不同养殖品种池塘化学耗氧量(CODMn) 变化趋势及环境影响因素

为了解养殖池塘水体化学耗氧量的变化特征,于2012 年在佛山市顺德区内4 种不同养殖品种(云斑尖 塘鳢、草鱼、大口黑鲈、乌鳢）池塘采集样品进行分析。结果显示院不同时期4 个品种养殖池塘CODMn含量在3.71~ 50.76 mg/L 之间,其中大口黑鲈、乌鳢两个品种养殖池塘季节的变化有显著差异;云斑尖塘鳢、草鱼池塘的CODMn 含 量没有明显的季节性变化。不同品种养殖池塘CODMn含量从低到高依次为云斑尖塘鳢、大口黑鲈、草鱼、乌鳢。养殖 池塘水体CODMn污染指数（Pi）范围在0.67~8.46 之间,超标率为92.9%。图谱分析结果显示,5~8 月间不同养殖池塘 水体中云斑尖塘鳢、大口黑鲈养殖池塘CODMn有比较相近特征,而草鱼、乌鳢养殖池塘与其他池塘特征相差较大。9~ 12 月间不同养殖池塘水体中CODMn 云斑尖塘鳢、草鱼、大口黑鲈养殖池塘有比较相近特征,而乌鳢养殖池塘与其他 池塘特征相差较大。对CODMn 与14 个水质因子进行相关分析发现,CODMn 与透明度、pH 值及硅酸盐存在负相关关 系,与盐度、电导率、叶绿素、磷酸盐、硝酸盐、氨氮等存在正相关关系,而与溶解氧及非离子铵不相关。     

Dietary pantothenic acid requirement of fingerling Channa punctatus (Bloch) based on growth,feed conversion,liver pantothenic acid concentration and carcass composition

A 16‐week feeding trial was conducted to determine the dietary pantothenic acid requirement of fingerling Channa punctatus. Six casein–gelatin‐based diets (450 g/kg CP; 18.39 kJ/g GE) with graded levels of pantothenic acid (0, 10, 20, 30, 40 and 50 mg/kg diet) were fed to triplicate groups of fish (6.2 ± 0.71 cm; 4.26 ± 0.37 g) near to apparent satiation. The growth evaluation in terms of absolute weight gain (AWG), feed conversion ratio (FCR) and protein retention efficiency (PRE) indicated the best performance (p < .05) in fish fed diet containing 30 mg/kg pantothenic acid. Highest haemoglobin, haematocrit and RBCs counts were also obtained in fish fed diet with 30 mg/kg pantothenic acid. Mean cell haemoglobin and mean cell volume were found to be lowest in fish fed pantothenic acid‐free diet indicating the anaemia in this group of fish. Superoxidase dismutase and catalase activities of liver tissue were found to improve (p < .05) with the increasing levels of dietary pantothenic acid from 0 to 30 mg/kg. However, liver pantothenic acid concentration responded positively with the increasing levels of pantothenic acid up to 40 mg/kg diet and then stagnation in liver pantothenic acid concentration with the further inclusion of pantothenic acid was recorded. Second‐degree polynomial regression analysis of AWG, FCR and PRE exhibited the pantothenic acid requirement at 36.4, 32.8 and 34.7 mg/kg diet, respectively. Data generated during this study would be useful in formulating pantothenic acid‐balanced commercial feeds for the intensive culture of this fish.     

乌鳢腐皮病病理形态学研究

乌鳢腐皮病的 主要眼观病 变是病鱼体 表鳞片脱落,皮 肤溃烂,有出 血和炎 性渗出 物。主要组织学所见是局部皮肤和骨骼肌急性炎症反 应和坏死。肝 脂肪变性,肾间质充血,肾小管上皮细胞空泡变性。肝脏和肾脏细胞肿胀,线粒体结构模糊、空泡化。     

