Molecular evidence for the lack of transmission of the monogenean Sparicotyle chrysophrii (Monogenea, Polyopisthocotylea) and isopod Ceratothoa oestroides (Crustacea, Cymothoidae) between wild bogue (Boops boops) and cage-reared sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax)

In the Mediterranean area, wild fish have often been suggested as either the reservoirs of the causative agents or at least the carriers of the pathogens responsible for disease outbreaks in cultured fish. However, no epidemiological investigations on actual pathogen/disease interactions between farmed and wild fish have been conducted even for the most important fish pathogens. Only sporadic isolations and identifications of various pathogens in wild fish have been done and real associations with the pathological conditions that exist within the farm environment and vice versa have not been established. Monogenean ectoparasite Sparicotyle chrysophrii and isopod Ceratothoa oestroides are commonly found in the Mediterranean cage-reared sea bream and sea bass and in the surrounding wild fish population. Both species were recognized as pathogens that seasonally inflict serious losses in fingerlings and juveniles of sea bream and sea bass, being potentially propagated and exchanged during wild and caged fish interaction. In order to evaluate the degree of pathogens transfer between wild and farmed fish, we investigated genetic population structures of these two important parasitic pathogens inferred by mtDNA cytochrome oxidase I locus. Parasites isolated from wild and farmed fish on the two most productive Adriatic fish farms showed genetic heterogeneity, contradicting widely accepted hypothesis of cross-contamination, at least in case of S. chrysophrii and C. oestroides. As far as we know, this is the first report that in a study of pathogen transfer molecular evidence was employed to asses the genetic population structure of shared parasites.     

渤海半滑舌鳎人工育苗工艺技术的研究

对渤海半滑舌鳎人工育苗的水温、盐度、饵料等培育条件与种苗发育、生长及成活率的关系进行了试验,建立了人工育苗工艺流程。结果表明半滑舌鳎受精卵在不同水温范围内的孵化率有明显差别。种苗培育分前期、后期和幼鱼期3个阶段。前期鱼苗成活率为12.9％;后期为66.0％;幼鱼期为100％。饵料种类为轮虫、挠足类和卤虫,开口饵料为轮虫。1987年2次分别育出仔鱼4.8万尾和0.6万尾;1989年育出仔鱼3.13万尾,45天内培育出完全变态的鱼苗3080尾。种苗培育80天,体长达30.0mm,外形与成鱼完全相同,达到放流规格。     

The Potential for the Restoration of Marine Ornamental Fish Populations Through Hatchery Releases

Populations of tropical and subtropical marine fish are being depleted worldwide to supply increasing demands of the aquarium industry and fresh seafood market. Overfishing and destructive harvest techniques have left some marine fish populations virtually extirpated in a number of primarily underdeveloped countries. In situations where only small remnant populations and significantly degraded habitat remain, population recovery even under the complete absence of collection will be slow, with the high potential for population loss due to natural environmental and recruitment variability. Stock enhancement, supplementing natural recruitment with hatchery produced fry, has the potential to significantly increase the rate of population recovery while maintaining population vigor.Stock enhancement research on Pacific threadfin has demonstrated measurable positive impacts on recreational and commercial fisheries for this species in experimental scale releases; similar successes can be expected for enhancement efforts directed toward species of ornamental value. The major technological barrier to ornamental fish enhancement, the development of appropriate culture capabilities, is being addressed in research directed to the commercial production of fish for the aquarium trade.     

主成分分析对黄海6种主要饵料鱼类的质量分析评价

根据黄海6种饵料鱼类的碳氮比、脂肪含量、蛋白质含量、碳含量及非水分含量5个指标,采用主成分分析法对其进行质量排序。结果表明,依代表生物基本能量的第1主成分,6种鱼的质量顺序为鳀Engraulis japonicus、凤鲚Coilia mystus、黄鲫Setipinna taty、赤鼻棱鳀Thryssa kammalensis、细条天竺鲷Apogonichthys lineatus和黑鳃梅童鱼Collichthys niveatus;依代表营养价值的第2主成分,6种鱼的质量顺序为黄鲫、凤鲚、黑鳃梅童鱼、赤鼻棱鳀、鳀和细条天竺鲷;营养质量的综合排序为凤鲚、黄鲫、鳀、赤鼻棱鳀、细条天竺鲷和黑鳃梅童鱼。结果表明,单一营养质量指标或同类营养质量指标都不能完全代表整个饵料鱼类的质量。     

Median Lethal Concentration (LC50) of Piscicidal Plants and Their Utilization in Aquaculture

Aqueous and ethanol extracts of Acacia pennata (bark), Catunaregam uliginosa (fruit), Diospyros lenceofolia (fruit), and Sapindus mukorossi (fruit) were evaluated as piscicides on the freshwater fish Danio dangila, Danio rerio, and Puntius shalynius, and the air-breathing Heteropneustes fossilis. Catunaregam uliginosa (fruit) possessed relatively higher piscicidal potency followed by Sapindus mukorossi (fruit), Acacia pennata (bark), and lastly Diospyros lanceofolia (fruit). Catunaregam uliginosa can thus be used for eradicating unwanted wild fishes in a short time span at low concentrations so that the health of aquatic environment is maintained.     

