Sequence of the domestic duck (Anas platyrhynchos) growth hormone-encoding gene and genetic variation in the promoter region

The duck growth hormone encoding gene and its promoter region were amplified by polymerase chain reaction (PCR). A total of 5.25 kb were cloned and sequenced. Duck growth hormone (GH) consists of five exons and four introns and is structurally similar to mammalian and chicken GH gene. Although the distal region of duck GH promoter showed no similarity to chicken and turkey promoters, the proximal region of the promoter contained two putative Pit‐1 binding sequences, and showed similarity to chicken and turkey GH promoters. Genetic variation was detected at five positions of the promoter region. The results of this study indicate that the expression of duck GH is likely regulated in a similar manner to that of chicken GH via enhancer‐type cis‐acting elements and the presence of genetic variation in the duck GH gene may be applicable to marker‐assisted selection.     

30个紫花苜蓿品种对苜蓿花叶病毒病的田间抗性初步研究

为了比较不同紫花苜蓿品种对病毒病的抗性,对30个紫花苜蓿品种的病毒病发病情况进行了田间调查,利用小RNA深度测序技术结合RT-PCR技术检测鉴定各紫花苜蓿品种中的病毒种类,并测定了各紫花苜蓿品种的发病率、病情指数、相对株高、相对单株干重、相对茎秆直径、相对叶面积、相对叶长和相对叶宽,综合比较各紫花苜蓿品种的抗性,并对部分指标进行系统聚类分析。结果表明:30个紫花苜蓿品种均只受到苜蓿花叶病毒(alfalfa mosaic virus, AMV)的侵染,所有紫花苜蓿品种的田间发病率均超过94%,病情指数范围为31.53～55.50;30个紫花苜蓿品种中,抗性较强的品种有1个,为射手2号,抗性一般的品种有6个,其余23个品种的抗性较差,分别占供试品种的3.33%,20.00%和76.67%;聚类分析结果表明,抗性较强的射手2号与其他紫花苜蓿品种的亲缘关系较远,与其杂交有可能产生较大的杂种优势。     

高粱—苏丹草杂交种的应用可行性研究及其选育

利用生产上推广的６个粒用高粱杂交种和４个高粱杂交种为对照,与随机组配的１５个高粱－苏丹草杂交种进行比较。结果表明,高粱－苏丹草杂交种做饲用生产能力上仅次于甜高粱杂交种,但在早熟优质等若干特性上优于甜高粱,有些组合还高于甜高粱杂交种的生产能力。该类型杂交种干物质及绿色体的日生产能力高于甜杂２号２１．１％和４１．２％,原因是杂最高。     

Comparison of morphological and DNA-based techniques for stomach content analyses in juvenile chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis>: a case study on diet richness of juvenile fishes

To identify the stomach contents of marine organisms, morphological observations are commonly conducted. However, the results obtained by this traditional method are frequently biased, as it is difficult to detect partially digested, soft-bodied organisms. To resolve this, recent studies have used DNA-based (DNA barcoding) analyses to examine the diet breadth of marine organisms. Here, we compared the prey richness of juvenile fishes using morphological observations and DNA-based analyses, with a focus on juvenile chum salmon Oncorhynchus keta. A higher number of prey taxa were successfully identified using DNA-based analyses than morphological observations. However, we also noticed several shortcomings of the DNA-based analyses, as reported in other diet-analysis studies that used molecular techniques. For example, the degree of digestion among prey taxa might have resulted in differential sensitivity to DNA detection. Additionally, several prey taxa could not be precisely identified, as the sequence data for some of the targeted organismal groups are unavailable in public gene databases. Remarkably, it is also possible that DNA-based analyses detected secondary prey, and therefore, the richness of prey taxa was likely overestimated. Thus, dietary analyses of juvenile fishes need to be carefully conducted, considering the respective advantages and disadvantages of DNA-based and morphological techniques.     

