滇池金线鲃、西畴金线鲃及其杂交F1代的形态分析

根据传统形态度量学和框架结构形态学法测量了15月龄的杂交F1代(滇池金线鲃Sinocyclocheilus grahami♀×西畴金线鲃S.xichouensis♂)以及滇池金线鲃(S.grahami)和西畴金线鲃(S.xichouensis)的10项传统可量性状数据和24项框架结构数据以及鳍条、侧线鳞和脊椎骨等可数性状数据。并用方差分析和多元统计分析法(聚类分析,判别分析和主成分分析)对三者的传统可量性状和框架结构数据进行分析。结果显示:三者的可数性状差别不大,杂交F1代体表花纹与双亲相比发生一定变化。聚类分析结果表明,杂交F1代的形态与母本滇池金线鲃形态较为相似。采用逐步判别分析方法建立了3种鱼的判别函数,判别准确率较高(90%,90%,100%)。主成分分析结果及主成分散点图显示:三者均有重叠区域不容易从形态上清楚分开,但杂交F1代明显更接近母本滇池金线鲃。结合方差分析和主成份分析发现杂交F1代与双亲不同的性状主要集中在头部和尾部。     

20种中草药杀灭离体小瓜虫的药效研究

选用20种不同中草药,研究其不同浓度的水提物对多子小瓜虫(Ichthyophthirius multifiliis)成虫、包囊和幼虫的离体杀灭实验效果。结果显示:0.1 g/L槟榔和乌梅对各个阶段的虫体均有杀灭效果,0.1 g/L大黄和黄芩1 h内对幼虫有杀灭效果,1.0 g/L浓度能杀灭成虫和包囊,表明槟榔、乌梅、大黄、黄芩的杀虫效果相对较好;贯众、乌药、枳壳等13种中药浓度达到10 g/L、50 g/L或100 g/L才具有一定杀虫作用,但效果不很显著;熟地黄、茯苓和黄芪即使浓度达到100 g/L时,也不能杀灭虫体。     

四氢异喹啉衍生物的合成及体外抗多子小瓜虫活性的研究

合成四氢异喹啉衍生物并进行杀多子小瓜虫(Ichthyophthirius multifiliis)药效评价。以1-甲基-1,2,3,4-四氢异喹啉为起始原料,在2位的胺基上引入与环己甲酰氯、苯甲酰氯、噻吩甲酰氯、乙酰氯以及氯乙酰氯等不同的酰基进而合成5种四氢异喹啉衍生物(化合物1~化合物5),研究其对小瓜虫掠食体和包囊的杀虫活性,并对杀虫活性物质进行安全性评价。结果显示,5种化合物均具有一定的杀虫活性,其中,化合物1 [(1-甲基-3,4-二氢异喹啉-2(1H)-基)-苯基-甲酮]的杀虫活性最强,其对多子小瓜虫掠食体4 h的100%杀灭浓度为24.0 mg/L,对包囊6 h的100%杀灭浓度为60.0 mg/L,对掠食体的半数致死浓度(LD₅₀)为16.4mg/L。急性毒性实验结果显示,化合物1对翘嘴红鲌(Erythroculter ilishaeformi)的48 h LD₅₀为234.3 mg/L,其安全浓度为64.1 mg/L。研究表明,化合物1[(1-甲基-3,4-二氢异喹啉-2(1H)-基)-苯基-甲酮]是一种具有较好开发前景的杀小瓜虫药物。     

四氢异喹啉衍生物的合成及体外 抗多子小瓜虫活性的研究

合成四氢异喹啉衍生物并进行杀多子小瓜虫(Ichthyophthirius multifiliis)药效评价。以1-甲基-1,2,3,4-四氢异喹啉为起始原料,在2位的胺基上引入与环己甲酰氯、苯甲酰氯、噻吩甲酰氯、乙酰氯以及氯乙酰氯等不同的酰基进而合成5种四氢异喹啉衍生物(化合物1~化合物5),研究其对小瓜虫掠食体和包囊的杀虫活性,并对杀虫活性物质进行安全性评价。结果显示,5种化合物均具有一定的杀虫活性,其中,化合物1 [(1-甲基-3,4-二氢异喹啉-2(1H)-基)-苯基-甲酮]的杀虫活性最强,其对多子小瓜虫掠食体4 h的100%杀灭浓度为24.0 mg/L,对包囊6 h的100%杀灭浓度为60.0 mg/L,对掠食体的半数致死浓度(LD50)为16.4 mg/L。急性毒性实验结果显示,化合物1对翘嘴红鲌(Erythroculter ilishaeformi)的48 h LD50为234.3 mg/L,其安全浓度为64.1 mg/L。研究表明,化合物1 [(1-甲基-3,4-二氢异喹啉-2(1H)-基)-苯基-甲酮]是一种具有较好开发前景的杀小瓜虫药物。     

