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1.
    
Pinctada margaritifera is an economically important marine bivalve species for cultured pearl production in French Polynesian aquaculture. In order to evaluate the influence of donor oyster age on pearl quality traits, experiments were conducted over 6 years using both grafts and surgreffe operations. At harvest, six pearl quality traits were recorded and compared: surface defects, lustre, grade, darkness level and visual colour. Analysing the quality traits of pearls harvested in the initial graft process and those of pearls obtained from surgreffe experiments allowed a comparison of the influence of pearl sac cells originating from the initial mantle graft, which aged together with their recipient oysters. The results demonstrated a significant decrease between these successive grafts in lustre, grade (A‐B‐C), darkness level, and green colour – traits that are of major importance in the pearl market. The duplicated graft experiment allowed the comparison of donor oyster families at 2 and 5 years old, where a mantle graft was inserted into recipient oysters aged 2.5 years. The results showed the same tendencies to a lesser extent, with (i) an improved pearl grade, predominantly through a most important rate of 0 surface defect category, and (ii) a green/grey ratio in favour of the younger donor. A comparison between the graft‐surgreffe and the duplicated graft experiments also highlighted: (i) the indirect role played by the younger recipient oysters, which must be optimized for optimal pearl quality realization, and (ii) the complex interplay between the donor and recipient oysters.  相似文献   

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3.
The black‐lipped pearl oyster, Pinctada margaritifera, is the most important farmed mollusc species in French Polynesia. Donor oyster selection among wild P. margaritifera individuals, chosen according to their inner shell colour, makes it possible to obtain the broadest range of cultured pearl colours of any species. This study demonstrates the relative influence of using black [B] or red [R] outer shell phenotypes, combined with green [G] or yellow [Y] inner shell phenotypes, on pearl darkness level, colour categories and lustre. A large scale grafting experiment was designed and carried out over five grow‐out locations, covering three archipelagos: Tuamotus, Society and Gambier. Results revealed that the [B + G] phenotypes may be used as donors to produce dark green pearl, which suit the demands of the Asian market; whereas, phenotypes incorporating [R] and/or [Y] phenotypes may be used to obtain multicolour pearls of medium/light darkness, which suit the demands of the European market. From an environmental point of view, the 1) [B] phenotype showed no significant variation for light and other pearl colour production, and 2) [Y] phenotype produced both the same rate of pearl darkness level and green colour pearls whatever the grow‐out location. A classification tree model was built to predict, according to shell phenotype and culture location, the colour and darkness level of harvested pearls. Lustre was shown to be more influenced by the environment than by phenotype. These results should be taken into account in pearl farm production management and in selective breeding programmes.  相似文献   

4.
    
The black‐lipped pearl oyster, Pinctada margaritifera, is the most important farmed species in French Polynesia and the basis of the most valuable export industry. Mass production of black pearls relies on a surgical operation requiring tissue from a donor pearl oyster to be grafted, together with a nucleus made of shell, into the gonad of a recipient oyster. Improving pearl size through family selection remains one of the main challenges for future aquaculture development. This study analyses the relative contribution of donor and recipient oysters to pearl size. To this end, hatchery‐produced donor oysters of two batches, large and small (based on shell height), were used to supply grafts for recipients, which were then monitored individually for their growth performance by recording shell height, width, and thickness, and total live weight (flesh + shells) every 6 months (four biometric measurement times) over 20 months of culture. Pearls issued from the two batches of donors showed no significant differences in nacre weight or thickness. In contrast, recipient oyster shell height and total weight were increasingly positively correlated with these pearl size parameters over the culture period, becoming significant at 8 months post‐grafting. Potential therefore exists to use shell height and oyster weight as phenotypic indicators for selective breeding of recipient oysters with high growth performance to increase pearl size in P. margaritifera.  相似文献   

5.
    
