Biological Silages from Tunisian Shrimp and Octopus By-Products

Biological silages were prepared from shrimp head and octopus viscera by-products recuperated from the Tunisian seafood industry. Physical and biochemical changes and microbiological profiles were determined for raw materials during fermentation and on end-products. Results showed that biological silage significantly affected (p < 0.05) moisture, protein, and ash contents of shrimp head (CSHS) and octopus viscera silages (COVS). CSHS and COVS were stable, and their final pH values were 4.31 ± 0.01 and 3.71 ± 0.00, respectively. Proteolysis activity was confirmed by a significant increase (p < 0.05) of soluble nitrogen and low molecular weight of protein (<260 Da) found on the end-products for both silages. Lipid oxidation was delayed by addition of 150 ppm ethoxyquin to the raw material prior to fermentation. Biogenic amines detected in raw shrimp and octopus samples decreased significantly (p < 0.05) during the silage process. Histamine and tyramine, detected at high levels on octopus viscera, were absent in the end-products. Tyramine was produced in CSHS, indicating the possibility of the bacterial decarboxylation of tyrosine. Microbiological profiles showed that both silage products were free from pathogenic and spoilage bacteria. Therefore, biological silage can be used as a conservation procedure of shrimp and octopus by-products. The storage period could be shorter than 30 days, and further analysis should be carried out to ascertain safety and nutritional value of silage products.     

Dietary Protein Hydrolysates from Animal By-Products: Digestibility and Enzymatic Activity for Dourado Salminus brasiliensis

Fishmeal (FM) is a high-cost and scarce feedstuff. Notwithstanding, the formulation and processing of diets for carnivorous fish strongly rely on FM as a protein source, given its palatability and biological value. Animal by-product hydrolysates are high-quality feedstuff and can substitute FM in aquafeeds. This study evaluated the digestibility of hydrolysates from tilapia residue (TR), tuna head (TH), swine liver (SL), and poultry liver (PL), and the profile of digestive enzymes in juvenile dourado, Salminus brasiliensis, a carnivorous Characin, fed diets containing graded levels of the hydrolysates. Inclusion of hydrolysates in diet formulations lowered the pH of feed but did not alter feed intake by fish. Higher apparent digestibility coefficients (ADCs) of diets were recorded for fish fed diets containing TR and SL, and lower ADCs were recorded for fish fed diets containing TH. Protease and lipase activities in the animal’s stomach were higher, especially for those fed with diets containing SL. Amylase activity was higher in pyloric caeca, whereas in the intestines, the higher activity was seen in fish fed control and TR diets. Animal by-product hydrolysates were highly digestible for dourado, and the enzymatic profile of fish was influenced by the nutrient contents of diets.     

The Effectiveness of Official Methods to Measure the Real Glazing Percentage in Frozen Seafood: An Analysis with Frozen Pacific White Shrimp (L. vannamei)

The aim of this study was to evaluate the effectiveness of official methods to quantify the real glazing percentage in frozen Pacific white shrimp (Litopenaeus vannamei) with different glazing percentages. Samples of frozen peeled shrimp were glazed with cold water (0 ± 1°C) at glazing levels of 15, 30, 40, 50, and 60%. The glazing percentage was quantified based on Brazilian methodologies (INMETRO and MAPA) and International methodologies (CODEX, AOAC, and NIST). The official methods were inefficient in quantifying the real glazing percentage, especially with regard to the samples containing higher glazing percentages (> 30%). As an alternative, changes were done to improve the glazing measurement method (mix of the best parameters from all methodologies), which best describes the reliable value of the glazing percentage of frozen shrimp samples and confirms that this methodology can be an alternative used by inspectors after collaborative study for validation. In this sense, a critical review and possible changes in the official methodologies may be suggested in order to improve them for use to combat economic fraud in the seafood frozen products.     