Susceptibility of three strains of blue catfish,Ictalurus furcatus (Valenciennes), to Ichthyophthirius multifiliis

This study compared the susceptibility of three blue catfish strains (D&B, USDA 101 and USDA 102) to the parasite Ichthyophthirius multifiliis (Ich). In Trial I, a cohabitation study (all strains stocked communally) was conducted and fish were exposed to theronts at 0, 200, 1000, 5000 or 25 000 theronts fish^?1, respectively. All fish died when exposed to theronts at 5000 or 25 000 theronts fish^?1. When exposed to 1000 theronts fish^?1, USDA 102 strain of blue catfish showed significantly lower mortality (78.5%) compared to USDA 101 and D&B strains (92.7% and 100%). In Trial II, the same three strains of blue fish were evaluated for their susceptibility to Ich with strains challenged in separate tanks by adding Ich theronts at 0, 200 and 1000 theronts fish^?1, respectively. All D&B and USDA 101 blue catfish died; however, 42.3% of USDA 102 strain survived the infection when exposed to 1000 theronts per fish. The results indicate that there are differences among strains of blue catfish for susceptibility to Ich, and these differences will be useful in the development of improved catfish germplasm for commercial aquaculture.     

Experimental evidence for direct in situ binding of IgM and IgT to early trophonts of Ichthyophthirius multifiliis (Fouquet) in the gills of rainbow trout, Oncorhynchus mykiss (Walbaum)

Freshwater fish are able to mount a protective immune response against the parasite Ichthyophthirius multifiliis (Ich) following a non‐lethal exposure. Factors involved in immunity comprise cellular and humoral factors, but antibodies have been suggested to play a prominent role in protection. However, host antibodies have not yet been demonstrated to bind to the parasite in situ. By the use of immunohistochemical techniques, this study demonstrated that IgT and IgM bind to surface structures, including cilia, on the early feeding stage of the parasite in the gills of immune rainbow trout, Oncorhynchus mykiss, shortly (2 h) after invasion. No binding of IgT and no or only a weak binding of IgM was observed on the parasites in the gills of similarly exposed but naïve rainbow trout. This study indicates that antibodies play an important part in the protection of immune fish against Ich although additional humoral and cellular factors may contribute to this reaction.     

Heavy infection of Ichthyophthirius multifiliis in striped catfish (Pangasianodon hypophthalmus,Sauvage 1878) and its treatment trial by different therapeutic agents in a control environment

ABSTRACT

Striped catfish (Pangasianodon hypophthalmus) fingerlings were stocked (60 fishes/m³) in cemented square tanks for ornamental fishery purposes at the College Fish Farm in Mangalore. A total of 400 fishes with a mean weight (g) ranging from 3.24 ± 1.21 to 6.70 ± 1.13 and a mean length (cm) of 7.50 ± 0.94 to 9.50 ± 1.10 were examined. A severe outbreak of salt-like granule white spots was found on the body surface. Ichthyophthirius multifiliis, a ciliate pathogen, was identified as the causative agent by clinical signs, wet mount, and histopathological observations. Infected fishes were transferred and equally distributed to the 0.45 m³ glass aquaria and treated with three treatments: (T1) methylene blue + salt; (T2) raising temperature with salt; and (T3) formalin + malachite green. The best fingerling survival (55 ± 9.36%) was obtained by elevated water temperature with salt in T2.     

