Replacing fish oil and astaxanthin by microalgal sources produced different metabolic responses in juvenile rainbow trout fed 2 types of practical diets

Dietary fish oil supplementation provides n-3 long-chained polyunsaturated fatty acids for supporting fish growth and metabolism and enriching fillet with eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; c22:6n-3). Two experiments were performed as a 3 × 2 factorial arrangement of dietary treatments for 16 wk to determine effects and mechanisms of replacing 0%, 50%, and 100% fish oil with DHA-rich microalgae in combination with synthetic vs. microalgal source of astaxanthin in plant protein meal (PM)- or fishmeal (FM)- based diets for juvenile rainbow trout (Oncorhynchus mykiss). Fish (22 ± 0.26 g) were stocked at 17/tank and 3 tanks/diet. The 100% fish oil replacement impaired (P < 0.0001) growth performance, dietary protein and energy utilization, body indices, and tissue accumulation of DHA and EPA in both diet series. The impairments were associated (P < 0.05) with upregulation of hepatic gene expression related to growth (ghr1and igf1) and biosynthesis of DHA and EPA (fads6 and evol5) that was more dramatic in the FM than PM diet-fed fish, and more pronounced on tissue EPA than DHA concentrations. The source of astaxanthin exerted interaction effects with the fish oil replacement on several measures including muscle total cholesterol concentrations. In conclusion, replacing fish oil by the DHA-rich microalgae produced more negative metabolic responses than the substitution of synthetic astaxanthin by the microalgal source in juvenile rainbow trout fed 2 types of practical diets.     

Cytotoxicity of cycloartane triterpenoids from aerial part of Cimicifuga foetida

Our previous study had demonstrated cytotoxicity of EtOAc fraction from aerial part of Cimicifuga foetida on various cancer cell lines. In the present study, we investigated the cytotoxicity of five cycloartane triterpenoids isolated from the EtOAc fraction. Compounds (1,2,3) showed moderate cytotoxic activity on R-HepG2 cells and drug resistant sub line R-HepG2 but exhibited less toxicity against primary cultured normal mouse hepatocytes. Compounds (4) and (5) were inactive on all tested cell lines.     

Allometric equations for accurate estimation of above-ground biomass in logged-over tropical rainforests in Sarawak, Malaysia

Although allometric equations can be used to accurately estimate biomass and/or carbon stock in forest ecosystems, few have been developed for logged-over tropical rainforests in Southeast Asia. We developed allometric relationships between tree size variables (stem diameter at breast height (dbh) and tree height) and leaf, branch, stem and total above-ground biomass in two logged-over tropical rainforests with different soil conditions in Sarawak, Malaysia. The study sites were originally classified as mainly lowland dipterocarp forest and have been selectively logged in the past 20 years. In total, 30 individuals from 27 species were harvested to measure above-ground parts. The correlation coefficients for the allometric relationships obtained for total above-ground biomass as a function of dbh had high values (0.99), although the relationships for leaf biomass had a relatively low coefficient (0.83). We also found relatively high coefficients for allometric relationships between tree height and plant-part biomass, ranging from 0.82 to 0.97. Moreover, there were no differences for allometric equations of total above-ground biomass between study sites. A comparison of equations of above-ground biomass in various previously reported tropical rainforests and pan-tropic general equations imply that our allometric equations differ largely from the equations for tropical primary forests, early successional secondary forest, and even for the general models. Therefore, choosing the biomass estimation models for above-ground biomass in the logged-over forests of Southeast Asia requires careful consideration of their suitability.     

不同覆盖方式对烤烟成熟期根系活力和叶片衰老特性的影响

以烤烟K326为试材,在大田条件下研究了前膜后草、地膜覆盖、无覆盖3种不同覆盖方式下烤烟成熟期根系活力和叶片衰老特性变化.结果表明,与常规栽培相比,前膜后草覆盖方式下,烤烟成熟期根系活力显著提高,叶片叶绿素和可溶性蛋白质含量较高,叶片保护酶SOD、POD、CAT活性较强,MDA含量较低,烤烟衰老速度缓慢,延长烤烟成熟期,提高烤烟经济性状;而地膜覆盖方式下,烤烟根系活力降低,叶片叶绿素和可溶性蛋白质含量急剧下降,叶片保护酶SOD、POD、CAT活性下降,烤烟膜脂过氧化程度加剧,烤烟衰老速度加快.     

