两种鲤鲫杂交回交子代染色体核型分析及比较

采用PHA和秋水仙素体内注射制备两种鲤鲫杂交回交子代鱼（鲤鲫杂交♀×德国镜鲤♂;鲤鲫杂交♀×鲤♂）的染色体。结果表明：两种鲤鲫杂交回交子代染色体组由150条染色体组成,按着丝粒位置染色体组型可分为四组,每个染色体小组均由三条同源染色体组成。其中鲤鲫杂交♀×鲤♂回交的染色体数目为3n=150,染色体臂数NF=234,其核型公式为：3n=60m＋24sin＋36st＋30t;鲤鲫杂交♀×德国镜鲤♂回交染色体数目为3n=150,染色体臂数NF=258,其核型公式为：3n=63m＋45sin＋12st＋30t。     

松花江鲤鱼肌肉肌苷酸含量和鱼肉保鲜时间的研究

纸层析法对松花江鲤鱼肌肉肌苷酸含量和鱼肉保鲜时间作了研究，结果表明：室温２０℃下，鲤鱼肌肉存放３小时左右，肌苷酸含量达到了最高值为６．３２６±０．１２μｍｏｌ／ｇ，保鲜时间为９小时。冷冻－１８℃下，鲤鱼肌肉存放１０天，肌苷酸含量达到了峰值为５．９３１±０．１３μｍｏｌ／ｇ，保鲜时间为２０天。     

不同饲料原料对草鱼生长和肌肉品质的影响

分别以专用配合饲料、浸泡蚕豆、浸泡豌豆喂养体质量为(1540.9±57.5)g的草鱼(Cteno-pharyngodon idellus)90d,以考察不同原料对草鱼生长和肌肉品质的影响。结果表明,配合饲料组、浸泡蚕豆组和浸泡豌豆组草鱼的增重率分别为17.3%、13.7%和12.2%,饵料系数分别为5.00、4.09和5.08,三种原料对草鱼的脏体比、肝体比没有显著影响;与普通草鱼相比,三种原料组草鱼肌肉粗脂肪含量和肌肉失水率显著降低(P0.05),胶原蛋白含量和肌原纤维长度显著增加(P0.05)。上述结果表明,三种原料均可显著改善草鱼肌肉品质;与浸泡蚕豆组相比,专用配合饲料组显著提高了草鱼的生长性能。     

滁州鲫鱼食性的初步研究

对滁州鲫鱼的食性进行了调查研究。结果表明:滁州鲫是一种杂食性鱼,它的主要食物组成是轮虫、枝角类、桡足类、单胞藻类和有机碎屑等,随着体长的增长,食物中大型浮游动物、水生植物所占比例明显增加。对食物的摄食量上有季节性变化,在夏、秋两季摄食量最大,春季次之,冬季最少。     

Effects of dietary thiamin supplement on growth,body composition and intestinal enzyme activities of juvenile Jian carp (Cyprinus carpio var. Jian)

A total of 1050 juvenile Jian carp (Cyprinus carpio var. Jian) (8.20 ± 0.02 g) were fed diets containing seven graded levels of thiamin (0.25, 0.48, 0.79, 1.06, 1.37, 1.63 and 2.65 mg kg^?1) for 60 days to investigate the effects of thiamin on growth, body composition and digestive enzyme activities. Percent weight gain (PWG), feed intake and feed efficiency (FE) were the lowest in fish fed the basal diet (P < 0.05). Protein productive value and lipid productive value increased with increasing dietary thiamin levels up to 1.06 and 0.79 mg kg^?1 diet, respectively (P < 0.05). Body protein and lipid increased with increasing dietary thiamin levels (P < 0.05), while moisture and ash of fish carcasses decreased with the increase in dietary thiamin supplementation (P < 0.05). Intestinal folds height had a similar trend to PWG (P < 0.05). Activities of α‐amylase, lipase, trypsin, Na⁺, K⁺‐ATPase, alkaline phosphatase and gamma‐glutamyl transpeptidase in intestine were all affected by the dietary thiamin (P < 0.05). In conclusion, thiamin could improve growth and intestinal enzyme activities of juvenile Jian carp. The dietary thiamin requirement of juvenile Jian carp (8.0–60.2 g) based on PWG was 1.02 mg kg^?1 diet.     

