Effects of dietary fish oil replacement with blended vegetable oils on growth,lipid metabolism and antioxidant capacity of subadult swimming crab Portunus trituberculatus

A 120‐day trial was conducted to assess the effects of dietary fish oil replacement with vegetable oils on growth, lipid metabolism and antioxidant capacity of subadult swimming crab Portunus trituberculatus. Five isonitrogenous and isolipidic diets were formulated to replace 0, 250, 500, 750 and 1000g/kg of fish oil with a mixture of soybean and rapeseed oil (defined as D1–D5), and each treatment had 30 replicate crabs. Dietary fish oil replacement had no significant effects on growth of the crabs, while the D3 had the highest hepatosomatic index and total lipids in hepatopancreas. The triglyceride and lipase activities in hepatopancreas increased significantly with increasing dietary fish oil replacement. The D4 had the highest levels of alkaline phosphatase (ALP) and acid phosphatase (ACP) in the hepatopancreas, as well as the haemolymph ALP, ACP and peroxidase. The highest levels of haemolymph total antioxidant capacity, catalase and malondialdehyde were detected in D1. Total n‐3 polyunsaturated fatty acids levels in hepatopancreas decreased significantly with increasing dietary fish oil replacement. In conclusion, dietary fish oil replacement had no significant effects on growth of P. trituberculatus, and 500g/kg of fish oil replacement could improve antioxidant capacity, but excessive replacement level will enhance lipid accumulation and peroxidation in the hepatopancreas.     

Nitrate removal efficiency and bacterial community of polycaprolactone-packed bioreactors treating water from a recirculating aquaculture system

A denitrification reactor packed with polycaprolactone (PCL) as a carbon source and biofilm carrier was developed to remove nitrate nitrogen (\( {\mathrm{NO}}_3^{-}-\mathrm{N} \)) from the water of a recirculating aquaculture system for 115 days. The hydraulic retention time was set to 6 h, and the water flow rate was 0.95 L h^?1. The removal rates of \( {\mathrm{NO}}_3^{-}-\mathrm{N} \) ranged from 34.67 to 155.7 g \( {\mathrm{NO}}_3^{-}-\mathrm{N} \) m^?3 day^?1 when the effluent \( {\mathrm{NO}}_3^{-}-\mathrm{N} \) concentrations ranged between 1.62 and 72.25 mg L^?1. No obvious changes in the Fourier transform infrared spectra of the PCL before and after use were observed. Bacterial community structure in the biofilm of the PCL granules was analyzed using Illumina MiSeq sequencing technology. Proteobacteria and Bacteroidetes were predominant in the biofilm, with relative abundances of 63.9 and 27.4%, respectively. Three genera, Acidovorax, Azospira, and Diaphorobacter, were capable of both denitrification and PCL degradation. This study indicates that PCL-packed reactors may be used and optimized for removing nitrate from aquaculture effluents.     

北部湾多齿蛇鲻摄食习性及随生长发育的变化

2008年10月至2009年9月,对北部湾多齿蛇鲻逐月采样共749尾(实胃数408个),通过胃含物分析法研究其摄食习性及随生长发育的变化。结果表明,北部湾多齿蛇鲻捕食种类包括鱼类、头足类以及虾类等饵料生物,其中可鉴定出的鱼类种类有17种。以相对重要性指数百分比为指标,鱼类为最主要饵料(98.8%),其中优势饵料种类有蓝圆鲹(34.9%)、少鳞犀鳕(26.6%)、长颌棱鳀(4.30%)和条鲾(2.5%)。多齿蛇鲻摄食强度、饱满指数和成熟系数的月份差异十分显著,而以Brillouin指数表征的各月份营养多样性则无显著差异。一年中呈现3个产卵高峰期(3-4月、6月及11月),产卵期间摄食强度没有降低,仍然强烈索饵。随着体长的增长,北部湾多齿蛇鲻饵料生物个数变化较小,但平均单个饵料生物质量却明显增加。聚类分析表明,北部湾多齿蛇鲻各体长组间食物组成相近,其中136～255mm各体长组相似性系数均大于60%。     

Ascorbate levels and the activity of key enzymes in ascorbate biosynthesis and recycling in the leaves of 22 Chinese persimmon cultivars

