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1.
Salmo trutta abanticus is a non‐anadromous trout species native to Lake Abant and Seven Lakes in Turkey. A restocking programme by captive breeding was initiated in 1999 to support S. trutta abanticus population. Reared 2‐year‐old juveniles from randomly caught wild parental individuals in Maçka breeding farm were introduced into Lake Abant. We aimed to compare genetic and morphological divergences between wild‐ and captive‐bred populations using seven microsatellite loci and geometric morphometric measurements. A significant genetic and morphological divergences were detected between all population in Fst and canonical variate analysis based on geometric morphometric with 10 homolog landmark. Eighty‐six microsatellites alleles were recorded across loci. Number of private alleles, observed alleles and observed heterozygosity are statistically significant higher in Maçka captive‐bred population than Lake Abant and Seven Lakes populations. Of 42 tests, three departures from Hardy–Weinberg equilibrium were detected in all populations after Bonferroni correction. Two pairs of loci (Ssa85 – Str73 and Str73‐Str543) in Maçka, one pairs of loci (Ssa85‐Str73) in Abant and two pairs of loci (Ssa85‐Str60 and Str73‐Str543) in Seven Lakes populations show linkage disequilibrium. Population structure analysed with Structure software showed three genetic groups (?K = 3) in our studied populations. Relatedness estimates show higher mean relatedness values (r = 0.220 ± 0.230) for Maçka captive‐breed population than wild populations of Abant Lake and Seven Lakes (r = 0.140 ± 0.210 and r = 0.170 ± 0.200 respectively).  相似文献   

2.
Growth and variation in size of turbot and sole larvae originating from different genetic sources were compared at different stocking densities, including genetically based information that might lead to a better knowledge of heterogeneity in cultivated populations. There was no effect of density on growth rate in either species. However, between the two sole batches there was an earlier metamorphosis of faster growing fish from Norway. In sole groups after metamorphosis, variation was stable and therefore no development of size variation was observed. There was no density effect on size variation within turbot batches before, or after metamorphosis. Spreading rate and growth rate were positively correlated in sole larvae indicating that growth of the smaller fish was not equal to the larger ones, but size variation followed a different pattern in turbot. No evidence for either overall significant heterozygosity excess, or deficiency was evidenced in the farmed strains of either species . However, significant differences between farmed populations in terms of genetic variability (θ) were reported, which was rather attributed to within differentiation than between strains. One could safely argue that different strains of Dover sole originated from different genetic sources (factorial analysis). Moreover, when the analysis was extended to individual loci to assess whether specific loci had any consistently larger, or smaller effect on heterozygosity, locus specific significant trends were discerned in turbot. A positive Heterozygosity Fitness (growth rate) Correlation (HFC) suggests that heterozygotes reported enhanced growth rates compared with homozygous ones in flatfish larvae, thus special precautions should be taken into account whenever different genetic structure patterns emerge, because of various flatfish broodstock geographical origin and year class samples.  相似文献   

3.
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4.
Interspecific hybrids between Haliotis discus hannai Ino and Haliotis gigantea Gmelin were produced in this study. The hybridity of the interspecific hybrids was confirmed by using the methods of amplified fragment‐length polymorphism (AFLP) and microsatellite [simple sequence repeats (SSR)] markers. Five AFLP primer combinations were used to develop the AFLP profiles of H. discus hannai, H. gigantea and their reciprocal hybrids. AFLP analysis revealed that genetic variations of H. discus hannai and H. gigantea were relatively diverse and each species holds species‐specific bands. The AFLP profiles of reciprocal hybrids showed that all of the hybrids inherited bands specific to H. discus hannai and H. gigantea. Of a total of 20 microsatellite loci, which were selected from H. discus hannai microsatellite markers evaluated, eight loci were polymorphic in H. gigantea samples, with an average of 3.375 alleles per locus. Preliminary screening showed that, two of these eight microsatellite loci (Awb002 and Awb022) could be used as species‐specific markers to distinguish the hybrids and their parental species. Simple sequence repeats analysis showed that the reciprocal hybrids inherited one allele from each parent for both of the two SSR loci investigated. These data strongly suggest that the induced interspecific hybrid is a true hybrid between H. discus hannai and H. gigantea.  相似文献   