中日水产品流通体系的比较与启示

日本是世界上最大的水产品消费国和进口国,其水产品流通体系具有很强的代表性、借鉴性,文章通过分析日本水产品流通渠道的形式和特征,结合中国现阶段水产品流通结构的比较,提出中国构建有效水产品流通渠道的建议。     

1999-2000年福建省水产品进出口贸易实证分析

我国加入世界贸易组织在即,水产品贸易和流通将成为我国水产经济的主要研究领域,对渔业经济和管理将会产生一定的影响。本文分析了福建省1999-2000年不同水产品的贸易特征、与主要贸易国的贸易量、比较分析了不同进出口水产品的平均价格,得到了有一定参考价值的数据和资料。     

Seasonal changes in distribution and abundance of euphausiids in the coastal area of north-eastern Japan

ABSTRACT:   Seasonal changes in distribution and abundance of euphausiids off south-eastern Hokkaido (41°−43°N), Sanriku (38°−41°N), and Joban (36°−38°N) were investigated using cylindrical-conical nets every two months from March 1997 to February 1998. Twenty-six species of seven genera of euphausiids occurred during the survey. Among them, subarctic-transitional Euphausia pacifica was the most abundant throughout the year in coastal waters, as their relative contribution to the total abundance of euphausiids was 89–92%. This species occurred in each coastal water throughout the survey and was abundant from winter to early summer (February–June) off Sanriku and Joban and in autumn in south-eastern Hokkaido. Thysanoessa inspinata occurred off south-eastern Hokkaido and Sanriku throughout the survey, mainly in spring (April) but rarely occurred off Joban. Three other subarctic Thysanoessa species occurred mainly off south-eastern Hokkaido from winter to spring. Conversely, warm- and transitional-water epipelagic species occurred exclusively off Sanriku and Joban in autumn. The characteristics of seasonal distributional patterns of euphausiids are discussed in relation to the spatial and temporal changes of oceanographic conditions and several predators off north-eastern Japan.     

日本鲑科(Salmonidae)鱼名集览生态分布及开发利用

日本鲑科鱼类种类多,生态类型复杂,名称繁多,对我国水产工作者参考文献及开展中日学术、技术交流带来诸多不便。本文根据日文文献中一般分类标准综述了日本鲑科鱼的各类名称、生态分布及开发利用情况,提供水产同行参考。     

The zooplankton biomass in the Sea of Japan

We examined seasonal, annual variation and horizontal distribution of zooplankton in the Sea of Japan from 1966 to 1990. Zooplankton was most abundant in the spring. The spring maximum appeared in February–March and in April–May in the southern and eastern parts of the study areas, respectively. In the summer and autumn, a secondary peak was most conspicuous in the eastern part. The difference between the estimated biomass at night and day was large in the spring and small in summer and autumn. The biomass in the offshore southern area peaked about every 3 years between 1966 and 1983, and increased abruptly in 1990. The density in the area north of 39°N or 40°N was high. Total biomass estimated in the upper 150 m layer in the Sea of Japan (10⁶ km²) was 9.5 × 10⁶ t in the daytime and 16.6 × 10⁶ t at night.     

养殖生产中应重视海珍品养殖科技档案的管理

近年来 ,世界渔业由开发型向管理型逐步转变 ,水产养殖业越来越受到人们的关注。海珍品养殖作为水产养殖业中最具活力的新的经济增长点 ,有力地推动了水产养殖业的发展。随着海珍品养殖技术的迅速发展 ,产生了大量的科技档案。这些档案 ,不仅是海珍品养殖科学研究的真实记录 ,而且是重要的信息资源 ,是国家的宝贵财富。因此 ,应把加强对海珍品养殖科技档案的管理作为当前养殖生产、科技管理中的重要内容来抓 ,全力做好四个方面的工作。一、高度重视 ,确保原始资料齐全完整。海珍品养殖资料的收集 ,是养殖科技档案管理过程中的重要环节。从海…     

Reforming Wakame Aquaculture in Japan with Relaxed Processing Standards: From Consumer and Producer Viewpoints

