鲍遗传育种研究进展

Abalones are important farming species with a high economic value. They have already been farmed for more than 50 years. As problems and new requirements rose continuously in culture industry of abalone, studies on genetic and breeding techniques are needed to improve characteristics and to gain new traits. This review concentrates on advances in genetics and breeding techniques in abalone. As for genetic studies, karyological analyses, allozyme, DNA markers and genetic diversity were reviewed. So far, karyological analyses in abalone have been performed in 12 species that can be divided into three groups according to the chromosome number. In some economically important species, loci of allozymes and. microsatellites have been isolated and applied to investigate the genetic structure of natural and hatchery populations and to identify the result of chromosome set manipulation, but the related reports are only a few yet. The resultsof investigation with DNA markers and allozymes showed that the genetic structure of natural populations presents two characteristics: excessive homozygosity and subdivision. Advances of various breeding techniques, including introduction, selection,hybridization, polyploidy, gynogenesis and gene manipulation, were reviewed in the other part. Although Haliotis discus discus, introduced from Japan, has become one of the most important culture species in China, the economic, social and environmental effects of introduction have been rarely studied. Selection is one of the most important and basic breeding techniques, but the studies on selection are only a few and preliminary, referring to the relations between genetic characteristics and the traits of growth and resistance, genetic diversity and heritability of quantitative traits, and the effect of selection. Interspecific hybridization was the first breeding program carded out in abalone. Experimental hybridization have been carded out for about 20 crosses. Heterosis,such as faster growth and high survival rate, has been observed in some crosses. Triploids have been successfully induced in many species of abalone with physical or chemical shock, e.g.H, discus hannai, H. rufescens, H.diversicolor diversicolor and H. rnidae. Field experiments were conducted in some species of triploid abalone. In comparison with triploid, the research on tetraploid is still in quest stage. The progress of induction of gynogenesis in abalone is quite slow. Conditions of sperm inactivation, diploid restoration and nuclear behavior of gynogenetically activated eggs have been researched on in H. discus han nai. Notwithstanding the gene transfer technology in abalone is in the quest stage, the research have already involved preparation of exogenic DNA,means of gene transfer, identification integration and expression of target gene, etc. Three research directions in these topics were proposed : to investigate the germplasm resources of abalone deeply and widely, to make use of traditional breeding methods and modem biotechnique synthetically, and to combine the science research with production practice.     

配合饲料投喂量和粒径对绿盘鲍稚鲍生长和存活的影响

在水温15.8～24.7℃下,将小规格(壳长为1.03±0.02 cm)和中规格(壳长为1.57±0.03 cm)绿盘鲍(GS-02-003-2018)(皱纹盘鲍Haliotis discus hannai Ino♀×绿鲍H.fulgens♂)稚鲍分成A、B、C和D 4个组,饲养在240 mm×170 mm×285 m...     

高效纤维过滤器净化海水培育鲍鱼试验

使用高效纤维过滤器可对海水进行深度净化,浊度脱除率85%～90%,细菌滤除率81 8%～100%。使用该过滤器过滤海水培育鲍苗等海珍品幼苗,能有效地提高幼苗的成活率并改善其生长状况,鲍苗死亡率减少8 9%。     

坑道养鲍技术研究

利用坑道将海水温度调到鲍的最适生长水温１４－２１℃。结果：鲍能常年生长，养殖２０个月，平均壳长６ｃｍ，体重２６ｇ，成活率９３．４％。在总面积１０００ｍ＾２坑道内，养成鲍１０ｔ，产值３６０万元，创利税２３８万元。     

Understanding pressures on fishery resources through trade statistics: a pilot study of four products in the Chinese dried seafood market

This study investigates the dried seafood trade, centred in Chinese markets, in order to better understand the pressures its demand exerts on global marine resource stocks. Using Hong Kong, the region's largest entrepôt, as a focal point, the trade in shark fins, abalone, bêche‐de‐mer and dried fish is characterized in terms of product history, volume, source fisheries and species composition. Trends identified in the Hong Kong market are interpreted in the context of the larger Chinese market. Shark fin imports grew 6% per year between 1991 and 2000, most likely because of market expansion in Mainland China, posing increasingly greater pressures on global shark resources. In contrast, the quantities of dried abalone traded through Hong Kong remained steady, but inferences based on this trend are discouraged by suggestions of increasing preferences for fresh product forms and growing domestic production in Mainland China. Hong Kong's imports of dried bêche‐de‐mer (sea cucumber) have decreased, while the percentage of imports re‐exported has remained steady, suggesting that Hong Kong continues as an entrepôt for Mainland China despite declining domestic consumption. Few conclusions can be drawn regarding dried fish products, including whole fish and fish maws, because of a lack of product differentiation in customs data, but a market survey was conducted to provide information on species composition. Comparison of Hong Kong dried seafood trade statistics to those of other key trading partners indicates that, in general, Hong Kong's duty‐free status appears to encourage more accurate reporting of traded quantities. Under‐reporting biases ranged from 24 to 49% for shark fin and bêche‐de‐mer, respectively. Comparison to United Nations (UN) Food and Agriculture Organization (FAO) databases indicates additional under‐reporting for shark fin such that an alternative minimum estimate of world trade is at least twice the FAO estimates in 1998–2000. The results of a survey of Hong Kong traders provide insight into their attitudes toward harvest, economic and regulatory factors, and suggest that conservation efforts are unlikely to emerge from, or be actively supported by, dried seafood trade organizations. The market's apparent sensitivity to economic sentiment, however, reveals an opportunity for consumer education to play a role in shaping future market growth and resource conservation. Recommendations are provided for improving trade statistics and for developing better analytical techniques to complement traditional methods for monitoring the exploitation and management of fisheries resources.     