Understanding the respective roles played by donor and recipient pearl oysters in pearl quality determination in relation to the environment is a challenge for the pearl industry. In most Pinctada species, pearl size is mainly related to recipient oyster growth performance but also relies to some extent on the biomineralisation activity of the pearl sac, a tissue that originates from the donor oyster mantle. We examined donor effect on pearl size in response to culture in the lagoons on Arutua and Apataki atolls. Overall, nacre weight and thickness were greater in Arutua than in Apataki, but sensitivity to the environment differed between donors. Some donors were associated with significantly heavier and thicker nacre in Arutua (I group), while others had similar results at the two sites (NI group). On average, up to 20% of the pearl size could be attributed to the donor but, in group I, donor effect was responsible for up to 36% of nacre weight determination. Additionally, a real‐time PCR expression study of eight matrix protein genes related to biomineralisation in the pearl sac showed that MSI60, pearlin and pif177 were significantly and positively correlated with nacre weight and thickness, with the latter two genes explaining the larger pearl size observed in Arutua. Donor oysters in P. margaritifera therefore play a key role in pearl size improvement, related to the role of the shell matrix protein genes. Understanding such contributions could help in the design of genetic selection plans for specific and adapted donor oyster lines.  相似文献   

6.
    
In French Polynesia, the aquaculture of Pinctada margaritifera is carried out in numerous grow‐out sites, located over three archipelagos (Gambier, Society and Tuamotu). To evaluate the impact of macro‐geographical effects of these growing sites on pearl quality traits, five hatcheries produced families were used as homogeneous donor oysters in an experimental graft. The molluscs were then reared in two commercial locations: Tahaa Island (Society) and Rangiroa atoll (Tuamotu). At harvest, eight pearl quality traits were recorded and compared: surface defects, lustre, grade, circles, shape categories, darkness level, body and secondary colour and visual colour categories. Overall inter‐site comparison revealed that: (1) all traits were affected by grow‐out location except for lustre and round shape, and (2) a higher mean rate of valuable pearls was produced in Rangiroa. Indeed, for pearl grade, Rangiroa showed twice as many A‐B and less reject samples than Tahaa. This was related to the number of surface defects (grade component): in Rangiroa, twice as many pearls had no defects and less pearls had up to 10 defects. Concerning pearl shape, more circled and baroque pearls were found in Tahaa (+10%). For colour variation, 10% more pearls have an attractive green overtone in Rangiroa than in Tahaa, where more grey body colour were harvested. Lustre does not seem to be affected by these two culture site (except at a family scale). This is the first time P. margaritifera donor family have been shown to vary in the quality of pearls they produce depending on their grow‐out location.  相似文献   

7.
    
Cultured pearls produced with Pinctada margaritifera, using the surgreffe method (implantation of a second nucleus following pearl harvest) were studied for the first time to: (1) examine family effect on nacre thickness, nacre weight and nacre deposition speed and (2) compare variation in these three traits with that obtained from the cultured pearls previously harvested after the corresponding initial grafts. A surgreffe experiment using 783 recipient oysters was realized in Rangiroa atoll (French Polynesia). After 24 months of culture, 389 cultured pearls were harvested. Significant donor family effect was found for the harvested pearl rate from surgreffe (= 0.046). Highly significant donor family effect was recorded for nacre thickness (= 0.004). Very highly significant donor family effects were recorded for nacre weight and nacre deposition speed (< 0.0001). Comparison between surgreffe and initial graft showed: (1) no significant effect for the average cultured pearl rate harvested (= 0.052) and average cultured pearl nacre deposition speed (= 0.622) and (2) very highly significant differences (< 0.0001) for the average cultured pearl nacre thickness and nacre weight. This study highlighted three major implications for pearl industry management: (1) donor family effect was maintained from initial graft to surgreffe, for nacre thickness, weight and deposition speed, (2) the persistence of the pearl sac metabolic activity over three years of culture and (3) the relation between harvested pearl rate and the size of the nucleus inserted in the pearl sac.  相似文献   