青海12号蚕豆栽培技术优化研究

采用二次饱和D－最优化设计,以肥料（x1）、密度（x2）与打顶期（x3）等3项蚕豆主要农艺措施为试验变量,建立青海12号蚕豆产量与主要变量的数学模型,以模型为基础,分析各因素对青海12号蚕豆产量的影响效应,并决策优化栽培方案,为丰产栽培技术规范制定提供依据。     

恩施烟区土壤和烤烟总氮含量及其关系研究

2006-2007年,以湖北省恩施烟区有代表性的宣恩县和咸丰县为试验地点,选取了129个土壤样本和124个烤烟样本,分析了该区土壤氮素含量和烤烟总氮含量状况及其关系,结果表明:土壤全氮和碱解氮含量变幅分别为0.70~3.90 g.kg-1和66.8~233.9 mg.kg-1,平均分别为(1.65±0.34)g.kg-1和(131.69±30.97)mg.kg-1,全氮含量的变异系数略小于碱解氮含量变异系数.全氮和碱解氮含量均以表层0~20 cm含量最高,20~40 cm居中,而40~60 cm最低;烤烟总氮含量变幅为15.80~29.50 g.kg-1,平均为(21.30±3.30)g.kg-1,变异系数为15.49%;烤烟总氮含量在品种间、等级间和海拔高度间均存在显著差异,品种间表现为:‘K326’>‘云烟85’>‘云烟87’,等级间表现为:B2F>C3F>X2F,海拔间表现为:低海拔>中海拔>高海拔;烤烟总氮含量随土壤碱解氮含量的升高而升高,土壤氮素含量亦随海拔的升高而升高,而烤烟总氮含量则随海拔的升高而降低.     

欧李在干旱、半干旱地区高速公路绿化中的应用

适地适树是高速公路绿化成功的关键因素。根据干旱、半干旱地区高速公路绿化的特点,介绍了欧李的形态特征、生物学特性。阐述了欧李在干旱、半干旱地区高速公路绿化的综合开发利用价值,为欧李在干旱、半干旱地区高速公路绿化中的应用提供了科学的依据。     

低浓度NaHSO3对不同基因型小麦光合性能的影响

为了明确小麦对低浓度NaHSO3的响应及其机理,以京411和小偃54及其单粒传杂交后代稳定优选株系6号、7号和10号及扬麦14号和16号为材料,研究了不同基因型小麦光合性能对低浓度NaH-SO3的响应。结果表明,低浓度NaHSO3对小麦净光合速率(Pn)的影响在基因型间存在显著差异,极显著增加京411和扬麦16的Pn,显著增加扬麦14的Pn,而对其他基因型小麦的Pn影响不大。从小麦光合性能指标看,被低浓度NaHSO3促进指标和程度较多的基因型是京411和扬麦16,受影响程度较大的指标是气孔导度(Gs)和非荧光化学淬灭(qN)。推测,低浓度NaHSO3可能通过增加小麦叶片气孔导度和增强PSII的光保护能力来提高光合作用。     

甘蔗组培裸根苗小拱棚大田移栽技术试验报告

为了提高甘蔗组培裸根苗在不同季节的大田移栽成活率,通过搭建小拱棚对‘新台糖22号’甘蔗脱毒组培裸根苗进行栽培。比较不同增殖苗处理方式和小拱棚顶部不同透气孔的设置、不同假植天数及不同季节对甘蔗组培裸根苗大田移栽成活生长的影响。研究缩短甘蔗组培苗育苗周期的同时又能提高甘蔗组培苗的大田移栽成活率及生长速度的方法。结果表明：不同增殖苗处理方式之间的成活生长差异不显著;移栽当天在小拱棚顶部设置直径1~2 cm的透气孔,裸根苗移栽成活率可高达93.5%,与对照差异达到极显著水平;假植天数为20~40天,每年的2月至10月均适合运用小拱棚进行甘蔗组培裸根苗的大田移栽。从根本上达到了缩短育苗周期,减少中间生产环节,降低育苗成本的目的。     

水稻维生素C合成相关基因的表达分析

根据拟南芥中参和维生素C合成和代谢关键酶的氨基酸序列,经在公共数据库中搜索比对获得了水稻中参与维生素C合成相关基因的信息.在此基础上,利用实时定量PCR技术对这些基因在水稻不同组织器官以及发育种子中的表达进行分析.结果表明:水稻维生素C合成相关基因在叶中的表达量最高,其次是叶鞘和籽粒,茎和根中的表达量最低,而幼嫩叶片中...