二溴对甲基偶氮甲磺光度法测定野生水产中微量铅

采用二溴对甲基偶氮甲磺光度法测定了野生水产中的微量铅。在0.24mol·L-1磷酸介质中,铅与二溴对甲基偶氮甲磺形成1∶2蓝色配合物,最大吸收波长为640nm,表观摩尔吸光系数为7.85×104,铅含量在0.04～0.80μg·mL-1内符合比耳定律。方法的回收率在98.5%以上,可用于鄱阳湖野生水产中微量铅的测定。

河南省主要野生水产动物重金属含量分析与安全评价

测定了河南省主要野生水产动物Cd、Cr、Pb、As和Hg的含量,并根据单因子污染指数评价法对河南省主要野生水产动物的品质进行安全评价。结果表明,8种河南省主要野生水产动物的所有样品中均检出Pb和Cr,但未检出Cd。在鲤鱼(Cyprinus carpio)、鲫鱼(Carassius auratus)、克氏原螯虾(Procambarus clarkia)、青虾(Macrobranchium nipponense)和鳙鱼(Aristechthys nobilis)中检出Hg,检出率分别为37.5%、32.5%、60.0%、35.0%和7.5%。在鲤鱼、鲫鱼、青虾、白鲢(Hypophtyalmichthys molitrix)和草鱼(Ctenotharyngodon idellus)中检出As,检出率分别为15.0%、7.5%、5.0%、5.0%和15.0%。单因子污染指数评价结果表明,8种河南省主要野生水产动物均受到不同程度的Pb污染,克氏原螯虾受到轻度的Hg污染,鲤鱼、鲫鱼、白鲢和草鱼受到轻度的As污染。

Comparative study of the nutritional composition and toxic elements of farmed and wild Chanodichthys mongolicus

Information of the difference in quality between farmed and wild fish is central to better ensuring fish products produced in aquaculture meet regulatory and consumer requirements. Proximate composition, amino acid and fatty acid profiles, and toxic elements contents of fanned and wild Chanodichthys mongolicus were established and compared. Significantly higher crude protein content while lower moisture content in farmed fish compared to wild fish were observed （P〈0.05）. The percentages of total amino acids （TAA）, total essential amino acids （TEAA）, total non-essential amino acids （TNEAA） and total delicious amino acids （TDAA） in farmed fish were all significantly higher than those in the wild equivalent （P〈0.05）. Compared to the FAO/WHO recommended reference values, the ratios of TEAA/ TAA （39.84%o-40.33%） were comparable to 40% and TEAA / TNEAA （66.22%-67.60%） were above 60%. Fatty acid profiles in both farmed and wild C. mongolicus were dominated by monounsaturated fatty acid （MUFA）, with farmed fish contained much more MUFA content compared to wild counterpart （P〈0.05）. Notably, wild fish exhibited significantly higher levels of total polyunsaturated fatty acid （PUFA） including eicosapentaenoic acid （EPA） and docosahexaenoic acid （DHA） than fanned fish （P〈0.05）. The EPA （C20：503） and linoleic acid （C18：206） were the predominant PUFA in wild and farmed C. mongolicus, respectively. Moreover, farmed fish displayed an overall lower toxic element levels （As, Cd, Pb and Hg） in comparison with wild fish, and both were far lower than the established limit standard. In conclusion, our results suggest that the nutritional quality of fanned C. mongolicus was inferior to their wild counterpart with respect to fatty acids nutrition, and therefore further studies should focus on the improving C. mongolicus diet in order to enhance the overall nutritional composition.

Edible Peanut Worm(Sipunculus nudus) in the Beibu Gulf： Resource, Aquaculture, Ecological Impact and Counterplan

Sipunculus nudus is an important economic species because of its high nutritional and medicinal values. The exploitation and utilization of S. nudus primarily occur in the coastal regions of the Beibu Gulf. However, wild resource of S. nudus is rapidly decreasing because of the overexploitation, which has led to considerable developments of artificial breeding techniques. The cultivation scale of S. nudus has increased in response to successful artificial breeding; however, methods for culturing S. nudus in tidal flats or ponds require further study. Most studies have focused on the breeding, nutrition, medical value and ecological impact of these worms. Studies on the distribution, sediment requirements, nutrition characteristics, breeding techniques and aquaculture ecology of this species are summarized in this paper to promote the development of the aquaculture industry for S. nudus. The high biomass of S. nudus in the Beibu Gulf is positively correlated with the sediment characteristics and water quality of the region. The production of peanut worm has improved to some extent through culturing; however, the nutrient value and ecological environment problems have been observed, which reflect the over exploitation of trace elements and the sediment. These problems will worsen unless they are resolved, and the release of organic materials, nitrogen and phosphorus during harvesting impacts the coastal environment. Moreover, genetic erosion is a potential risk for larvae in artificial breeding programs in tidal flats. Therefore, culturing and collecting methods should be improved and the wild resource conservation should be implemented to promote the sustainable development of the peanut worm.

Pond culture of seaweed Sargassum hemiphyllum in southern China

The seaweed Sargassum hemiphyllum is widely distributed throughout the coastal waters of Asia and has high commercial value. In recent years, its natural biomass has declined due to over-exploitation and environmental pollution. To seek for a feasible way to culture this seaweed efficiently, we designed a simple long-line system in a shrimp pond for the culture during winter, and the growth and nutritional composition of the seaweed were examined. Results show that the cul^re system was durable and flexible allowing S. hemiphyllum to grow vertically offthe muddy bottom of the pond. Although the length of pond- cultured S. hemiphyllum was inhibited by water depth, the weight-specific growth rate （（1.65±0.17）%/d） was nearly three times higher than that of wild plants （（0.62±0.19）%/d）. The crude protein （6.92%±0.88%） and ash content （21.52%±0.07%） of the pond-cultured seaweed were significantly lower than those of the wild plants （9.38%±-0.43% and 26.93%±0.07%, respectively）; however, crude fat （1.01%±0.04%） was significantly higher than that of the wild plants （0.87%±0.02%）. In addition, the nutritional composition of both pond-cultured and wild S. hemiphyllum was comparable to or even higher than those of other common seaweeds being used as food and/or aquaculture fodder. Future studies shall be focused on the impact of environmental parameters on its growth and nutritional composition.