Immune responses and host protection of channel catfish, Ictalurus punctatus (Rafinesque), against Ichthyophthirius multifiliis after immunization with live theronts and sonicated trophonts

The humoral immune responses and host protection of channel catfish, Ictalurus punctatus (Rafinesque), against Ichthyophthirius multifiliis (Ich) were determined after immunization with live theronts and sonicated trophonts. Immunizations with live theronts or sonicated trophonts were carried out by both bath immersion and intraperitoneal (i.p.) injection. Cutaneous and serum immunoglobulin (Ig) levels and anti-Ich antibodies were measured 12 and 21 days post-immunization. The level of Ich infection and survival of catfish were determined after theront challenge. Cutaneous and serum anti-Ich antibodies were significantly higher (P < 0.05) in fish immunized with live theronts by immersion or i.p. injection, or with sonicated trophonts administered by i.p. injection, than in fish immunized with sonicated trophonts by immersion, with bovine serum albumin by i.p. injection, or non-immunized controls. Host protection was noted only in fish immunized with live theronts by immersion or i.p. injection or with sonicated trophonts by i.p. injection. There was a positive correlation between higher levels of anti-Ich antibodies and host survival in the immunized fish.     

美洲红点鲑和白斑红点鲑及其杂交子代幼鱼的生长曲线拟合

自2011年11月至2013年1月,对美洲红点鲑(Salvelinus fominalis)和白斑红点鲑(Salvelinus leucomaenis)及其杂交子代从受精卵到1年零两个月幼鱼的生长特性进行了研究。以美洲红点鲑和白斑红点鲑为亲本,建立2×2双列杂交组合,采用Logistic、Gompertz和Von Bertalanffy 3种动物生长模型对美洲红点鲑(A)和白斑红点鲑(B)及其杂交子代进行生长曲线拟合并分析比较其生长性能。实验设置自交组AA、BB和杂交组AB(A♀×B♂)、BA(B♀×A♂)4个实验组。根据模型拟合的R2值判断各组生长性能的拟合程度,并对其体质量、体长、成活率及肥满度进行比较。结果发现,Gompertz生长模型的拟合效果最好,R2均大于0.99,其中AB组生长优势明显。成活率由高到低依次为:AA、AB、BA、BB,但AA组与其他3组的成活率差异不显著(P0.05)。增重率(g/d)和肥满度(g/cm3)等生长指标均由高到低依次为:AB、AA、BA、BB,各组间差异显著(P0.05)。研究结果显示,正交子代(A♀×B♂)幼鱼生长性能明显高于反交子代(B♀×A♂)及其亲本,可见此杂交组合可能具有较高的推广潜力。     

Effects of Dietary Protein and Lipid Levels with Different Protein‐to‐Energy Ratios on Growth,Feed Utilization,and Plasma Biochemical Parameters of Dianchi Golden‐line Barbell,Sinocyclocheilus grahami

An 8‐wk feeding trial was conducted to evaluate the effects of varying dietary protein and lipid levels with different protein‐to‐energy (P/E) ratios on growth, feed utilization, and plasma biochemical parameters of Sinocyclocheilus graham. Nine experimental diets were formulated to contain three protein levels (35, 40, and 45%), and each with three lipid levels (4, 8, and 12%), to produce a range of P/E ratios from 71.31 to 98.64 mg protein/kcal. Each diet was randomly assigned to triplicate groups of 25 fish. Fish grew best when fed the diet containing 45% protein and 12% lipid. However, fish fed the diet with 40% protein and 8% lipid had similar weight gain and specific growth rate as those fed the above diet but showed relatively better feed conversion ratio, protein efficiency ratio, and protein and energy retentions. Additionally, plasma total amino acids and blood urea nitrogen contents and γ‐glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase activities in fish fed the diet containing 40% protein and 8% lipid were relatively low among the dietary treatments. These results may indicate that a diet containing 40% protein and 8% lipid with P/E ratio of 84.05 mg protein/kcal would be suitable for the optimal growth, feed utilization, and health of S. graham.     

Morphological and molecular biological studies on intramuscular Myxobolus spp. of cyprinid fish

The validity of Myxobolus species infecting the skeletal muscles of six cyprinid fish species was studied by morphological and molecular biological methods. Intracellularly developing Myxobolus spores identified as M. cyprini from the common carp, M. musculi from the barbel, and M. pseudodispar from the roach, rudd, common bream and white bream were very similar in their shape and size. Nonetheless, in species identified as M. pseudodispar, the occurrence of spores with an asymmetrical shape was higher than in M. cyprini, while asymmetrical spores were only occasionally found in M. musculi. The DNA sequence analysis of the polymerase chain reaction (PCR)‐amplified 18S rRNA gene of Myxobolus spores from these fish showed a similar phylogeny to that of their host species. As morphological studies and DNA sequence analysis demonstrated slight but real differences in the spores infecting muscles of the six cyprinid species, it is suggested that M. musculi, M. pseudodispar and M. cyprini are valid species.