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1.
The high phenotypic plasticity in the shell of oysters presents a challenge during taxonomic and phylogenetie studies of these economically important bivalves. However, because DNA can exhibit marked differences among morphologically similar species, DNA barcoding offers a potential means for oyster identification. We analyzed the complete sequences of the cytochrome oxidase subunit I （COI） of five common Crassostrea species in China （including Hong Kong oyster C. hongkongensis, Jinjiang oyster C. ariakensis, Portuguese oyster C. angulata, Kumamoto oyster C. sikamea, and Pacific oyster C. gigas） and screened for distinct fragments. Using these distinct fragments on a high-resolution melting analysis platform, we developed an identification method that does not rely on species-specific PCR or fragment length polymorphism and is efficient, reliable, and easy to visualize. Using a single pair of primers （Oyster- COI-1）, we were able to successfully distinguish among the five oyster species. This new method provides a simple and powerful tool for the identification of oyster species.  相似文献   

2.
A new enzyme (alkaline protease 894) obtained from the marine extremophile Flavobacterium yellowsea (YS-80-122) has exhibited strong substrate-binding and catalytic activity, even at low temperature, but the characteristics of the hydrolysis with this enzyme are still unclear. The pearl oyster Pinctada martensii was used in this study as the raw material to illustrate the kinetic properties of protease 894. After investigating the intrinsic relationship between the degree of hydrolysis and several factors, including initial reaction pH, temperature, substrate concentration, enzyme concentration, and hydrolysis time, the kinetics model was established. This study showed that the optimal conditions for the enzymatic hydrolysis were an initial reaction pH of 5.0, temperature of 30°C, substrate concentration of 10% (w/v), enzyme concentration of 2 500 U/g, and hydrolysis time of 160 min. The kinetic characteristics of the protease for the hydrolysis of P. martensii were obtained. The inactivation constant was found to be 15.16/min, and the average relative error between the derived kinetics model and the actual measurement was only 3.04%, which indicated a high degree of fitness. Therefore, this study provides a basis for the investigation of the concrete kinetic characteristics of the new protease, which has potential applications in the food industry.  相似文献   

3.
以近江牡蛎的担轮幼虫为材料,采用秋水仙素——低渗处理——空气干燥制片法制作染色体标本,对其核型进行分析,结果表明,近江牡蛎体细胞染色体数目2n=20,NF=40,核型公式为20m。  相似文献   

4.
studies have compared oyster reefs with adjacent natural shallow-water habitats.Here the resident benthic macroinvertebrate communities in an artificial oyster(Crassostrea ariakensis) reef and in adjacent natural estuarine shallow-water habitats(salt marsh,intertidal mudflat,and subtidal soft bottom) in the Changjiang(Yangtze) River estuary were described.The mean total densities and biomass,Margalef’s species richness,Pielou’s evenness and Shannon-Weaver biodiversity indices of the resident benthic macroinvertebrate communities differed significantly among the habitats.Significantly higher densities and biomass of benthic macroinvertebrates occurred in the oyster reef compared with the other three habitats.Ordination plots showed a clear separation in benthic macroinvertebrate communities among the four habitat types.The results demonstrated that the artificial oyster reef supported distinct and unique benthic communities,playing an important role in the complex estuarine habitat by supplying prey resources and contributing to biodiversity.In addition,the results suggested that the oyster reef had been restored successfully.  相似文献   

5.
A 9-week feeding trial was conducted to investigate the effects of dietary carbohydrate to lipid ratio(CHO:LIP) on the growth performance and feed utilization of juvenile turbot Scophthalmus maximus(initial body weight 8.75 g ± 0.04 g). Four isonitrogenous and isoenergetic low protein level(39%) diets were formulated with increasing ratios of dietary carbohydrate to lipid(2:18, 6:18, 18:12 and 28:6). A high protein level(50%) diet with the 2:12 ratio of carbohydrate to lipid was used as the control. Results showed that the survival rate, contents of moisture, crude protein and ash in muscle were not significantly affected by dietary treatments. With the dietary CHO:LIP ratio increased from 2:18 to 18:12, weight gain rate significantly increased(P < 0.05). Higher dietary CHO:LIP ratio(28:6) resulted in the significantly decreased weight gain rate(P < 0.05). Meanwhile, this treatment also resulted in the highest daily feed intake and liver glycogen content, as well as the lowest feed efficiency(P < 0.05). Muscle glycogen content in fish fed the diet with 2:12 or 2:18 CHO:LIP ratio was significantly lower than those fed with the other three diets(P < 0.05). The present results confirmed that the juvenile turbot can utilize carbohydrate. Furthermore, the appropriate ratio of dietary carbohydrate to lipid was important to the growth and feed utilization of turbot. The proper CHO:LIP ratio based on the growth performance in the present study was determined to be 18:12 when the dietary protein level was 39%.  相似文献   