This study investigated potential production reforms of wakame aquaculture in Japan through modification of processing standards. The research focused on the destemming process and examined both the consumers’ and producers’ perspectives. An auction experiment was conducted to measure consumer preferences for wakame with different destemming standards (1, 4, 7, and 10 mm). It was found that, although consumer preferences were diverse, there was no preference between the present (1-mm) and 4-mm standards. In addition, a production experiment was used to measure the amount of labor that could be saved (and thereby the improvement in profit) by relaxing the standard from 1 mm to 4 mm. It was concluded that this new standard would increase productivity by 13.3% without affecting consumer demand, which will improve the structure of this industry for competition against cheaper foreign products.     

Genetic variation between populations of starspotted dogfish Mustelus manazo in central Japan and northern Taiwan

SUMMARY: The genetic structure of the samples of Mustelus manazo between central Japan and Taiwan was investigated by starch gel electrophoresis. From a total of 20 enzyme loci scored, only two of them ( CK-A and sSOD-1 ) showed polymorphism with sufficient allelic variation that would be useful for analysis of population structure. The Taiwanese samples have unique allele of CK-A 52 and sSOD-1 40 that are absent in the Japanese samples. Mean heterozygosity values were 0.027 and 0.055 for two Taiwanese samples and 0.008 and 0.013 for two Japanese samples. The chi-square analysis shows significant differences ( P < 0.001) between the pooled central Japanese samples and Taiwanese samples indicating that they are two separate populations with moderate divergence ( F_ST = 0.063). A possible explanation of population divergence between the two countries is also discussed.     

我国水产品质量安全问题与对策

我国水产品的品种繁多 ,仅鱼类就有 30 0 0多种 ,虾类 30 0多种 ,蟹类 60 0多种 ,头足类 90多种。不仅是世界上最大的水产品生产国 ,也是世界上最大的消费国。水产品生产为改善我国居民的消费结构 ,提高饮食营养水平做出了积极的贡献。由于水产品易受海、淡水域环境污染的影响和药物在水产养殖中的大量使用 ,因此水产品安全性倍受国内外的关注。本文就我国水产品质量安全问题进行综述和剖析 ,并提出对策和建议。1我国水产品的质量安全现状1 .1水产品质量的现代内涵安全卫生是反映食品质量的主要指标 ,离开了安全卫生 ,就无法对食品质量的优…     

日本资源管理型渔业体系下的典型作业方式管制实践

通过文献研究,对日本资源管理型渔业体系下的典型作业方式管理措施进行梳理,以期对我国典型作业方式准入制度的构建和完善提供参考。对围网、底拖网、刺网和流网、定置网及鱿钓等5种日本渔业主要作业方式的管理措施体系进行了分类和介绍,认为日本的渔业管理通过不同层级的权限许可,根据海洋渔业资源的自然属性差异采取区域化的管理模式,并以恢复渔业资源为目标,逐步推进从总可捕量管理制度向捕捞努力量控制制度的转变。     

Genetic population structure of the deep-sea whelk Buccinum tsubai in the Japan Sea

ABSTRACT:   The purpose of the present paper was to examine the genetic population structure of Buccinum tsubai in the Japan Sea. Mitochondrial 16SrRNA gene sequence analysis was performed with specimens from various stations in the Japan Sea. Mitochondrial lineages were clearly patterned geographically in four separate areas: the Hokkaido area, the Yamagata–Toyama area, the Yamato Bank area, and the San'in area. The main distribution depth range of B. tsubai is between 200 m and 1000 m isodepths, and the horizontal distance between the 200 m and 1000 m isodepth lines represents the specific spatial scale of the habitat (SSSH). These four areas were separated either by the complete discontinuity of the SSSH area or by its narrow spatial extension. Genetic distances between the main haplotypes of each area were calculated as Jukes–Cantor distances, the value of which ranged between 0.012 and 0.017. This value seemed to be unrelated to the geographic distance. There was no tendency for clustering according to depth. In future, the morphological characters of the four lineages of B. tsubai should be compared in detail in order to elucidate significant genetic differences among them.     