Generation and characterization of aptamers against grass carp reovirus infection for the development of rapid detection assay

Grass carp reovirus (GCRV) causes devastating viral haemorrhagic disease in farmed grass carp (Ctenopharyngon idellus). As novel molecular probes, aptamers have been widely applied in rapid diagnosis and efficient therapies against virus or diseases. In this study, three single‐stranded DNA (ssDNA) aptamers were selected against GCRV‐infected CIK cells via SELEX (systematic evolution of ligands by exponential enrichment technology). Secondary structures predicted by MFOLD indicated that aptamers formed stem‐loop structures, and GVI‐11 had the lowest ΔG value of ?30.84 KJ/mol. Three aptamers could specifically recognize GCRV‐infected CIK cells, with calculated dissociation constants (Kd) of 220.86, 176.63 and 278.66 nM for aptamers GVI‐1, GVI‐7 and GVI‐11, respectively, which indicated that they could serve as specific delivery system for antiviral therapies. The targets of aptamers GVI‐1, GVI‐7 and GVI‐11 on the surface of GCRV‐infected cells could be membrane proteins, which were trypsin‐sensitive. Furthermore, FAM‐labelled aptamer GVI‐7 could be applied to detect GCRV infection in vivo. It is the first time to generate and characterize aptamers against GCRV‐infected cells. These aptamers have great potentials in development of rapid diagnosis technology and antiviral agents against GCRV infection in aquaculture.     

白鲢出血病病原菌的鉴定

从患出血病的白鲢体内分离出两株细菌(编号为水_1、水_2),分别感染健康白鲢,人工复制白鲢出血病获得成功。对这两株细菌进行形态、营养需求、生长特性、以及生化反应等观察,作者认为,水_1菌为产碱假单胞菌(Pseudomonas alcaligenes);水_2菌为嗜水气单胞菌(Aeromonas hydrophila)。前者隶属于假单胞菌科(Pseudomonaceae),后者隶属于孤菌科(Vibrionaceae)。     

鲢肠道淀粉酶的分离纯化及部分性质研究

以鲢(Hypophthalmichthys molitrix)加工下脚料为原料,分离提纯其中的淀粉酶并对其部分性质进行了研究。结果表明经多级分离,得到了一种相对分子质量约2.15×104的淀粉酶,命名为SCIG1。SCIG1是鲢肠道淀粉酶的一种,酶活性的最适温度为30℃,最适pH5.5。     

鳙小卫星DNA的克隆

鳙基因组ＤＮＡ 经内切酶Ｓａｕ３ＡⅠ完全酶切后,与Ｂａｍ ＨⅠ－ ｐＵＣ１８ 质粒连接,转化ＤＨ５α后,获得９３３ 个重组体。用人源小卫星探针３３ ．１５ 对重组体进行原位杂交筛选,获得１４ 个阳性克隆,取其中的１ 个阳性克隆（ 即小卫星ｐＢＣ１７４） 作探针,与５ 尾鳙和４ 尾鲢基因组ＤＮＡ 杂交,能产生具有高度变异性的、个体特异性的ＤＮＡ 指纹图,表明克隆的鳙小卫星ｐＢＣ１７４ 可用于鱼类ＤＮＡ 指纹分析。     

鲢、鳙对三角帆蚌池塘藻类影响的围隔实验

以浙江金华汤溪威旺养殖基地的三角帆蚌养殖水体为研究对象,通过围隔实验比较研究了单养鲢、鳙和三角帆蚌的池塘浮游植物密度、生物量和优势种(属)组成等的差异,以及养蚌池混养鲢鳙对水体浮游植物密度、生物量以及优势种变化的影响。结果表明,养蚌(10#)围隔的浮游植物平均密度和生物量均显著高于高密度鲢(12#)围隔(P<0.05),其蓝藻数量及生物量显著高于高密度鲢(12#)和低密度鳙(13#)围隔(P<0.05),绿藻数量则显著低于低密度鲢单养(11#)围隔(P<0.05)。在鱼蚌混养的情况下,单养蚌(10#)围隔浮游植物平均数量显著高于鲢-蚌混养(15#,16#)和鳙-蚌混养(17#,18#)围隔(P<0.05),其蓝藻数量及生物量极显著高于鲢-蚌混养(15#,16#)或鳙-蚌(17#,18#)围隔(P<0.01),其绿藻数量显著低于混养高密度鲢(16#)或低密度鳙(17#)的混养围隔(P<0.05)。研究结果充分说明,鲢、鳙和三角帆蚌三者对水体藻类组成的影响有别,三角帆蚌养殖池中适当混养鲢或鳙可以有效控制蓝藻(铜绿微囊藻)的生长,促进绿藻(四尾栅藻)的生长,并最终有利于三角帆蚌的养殖,混养鲢密度的增加有利于控制藻类生长,而鳙密度的增加促进了裸藻等中大型藻类的生长。