut trouvéétait un canal artériel. Dans trois autres cas, il s'agissait d'une malformation peu commune de la tricuspide produisant un rétressissement prononcé. Ces trois chiens avaient une communication inter-auriculaire, et, chez un chien, on démontra que l'apport du sang vers le poumon se faisait par une artère bronchiale. Cette portée était le produit de croisements consanguins, ce qui pouvait expliquer la fréquence de malformations. Zusammenfassung—Vier Faelle werden berichtet von congentialer Missbildung des Herszen in einem Wurf von elf Hunden. In einem Fall war der einzige Defekt, der gefunden werden konnte, ein offener ductus arteriosus. In den drei anderen Faellen war eine ungewoehnliche Missbildung der Tricuspidalklappe, die zu einer erheblichen Stenose fuehrte. Diese drei Hunde hatten eine (Blut-) Stromablenkung von rechts nach links im Vorhof-Niveau, und in einem Hund war wes moeglich zu zeigen, dass die hauptsaechliche Gefaessversorgung zu den Lungen durch die Bronchialarterie ging. Der Wurf war das Ergebnis von Inzucht und diese koennte die Ursache sein fuer das vererbungs-bedingte Auftreten der Missbildungen.