广西引种伞房属三种桉树的生长和抗病性早期选择

目的 了解伞房属斑皮桉、大叶斑皮桉和柠檬桉2个亚种(柠檬桉和斑皮柠檬桉)引种广西的生长情况,初步选育抗病的树种、种源、家系,为桉树锯材树种定向培育提供科学依据。 方法 以广西国有三门江林场伞房属桉树种源/家系试验林为研究材料,调查林龄3个月试验林的树高和病害情况,采用抗病指数分析试验林病害情况,方差及变异分析性状差异性与遗传变异情况,独立淘汰法初步选择抗病树种、种源、家系。 结果 树种间树高、保存率、抗病指数差异极显著(P＜0.001);斑皮桉和大叶斑皮桉种源间树高、保存率、抗病指数差异不显著,但2树种3性状在家系间差异极显著(P＜0.01),斑皮桉抗病指数家系间差异不显著除外;斑皮柠檬桉种源间和家系间树高、抗病指数差异极显著(P＜0.001),保存率差异不显著;柠檬桉种源间和家系间仅抗病指数差异极显著(P＜0.01)。各性状遗传力和重复力变化范围为0.05～0.43,受弱至中等强度遗传控制。柠檬桉比其他3个树种生长快,最抗病;共选出7个抗病种源和47个抗病家系,其树高、保存率、抗病指数平均值比总体平均值高57.1%、1.8%、67.4%和57.1%、0.9%、69.8%,种源和家系的树高、抗病指数遗传增益分别为12.0%、21.9%和17.1%、21.6%。 结论 选择出的抗病树种柠檬桉、抗病种源和家系为下一步改良提供种质材料。     

斑鳢、乌鳢及其杂交种遗传差异的AFLP分析

本文采用AFLP分子标记技术对斑鳢、乌鳢和杂交鳢（斑鳢（母本）与乌鳢（父本））共85个个体（其中斑鳢、乌鳢各30个,杂交鳢25个）进行了遗传差异分析。结果表明11对引物组合共检出了459个不同的扩增片段,扩增出的多态谱带数350条,多态性比例为76.25%,平均每对引物组合扩增出31.8条多态条带。乌鳢与斑鳢种群间存在稳定的、可以简单地借以进行群体鉴别的标记条带169条,其中父本（乌鳢）特异性条带78条,72条能够稳定地遗传给杂交鳢;母本（斑鳢）特异性条带89条,71条能够稳定地遗传给杂交鳢。杂交鳢另外出现了3条非双亲的条带。遗传差异的分子方差分析结果发现,斑鳢与乌鳢种群间的遗传相似度为0.5161,杂交鳢与斑鳢和乌鳢种群间的遗传相似度相近,分别为0.7189和0.7476,斑鳢与乌鳢之间以及杂交鳢与斑鳢和乌鳢之间的种群间遗传距离分别为0.6615、0.3300和0.2909,即AMOVA分析显示斑鳢、乌鳢和杂交鳢间存在极显著的遗传分化。UPGMA聚类分析显示,在个体间,斑鳢与乌鳢能区分成两大类,杂交鳢则分散于斑鳢和乌鳢种群中;在群体间,杂交鳢首先与乌鳢聚类,然后与斑鳢相聚,表明杂交鳢种群总体上更偏向于父本乌鳢。研究结果表明,杂交鳢与斑鳢和乌鳢发生混杂的可能性很大,应该对杂交鳢进行隔离养殖。本文结果将为斑鳢、乌鳢和杂交鳢的遗传分析提供实验依据,也为其种质的合理利用提供参考。     

饵料鱼大小对乌鳢捕食的影响

测量了乌鳢口裂形态,以泥鳅(Misgurnus anguillicaudatus)作为饵料鱼,估算了不同规格乌鳢的摄食率,研究了饵料鱼大小对乌鳢捕食的影响.乌鳢口宽(M_w,cm)、口高(M_H,cm)和口面积(M_A,cm~2)与其全长(T_L,cm)的回归方程分别为:M_W=1.65~(e0.0242TL);MH=1.64 ~(e0.022TL);MA=2.12e~(0.0465TL).当水温保持在22～23℃时,4个规格组的乌鳢对泥鳅的摄食率无显著的差别(ANOVA,P>0.05),均值为1.68%.乌鳢对泥鳅的捕食具有明显的大小选择性,乌鳢最喜欢捕食猎物/捕食者大小比为0.25的泥鳅,很少捕食或不捕食猎物/捕食者大小比小于0.06或大于0.45的泥鳅.     