Dietary Moringa oleferia leaf meal induce growth,innate immunity and cytokine expression in grass carp,Ctenopharyngodon idella

The present research was designed to investigate the growth promoting and immunostimulating properties of Moringa oleferia leaf meal (MLM) in grass carp. Juvenile grass carp (22.03 g ± 1.164) were fed with diets supplemented with 0, 50, 100 and 150 g/kg MLM for 48 days. At the end of feeding trial, skin mucus was used for analysis of lysozyme, protease, antiprotease and peroxidase activity. Head kidney was used for expression analysis of tumour necrosis factor‐alpha, interleukin‐8 and interferon‐γ. The obtained results showed that fish fed with 100 and 150 g/kg MLM had significant increase in weight gain and specific growth rate (p < .05). However, condition factor was not altered. The MLM (50 and 100 g/kg) inclusion resulted in higher mucus lysozyme and protease activity (p < .05), while peroxidase activity increased only in fish fed with 100 g/kg MLM and antiprotease activity was not altered. Expression of tnf‐α increased in a dose‐dependent manner, and significant (p < .05) increase was recorded in fish fed with 150 g/kg MLM. The expression of il‐8 and ifn‐γ increased in fish fed with 50 and 150 g/kg MLM; however, the increase was not significant (p > .05). In conclusion, supplementing juvenile grass carp feed with MLM up to 150 g/kg has growth promoting and immunostimulating effects.     

胶州湾鱼类生物量粒径谱特征

为了解胶州湾海域鱼类群落粒径结构特征,本研究根据2016-2017年4次底拖网调查数据构建了胶州湾鱼类生物量粒径谱,比较分析了各季节鱼类生物量粒径谱特征参数的异质性。结果显示,胶州湾Sheldon型鱼类生物量粒径谱呈现单峰模式,鱼类粒径范围为-3~10粒径级,粒径分布相对均匀,且峰值位于5~6粒径级,主要由大泷六线鱼和褐菖鲉等小型鱼类构成。各季节鱼类标准化生物量粒径谱曲率和曲度差异显著,其中春季曲率最大且曲线较平缓,夏季曲率最小且曲线相对陡峭。谱线曲度和曲率的季节变化主要与粒径小的细纹狮子鱼、大泷六线鱼、玉筋鱼及长丝虾虎鱼等地方常栖性种类和赤鼻棱鳀、白姑鱼等季节洄游性种类的出现有关。Abundance-biomass comparison(ABC)曲线表明,春季处于未干扰状态,冬季处于中度干扰状态,夏秋季处于严重干扰状态。研究表明,胶州湾鱼类群落总体处于严重干扰状态,鱼类生物量谱呈现单峰型,粒径结构以小型粒径鱼类为主,且地方常栖性和季节洄游性鱼类等补充群体的数量和粒径大小影响鱼类生物量粒径谱的峰型和曲率。     

Detection and molecular characterization of infectious spleen and kidney necrosis virus from major ornamental fish breeding states in Peninsular Malaysia

‘Gold standard’ OIE reference PCR assay was utilized to detect the presence of infectious spleen and kidney necrosis virus (ISKNV) in freshwater ornamental fish from Malaysia. From total of 210 ornamental fish samples representing 14 species, ISKNV was detected in 36 samples representing 5 fish species. All positive cases did not show any clinical signs of ISKNV. Three restriction enzymes analyses showed that the fish were infected by identical strains of the same virus species within Megalocytivirus genus. Major capsid protein (MCP) genes of 10 ISKNV strains were sequenced and compared with 9 other reference nucleotide sequences acquired from GenBank. Sequence analysis of MCP gene showed that all strains detected in this study were closely related to the reference ISKNV with nucleotide sequence identity that was ranging from 99.8% to 100%. In addition, phylogenetic analysis of MCP gene revealed that viruses from genus Megalocytivirus can be divided into three genotypes: genotype 1 include reference ISKNV and all other strains that were detected in this study, genotype 2 include viruses closely related to red sea bream iridovirus (RSIV), and genotype 3 include viruses closely related turbot reddish body iridovirus (TRBIV).     

Comparative effects of Shirazi thyme and vitamin E on some growth and plasma biochemical changes in common carp (Cyprinus carpio) during cadmium exposure

Phytobiotics include a large number of active components which potentially have a growth‐promoting effects and antioxidant properties. This study was conducted to investigate the protective effects of Shirazi thyme and vitamin E on growth and plasma biochemical parameters of common carp exposed to cadmium. Fish (34 ± 3 g) were divided into four groups and fed four distinct diets including commercial diet without any additive (for control and metal only group) and supplemented with either 1% ground Shirazi thyme or 100 mg kg^?1 vitamin E for 45 days. At the end of the feeding trial, all treatments except control group were exposed to sub‐lethal concentration of waterborne cadmium for 15 days and sampling was done on days 0, 7 and 15 after the metal exposure. According to the results, dietary inclusion of thyme prevented the harmful effects of cadmium and also improved fish growth and nutritional indices including weight gain, feed conversion ratio, specific growth rate and condition factor. Results also revealed that Shirazi thyme was more effective than vitamin E. Similarly, no changes in the hepatosomatic, viscerosomatic and bile somatic indices were observed. Plasma enzymes (AST, ALT, ALP and LDH) and metabolites were not altered due to thyme supplementation compared to the control. In conclusion, dietary supplementation of 1% ground Shiraz thyme improved the growth and health status of fish and showed better hepatorenoprotective properties than vitamin E during waterborne cadmium exposure in common carp juveniles. It might be conceivable to consider Shirazi thyme as a potential phytobiotic for incorporation in fish diet.