Abstract:The swordtip squid is one of the important economic squid resources in the East China Sea. Studying the composition, age, and growth pattern of its spawning population is the basis for understanding its life history. Based on the samples of the East China Sea swordtip squid collected from the trawl nets in September and February of 2017 and 2018, this study used the age information of otoliths to study the sex and year differences in population composition and growth patterns. The results showed that there were differences in population mantle length and body weight composition between years, but there was no significant difference between genders (P> 0.05). It was found by reading the age of otoliths and performing inverse calculation that the two-year dominant day-age group was 190-220d, and there were significant differences in age composition of male during the year (P <0.05). The inverse calculation results showed that the peak hatching period was from March to May and August. The spring and summer spawning groups are the dominant hatching groups. The mantle length and body weight growth of the spawning group in spring were best fitted with a logistic curve, and the spawning group in summer were best fitted with a Von-Bertanffy and a logistic curve. In 180-270d, the mantle length and body weight growth rate of spring spawning group was faster than that of summer spawning group. After 240d, the male mantle growth rate was faster than that of female, and the body weight growth rate was slower than that of female. The age of the 50% maturity of the spawning population in spring is younger than that of the summer spawning group, and male individual is younger than the female. According to comprehensive analysis, the growth differences of different spawning groups may be related to the environmental factors and growth mechanisms of the habitated sea areas. Therefore, Reveal the age and growth of the population through the otolith age information, and provide basic data for a comprehensive understanding of the life history characteristics of the swordtip squid.

Abstract:Abstract: This study intended to explore the effects of different levels of lysine in feed on the growth performance, body composition and blood indices of Pacific white shrimp Litopenaeus vannamei after replacing fish meal with fermented soybean meal at an optimal level, and to estimate the optimal dietary lysine requirement of juvenile Pacific white shrimp. Five isonitrogenous and isolipidic practical diets(containing 41.5% crude protein and 7.5% crude lipid) were formulated with dietary supplemental lysine levels of 0, 0.25%, 0.50%, 0.75% and 1.00%, and the measured values of dietary lysine contents were 2.43%, 2.65%, 2.87%, 3.06%, 3.24%, which were recorded as Lys0, Lys25, Lys50, Lys75, Lys100. The Pacific white shrimp with an average initial body weight about (2.0±0.1g) was randomly divided into 5 groups with 3 replicates per group and 50 shrimp per replicate. The feeding experiment lasted for 56 days in indoor cement pools. The results showed that: With the increase of feed lysine level, the weight gain rate and specific growth rate increased first and then decreased, reaching the highest in the Lys75 group with the lowest feed conversion ratio (P<0.05). The survival rate was not affected by feed lysine level (P>0.05). Muscle in Lys75 group had the highest crude protein and crude fat content, while crude ash and moisture content were not affected by feed lysine level (P>0.05). A variety of essential and non-essential amino acids in the muscle showed a trend of first increasing and then decreasing with the increase of feed lysine level. The turning point was in the Lys50 or Lys75 group. With the increase of feed lysine level, the activities of alanine aminotransferase and aspartate aminotransferase in serum increased first and then decreased, while the triglyceride content gradually increased, and the superoxide dismutase activity of Lys75 group was significantly lower than the other four groups (P<0.05). Based on the quadratic regression model of SGR and FCR with dietary lysine content, The optimal lysine requirements of Litopenaeus vannamei were 2.88% (6.94% of dietary crude protein) and 2.89% (6.96% of dietary crude protein) respectively.

