Nutrient digestibility profile of premium (category III grade) animal protein by-products for temperate marine fish species (European sea bass, gilthead sea bream and turbot)

Three trials, with classical experimental designs for in vivo digestibility studies, were conducted to determine the apparent digestibility coefficient (ADC) of protein (ADCp), lipid (ADCl), energy (ADCe) and amino acids (AA) in selected animal by-products fed to European sea bass, Dicentrarchus labrax (Trial 1), gilthead sea bream, Sparus aurata (Trial 2), and turbot, Psetta maxima (Trial 3). In each trial, five experimental diets [including a reference diet (RD)] where fish meal (FM) was used as the sole protein source were fed ad libitum to the fish for a period of 4 weeks. Test diets were based on the FM RD and obtained by replacing 30% of the RD with a category III designated European animal by-products (fit for human consumption), namely: steam hydrolysed feather meal (HFM), enzyme-treated feather meal (EFM), poultry meat meal (PMM) and spray-dried haemoglobin meal (SDHM). Faecal material was collected using the 'Guelph system', and nutrient and energy digestibility coefficients were related to the measurement of chromic oxide (Cr₂O₃) incorporated into the diet at a rate of 0.5%. Without any exception, FM diets yielded the best digestibility values for all macro-nutrients and by all fish. Among the test ingredients, ADCp was consistently higher for PMM and SDHM in the three species (85.5%, 91.1% in sea bass; 79.2%, 82.8% in sea bream; and 78.4%, 74.8% in turbot). Conversely, ADCp of HFM and EFM were less efficiently digested (67.2%, 68.2% in sea bass; 21.5%, 21.7% in sea bream; and 46.6%, 36.0% in turbot). However, the novel processing method applied to feather meal did not considerably influence the digestibility of most of the nutrients in this feedstuff. The current investigation yielded valuable numerical ADC for EAA considered to be of prime importance in generating balanced diet formulations.     

Competition between farmed and wild fish: The French sea bass and sea bream markets

ABSTRACT

Aquaculture is contributing at an increasing rate to the world seafood supply. The interaction between fisheries and aquaculture is especially important for the seafood market where supply of wild and farmed fish can affect price dynamics. We examine market interactions in the French fresh sea bass and sea bream markets. We test for long-term price parity between farmed and wild products for these two species, applying a bivariate cointegration approach to market delineation. We also conduct the Law of One Price (LOP) test between price series. Our data base consists of monthly domestic price series for fish purchased by French households from 2007 to 2012. Our empirical results show that the fresh fish markets for whole wild and farmed sea bream are partially integrated, yet those for whole wild and farmed sea bass are not integrated. The substantially higher price for wild sea bass relative to farmed sea bass suggests that consumers may be more sensitive to seafood production processes when it comes to higher-value species.     

Price interactions between wild and farmed products: Turkish sea bass and sea bream markets

We investigate empirically market interactions in the Turkish wild and farmed sea bass and sea bream markets. For gilthead sea bream and European sea bass, we conduct a Granger causality test between the prices of the wild and farmed products, based on the estimation of a vector autoregressive model. Our data set consists of annual fish prices from 1996 to 2016. Our empirical results show that the wild and farmed sea bass are neither substitutes nor complements: the markets for each product are independent. However, in the case of sea bream, the price variations for farmed sea bream have a causal impact on the price of wild sea bream. Moreover, the price of wild sea bream Granger-causes the price variation of farmed sea bream. Thus, the wild and farmed sea bream markets are integrated.     

