滨旋花和兴安天门冬种子萌发特性的研究

从温度、pH值、盐分及混播方面对滨旋花和兴安天门冬种子萌发特性进行了研究。结果表明，滨旋花种子萌发的适宜温度为15～2．3℃，最适温度为20℃；而兴安天门冬种子萌发的适宜温度为23-28℃，其中25℃时发芽率最高；二者的种子适合在稍偏碱性环境下萌发；盐分对种子的萌发有抑制作用。滨旋花种子硬实率高，属于环境强迫休眠，人工处理种皮，可以解除休眠。     

Comparative study of the intestinal microbial community of wild and cultured kaluga sturgeon,Huso dauricus

The kaluga, Huso dauricus (Georgi 1775), is a large‐sized semi‐anadromous sturgeon native to the Amur River basin. Gut microbes play an important role in the growth and development of fish. Because wild samples of this species are difficult to obtain, very few studies have analysed the microbial community of the kaluga gut. Here, we used high‐throughput sequencing to determine differences in the intestinal microbial communities of wild and cultured kaluga, to lay the foundation for development of micro‐ecological preparations that might ultimately assist with conserving wild kaluga by benefitting sturgeon aquaculture. Two 2‐year‐old (wild) fish collected from the Heilongjiang River basin were size‐ and age‐matched with two 2‐year‐old (cultured) fish obtained from a breeding base in Yunnan Province, for molecular analysis of gut samples. In total, 483,008 16S rRNA sequences were obtained. The intestinal microbial diversity was greater in the wild kaluga than in the cultured fish. The dominant phyla in the gut community of wild kaluga were Proteobacteria (47.9%), Fusobacteria (30.5%) and Firmicutes (8.85%), whereas samples from the cultured kaluga were dominated by Fusobacteria (78%). This result may be attributed to differences in environmental conditions, particularly water quality and temperature, as well as diet between the wild and cultured animals. The findings provide basic data to assist further research and the development of feed as a part of artificial breeding technology.     

中国达氏鳇野生群体和两个养殖群体的线粒体遗传多样性分析

达氏鳇(Huso dauricus)是黑龙江流域土著鲟,近几十年来野生资源急剧下降,被确定为濒危物种之一。本研究采用线粒体DNA的Cyt b基因和D-loop区域的多态性信息评估了黑龙江抚远段野生群体、北京房山国家级鲟鱼原种场的保种群体及浙江衢州国家级鲟鱼良种场的繁殖群体等3个达氏鳇群体的遗传多样性水平。所有测试个体在Cyt b基因位点的核苷酸水平上没有检测到多样性,均具有相同的Cyt b单倍型,而在D-loop区域中发现了9种单倍型,对于D-loop区,单倍型多样性(H_d)达到0.593,但核苷酸多样性(π)仅为0.00213。在8尾野生个体中检测到6种D-loop单倍型,2个养殖群体共计58尾个体共计检出5种D-loop单倍型个体。分析结果显示:野生达氏鳇群体遗传多样性极低,历史上可能经历过严重的遗传瓶颈,同时达氏鳇人工繁殖过程中每批次可能只有极少个体参与了繁殖。此外,基于Cyt b基因部分序列的分析结果提示,达氏鳇与其他太平洋鲟类的亲缘关系较近,而与欧鳇(Huso huso)关系较远,传统上鳇属(Huso)的分类地位得不到有效的分子生物学数据支持。     

不同投饲率对达氏鳇幼鱼生长及体成分的影响

选取同一种饲料,设1.0％、1.5％、2.0％、2.5％、3.0％、3.5％和4.0％七个投饲率水平,在溶氧为7.8 mg· L-1、水温13℃～18℃的流水养殖条件下,对体重99.21～385.92 g达氏鳇进行为期75 d的生长试验,结果表明,随着投饵率投饲率的增加,达氏鳇的相对增重率、特定生长率先升高后降低,2....     

养殖达氏鳇人工繁殖的初步研究

于2008年4月13—16日,对4尾人工养殖初次性成熟的雌性达氏鳇Huso dauricus进行人工繁殖试验。结果表明:有2尾达氏鳇成功产卵,2尾达氏鳇没有产卵,产卵率为50%;共采集卵19.5 kg,其中对8 kg卵(24万粒)进行授精,受精率为83.3%,孵化率为85.2%,共出鱼苗17.2万尾。通过对没有产卵的2尾达氏鳇解剖发现,达氏鳇卵巢中均有部分不同程度的退化卵。     

养殖条件下施氏鲟（♂）X达氏鳇（♀）杂交后代的生长特性

2008年～2011年研究了人工养殖条件下的施氏鲟Acipenserschrenckii（6）×达氏鳇Husodauncus（早）杂交后代（f谷称大杂交）的生长特性。结果表明：1～7龄大杂交体长、体重相对增长率及生长指标随年龄的增长而逐渐下降,呈“异速生长一等速生长一异速生长”的变化趋势。不同年龄大杂交的体长与体重均呈幂指数关系,R2值变幅为0．95～0．99。其中,1-3龄大杂交a值〉3,呈强异速生长。此后随年龄的增加,异速生长减弱,发育趋向均匀。5龄时a值为2．94接近3,7龄a值为2．63〈3。大杂交肥满度随年龄增加而增大,其与体重的相关性（R2＝0．94）高于与体长的相关性。采用7种生长方程对不同年龄大杂交的体长生长和体重生长进行拟合,其中Gompertz、Quadratic、VBGF和Cubic4种生长方程式对大杂交体长生长的拟合效果较好,除Cubic生长方程外,其它6种生长方程对其体重生长的拟合度均较低。7种生长模型中,均以Cubic生长方程对大杂交的体长生长和体重生长的拟合R2值最大,RSS值最小,说明Cubic生长方程对不同年龄大杂交的生长具有最好的拟合效果,拐点体重、体长和年龄分别为28．53kg、82．11cm和4．22龄。     