5.
The biological benefits of copepods as live feed for marine finfish larvae have already been well established in the literature. Copepods have better biochemical compositions that improve growth, reduce malpigmentations and allow successful farming of ‘new’ marine finfish species. However, their current usage is quite limited. One of the reasons has been lack of economic knowledge concerning the cost‐effectiveness of copepod application compared to other commonly used feed items such as the brine shrimp Artemia. In this study, a cost‐effectiveness analysis is made on two alternative live feed items (copepods and Artemia) in juvenile turbot farming. Unit cost of production and profit are compared between the two feeding regimes using a unique data set from an existing turbot fry production facility in Denmark. The result reveals that copepods are not only biochemically superior but they are also economically a cost‐effective alternative. Thus, a commercial use of copepods will significantly reduce the production costs for turbot. Furthermore, the unexploited economic potential can be utilized for the successful farming of other high‐valued marine finfish species such as tuna, flounders, cod, sole and halibut. Generally, the biochemical superiority coupled with economic benefits can lead to the commercial utilization of copepods as complementary live feed in the short run and in some situations as a substitute in the long run.  相似文献   

6.
Among the variety of cultured marine species, the turbot Scophthalmus maximus is a fish of growing importance in European aquaculture. In this paper, an advanced application of AFLPs to estimate the genetic diversity of haploid gynogenetic families with the aim of obtaining a preliminary genetic map is presented. Ten EcoRI/TaqI primer combinations were tested in four families comprising diploid mothers and their haploid progenies. The amplified fragment length polymorphism (AFLP) analysis revealed an average of 6.8 polymorphic bands per primer combination and a total number of 88 polymorphisms out of 579 fragments. Among various primer pairs, seven combinations were selected in relation to the quality of profiles and number of polymorphic fragments, to be used in the determination of genetic linkage relationship between AFLP markers within the largest haploid family. Co‐migration of non‐homologous fragments was also investigated in one primer combination adding a fourth selective nucleotide to the three used in the classic TaqI AFLP protocol. Surprisingly, a rate of 38.7% of non‐homologous fragments co‐migrating with monomorphic bands was identified, due to the combined effect of homoplasy and the protocol used. Additional polymorphic markers discovered by this protocol were included in the linkage map. The turbot AFLP linkage map comprises 52 AFLP markers distributed in 12 linkage groups. On the basis of this map, turbot expected total genome length sums up to 1225.6 cM. The results confirm the usefulness of AFLPs in revealing genome segregation in haploid turbot progeny.  相似文献   

7.
Presumed hybrids between Haliotis rufescens and H. fulgens abalones, produced in a commercial abalone laboratory, were evaluated for progeny viability, gonad characteristics and for their ‘true’ status as hybrids by means of allozyme and microsatellite analyses. Four out of 10 evaluated allozyme loci proved to be useful for the genetic certification of hybrids, Gpi, Mdh‐1, Mdh‐2 and Sod, as they had exclusive alleles for each of the abalone reference species from which the presumed hybrids were produced. Three microsatellite loci were also evaluated for their usefulness in abalone hybrid certification. Two were not useful for hybrid certification as the reference abalone species shared some of the same alleles. The third loci (Hka 56) also had shared alleles between the two species, but at very different frequencies. Therefore, this permitted a presumptive certification of hybrids, which, however, was not error‐proof as two allozyme certified hybrids were wrongly classified as H. rufescens rather than as hybrids. Progeny viability of the only female certified to be a hybrid was significantly lower compared with one viability of the other females spawned, which were certified as H. rufescens. However, the number of eggs spawned by the only certified hybrid female was as large as those spawned by females certified as H. rufescens. Gonads of abalones sampled for the macroscopic appearance of sterility indicated that in the absence of any gonad development, no distinctive difference allows for hybrid identification, as there were undifferentiated individuals that were both hybrid and non‐hybrid. On the other hand, two certified hybrid males were characterized by spermatocytes being the most abundant gamete type, although one had some spermatozoa present, indicating only partial sterility. Among the two female hybrids found, vitellogenesis was observed to proceed up to vitellogenic oocytes.  相似文献   