The objective of this study was to determine diversities of ascorbic acid (AsA) and activities of enzymes involved in AsA metabolism, and to determine their relationships to AsA content in the leaves of Chinese persimmon (Diospyros kaki) cultivars. Results showed that there were huge differences not only in the contents of AsA and glutathione (GSH) but also in the enzyme activities of l-galactono-1,4-lactone dehydrogenase (GLDH, EC 1.3.2.3), dehydroascorbate reductase (DHAR, EC 1.8.5.1), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) in the leaves of 22 Chinese persimmon cultivars. Control of AsA levels mainly depended on the capacity for biosynthesis and GLDH activity played a main role in determining AsA levels in the leaves of persimmon. Both MDHAR and DHAR, MDHAR in particular, also played an important role in maintaining AsA redox state by reducing oxidized AsA back to AsA. But contents of GSH and hydrogen peroide (H₂O₂) and activity of APX were not significantly correlated with AsA content in the leaves of persimmon.     

茎芥菜胞质四倍体白菜雄性不育系花药发育的研究

 以茎芥菜胞质雄性不育系与四倍体白菜杂交获得的同源四倍体白菜异源胞质雄性不育系及其保持系为材料,采用形态学和石蜡切片方法研究其花药解剖结构及发育。结果表明：该雄性不育为结构性雄性不育,其退化或畸形雄蕊分为5种类型：盾状雄蕊、条状雄蕊、片状雄蕊、羽状雄蕊和瓣状雄蕊。该雄性不育系花药发育败育有两个时期,盾状雄蕊花药败育于孢原细胞分化期,雄蕊整个发育时期均处在孢原细胞分化期,无绒毡层与花粉母细胞的分化,不形成药室,属孢子体败育型;其它类型雄蕊,花药败育发生在雄蕊原基分化时期,由于雄蕊原基偏离正常的分化轨道,形成瓣状化雄蕊。     

基于Fluent的风洞典型风蚀地表风速廓线的模拟

利用计算流体动力学(CFD)软件Fluent对OFDY-1.2型可移动式风蚀风洞中模拟典型农田风蚀地表风速廓线进行数值模拟,通过改变棒栅、尖塔和粗糙元的尺寸、形状和位置,分别用软件和室内风洞实验模拟出了与野外实地测试廓线相吻合的风速廓线。同时,对野外实测、室内风洞模拟和软件数值模拟的风速廓线进行了离散程度分析。     

大豆磷脂及其应用

大豆作为我国主要的粮食作物之一,在黑龙江省有广泛的种植,它含有丰富的生理活性物质。大豆磷脂是在豆油精炼加工中提取的纯天然产品,在食品、医药、畜牧等方面已被大量应用。     

可持续发展与人造板工业体系

应用可持续发展的观点阐述了建立可持续发展人造板工业体系的相关问题     

“六五”至“十二五”期间我国棉花品种纤维品质评价分析

对"六五"至"十二五"期间国家棉花区域试验参试品种纤维品质进行了总结和分析,结果表明,我国棉花品种的综合纤维品质总体趋势是稳步改良,逐年提升。黄河流域棉区品种的纤维长度和断裂比强度呈优化发展趋势;长江流域棉区品种纤维长度、断裂比强度和纺纱均匀性指数呈优化发展趋势;西北内陆棉区品种纤维品质总体表现有上升趋势,但近5年来纤维品质表现略有下降趋势。     

密肥组合对稻茬晚播小麦籽粒产量和效益的影响

为筛选适宜南方晚播稻茬中筋小麦高产高效栽培的密肥组合,以中筋小麦品种扬麦20为材料,研究了江苏淮南地区晚播(11月20日之后播种)条件下密度、施氮量、氮肥基追比对稻茬小麦籽粒产量和效益的影响.结果表明,晚播小麦密度与籽粒产量、效益均呈二次曲线关系,密度为315×104株·hm-2时,籽粒产量最高,达6 721.65～7 884.91 kg·hm-2,效益达3 783.6～5 111.55元·hm-2;施氮量为270 kg·hm-2时籽粒产量极显著高于施氯量210 kg· hm-2处理.在本试验条件下,基本苗为315×104株·hm-2、总施氮量270 kg·hm-2、基肥∶壮蘖肥∶拔节肥∶孕穗肥为3∶1∶3∶3时,晚播小麦的籽粒产量和效益最高.