绿肥翻压与氮肥减施对水稻产量、品质及土壤肥力的影响

为探明绿肥山黧豆种植翻压下减量施用化学氮肥的潜力,通过3年田间定位试验,设置冬闲+100% N肥（常规施肥,CK）、山黧豆+60% N肥（GM+N60）、山黧豆+70% N肥（GM+N70）、山黧豆+80% N肥（GM+N80）、山黧豆+不施肥（GM）和冬闲+不施肥（NF）共6个处理,研究不同处理对水稻产量、品质及土壤肥力的影响。结果表明,与CK相比,山黧豆与氮肥减量配施能提高水稻产量,GM+N70和GM+N80处理显著提高水稻产量,分别增产13.84%和7.25%;且能提高稻米糙米率、精米率、整精米率和蛋白质含量,降低垩白度及垩白粒率和直链淀粉含量。其中,GM+N70处理的整精米率最高,为78.02%,垩白粒率最低,为18.11%;GM+N80处理的直链淀粉含量最低,为14.26%。山黧豆与氮肥减量配施能明显提高土壤有机质、全氮、碱解氮和速效钾含量,对土壤有效磷含量无显著影响。综上,种植翻压山黧豆与氮肥减量20%~30%配施有利于提高水稻产量、品质及土壤肥力,为构建四川稻区山黧豆种植翻压还田后科学施用氮肥提供理论依据。     

卤虫卵化学成分的分离与分析

本试验对卤虫卵的化学成分进行分离和分析。卤虫卵的含油量为7．1％，油中不皂化物的含量为4．9％，主要为胆甾醇。脂肪酸中含有较大量的油酸、棕榈酸、棕榈油酸、花生四烯酸和二十碳五烯酸。卤虫卵含蛋白质为20．9％，还含有多种氨基酸。     

东海外海绿鳍马面鲀摄食习性的研究

1.东海外海的绿鳍马面鲀是一种主食浮游甲壳类,兼食软体动物和珊瑚的杂食性鱼类。2.1—6月绿鳍马面鲀摄食强度有两次高峰,分别出现在2—3月和5月。4月摄食强度最低,这可能和产卵习性有关。产卵前和产卵后均大量摄食,而在产卵盛期则少食或不食。3.绿鳍马面鲀的摄食强度以南部鱼群为最高,中部鱼群次之,北部鱼群最低。饵料种类组成也不一样,北部鱼群主要是摄食浮游甲壳类,而南部和中部鱼群除摄食浮游甲壳类外还摄食不少珊瑚、角贝和扁卷螺。4.绿鳍马面鲀一昼夜内,主要在下午到上半夜摄食,而在下半夜到上午则较少摄食和暂停摄食,明显地有昼夜垂直移动现象,产生此现象,不仅仅是由于追食饵料生物所引起,主要与其本身生活习性有关。     

大鹏澳网箱养殖海域磷酸盐在沉积物-海水界面交换速率的研究

应用实验室培养法研究了大亚湾大鹏澳网箱养殖海域磷酸盐(PO_4-P)在沉积物-海水界面上的交换通量；并根据改进的连续函数法计算了PO_4-P在沉积物-海水界面上交换速率。结果表明：(1)PO_4-P在沉积物-海水界面上的交换通量随时间的变化关系满足以e为底的指数衰减函数；(2)整个调查海域PO_4-P在沉积物-海水界面上的交换速率为0．27～2．47 mmol·m~(-2)·d~(-1)。其中,网箱养殖区PO_4-P的交换速率(0．82～2．47 mmol·m~(-2)·d~(-1))明显高于对照区PO_4-P的交换速率(0．27～0．62 mmol·m~(-2)·d~(-1)),长时期的养殖活动使养殖区沉积环境中的磷得以积累,PO_4-P在沉积物-水界面上的交换速率升高。     

水库网箱养殖翘嘴红鲌Erythroculter ilishaeformis(Bleeker)的初步试验

利用二只5m×5m×2.5m无结节PE封闭式网箱,投放平均尾重0.24g,全长70～100mm翘嘴红苗种计11,000尾,放养密度为220尾/m2;经304d饲养,平均尾重达到200g,最大个体350g;群体净增43.98倍,饲料系数1.51,成活率92%,净增产1,797kg,每m2利润801.6元,投入与产出之比为1:2.94。翘嘴红俗称太湖白鱼、白条。该品种具有肉质鲜美,营养价值高,生长快,适温范围广,抗病力强等特点,是适合水库网箱养殖的淡水名优品种之一。     

Effect of simulated transport stress on the rat small intestine: A morphological and gene expression study

The present study investigated the effects of simulated transport stress on morphology and gene expression in the small intestine of laboratory rats. Sprague Dawley rats were subjected to 35 °C and 0.1×g on a constant temperature shaker for physiological, biochemical, morphological and microarray analysis before and after treatment. The treatment induced obvious stress responses with significant decreases in body weight (P < 0.01), increases in rectal temperature, serum corticosterone (CORT), serum glucose (GLU), creatine kinase (CK) and lactate dehydrogenase (LDH) levels (P < 0.01), as well as expression of Hsp27/70/90 mRNA (P < 0.05; P < 0.01). The rat jejunum was severely damaged and apoptotic after mimicking transport stress, which may mainly be related to cell death, oxidation reduction and hormone imbalance determined by microarray analysis. The bioinformatics analysis from the present study would provide insight into the potential mechanisms underlying transport stress-induced injury in the rat small intestine.     