Production of High Quality Fish Oil by Thermal Treatment and Enzymatic Protein Hydrolysis from Fresh Norwegian Spring Spawning Herring By-Products

There is an increasing demand for omega-3 containing fish oils. By-products from fish fillet production can be utilized for the production of fish oils and be a valuable source of omega-3 for human consumption. The aim of this work was to evaluate industrial processes for production of quality oil for human consumption made from Norwegian spring spawning herring by-products. A mobile production plant was used to compare two industrial processes, thermal treatment (wet rendering) and enzymatic protein hydrolysis, for production of oil from herring by-products immediately after filleting. Results show that high quality herring oil can be produced from fresh by-products. The use of by-products immediately after filleting resulted in a low amount of free fatty acids for all the produced oils (below 0.4%). Thermal treatment at 70°C resulted in an oil with lower oxidation status and higher stability compared to the oils produced by enzymatic protein hydrolysis. Nevertheless, both processing methods gave a crude oil of high quality compared to crude oils on the market.     

Genetic and phenotypic comparison of Nocardia seriolae isolated from fish in Japan

The phenotypic and genetic characterizations of 58 isolates of the fish pathogen Nocardia seriolae , from amberjack, Seriolae dumerili , yellowtail, Seriola quinqueradiata , Japanese flounder, Paralichthys olivaceus , and chub mackerel, Scomber japonicus, in Japan from 1970–2005, were examined to investigate the epidemiological relationship between isolates. The phenotypic and genetic characterizations were determined by α-glucosidase activity and biased sinusoidal field gel electrophoresis (BSFGE) analysis, respectively. There was no α-glucosidase activity in strains isolated from 2000–05 ( n  = 50) with a few exceptions ( n  = 3), while all strains isolated from 1970–90 ( n  = 8) were positive. In BSFGE analysis, digestions with restriction enzymes Xba  I and Ase  I produced 15 and 16 restriction patterns, respectively. All restriction patterns obtained from 50 strains isolated during 2000–05 were unrelated to those obtained from eight strains isolated during 1970–90, with the exception of two strains isolated during recent outbreaks. Based on the phenotypic and genetic characterizations, recent outbreaks of nocardiosis in Japan are suggested to be epidemiologically unrelated to earlier outbreaks in Japan. Although a low genetic relationship was observed in the restriction pattern between recent and earlier isolates, identity was confirmed between these groups of isolates because five representative strains showed 99.9% homology with N. seriolae ATCC43993^T in the 16S rRNA sequence.     

Functions and Uses of Phosphates in the Seafood Industry

Food-grade phosphates have many functional uses in seafood products, including, but not limited to, the retention of moisture and flavor; the prevention of lipid oxidation; shelf-life extension and cryoprotection. Condensed phosphates such as, sodium tripoly- and hexameta- phosphates and blends are most often used. Information on the uniform and consistent application of phosphates to seafood products is generally lacking and the process protocol in many seafood plants is often derived empirically. Abuse of phosphates leads to dramatic increases in the ratio of water to protein and charges of economic fraud. The objective of this work is to summarize previous efforts related to the responsible application of phosphates to seafood products.     

Quality Issues in the Danish Seafood Industry

Abstract

A questionnaire on quality management and measurement issues was conducted in the Danish seafood industry. The aim of the survey was to investigate to what extent the industry uses quality management systems, and which measurement methods are used. The results showed that the mandatory Own Check Systems, EU directive no. 91/439, were very well established. However, the application of more comprehensive systems was only found in 4% of the participating companies. Characteristics common to these companies were a high export rate, over 100 employees, and high turnover. The survey demonstrated that the measuring and control methods utilized by companies were mainly directed at controlling temperature, weight, sensory aspects, and microbes.