6.
In this study, Pearl oyster mantle type V collagen(POMC) and tilapia scale type I collagen(TSC) were extracted and hydrolyzed by various proteases in order to obtain peptides. The antioxidant activity of the peptides was investigated by DPPH, hydroxyl radical scavenging experiments and a dynamic digestion model in vitro. The results show that there are significant differences in amino acid composition between POMC and TSC. The collagen peptides obtained from pearl oyster mantle(POMCP) by treating with alkaline protease exhibited higher antioxidant activity than that from tilapia scale(TSCP) treated with papaya protease, and both of them showed greater DPPH and hydroxyl radical scavenging activity than other peptides. After being separated via Sephadex G-25 chromatography, the M1 fraction isolated from POMCP, and the S1 fraction from TSCP with which both had higher molecular weights showed the strongest antioxidant activity than other fractions, and the M1 fraction exhibited stronger antioxidant activity than the S1 fraction in scavenging free-radicals and protecting cells from the oxidation damage. Furthermore, after treating the dynamic digestion system model in vitro, the DPPH and hydroxyl radical scavenging activity of the M1 fraction increased slightly. These results suggest that POMCP exhibits stronger antioxidant activity than TSCP, which means that PMOP may be a good candidate to be a potential natural antioxidant in the food-processing industry.  相似文献   

7.
The paper reviews the recent advances in studying grouper nutrition requirement for the development of cost-effective and environmentally friendly artificial diets. It consists of seven parts: protein and amino acid, lipid and essential fatty acid, carbohydrate, vitamin, mineral, alternative protein source, broodstock and larval nutrition. The review provides some basic information for further investigation of nutrient requirements of groupers.  相似文献   

8.
The paper reviews the recent advances in studying grouper nutrition requirement for the development of cost-effective and environmentally friendly artificial diets. It consists of seven parts: protein and amino acid, lipid and essential fatty acid, carbohydrate, vitamin, mineral, alternative protein source, broodstock and larval nutrition. The review provides some basic information for further investigation of nutrient requirements of groupers.  相似文献   

9.
1　Introduction　Chinaisboththelargestproducerandthelargestconsumerofchemicalfertilizersintheworld .Since1984 ,Chineseconsumptionofchemicalfertilizerhasincreasedmorethanonetimes ,fromabout 17millionmetrictonsto 35millionmetrictons .However ,dur ingthesameperiod ,theyieldoffoodproductionhasincreasedonlyabout 10 % .Thediscrepancybetweenfertilizerconsumptionandyieldincreasehasindicatedthedrasticdecreaseofthebenefitsofchemicalfertiliz ers .Infact ,theutilizationefficiencyofnitrogenfer tilizerinC…  相似文献   

10.
Mass selection for fast growth was conducted in three Pacific oyster (Crassostrea gigas) stocks from China, Japan and Korea using previously established lines (CS1, JS1, and KS1). To determine whether continuous progress can be achieved by selection for growth, the progeny of three second-generation Pacific oyster lines was selected for shell height and evaluated via a 400-day farming experiment. When harvested at the end of the experiment, the selected crosses of CS2, JS2, and KS2 lines grew by 9.2%, 10.2% and 9.6% larger than the control crosses, respectively. During grow-out stage, the genetic gain of three selected lines was (10.2 ± 1.4)%, (10.4 ± 0.3)%, and (8.4 ± 1.6)%, respectively; and the corresponding realized heritability was 0.457 ± 0.143, 0.312 ± 0.071 and 0.332 ± 0.009, respectively. These results indicated that the selection for fast growth achieved steady progress in the second generation of oyster. Our work provides supportive evidence for the continuity of the Pacific oyster selective breeding program.  相似文献   