8.
The consequence of elevated ocean temperatures on commercial fish stocks is addressed using time series of commercial landings (1906–2004) and juvenile survey catch data (1904–2006) collected around Denmark. We analyze (i) whether warm‐water sole (Solea solea) has increased relative to Boreal plaice (Pleuronectes platessa) and (ii) whether two related warm‐water species (turbot, Psetta maxima and brill, Scophthalmus rhombus) show similar responses to increasing temperature or, alternatively, whether turbot (which has a broader juvenile diet) has been favored. Since the early 1980s, both sole and turbot have constituted an increasing part of the commercial landings and survey catches, as compared with plaice and brill, respectively. These changes in species composition were linked to sea surface temperatures, Northern Hemisphere temperature anomalies (NHA) and the North Atlantic Oscillation. NHA was closely related and explained 43% of the observed variation in sole survey catches relative to the plaice catches and almost 38% of the observed variation in the sole landings relative to the plaice landings. For the less common species, turbot and brill, none of the global change indicators explained more than 15% of the variation, although all showed a positive relationship. Survey catch per unit effort increased significantly for both sole and turbot around the early 1980s, whereas catch per unit effort for plaice and brill remained constant. The results indicate that the abundance of warm‐water species is likely to increase with increasing temperature but also that species with similar life histories might react differently according to degree of specialization.  相似文献   

9.
Megalocytivirus belongs to the Iridoviridae family and is known to affect finfish. Megalocytivirus epizootics have been reported to occur in several cultured fish species in China; however, no megalocytivirus associated with rock bream, Oplegnathus fasciatus (Temminck & Schlege), has been documented. In this study, we characterized for the first time a megalocytivirus, rock bream iridovirus (RBIV)‐C1, detected in cultured rock bream in a fish farm in China that had been inflicted with a high‐mortality disease outbreak. Sequence analysis of three conserved genes showed that RBIV‐C1 shares over 90% overall identities with a number of known megalocytiviruses. Electron microscopic examination revealed RBIV‐C1 as hexagonal particles similar to those reported for megalocytiviruses. In vivo infection study indicated that, following inoculation into rock bream, RBIV‐C1 induced 100% mortality and upregulated the expression of Mx, IL‐1β and IL‐8. The infected fish exhibited pathological signs similar to those observed in naturally diseased fish. Furthermore, studies in a turbot (Scophthalmus maximus L.) model indicated that RBIV‐C1 induced acute infection in turbot that led to 100% mortality. These results indicate that RBIV‐C1 is highly virulent to rock bream as well as turbot and that RBIV‐C1 is closely related to a number of previously reported megalocytivirus and likely a genetic variant of the latter.  相似文献   

10.
Growth data of two different commercial turbot (Scophthalmus maximus) strains reared in recirculating aquaculture systems were analysed with the aim to determine the most suitable model for turbot. To assess the model performance three different criteria were used: (1) The mean percentage deviation between the estimated length and actual length; (2) the residual standard error with corresponding degrees of freedom and (3) the Akaike information criterion. The analyses were carried out for each strain separately, for sexes within strains and for a pooled data set containing both strains and sexes. We tested a pre‐selection of six models, containing three to four parameters. Models were of monomolecular shape or sigmoid shape with a flexible point of inflection including the special case of monomolecular shape in defined cases of their parameters. The 4‐parametric Schnute model achieved best fit in 62% of all cases and criteria tested, followed by the also 4‐parametric generalized Michaelis–Menten equation in 48% and the 4‐parametric Janoschek model (38%). The von Bertalanffy growth function achieved only 29%, Brody 24% and a new flexible function 19% best fit. In a 1–1000 day growth‐simulation sigmoid shaped curves were produced by the Schnute model in 71% of cases. The Janoschek and the Michaelis–Menten model each produced sigmoid curves in 57% of all cases. This indicates that a flexible 4‐parametric function reflects the growth curve of turbot the best and that this curve is rather sigmoid than monomolecular shaped.  相似文献   

11.
In the present work, EST‐SSR (expressed sequence tag‐simple sequence repeat) loci were obtained by screening 45 000 ESTs from the Pacific white shrimp Litopenaeus vannamei, which was available in a database of the ShEST (Shrimp EST Genome Project) consortium. Fifty‐two of 600 EST‐SSR loci were selected. From this total, 21 EST‐SSRs were polymorphic among 40 individuals and had their gene products ascribed. Two to 20 alleles per locus were detected and the observed heterozygosity ranged from 0.15 to 0.86. Eight loci presented a significant heterozygote deficit after the Bonferroni correction, which was attributed to null alleles. Seven loci were able to have their protein products, molecular functions and biological processes determined. Our results are promising for future studies that relate the levels of these gene polymorphisms with different biological responses to stress in aquaculture.  相似文献   