Rheological properties and structural changes in raw and cooked abalone meat

SUMMARY: In a study of the relationship between structural changes and rheological parameters of raw and cooked abalone meat, abalone Haliotis discus was cooked in boiling water for 3 h, then cut up and separated into cross- and vertical sections. Structural change was observed using a light microscope and scanning electron micrography. The rheological parameters were obtained by stress-relaxation experiments. Microscopic photography revealed that structural change between muscle fibers in both sections of the cooked meat was greater than that in the raw meat. The elastic modulus and rupture strength in both sections of cooked meat showed no difference between the cross- and vertical sections, and were smaller than those for the raw meat. The relaxation time for the cooked meat was also greater than for the raw meat. These results were mainly because of collagen being gelatinized during heating. These changes were also observed by staining collagen and differential scanning calorimetry.     

An assessment of the efficacy of two lysine microencapsulation techniques to determine the quantitative lysine requirement of the South African abalone, Haliotis midae L.

The quantification of the essential amino acid requirements of a species is a prerequisite to the formulation of biologically optimized diets. In this study, crystalline L -lysine was used in an attempt to determine the quantitative lysine requirement of juvenile Haliotis midae . Two microencapsulation techniques [gelatine/acacia and cellulose acetate phthalate (CAP)] were used to retard leaching of crystalline L -lysine incorporated into semipurified test diets. An assessment of the efficacy of the encapsulation techniques, revealed that despite effective lysine supplementation, H. midae fed semipurified test diets containing encapsulated crystalline L -lysine failed to promote significant improvements in either growth, feed or protein efficiency ( P  > 0.05). The failure of the crystalline L -lysine to illicit growth and nutritional responses is discussed.     

Effect of tremata closures on the oxygen consumption rhythm of ezo abalone Haliotis discus hannai

Cultured adults of ezo abalone, Haliotis discus hannai (shell length, 89.3 ± 6.4 mm and flesh dry weight, 13.0 ± 1.6 g; n = 12) were exposed to different temperatures (10 and 25 °C) to determine whether respiration effects were induced by artificial closure of the second and third tremata (respiratory pores). A respirometer was used to determine the oxygen consumption rates (OCRs) as measures of metabolic activity. The closed tremata were the second and third of the four open tremata anterior to the head of the abalone. The OCRs of starved abalone were measured under constant conditions (CC: constant dark and constant temperature) during a 240-h period, consisting of 120 h before and 120 h after the closure of tremata. The endogenous rhythm of the OCRs in cultured ezo abalone exhibited a dominant circadian rhythm (unimodal rhythm) in the latter half of the experimental period and occasionally showed a weaker but similar circatidal rhythm (bimodal rhythm) in the first half of the experimental period regardless of temperature. The results from the present study indicate that the rhythmicity of the OCRs in starved abalone is not affected by closure of the second and third tremata. This study offers essential physiological information for utilizing tremata in developing a tagging technique in abalone.     

Inhibition of SARS-CoV-2 Virus Entry by the Crude Polysaccharides of Seaweeds and Abalone Viscera In Vitro

Much attention is being devoted to the potential of marine sulfated polysaccharides as antiviral agents in preventing COVID-19. In this study, sulfated fucoidan and crude polysaccharides, extracted from six seaweed species (Undaria pinnatifida sporophyll, Laminaria japonica, Hizikia fusiforme, Sargassum horneri, Codium fragile, Porphyra tenera) and Haliotis discus hannai (abalone viscera), were screened for their inhibitory activity against SARS-CoV-2 virus entry. Most of them showed significant antiviral activities at an IC50 of 12~289 μg/mL against SARS-CoV-2 pseudovirus in HEK293/ACE2, except for P. tenera (IC50 > 1000 μg/mL). The crude polysaccharide of S. horneri showed the strongest antiviral activity, with an IC50 of 12 μg/mL, to prevent COVID-19 entry, and abalone viscera and H. fusiforme could also inhibit SARS-CoV-2 infection with an IC50 of 33 μg/mL and 47 μg/mL, respectively. The common properties of these crude polysaccharides, which have strong antiviral activity, are high molecular weight (>800 kDa), high total carbohydrate (62.7~99.1%), high fucose content (37.3~66.2%), and highly branched polysaccharides. These results indicated that the crude polysaccharides from seaweeds and abalone viscera can effectively inhibit SARS-CoV-2 entry.