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.     

红水河干流梯级运行后鱼类资源调查

于2009年6月和11月对红水河干流龙滩水库、岩滩水库、大化水库、百龙滩水库、乐滩水库、桥巩水库进行了鱼类资源调查。结果显示:调查的鱼类144种,分属10目23科93属,其中鲤形目66属100种,占种数的69.4%;鲈形目11属18种,占种数的12.5%;鲇形目同为18种,分9属,亦占种数的12.5%;其余鳗鲡目1属2种,鲱形目、鲑形目、鳉形目、脂鲤目、合鳃鱼目、鲀形目等6目均为1属1种。本次调查结果表明:红水河干流鱼类种类明显减少,渔获物中小型鱼类数量占优势。     

Quality characteristics in raw and smoked fillets of Atlantic salmon, Salmo salar, fed high-energy diets

Atlantic salmon, Salmo salar , were fed four levels of dietary fat (256, 308, 346 and 389 g kg⁻¹ of diet) for 138 days, with the purpose of studying quality characteristics in raw and smoked fish fillets. Dietary fat levels up to 346 g kg⁻¹ resulted in increased fat content of the raw fillets. The dietary fat levels had a less systematic effect on perceived fatness of the smoked fillets and caused a trend towards better odour and flavour. The fat content of raw fillets was significantly ( P ≤ 0.05) correlated to lower smoke odour, greater rancid flavour, fatness, and a yellower hue of the smoked fillets. Astaxanthin levels of the raw fillets varied between 6 and 11 mg kg⁻¹ of fillet and were significantly ( P ≤ 0.05) correlated with greater intensity of smoke odour, lower off-odour, and less whiteness, greater colour intensity and a redder hue of the smoked fish. It is proposed that salmon fillets can be graded according to weight, fat content and colour values prior to smoking to obtain more standardized quality characteristics of the final product after processing.     

The effect of different HUFA enrichment emulsions on the nutritional value of rotifers (Brachionus plicatilis) fed to larval haddock (Melanogrammus aeglefinus).

A feeding study was conducted in the winter 2001 to determine the effects of feeding rotifers (Brachionus plicatilis) enriched with various levels of essential fatty acids on the growth and survival of haddock larvae (Melanogrammus aeglefinus). Rotifer enrichment treatments were: 1) mixed algae, 2) high DHA (docosahexaenoic acid, 22:6n-3), 3) high DHA and EPA (eicosapentaenoic acid, 20:5n-3), and 4) DHA, EPA, and AA (arachidonic acid, 20:4n-6). Larvae were fed rotifers enriched with the different treatments from days 1 to 16 post-hatch. From day 17 until 25 all treatment groups were fed rotifers reared on mixed algae and then weaned onto the International Council for Exploration of the SEA (ICES) Standard Reference Weaning diet (http://allserv.rug.ac.t/aquaculture/rend/rend.htm) over a five day period. The experiment was terminated on day 41 post-hatch. The enrichment treatments affected the fatty acid composition of the rotifers and correlated with the accumulation of these fatty acids in the haddock larvae. However, no significant differences in larval growth or survival to 40 days post hatch were detected, suggesting that all treatments provided the minimal essential fatty acid requirements for haddock.