11.
Linkage disequilibrium (LD) can be applied for mapping the actual genes responsible for variation of economically important traits through association mapping. The feasibility and efficacy of association studies are strongly dependent on the extent of LD which determines the number and density of markers in the studied population, as well as the experimental design for an association analysis. In this study, we first characterized the extent of LD in a wild population and a cultured mass-selected line of Pacific oyster (Crassostrea gigas). A total of 88 wild and 96 cultured individuals were selected to assess the level of genome-wide LD with 53 microsatellites, respectively. For syntenic marker pairs, no significant association was observed in the wild population; however, three significant associations occurred in the cultured population, and the significant LD extended up to 12.7 cM, indicating that strong artificial selection is a key force for substantial increase of genome-wide LD in cultured population. The difference of LD between wild and cultured populations showed that association studies in Pacific oyster can be achieved with reasonable marker densities at a relatively low cost by choosing an association mapping population. Furthermore, the frequent occurrence of LD between non-syntenic loci and rare alleles encourages the joint application of linkage analysis and LD mapping when mapping genes in oyster. The information on the linkage disequilibrium in the cultured population is useful for future association mapping in oyster.  相似文献   

12.
The complexity and diversity of peptide mixture from protein hydrolysates make their characterization difficult. In this study, a method combining nano LC-MS/MS with molecular docking was applied to identifying and characterizing a peptide with angiotensin-? converting enzyme (ACE-I) inhibiting activity from Venerupis philippinarum hydrolysate. Firstly, ethanol supernatant of V. philippinarum hydrolysate was separated into active fractions with chromatographic methods such as ion-exchange chromatography and high performance liquid chromatography in combination. Then seven peptides from active fraction were identified according to the searching result of the MS/MS spectra against protein databases. Peptides were synthesized and subjected to ACE-I-inhibition assay. The peptide NTLTLIDTGIGMTK showed the highest potency with an IC50 of 5.75 μmol L?1. The molecular docking analysis showed that the ACE-I inhibiting peptide NTLTLIDTGIGMTK bond with residues Glu123, Glu403, Arg522, Glu376, Gln281 and Asn285 of ACE-I. Therefore, active peptides could be identified with the present method rather than the traditional purification and identification strategies. It may also be feasible to identify other food-derived peptides which target other enzymes and receptors with the method developed in this study.  相似文献   

13.
Marine organisms constitute unlimited resource of bioactive substances due to their high biodiversity and represent a valuable source of new compounds. This study optimized the alkali-extraction conditions and antioxidant activities of soluble polysaccharides from the body wall of Sipunculus nudus. The effects of solid-liquid ratio, extraction duration, extraction temperature, and alkali concentration on the yield of S. nudus polysaccharides (SNP) were examined, according to which the optimal combination of extraction parameters was obtained by an orthogonal test. The relative influencing importance of different extraction parameters on the yield of SNP followed the order as solid-liquid ratio > extraction temperature > alkali concentration > extraction duration. The highest extraction yield, 1.98%, was achieved under an optimal extraction condition: temperature 60°C, solid-liquid ratio 1:6 g mL?1, duration 5 h, and alkali (NaOH) mass fraction 6%. The in vitro antioxidant activities examination showed that extracted SNP under this optimized condition had strong power in reducing certain hydroxyl and superoxide radical scavenging abilities. The promising results showed that extracted SNP could be a potent natural antioxidant.  相似文献   

14.
Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding programs in China were examined at ten polymorphic microsatellite loci to assess the level of allelic diversity and estimate the effective population size. These data were compared with those of their base population. The results showed that the genetic variation of the four generations were maintained at high levels with an average allelic richness of 18.8–20.6, and a mean expected heterozygosity of 0.902–0.921. They were not reduced compared with those of their base population. Estimated effective population sizes based on temporal variances in microsatellite frequencies were smaller to that of sex ratio-corrected broodstock count estimates. Using a relatively large number of broodstock and keeping an equal sex ratio in the broodstock each generation may have contributed to retaining the original genetic diversity and maintaining relatively large effective population size. The results obtained in this study showed that the genetic variation was not affected greatly by mass selection progress and high genetic variation still existed in the mass selection lines, suggesting that there is still potential for increasing the gains in future generations of C. gigas. The present study provided important information for future genetic improvement by selective breeding, and for the design of suitable management guidelines for genetic breeding of C. gigas.  相似文献   