12.
The microsatellite DNA technique was used to detect the genetic variations between wild and cultured populations of Kuruma prawn Marsupenaeus japonicus Bate 1888. All the six microsatellite loci screened in this study showed high polymorphism for their PIC (0.6701–0.8989), which was much more than the standard value of 0.5. A total of 73 alleles were observed over six loci from 93 shrimps. The mean number of allele locus ranged from 9.83 (cultured) to 11.83 (wild). The number of effective alleles varied from 6.86 (cultured) to 8.58 (wild). The average of observed heterozygosity (Ho) of populations varied from 0.6935 (cultured) to 0.7370 (wild), and that of expected heterozygosity (He) was 0.8169 (wild) and 0.8209 (cultured). Tests of Hardy–Weinberg showed that these loci deviated significantly or highly significantly in one or both populations. Compared with the wild population, the cultured population showed little reduction in genetic variation. The total number of alleles (71, 59) was not significantly (P=0.296) different between wild and cultured populations. The paired‐samples t test of observed heterozygosity and expected heterozygosity implied that there was no significant difference (P=0.572 and 0.891 respectively) between wild and cultured populations. However, some rare allele loss might have occurred in the cultured population. A total of 14 unique alleles were found in the wild population, but only two unique alleles were observed in the cultured population. Therefore, there is a need to monitor genetic variability of cultured population, and to improve the hatchery program for the conservation of wild Kuruma prawn resources.  相似文献   

13.
Primers were designed for eight microsatellite loci from Chinese shrimp Fenneropenaeus chinensis. Microsatellites were used to characterize three wild populations from the China coast of the Yellow and Bohai Seas (HB), and the west coast (KX) and south coast of the Korean Peninsula (KN). A total of sixty‐one alleles were obtained, and the average observed heterozygosity ranged from 0.660 to 0.756. Six of the 24 population‐locus cases showed a significant departure from the Hardy–Weinberg equilibrium, three of them from population KN, two from KX and one from HB. The Fst values indicated that genetic variation was greater within populations than between populations. Analysis using unweighted pair group method with arithmetic mean showed that the relationship between populations HB and KX was closer than between KN and the other two populations. Polymorphic information contents of the eight microsatellites ranged from 0.598 to 0.918. These results indicated that all eight microsatellite loci would be useful for the analysis of genetic variation in Chinese shrimp (F. chinensis) populations.  相似文献   

14.
In order to develop a microsatellite typing system for Lepeophtheirus salmonis (Krøyer), a DNA preparation method for individual sea lice suitable for analysis by polymerase chain reaction (PCR) was designed, and the DNA sequences of 50 L. salmonis microsatellite elements were determined. The microsatellites were composed of 60% perfect, 25% imperfect, and 15% compound repeats. Based on the flanking DNA sequences, four microsatellite‐PCR assays were optimized and used in a pilot study to analyse L. salmonis samples collected in Ireland, Norway and Scotland. Two of the microsatellite‐PCR assays targeted polymorphic loci amplifying seven and 10 alleles respectively. The results showed that microsatellite‐PCR typing could detect genetic variation both within and between the L. salmonis groups, and also was capable of amplifying group‐specific alleles.  相似文献   

15.
The histiophagous scuticociliate Philasterides dicentrarchi is the aetiological agent of scuticociliatosis, a parasitic disease of farmed turbot. Curcumin, a polyphenol from Curcuma longa (turmeric), is known to have antioxidant and anti‐inflammatory properties. We investigated the in vitro effects of curcumin on the growth of P. dicentrarchi and on the production of pro‐inflammatory cytokines in turbot leucocytes activated by parasite cysteine proteases. At 100 μm , curcumin had a cytotoxic effect and completely inhibited the growth of the parasite. At 50 μm , curcumin inhibited the protease activity of the parasite and expression of genes encoding two virulence‐associated proteases: leishmanolysin‐like peptidase and cathepsin L‐like. At concentrations between 25 and 50 μm , curcumin inhibited the expression of S‐adenosyl‐L‐homocysteine hydrolase, an enzyme involved in the biosynthesis of the amino acids methionine and cysteine. At 100 μm , curcumin inhibited the expression of the cytokines tumour necrosis factor‐alpha (TNF‐α) and interleukin‐1 beta (IL‐1β) produced in turbot leucocytes activated by parasite proteases. Results show that curcumin has a dual effect on scuticociliatosis: an antiparasitic effect on the catabolism and anabolism of ciliate proteins, and an anti‐inflammatory effect that inhibits the production of proinflammatory cytokines in the host. The present findings suggest the potential usefulness of this polyphenol in treating scuticociliatosis.  相似文献   