Fine tuning of feeding practices for hatchery produced Persian sturgeon,Acipenser persicus and Beluga sturgeon,Huso huso

In this work, we investigated the effects of various feeding treatments on the survival and growth of Huso huso and Acipenser persicus larvae during a 20‐day culture period. Three replicate groups (250 fish/replicate) of first‐feeding larvae were fed according to four main feeding regimes: (1) live food (live nauplii of brine shrimp Artemia urmiana); (2) indirect transition (5–7 days live food followed by gradual transition to formulated diet); (3) direct transition (using different combinations of live and formulated diet from the start feeding onwards); and (4) formulated feed (FD) from the start of feeding. In H. huso larvae, combining live food and manufactured diets (co‐feeding) from the first feeding stage onwards (direct transition) resulted in significantly higher weight gain than the other regimes. Survival was significantly higher in H. huso larvae fed solely live food or the direct transition regimes compared with indirect transition and FD. In A. persicus larvae, growth and survival were higher in the indirect transition feeding regime than in the other regimes. On the basis of the results of this study, we recommend co‐feeding of H. huso immediately from the commencement of exogenous feeding, but co‐feeding of A. persicus should start 7 days after prior feeding with live food.     

Ontogeny of the digestive system in hatchery produced Beluga (Huso huso Linnaeus, 1758); a comparative study between Beluga and genus Acipenser

The study on histological characteristics of the digestive system of Beluga (Huso huso) was conducted from hatching until 50 days posthatching at 16.5 °C. Development of the digestive system in this species followed the general pattern described for other Acipenserids, although there were differences in the timing of organ development among species. At hatching, the mouth was opened and digestive system was represented by a gastric cavity filled with yolk and lined by endodermal cells, and a partially differentiated hindgut. Gastric glands started to differentiate at 46.5 degree‐ days posthatching (ddph), the earliest appearance time among sturgeon fishes studied to date. At the onset of exogenous feeding (144.9 ddph), yolk sac reserves were not completely depleted in the stomach, suggesting a period of mixed nutrition. The complete development of the digestive system was not accomplished until 235.2 ddph when it showed all histomorphological features typical of juvenile specimens. According to histological results, it seems advisable to start co‐feeding H.huso larvae with inert diets at the onset of exogenous feeding, because exocrine pancreas and glandular stomach are fully differentiated, although the complete substitution of live prey by inert feed is not recommended until 235 ddph.     

达氏鳇肌肉组织转录组测序和功能分析

为发掘达氏鳇的功能基因,采用新一代高通量测序技术对达氏鳇肌肉组织转录组进行测序。结果获得原始数据14 447 211 200 bp,拼接获得了55 531条单基因序列(unigene),长度范围300~32 613 bp,平均长度941 bp。利用生物信息学方法对unigene进行了非冗余蛋白质数据库(Nr)相似搜索,此外还进行了GO的功能注释和KEGG代谢通路分析。结果一共有20 735条unigene(37.34%)与Nr数据库中的己知基因同源;根据GO功能可分为生物过程、细胞组分和分子功能3大类56分支;依据KEGG代谢通路分析可以分成290类。     

Digestibility of selected feedstuffs in subadult Caspian great sturgeon,Huso huso using settlement faecal collection and stripping methods

Apparent crude protein (ADC_CP), crude fat (ADC_CF) and gross energy (ADC_GE) digestibility coefficients of several typical and novel feedstuffs were determined to be employed in the formulated diets of subadult beluga (17.70 ± 0.234 kg) diets via two faecal collection methods of settlement (SFCM) and stripping (StM). The tested feedstuffs included three fish meals, three terrestrial animal by‐products, three plant protein concentrates, nine high‐protein plant meals and three low plant protein meals. ADC_CP values varied in different fish meals ranging from 89.5% for Mexican sardine meal to 93.2% for anchovy meal with SFCM. ADC_CP values for plant protein concentrates ranged from 82.8% for wheat gluten meal to 92% for soy protein with SFCM. ADC_CP ranged from 37.2% for whole wheat to 75.6% for spirulina meal with SFCM. ADC_GE was lower in low‐protein plant meals (64.1%) in comparison to high‐protein plant meals (70.2%). Fish meals showed the highest ADC_CF values. A significant (P < 0.05) quadratic regression relation (r² = 0.92) was observed among in vivo ADC_CP of five feedstuff classes fed to beluga and in vitro ADC_CP. The differences among ADC values appear to be significantly related to the effects of feedstuffs and therefore diet and faecal collection methods.