Effects of the acid-tolerant engineered bacterial strain Megasphaera elsdenii H6F32 on ruminal pH and the lactic acid concentration of simulated rumen acidosis in vitro

The aim of this study was to examine the effects of the acid-tolerant engineered bacterial strain Megasphaera elsdenii H6F32 (M. elsdenii H6F32) on ruminal pH and the lactic acid concentrations in simulated rumen acidosis conditions in vitro. A mixed culture of ruminal bacteria, buffer, and primarily degradable substrates was inoculated with equal numbers of M. elsdenii H6 or M. elsdenii H6F32. The pH and lactic acid concentrations in the mixed culture were determined at 0, 2, 4, 6, 8, 10, 12, 14, 16, and 18 h of incubation. Acid-tolerant M. elsdenii H6F32 reduced the accumulation of lactic acid and increased the pH value. These results indicate that acid-tolerant M. elsdenii H6F32 could be a potential candidate for preventing rumen acidosis.     

Immune responses of orange-spotted grouper,Epinephelus coioides,against virus-like particles of betanodavirus produced in Escherichia coli

Betanodaviruses are the causative agents of viral nervous necrosis (VNN), a serious disease of cultured marine fish worldwide. Virus-like particles (VLPs) are one of the good novel vaccine candidates to control this disease. Until now, betanodavirus vaccine studies mainly focused on the humoral immune response and mortality after virus challenge. However, little is known about the activation of genes responsible for cellular and innate immunity by vaccines. In the present study, VLPs of orange-spotted grouper nervous necrosis virus (OGNNV) were produced in prokaryotes and their ability to enter Asian sea bass cells was the same as native virus, suggesting that they possess a similar structure to OGNNV. VLPs immunogenicity was then determined by intramuscularly vaccinating Epinephelus coioides at different concentrations (1.5 or 15 μg g^?1 fish body weight, FBW) and immunizing frequencies (administration once, twice and thrice). A single vaccination with the dosage of 1.5 μg g^?1 FBW is enough to provoke high titer antibodies (average 3 fold higher than that of negative control) with strong neutralizing antibody titer as early as 1 week post immunization. Furthermore, quantitative PCR analysis revealed that eleven genes associated with humoral, cellular and innate immunities were up-regulated in the liver, spleen and head kidney at 12 h post immunization, correlating with the early antibody response. In conclusion, we demonstrated that VLP vaccination induced humoral immune responses and activated genes associated with cellular and innate immunity against betanodavirus infection in orange-spotted grouper.     

Clodronate treatment significantly depletes macrophages in chickens

Macrophages function as phagocytes and antigen-presenting cells in the body. As has been demonstrated in mammals, administration of clodronate [dichloromethylene bisphosphonate (Cl₂MBP)] encapsulated liposomes results in depletion of macrophages. Although this compound has been used in chickens, its effectiveness in depleting macrophages has yet to be fully determined. Here, we show that a single administration of clodronate liposomes to chickens results in a significant depletion of macrophages within the spleen and lungs of chickens up to 4 d post-treatment. This finding suggests that, in order to obtain depletion of macrophages in chickens for greater than 5 d, it is necessary to administer clodronate liposomes 4 d apart. The study also showed that 2 treatments of clodronate liposomes at 4-day intervals resulted in the depletion of macrophages for up to 10 d. The findings of the present study will encourage more precise studies to be done on the potential roles of macrophages in immune responses and in the pathogenesis of microbial infections in chickens.     

Apoptosis‐Like Events and In Vitro Fertilization Capacity of Sex‐Sorted Bovine Sperm

This study utilized three staining assays (Annexin V, mitochondrial membrane potential (JC‐1) and TUNEL) for flow cytometric analysis of apoptosis in sex‐sorted sperm from four different bulls (A, B, C and D). Correlations between sperm quality and IVF efficiency were then assessed to determine which assay provided the best prediction of IVF efficiency. The results of the Annexin V assays, as well as measures of viable sperm, early apoptosis, necrotic sperm and mitochondrial membrane potential (?ψm) showed that the sex‐sorted sperm collected from bull A significantly differed from those of the other three bulls (p < 0.05). In addition, the levels of DNA fragmentation in sex‐sorted sperm from bull A were significantly lower than those from bulls B and C (p < 0.05). The percentage of cells reaching the cleavage and blastocyst stages in sex‐sorted sperm from bull A were significantly greater than those from the other bulls (p < 0.05). A significant positive correlation was observed between viable sperm and the percentage of cells at the cleavage or blastocyst stages (p < 0.05). In contrast, a negative correlation was found between early apoptotic sperm and the percentage of cells at the cleavage or blastocyst stages (p < 0.05). In conclusion, these results indicated that the Annexin V assay was the most reliable technique for the prediction of the IVF success of sex‐sorted bovine sperm.