15.
The present study was conducted to evaluate the feasibility of replacing fish meal (FM) with bioactive peptides (BPs) in diet of white shrimp (Litopenaeus vannamei). The changes in growth performance, body composition, non-specific immunity, and water quality were examined after the shrimp were fed four diets, in which 0% (control), 33.3%, 66.7% and 100% of FM was replaced by BPs, respectively. The groups were designated as Con, 1/3BPs, 2/3BPs, and 3/3BPs. A total of 720 shrimp with an initial body weight of 1.46 ± 0.78 g were fed the experimental diets for 56 days. The results revealed that: 1) the weight gain rate (WGR) in 1/3BPs, 2/3BPs, and 3/3BPs was significantly higher than that in Con (P < 0.05), while no significant difference was found on survival rate and feed conversion ratio (FCR); 2) the whole-body crude protein (CP) and crude lipids (CL) were significantly different among groups, while there was no significant difference between crude ash and phosphorus contents; 3) the levels of acid phosphatase (ACP), lysozyme (LZM), superoxide dismutase (SOD), phenol oxidase (PO) and bactericidal activity increased significantly with the inclusion of BPs; 4) in terms of water quality, no significant difference was found in pH and dissolved oxygen among diets during the whole experimental period. Moreover, even though nitrite and ammonium levels tended to increase with time, there was no significant difference among groups. The results indicated that BPs is an applicable alternative of protein source, which can substitute FM in the diets of L. vannamei; it is able to effectively promote growth performance and improve immunity. Moreover, BPs in the diets had no negative impact on water quality.  相似文献   

16.
Palm oil is of great potential as one of the sustainable alternatives to fish oil (FO) in aquafeeds. In this present study, five isonitrogenous diets (32% crude protein) with elevated palm oil levels of 0%, 2%, 4%, 6% and 8% were used during an 8-week feeding trial to evaluate its effects on RNA/DNA ratio and lipoprotein lipase (LPL) and MyoD mRNA expressions in muscle of Oreochromis niloticus. The results showed that RNA, DNA content as well as ratio of RNA to DNA were significantly affected (P < 0.05), in each case the highest was recorded in fish group subjected to 6% palm oil level. There was a strong positive correlation between nucleic acid concentration (RNA concentration and RNA: DNA ratio) and specific growth rate (SGR), protein efficiency ratio (PER), while a negative correlation existed between nucleic acid concentration (RNA concentration and RNA: DNA ratio) and feed conversion ratio (FCR). The mRNA expressions of LPL and MyoD in muscle were not significantly affected by the different palm oil levels, although the highest expression was observed in fish fed with 6% palm oil level. There also existed a strong positive correlation between the mRNA expression of LPL, MyoD and SGR, PER, while their correlation with FCR was negative. In conclusion, elevated palm oil affected the RNA, DNA concentration as well as RNA/DNA ratio significantly, although the mRNA expression of LPL and MyoD were not affected significantly by elevated palm oil levels.  相似文献   

17.
An artificial oyster shell reef was deployed in Rongcheng Bay, East China. However, the effects of this reef on the surrounding macrobenthic communities were unknown. We compared sedimentary factors, macrobenthic biomass, abundance, and community composition and ecological indicators between the reef and non-reef areas over a one year period. The mean values for chlorophyll a （Chl a）, total organic matter （TOM）, total organic carbon （TOC）, and total nitrogen （TN） content in surface sediments in the reef area were slightly higher than those in the non-reef area. The Chl a levels differed significantly between the two areas, but the TOM, TOC, and TN were not significantly different. The abundance of crustaceans was significantly different between the two areas, but the abundance and biomass ofpolychaetes, echinoderms, mollusk did not differ significantly. The permutational multivariate analysis of variance （PERMANOVA） revealed that the macrobenthic community differed significantly through time and analysis of similarity multivariate analyses （ANOSIM） revealed that the macrobenthic community differed significantly in some months. The ecological indicators revealed that the environmental quality of the reef area was slightly better than that of the non-reef area. Overall, our results suggest that the artificial oyster shell reef may change the macrobenthic community and the quality of the environment. Despite the lack of an effect in the short term, long-term monitoring is still needed to evaluate the effects of artificial oyster shell reefs on macrobenthic communities.  相似文献   