短蛸(Amphioctopus fangsiao)幼体摄食行为和不同饵料对其生长、存活的影响

为了研究短蛸(Amphioctopus fangsiao)不同生长阶段的饵料需求,本研究采用刚孵化的短蛸幼体作为实验材料,首先观察不同环境条件下短蛸幼体的摄食行为,然后通过投喂不同的饵料,对短蛸幼体的生长过程进行研究。结果显示,卤虫无节幼体密度从0.1个/ml上升至1个/ml的过程中,密度在0.1个/ml时短蛸初孵幼体摄食量高;1–2 d龄幼体和2–3 d龄幼体有较为强烈的摄食行为,因此,需要从孵化第2天开始重视短蛸幼体的饵料情况。晚上是初孵幼体的摄食活跃阶段,在室内光和黑暗条件下均表现出高摄食量。投喂混合饵料时,短蛸幼体有较高的存活率和增长率;初孵幼体(0.03 g)培育过程中,卤虫无节幼体是关键饵料;当幼体开始附底(0.1 g)时,应及时进行饵料转换,虾苗和贝肉是附底幼体的重要饵料。该研究结果对短蛸规模化苗种繁育具有重要实用价值。     

不同早籼基因型水稻的空间诱变效应研究

本研究结果表明 ,空间搭载种子的发芽率、存苗率和结实率除迟熟品种外均低于对照 ,对秧苗的生长表现出刺激和抑制两种作用 ,生理损伤比地面γ射线处理的轻得多。空间搭载对杂种 1代处理的SP2 代单株有效分蘖的分离具有一定的稳定作用。SP2 代在株高、分蘖和抽穗期等性状上出现了较大的分离 ,突变频率和诱变效率因不同基因型材料差异较大 ,而且一些性状的突变具有一定的方向性。在空间处理的SP2 代就出现较多综合性状优良的突变体 ,可望直接育成新品种     

The effects of dietary Eucommia ulmoides Oliver on growth,feed utilization,antioxidant activity and immune responses of turbot (Scophthalmus maximus L.)

The present study was conducted to evaluate the effects of dietary Eucommia ulmoides (EU) on growth, feed utilization, antioxidant activity and immune responses of turbot fed a basal diet (CON) or EU‐supplemented diets with 5.0 g/kg (EU1), 10.0 g/kg (EU2) and 20.0 g/kg (EU3) EU leaf powder. After 70‐day trial, EU supplementation did not affect nutrient utilization, but reduced feed intake (FI) and specific growth rate (SGR) of fish at doses above 5.0 g/kg. Superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T‐AOC) activities in the EU‐supplemented groups were significantly higher than those in the control group at a dose of 20.0 g/kg. Significantly reduced malondialdehyde (MDA) contents were observed in EU‐supplemented groups at doses over 5.0 g/kg. Furthermore, fish fed 20.0 g/kg EU showed the highest lysozyme (LZM) activity among groups. The EU‐supplemented diets with doses above 5.0 g/kg significantly enhanced the mRNA expressions of cytokines. The expression level of major histocompatibility complex II alpha (MHC IIα) was significantly upregulated compared to that of the control fish when the supplemental level was at 20.0 g/kg. Taken together, the present study indicated that the EU could remarkably enhance the antioxidant activity, non‐specific immunity and maintain an active immune response in turbot.     

基于高斯随机扰动的潜在蒸散敏感性分析

旨在定量分析不同气象要素对潜在蒸散量敏感性大小的时空分布,以期为提高蒸散量计算精度提供依据。以1961年1月1日—2012年12月31日的日观测资料为基础,通过添加高斯分布随机扰动,计算各要素的敏感系数。研究表明：安徽全区年尺度上,日照时数和平均风速的敏感性最高,敏感系数分为0.1258和0.1089;月尺度上,4—9月蒸散量的主要敏感因素为日照时数,10月至次年3月的主要敏感因素为平均风速和实际水汽压。敏感性空间分布不均,淮河以北地区平均风速为主要敏感因素;淮河以南地区则仍是日照时数为主要敏感因素。     

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.