Dietary pyridoxine requirement of fingerling Channa punctatus (Bloch) based on growth performance,liver pyridoxine concentration,and carcass composition

Seven casein gelatin-based diets containing 450 g/kg CP and 18.39 kJ/g GE with different levels of pyridoxine (0, 2, 4, 6, 8, 10, and 12 mg/kg diet) were fed to fingerling Channa punctatus (4.66 ± 0.46 g) for 12 weeks to determine pyridoxine requirement. Highest absolute weight gain (AWG; 25.81 g/fish, P < 0.05), protein retention (PRE; 23.69%, P < 0.05), energy retention efficiencies (ERE; 69.63%, P < 0.05), and minimum feed conversion ratio (FCR; 1.48) were noted at 8 mg pyridoxine/kg diet. However, liver pyridoxine content achieved the positive correlation as the dietary pyridoxine increased up to 10mg/kg. On the basis of broken-line analysis of AWG, PRE, FCR, and liver pyridoxine data, pyridoxine requirement is recommended between 7.6 and 10.4 mg/kg of dry diet.     

Comparison of age estimates from scale, opercular bone, otolith, vertebrae and dorsal fin ray in Labeo rohita (Hamilton), Catla catla (Hamilton) and Channa marulius (Hamilton)

The present study was undertaken with a view to compare the precision and reliability of the age readings obtained from different bony structures of some important freshwater teleosts viz., Labeo rohita (Hamilton), Catla catla (Hamilton) and Channa marulius (Hamilton). Standard procedures were followed to prepare and study the age structures. In L. rohita and C. marulius percent agreement between reader's age estimates was highest for scales, i.e. 96.3% and 90.5%, respectively and in C. catla percent agreement was highest (93.3%) for opercular bone. When scale ages were compared with other alternative structures viz., otoliths, opercular bone, vertebral centra and dorsal fin rays, percent agreement was found highest between scale and opercular bone age estimates (77.8%) in L. rohita and between scale and otoliths (94.8%) in C. marulius. In case of C. catla highest percent agreement was found between opercular bone and scale age estimates. In L. rohita each of the ageing structure showed significant (P < 0.05) underestimation of age in comparison to scales. In C. catla mean age estimates from opercular bone were comparable (P > 0.05) to the values obtained from all other structures except dorsal fin rays. In C. marulius mean age estimates from scales were comparable (P > 0.05) to those from all other structures except from dorsal fin rays. Results indicated scales to be the most suitable structure for ageing L. rohita and C. marulius and opercular bone for C. catla. However, in C. catla also scales may be used as a non-destructive method of age estimation with satisfactory results.     

喷雾干燥微胶囊化罗非鱼油的研究

为满足消费者对美味鱼汤产品的需求,提高乌鳢 (Channa argus) 加工副产物的利用价值,以前期制备的乌鳢鱼头汤为原料,用麦芽糊精作助干剂,采用喷雾干燥法制备乌鳢鱼头汤粉末,以干燥粉末的水分质量分数、色泽、溶解性、堆积密度、冲调时间以及粘壁情况为评价指标对喷雾干燥工艺优化进行研究。结果表明,麦芽糊精能够有效提高喷雾干燥的集粉率、粉体亮度、溶解性,改善粘壁情况;麦芽糊精质量浓度为15 g·L ^{− 1}、喷雾干燥进风温度为170 ℃、进料速度为6 mL·min ^{− 1}时喷雾效果和产品品质最佳,所制得的乌鳢鱼头汤粉末具有含水量较低、堆积密度较大、溶解度较高、吸湿性较低和颗粒均匀等特性。综上,喷雾干燥法可作为乌鳢鱼头汤粉末的制备方法。