18.
Chromosome constitution was investigated in adult tetraploid Pacific oyster produced by blocking the first polar body of triploid eggs which were fertilized with haploid sperms. A high incidence of aneuploid and heteroploid mosaics were found among the offspring. Of 20 individuals identified, only 9 (45%) were eutetraploid which contained 40 chromosomes; 2 (10%) were aneuploid (hypotetraploid), which contained 39 and 38 chromosomes, respectively; and 9 (45%) were heteroploid mosaics. One mosaic was consisted of cells containing 40 and 39 chromosomes, respectiovely (1:1 in cell number), while the other 8 were consisted of cells containing chromosomes varying between tetraploid and triploid. It was also interesting to note that 3 mosaics even contained some diploid cells with 20 chromosomes. A certain number of cells of 2 tetraploids and 8 mosaics spread with 32–37 well-scattered and some clumped chromosomes at metaphase. The percentage of aneuploid cells with chromosomes varying between triploid and tetraploid correlated significantly with that of heteroploid mosaics cells with clumping chromosomes (P<0.05). Our findings suggested that reversion existed in both tetraploid and triploid oyster and chromosome clumping may underline the chromosome elimination in tetraploid oyster. It seems that the reversing cells, at least some of them, continuously eliminate their chromosomes until the most stable diploid state is established.  相似文献   

19.
Microsatellites are a ubiquitous component of the eukaryote genome and constitute one of the most popular sources of molecular markers for genetic studies. However, no data are currently available regarding microsatellites across the entire genome in oysters, despite their importance to the aquaculture industry. We present the fi rst genome-wide investigation of microsatellites in the Pacifi c oyster Crassostrea gigas by analysis of the complete genome, resequencing, and expression data. The Pacifi c oyster genome is rich in microsatellites. A total of 604 653 repeats were identifi ed, in average of one locus per 815 base pairs(bp). A total of 12 836 genes had coding repeats, and 7 332 were expressed normally, including genes with a wide range of molecular functions. Compared with 20 different species of animals, microsatellites in the oyster genome typically exhibited 1) an intermediate overall frequency; 2) relatively uniform contents of(A)n and(C)n repeats and abundant long(C)n repeats(≥24 bp); 3) large average length of(AG)n repeats; and 4) scarcity of trinucleotide repeats. The microsatellite-fl anking regions exhibited a high degree of polymorphism with a heterozygosity rate of around 2.0%, but there was no correlation between heterozygosity and microsatellite abundance. A total of 19 462 polymorphic microsatellites were discovered, and dinucleotide repeats were the most active, with over 26% of loci found to harbor allelic variations. In all, 7 451 loci with high potential for marker development were identifi ed. Better knowledge of the microsatellites in the oyster genome will provide information for the future design of a wide range of molecular markers and contribute to further advancements in the fi eld of oyster genetics, particularly for molecular-based selection and breeding.  相似文献   

20.
There is an increasing requirement for traceability of aquaculture products, both for consumer protection and for food safety. There are high error rates in the conventional traceability systems depending on physical labels. Genetic traceability technique depending on DNA-based tracking system can overcome this problem. Genealogy information is essential for genetic traceability, and microsatellite DNA marker is a good choice for pedigree analysis. As increasing genotyping throughput of microsatellites, microsatellite multiplex PCR has become a fast and cost-effective technique. As a commercially important cultured aquatic species, Pacific oyster Crassostrea gigas has the highest global production. The objective of this study was to develop microsatellite multiplex PCR panels with dye-labeled universal primer for pedigree analysis in C. gigas, and these multiplex PCRs were validated using 12 full-sib families with known pedigrees. Here we developed six informative multiplex PCRs using 18 genomic microsatellites in C. gigas. Each multiplex panel contained a single universal primer M13(?21) used as a tail on each locus-specific forward primer and a single universal primer M13(?21) labeled with fluorophores. The polymorphisms of the markers were moderate, with an average of 10.3 alleles per locus and average polymorphic information content of 0.740. The observed heterozygosity per locus ranged from 0.492 to 0.822. Cervus simulations revealed that the six panels would still be of great value when massive families were analysed. Pedigree analysis of real offspring demonstrated that 100% of the offspring were unambiguously allocated to their parents when two multiplex PCRs were used. The six sets of multiplex PCRs can be an important tool for tracing cultured individuals, population genetic analysis, and selective breeding program in C. gigas.  相似文献   

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