16.
The genetic diversity of cultured populations of the Pacific abalone (Haliotis discus hannai Ino) from northern China was analysed using seven microsatellite markers. The microsatellite loci were polymorphic for all the populations, with an average of 8.7 alleles per locus (range 8.0–9.4). The mean observed and expected heterozygosities were 0.547 (range 0.500–0.596) and 0.774 (range 0.754–0.787) respectively. The allelic diversity in terms of number of alleles per locus was considerably lower than that previously found in wild populations (range 21.8–23.0), indicating that bottleneck effects occurred when each population was founded. Significant genetic differentiation among the five cultured populations was shown using Fst and Rst values, and pairwise comparison based on allelic distribution. A neighbour‐joining analysis of the genetic distance did not show a consistent relationship between the geographic and the genetic distances, suggesting the existence of exchanges of breeds and eggs between the hatcheries. The results obtained in this study are useful for a number of areas of interest for fisheries management and the aquaculture industry, especially with regard to breeding programmes.  相似文献   

17.
A growth trial was conducted to evaluate the effects of chelated (Mintrex? Mn, Mn‐M) or inorganic (MnSO4·H2O, Mn‐S) manganese (Mn) on growth, feed utilization, tissue Mn deposition and liver superoxide dismutase (SOD) activity in turbot Scophthalmus maximus. A semi‐purified basal diet was formulated to be deficient in Mn (3.7 mg kg?1) and contained tricalcium phosphate and sodium phytate at levels of 20 and 5 g kg?1, respectively. Ten other diets were made by adding five levels (5, 10, 20, 35 and 55 mg Mn kg?1 diet) of either the Mn‐M or Mn‐S to the basal diet, respectively. The 11 experimental diets were fed to groups of turbot (mean initial weight: 4.6 g) for 8 weeks. Results showed that the specific growth rate (SGR), feed intake, whole body Mn/vertebra Mn concentration and Mn‐SOD activity in liver were significantly improved by Mn supplementation (P < 0.05). On the basis of SGR, vertebra Mn concentration or liver Mn‐SOD activity data, dietary Mn requirement was estimated to be 10.5, 46.3 or 12.9 mg kg?1 for turbot fed Mn‐S, and the same was estimated to be 7.6, 43.0 or 22.5 mg kg?1 for turbot fed Mn‐M, respectively. There was no significant difference in growth, feed intake, whole body Mn concentration or vertebra Mn concentration between the two dietary Mn sources (P > 0.05).  相似文献   

18.
Farmed turbot and sole were sampled at different stages of the production cycle for analysis of fillet lipid content and fatty acid (FA) composition. The entire data set along with our own published data on gilthead sea bream were fitted to dummy regression equations with turbot and sole as dummy variables, gilthead sea bream as a reference subgroup category, and diet FA composition and fillet lipid content as independent variables. The relative contribution of each independent variable to the total variance was found to vary within and among FAs and fish species, but strong correlation coefficients (0.76 <  r2 > 0.99) were found for almost all of the FA equations, including saturated FAs, monoenes and long‐chain polyunsaturated fatty acids (PUFA) of n‐3 and n‐6 series. Given the differences in lipogenic activities of the fish species, major interaction effects between fillet lipid content and dummy variables were found for monoenes and saturated FAs. The proposed equations (hosted at www.nutrigroup-iats.org/aquafat ) were able to fit different proportions of EPA, DPA and DHA underlying the fish species differences in FA desaturation/elongation pathways. The robustness of the model was proven with extra data from the three fish species, allowing a close linear association near to equality for the scatter plot of observed and predicted values.  相似文献   

19.
During 2005 and 2010, a survey of edwardsiellosis on eight turbot, Scophthalmus maximus (L.), farms was conducted in China. This report presents the detailed results of the study on this disease. Diseased turbot displayed two distinct types of gross signs: black discoloration of the dorsal skin on the posterior portion of the body; and red cutaneous foci on the ventral side. Internally, the most pronounced clinical signs in all fish examined were enlarged kidneys. The causal agent of the disease was finally proved to be one species of bacterium that was identified as Edwardsiella tarda by physiological and biochemical tests, API 32E and 16S ribosomal RNA sequence analysis. It is noteworthy that unlike the commonly described E. tarda strains, the isolates in this study were non‐motile strains without flagella. A histopathological study revealed that E. tarda infection was systemic in turbot and that kidney showed the most significant pathological changes, including acute focal necrosis, an influx of macrophages and formation of granuloma. The most common histopathological characteristics of this disease are the proliferation of macrophage in various organs and formation of granuloma. In addition, this article also gave background information on the disease and presented the results of virulence tests with the E. tarda strain identified in this study.  相似文献   

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