8.
合浦珠母贝全同胞家系贝壳珍珠质颜色分析   总被引:2,自引:0,他引:2  
合浦珠母贝(Pinctada fucata)小片贝的珍珠质颜色直接影响育珠贝所产珍珠的颜色。每个合浦珠母贝的珍珠质颜色都有自己的颜色特征值,即三刺激值和颜色参数。试验选择16个合浦珠母贝全同胞家系,用CSE成像分析色度系统测量并比较各家系左壳内侧外缘珍珠质颜色参数Lab和三刺激值,以筛选适合做插核小片贝的家系。珍珠质的颜色参数明度(L)为98.586~105.234,其中F16家系的明度最大,F3家系的明度最小;a(红绿色品)为-0.967~-6.577,b(黄蓝色品)为5.915~11.237,F14家系色品最偏向于绿色(-a),F16家系色品最偏向于黄色(b)。F3和F14家系贝壳外缘珍珠质的色差(ΔEab)最大(7.885),肉眼能明显觉察。16个家系的合浦珠母贝都属于白色系列,其中离白光中心最近(a2+b2最小)且个体颜色集中的F1家系最适合用作小片贝来选育培养。  相似文献   

9.
    
In an investigation of the potential for pearl production in New South Wales (NSW), Australia, changes in the physical and reproductive condition of the pearl oyster, Pinctada imbricata, were monitored for over 2 years. Using wild oysters gathered from close to the southern extent of the species' range in Port Stephens, NSW, a series of macroscopic and histological observations were made. Reproductive activity in P. imbricata was greatest from late spring to early autumn with oysters in poor reproductive condition during winter. Peaks in reproductive indices occurred in November 1998, March 1999, December 1999 and April 2000. Four indices of physiological condition were used: shell growth, byssal attachment, mantle thickness and mucoprotien layer. With the exception of the thickness and extent of the mucoprotein layer, these indices either showed little variation or the variation that occurred was not related to seasonal or reproductive changes. Changes in the mucoprotein layer were correlated with water temperature and suggest that this layer is metabolized during periods of high demand such as during gonadogenesis. Collectors deployed at two sites in Port Stephens demonstrated that spatfall occurs largely in the months of December and January following the spring and early summer peaks in reproductive activity (November 1998 and December 1999). Spatfall was not observed following the autumnal peaks (March 1999 and April 2000) in reproductive activity. Overall, reproductive patterns in P. imbricata are poorly suited to spat supply in Port Stephens. Farmers require spat in early spring (September) to allow maximum use of the ‘growing’ season (September–May). Reproductively capable oysters are not available from the wild until September and quantity of natural spatfall is too variable and occurs too late in the season (December–January). As a result, oysters are being conditioned in the hatchery in July, spawned in August and spat are supplied to farmers in mid September.  相似文献   

10.
    
The winged pearl oyster, Pteria penguin, is cultured primarily to produce half‐pearls (mabé). The mabé quality is influenced by culture techniques, but there is limited information in this field. P. penguin with mean (±SE) dorso‐ventral height of 250 ± 6.5 mm were used to investigate the influence of culture period and nucleus position on mabé quality. Oysters were relaxed using 1‐propylene phenoxetol, and five nuclei were glued at different positions to the inner surfaces of the oyster shells; three on the more concave left valve and two on the right valve. Nucleated oysters were then cultured for 10 months under commercial pearl farming conditions at Savusavu in Fiji. Nacre deposited at the base and top of the nuclei was measured monthly, from the 6th to the 10th months of culture and the different qualities of mabé produced at different positions were scrutinized. Nacre thicknesses at the base and top of the resulting mabé were significantly different at different months (P < 0.05) and the rate of nacre deposition was highest during the warmer months. The different positions of nuclei on the valve greatly affected the quality of mabé formed. After a 10‐month culture period, around 1 mm of nacre covered the nuclei although the best quality mabé were obtained after 9 months.  相似文献   

11.
    