环渤海海水养殖业发展现状及未来趋势

为进一步了解环渤海地区海水养殖业现状,促进近海及沿岸养殖业健康可持续发展,通过比较环渤海三省一市海水养殖的面积、产量、产值,对环渤海地区2012～2106年的海水养殖业现状进行了研究分析。有针对性地提出包括环境改变,养殖配置不合理等的问题,并重点对养殖环境面临的问题提出相应的建议。     

Emergence of pathogenic betanodaviruses belonging to the SJNNV genogroup in farmed fish species from the Iberian Peninsula

Betanodaviruses are the causative agents of viral nervous necrosis (VNN) or viral encephalopathy and retinopathy (VER) in cultured marine fish. Based on the RNA2 gene fish nodaviruses have been traditionally classified into four different genotypes and recently a fifth genotype has been proposed. This study presents sequencing data of 24 new nodaviruses obtained from three different fish species: sea bass, Dicentrarchux labrax (L.), sea bream, Sparus aurata L., and Senegalese sole, Solea senegalensis Kaup, cultured in the Iberian Peninsula (Spain and Portugal). Sequence analysis was performed on the T4 region (388 nt) of the coat protein gene. In addition, phylogenetic analysis, according to maximum parsimony and neighbour-joining methods, was performed using these sequences and other nucleotide sequences available in the databases or in the literature. Results obtained indicate that all these new nodaviruses should be classified into the striped jack nervous necrosis virus (SJNNV) genotype. This finding suggests that SJNNV genotype is emerging in the Iberian Peninsula and could easily spread throughout the Mediterranean, representing a serious threat to the fish farming industry.     

An overview of aquaculture in Turkey: With emphasis on sea bass and sea bream

Abstract

Aquaculture is a relatively recent industry in Turkey, enjoying great potential for development. Both freshwater and marine aquaculture are being practised in over 800 operational units. Rainbow trout (Oncorhynchus mykiss), Sea bream (Sparus aurata), Sea bass (Dicen‐trarchus labrax), comprise 90% of the total production, together with Atlantic salmon (Salmo salar), Common carp (Cyprinus carpio), Shrimp (Penaeidae spp.) and Mussel (Mytilus gal‐loprovincialis). Total aquaculture production reached 45 450 t in 1998, constituting 9% of total national fisheries production. Sea bass and sea bream farms are located along Aegean Sea and Mediterranean coasts and comprised 16% of the total number of aquaculture enterprises and 30% of total aquaculture production in 1997. Supplies of these two species have been steadily increasing in Turkey and other producing countries since 1990 resulting in market saturation and declining prices both locally and internationally. Mediterranean species including Epinephelus spp., Puntazzo puntazzo and Pagrus pagrus, are considered to be new candidates offering good prospects for mariculture.     

Susceptibility of marine fish species to a megalocytivirus, turbot iridovirus, isolated from turbot, Psetta maximus (L.)

Turbot iridovirus (TBIV), a member of the genus Megalocytivirus in the family Iridoviridae, was isolated from diseased turbot, Psetta maximus (L.), in Korea in 2003. In this study, experimental infection of turbot, Japanese flounder, Paralichthys olivaceus (Temminck & Schlegel), and rock bream, Oplegnathus fasciatus (Temminck & Schlegel), with TBIV was performed to evaluate the viral susceptibility of these fish species. After virus exposure, the mortalities of turbot reared at 22 and 25 degrees C were 60% and 100%, respectively, suggesting that TBIV is the causative agent of the mass mortality of turbot that occurred in Korea in 2003. Moreover, TBIV was detected in Japanese flounder and rock bream by polymerase chain reaction after experimental infection (26 days post-inoculation) despite no viral pathogenicity in these fish, suggesting that these two fish species are also susceptible to the virus. It is possible that horizontal transmission of TBIV occurs among these three fish species because turbot is routinely cultured with Japanese flounder and rock bream in Korea.     

天津海水工厂化养殖发展历程与现状分析

天津是国内工厂化海水养殖发展最快的区域之一,近几年随着天津滨海新区地下水的限采以及环保部门对养殖尾水排放的严格控制,海水工厂化养殖面临新的挑战。天津海水养殖发展一直受到土地和海水资源短缺因素的制约,天津海岸线为浅滩泥底潮汐带,海水比较浑浊,且工业污水和城市污水排放以及渤海和黄海较低的海水交换率造成海水富营养化。天津的气温变化大,适合室外露天养殖的时间短,但天津周边鲜活海产品巨大的市场需求和其丰富的地热资源及盐田卤水条件,促进了天津集约化的工厂化海水养殖的发展。回顾了天津海水工厂化养殖的发展历史,介绍了工厂化养殖设施装备的主要特点,分析、提出了海水工厂化养殖存在的问题及发展对策。     

陆基圆池循环水条件下养殖密度对大口黑鲈生长及养殖效能的影响

为研究陆基圆池循环水养殖条件下大口黑鲈(Micropterus salmoides)适宜的养殖密度,设置55、65、75、85、95尾/m²等5种养殖密度(分别标记为A1、A2、A3、A4、A5组),进行了63 d的大口黑鲈养殖试验,通过测定和分析试验鱼的体质量日增长率、体长日增长率、饲料系数、体质量均匀度和单位面积产量等指标,评价不同养殖密度对大口黑鲈生长和主要养殖效能的影响。结果显示:(1)从次低密度的A2组(65尾/m²)至密度最高的A5组(95尾/m²),试验鱼的体长日增长率基本上随着养殖密度的提高而下降,最高的A2组比A3、A4和A5组分别高了31.6%、82.9%和92.3%,并且差异显著(P<0.05);(2)从A2组至A5组,试验鱼的体质量日增长率和特定生长率均随着养殖密度的提高而下降;(3)A2组的饲料系数比A1、A3、A4和A5组分别降低了16.7%、28.6%、55.4%和56.9%;(4)单位面积产量和产品均匀度均在A2组达到最高。基于生长性能及养殖效能的综合评价,陆基圆池循环水养殖条件下大口黑鲈成鱼养殖阶段较适宜的养殖密度为65尾/m²。     

Microbiological controls across the productive cycle of Dicentrarchus labrax L. and Sparus aurata L.: a study from the environment to the final product

The microbiological quality of water, sediments and seafood products of three Sicilian marine fish farms (Castellammare Gulf, Capo d'Orlando and Porto Palo) was investigated in order to draw a complete picture of the health conditions from the start (environment) to the end (seafood product) of the productive cycle. Before the beginning of fish farming, low concentrations of faecal contamination indicators (faecal coliforms, Escherichia coli, enterococci) were found in the water of each examined area. Due to the enhanced organic load released from cages, the set‐up of fish farming significantly altered the distribution of faecal indicators and sometimes that of halophilic vibrios in the pelagic compartment. Significant differences in the density of heterotrophic bacteria were sometimes recorded at the sediment level. Despite this increase in microbial abundance, the microbiological conditions remained acceptable for the productive process. Pathogens (Salmonella spp., Vibrio parahaemolyticus, Listeria monocytogenes, Staphylococcus aureus) were mostly absent in seafood products. The study underlines that the achievement of good quality levels in aquaculture strongly depends on the conformity of the rearing environment to qualitative microbiological standards, highlighting the importance of sanitary controls along the different steps of the productive cycle.     

我国鱼类近缘杂交研究及其在水产养殖上的应用

基因型不同的动物体间相互交配的过程称为杂交(hybridization)。杂交是被广泛采用的育种手段。杂交的主要目的在于获得杂种优势,并通过杂交选育新品种或新品系。根据杂交亲本的亲缘关系,杂交可分为远缘杂交(remote hybridization,distant hybridization)和近缘杂交(closehybrid     

中国鱼类远缘杂交研究及其在水产养殖上的应用

在分析和归纳大量相关文献的基础上，对中国鱼类远缘杂交研究的概况及其有关问题进行全面的介绍和评述：（1）鱼类远缘杂交的等级，包括目间、科间、亚科间、属间和种间杂交；（2）鱼类远缘杂交的相容性，涉及鱼类远缘杂交的可交配性、鱼类远缘杂种的可育性以及鱼类远缘杂交不相容的原因分析等；（3）鱼类远缘杂交在水产养殖上的各方面应用，如杂种优势利用，鱼类性别控制以及诱导多倍体、雌核发育和雄核发育等。本文旨在为对今后进一步开展鱼类远缘杂交研究提供理论参考。     

Influence of dietary levels of soybean meal on the performance and gut histology of gilthead sea bream (Sparus aurata L.) and European sea bass (Dicentrarchus labrax L.)