Pinctada fucata martensii is an ideal animal for study of biomineralization. Although dozens of genes have been identified, the molecular mechanism of biomineralization remains still unclear. The purpose here was to discover the expression profiles of nine biomineralization genes in related tissues: mantle edge (ME), mantle centre (MC) and pearl sac (PS), and to explore the relationships between expression level and nacre thickness. The expression levels of seven genes (ACCBP, aspein, CaM, EFCBP, KRMP, nacrein and prismalin‐14) showed no significant difference between ME and MC, but were significantly higher than those in PS. The expression level of N19 was the same in ME and PS, significantly higher than that in MC. However, msi60 in ME, MC and PS showed no significant differences in expression level. In addition, the correlations of expression levels between ME, MC and PS were highly significant, indicating that there are some similar function and mechanism among the three tissues. Also the nine genes had significant correlation of expression levels between one another. Furthermore, no other genes from oysters which produced pearls of different grades showed significant difference in the expression level, except CaM in MC, which had significantly higher expression level in the medium pearl grade than in the plain nucleus grade. Moreover, the expression level of msi60 in MC of host oyster was significantly correlated with produced pearl layer thickness, suggesting that msi60 might play an important role in pearl formation and host oyster may also participate in the development of pearl.  相似文献   

12.
XLP涂料对合浦珠母贝成活率、生长及附着生物量的影响   总被引:2,自引:0,他引:2  
研究了XLP防污涂料对合浦珠母贝Pinctada fucata成活率、生长及附着生物量的影响。经XLP防污涂料处理后的贝,其附着生物量明显低于对照组;经防污涂料处理后的养殖网笼具,其附着生物量也明显低于对照组;贝和养殖网笼具同时用XLP防污涂料处理时,防生物附着的效果最好。经XLP防污涂料处理后,处理前期(30~60d)合浦珠母贝养殖成活率与对照组的成活率接近,或者略低于对照组;养殖120d后试验组成活率则高于对照组。使用XLP防污涂料处理后养殖120d,合浦珠母贝的个体大小及体重高于对照组。试验结果表明,使用XLP防污涂料能有效防御污损生物附着,有利于合浦珠母贝的养殖。  相似文献   

13.
14.
Clearance rate (CR) and ingestion rate (IR) of different sizes (89, 125 and 188 μm shell length) of Pinctada margaritifera larvae were determined when feeding on various microalgae. The microalgae tested were the diatoms, Chaetoceros muelleri and C. simplex, and flagellates, Tahitian Isochrysis aff. galbana, Pavlova lutheri and P. salina at 5 or 10 cells μL–1. Both CR and IR of microalgae tested in this study increased with increasing larval size; but at all larval sizes, diatoms resulted in lower CR and IR. Of the microalgae tested, P. margaritifera larvae showed greatest CR and IR with the two Pavlova spp. Maximum CR for P. salina was 10.5, 21.2 and 29.7 μL h–1 for larvae with shell lengths of 89, 125 and 188 μm, respectively. The highest IR values for P. margaritifera larvae with shell lengths of 89, 125 and 188 μm were 8.7, 81.0 and 165.7 cells·larva–1 h–1, respectively. CR and IR of P. salina were approximately five times higher than those recorded for C. muelleri and C. simplex.  相似文献   

15.
    
Cultured free round pearls are produced by implanting a spherical nucleus with a small piece of nacre‐secreting mantle graft from a donor oyster into the gonad of a recipient oyster (host). To examine the possible contribution of host and donor oysters to the colouration of the harvested pearls, the CSE‐1 Imaging and Color‐Measuring System were used to quantitatively measure the L*a*b* values of donor and host shells and the produced pearls in Pinctada martensii. Results showed that the colour of pearls had significant positive correlation (r = 0.1–0.22, P = 0.00) with that of donors, but had no correlation with that of host oysters, thus convincingly confirmed the contribution of nacre colour of donor to the realization of pearl quality of colour. To further clarify the relationship between the donor and the pearl colour, the donors from pearls of good and poor colour quality were further compared and the results demonstrated the significant difference in L* values (P < 0.05) and insignificant difference in a* and b* values, suggesting the necessity of selecting donors with bright and lustrous nacre in pearl production.  相似文献   

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17.
    
A 10‐day experiment was performed to examine different mono, binary and ternary dietary combinations on survival and growth of D‐shaped and umbone black‐lip pearl oyster, Pinctada margaritifera, larvae. The three tropical microalgae species were the flagellate Isochrysis galbana clone T. Iso (CS‐177) and diatoms Chaetoceros calcitrans (CS‐178) and Chaetoceros muelleri (CS‐176) which were fed to D‐shaped and umbone larvae at a density of 7000 and 14 000 cells mL?1, respectively. A second experiment was performed to investigate the feasibility of replacing T. Iso with a lipid emulsion for both D‐shaped and umbone larvae for 10 and 12 days, respectively. The treatments included only T. Iso, unfed and lipid emulsion to substitute T. Iso at levels of 10% (LIP10), 30% (LIP30) and 100% (LIP100). In the first experiment, results showed that a monospecific diet of T. Iso led to significantly higher (< 0.05) survival and growth of D‐shaped larvae than all the other treatments. Meanwhile, D‐shaped larval survival was significantly lower when only fed C. calcitrans as well as growth for those fed C. calcitrans or in combination with C. muelleri. However, for umbone larvae, survival and growth were significantly higher when fed a binary combination of T. Iso and C. muelleri or the ternary combination of T. Iso, C. muelleri and C. calcitrans compared with all other treatments. For the second experiment, results showed that with increasing lipid emulsion replacement, survival of both D‐shaped and umbone larvae significantly decreased (< 0.05); however, the LIP100 treatment was not significantly different (> 0.05) from the unfed treatment. For D‐shaped larvae, no significant growth difference was detected (> 0.05) between the T. Iso and LIP10 fed treatments while for umbone larvae, the T. Iso, LIP10 and LIP30 were not significantly different (> 005). These results indicate that microalgae combinations appear more necessary for later staged P. margaritifera larvae. In addition, the use of a lipid emulsion appeared to provide some nutrition to the larvae, although more research should be conducted to improve the use of such replacements.  相似文献   

18.
合浦珠母贝DNA的抽提和RAPD反应体系的优化   总被引:9,自引:5,他引:9  
分别从保存于-70℃和95%乙醇的合浦珠母贝组织提取总DNA。结果表明,乙醇保存标本用双蒸馏水预处理后所提的DNA与-70℃保存的标本所提的DNA质量均较好。用抽提的DNA为模板优化RAPD条件,得到适合于合浦珠母贝的RAPDPCR反应条件为:20μL反应体系中包括20ngDNA模板,1×PCRBuffer,0.1mmol·L-1dNTPs,2.5mmol·L-1MgCl2,0.2μmol·L-1引物,1UTaqDNA聚合酶。最佳退火温度40℃。PCR产物用非变性PAGE银染和琼脂糖EB染色检测所得到的主要带型相同,但PAGE能检测到更多的多态带。  相似文献   

19.
20.
    
This study reports a year‐round recruitment of spat of four commercial bivalve species; Pteria sterna, Euvola vogdesi, Pinctada mazatlanica and Pinna rugosa collected in the region of Puerto Peñasco, north‐eastern coast of the Gulf of California. Bimonthly recruitment of commercial bivalve spat on netlon® collectors was evaluated for six sites from June 2007 to August 2008. To describe spat recruitment abundances with environmental parameters, sea surface temperature (°C) and surface chlorophyll a concentration (mg m?3) were characterized by means of monthly Aqua/MODIS satellite data. For each species a repeated measures anova was used to evaluate differences in the number of spat between months, sites and depths. Maximum sea surface temperature was recorded in August–September (~31.5°C) and the minimum in January–February (~15°C), while the minimum surface chlorophyll a was observed in June–September (mean range = 1.5–2 mg m?3) and the maximum in January–March (mean range = 2–5 mg m?3). Spat recruitment showed distinct patterns; P. sterna can be characterized as having a Winter–Spring pattern, E. vogdesi a winter pattern, while P. mazatlanica and P. rugosa a summer spat recruitment pattern. This information constitutes part of the fundamental data needed for the development of aquaculture and conservation initiatives in the region based on wild spat supply.  相似文献   

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