The present study was performed to determine the effect of soybean meal (SBM) on the performance and gut histology of gilthead sea bream and European sea bass. Three isonitrogenous and isolipidic extruded diets (crude protein, 470 g kg⁻¹ diet; crude fat, 200 g kg⁻¹ diet) were formulated containing 0 (0 SBM), 180 (180 SBM) and 300 (300 SBM) g kg⁻¹ diet SBM and tested on both species in two separate experiments. Fish at an initial average weight of around 18 g were randomly allocated to 800 L square tanks connected to a closed recirculating system. The trials lasted 80 days for sea bream and 89 days for sea bass. Fish were hand-fed to apparent satiation. Increasing the level of SBM had no significant effects on the specific growth rate, feed intake and feed conversion rate in both the species. In the sea bream distal intestine, lamina propria was moderately and diffusely expanded in some fish due to an increase in cell infiltration represented by mononuclear cells, this finding being more frequent in animals fed diet 300 SBM. No other morphological alterations in intestinal folds, enterocytes or other inflammation signs were noticed in the sea bream distal intestine of any group. No histological differences were found in sea bass in any experimental group.     

Influence of tank volume on vitellogenesis and spawning performances in sea bass Dicentrarchus labrax L.

Sea bass, Dicentrarchus labrax (mean weight: 748±13 g), were maintained before and during vitellogenesis in 1, 3, 8, 16 and 32 m³ tanks, and then they were transferred to 2 m³ tanks, for the spawning season. During the first 2 months of the experiment, the growth rates were significantly lower in smaller tanks (1 m³). In August, the oocyte diameters were significantly lower in smaller tanks (1, 3 and 8 m³) than in larger (16–32 m³) tanks. At the end of the experiment, the fish mean weight in the 1 m³ tanks was significantly lower than in the 3 m³ tanks, but oocyte diameters and plasma oestradiol concentrations were not significantly different between the volumes. This shows a longer acclimation requirement in smaller volume rearing. Although all the females had not spawned, one spawn at least was collected in each volume. The variation in conditioning volume has not blocked the spawning process. The qualitative and quantitative characteristics of spawns were not significantly different between volumes. The conditioning volume of 3 m³ seems to be a minimal volume required to obtain good reproduction of sea bass.     

Price volatility dynamics in aquaculture fish markets

Abstract

In this paper, a time-varying student-t copula is used to capture information on price volatility dependence in the short-, medium-, and long-run horizon in the US market for frozen and fresh salmon, trout, tilapia and catfish. Using monthly data from July 1992 to March 2017, the volatility dynamics for these aquaculture species are assessed. The analysis allows indicating significant differences in the volatility relationships, depending on time-frequency. While short-run volatility has limited dependency, there is significant dependency in both the medium- and long-run, indicating that market integration is stronger in the long-run. The information is particularly important to buyers and producers utilizing the futures markets, as contracts are typically traded using a set of frequencies, and may help them manage and reduce price risk.     

基于渔盐一体化养殖的中国明对虾营养成分分析

为系统了解渔盐一体化生态养殖模式下中国明对虾(Fenneropenaeus chinensis)的营养价值,通过测定其肌肉基本营养成分(水分、粗蛋白、粗脂肪、灰分、总糖),蛋白质的氨基酸组成、脂肪酸组成、维生素和无机元素等,对其营养价值进行评价。结果显示:该养殖模式下,中国明对虾蛋白质含量较高,氨基酸种类齐全,必需氨基酸占氨基酸总量的39.03%,符合FAO/WHO的理想模式;呈味氨基酸含量高达43.73%;脂肪含量低;维生素B3和维生素E含量丰富;富含人体必需的钙、铁、锌、镁、硒等矿质元素,无重金属污染。研究表明:渔盐一体化生态养殖的中国明对虾是一种高蛋白、低脂肪、高矿物质、营养价值较高的优质海产虾类。