Abstract:The purpose of this study was to investigate the effects of four common sugar sources on the growth, digestive enzymes and intestinal flora of Litopenaeus vannamei.Chosen the weight of Litopenaeus vannamei was (0.36±0.02)g.Four kinds of common sugars(glucose, fructose, starch and sucrose)were selected from a variety of sugars as the sugar source to prepare the feed. Four treatments were carried out in total, three replicates for each treatment, 40 prawns for each repetition. The breeding period was 56 days, and the added amount of each sugar source was 20%.The test results show that:(1)The specific growth rate and protein efficiency of Litopenaeus vannamei were significantly different (P<0.05), the starch group was significantly higher than the other three groups (P<0.05), but there was no significant difference in the liver body ratio and the meat content rate between the groups (P>0.05).The whole body nutrition of shrimp,the CF of sucrose group was significantly lower than the other three groups (P<0.05), the ash of glucose group was significantly higher than the other three groups (P<0.05), and there was no significant difference between CP and Moisture (P>0.05).(2)There were significant differences in digestive enzyme activities among different groups of prawn(P<0.05),the activity of lipase in starch group and sucrose group was significantly higher than that in glucose group and fructose group (P<0.05). There was no significant difference between starch group and sucrose group (P>0.05), while the activity of pepsin in in starch group was significantly higher than that in other three groups (P<0.05).(3)There was no significant difference in OTU, ACE and Chao index among the groups (P>0.05), Shannon index starch group and sucrose group were significantly higher than glucose group, Simpson index starch group was significantly lower than sucrose group, and sucrose group was significantly lower than glucose group (P<0.05).On the level of phylum, the relative abundance of Proteobacteria in sucrose group was significantly higher than that in glucose group, while that in Bacteroides and actinomycetes in starch group was significantly higher than that in glucose group, but there was no significant difference between the groups.At the class level, there was significant difference in the intestinal microflora of prawn between the treatment groups. The Yellow bacilli,γ-Proteus, actinomycetes and fibrinophages in the intestinal tract of prawn in starch group were significantly higher than those in sucrose group and glucose group.In summary,the absorption and utilization of starch and sucrose by Litopenaeus vannamei is better than that of glucose and fructose. Meanwhile, starch and sucrose have certain influence on the diversity of intestinal flora of Litopenaeus vannamei. Starch and sucrose are the suitable sugar sources in Litopenaeus vannamei feed.

Abstract:Flavobacterium psychrophilum mainly infects salmonids and can cause bacterial cold water disease (BCWD), which usually occurs under low temperature conditions and has a high mortality rate, seriously limiting the healthy development of the salmonid aquaculture industry in China. In this experiment, two pathogenic bacterial strains (CH06 and CH07) were isolated from the muscle lesions of diseased rainbow trout (Oncorhynchus mykiss), and their biochemical characteristics, molecular characteristics, genotypes, serotypes, drug resistance and pathogenicity were analyzed. The results showed that CH06 and CH07 isolates were highly pathogenic to juvenile rainbow trout with the LD₅₀ values of 7.1 × 10^₅ and 1.1 × 10^₅ CFU / mL, respectively. The dosage of the challenge was inversely proportional to the time when the clinical signs appeared. CH06 and CH07 isolates had an egg-like appearance on TYES agar, produced flexirubin-like pigments, and were positive for oxidase and catalase. It can hydrolyze gelatin and casein, cannot hydrolyze starch or use fructose, galactose and esculin. The results of 16S rRNA gene alignment suggested that the homology of CH06 and CH07 isolates with the Flavobacterium psychrophilum reference strain NBRC15942 strain were 99.35% and 99.42%, respectively. Based on the biochemical and molecular characteristics results, CH06 and CH07 isolates were identified as Flavobacterium psychrophilum. The multiplex PCR method was used to identify the serotypes of CH06 and CH07 isolates as type 1 (Fd type). MLST analysis indicated that the genotypes of CH06 and CH07 isolates were ST-12 and ST-78, respectively. CH06 and CH07 isolates exhibited slightly different resistance profiles to 10 antibacterial drugs. They were both highly susceptible to ampicillin and trimethoprim-sulfamethoxazole, while CH06 isolate was reduced susceptible to enrofloxacin and florfenicol and CH07 isolate was moderately susceptible to enrofloxacin and florfenicol. Histopathological changes showed that the hepatocytes of the diseased fish were swollen and vacuoles degenerated. Some hepatocytes were lysed and necrotic and the nucleus was dissolved. The spleen was congested and hemorrhagic with reduced amounts of the lymphocytes and increased amounts of the red blood cells and the hemosiderin. The muscle fiber gap was widened and broken, uneven bending. Parts of the muscle cell sarcoplasmic dissolution was honeycomb-like. For the first time, this experiment detected Flavobacterium psychrophilum from domestically cultured rainbow trout, and this initial study on the taxonomic status, pathogenicity and drug resistance of the pathogens were expected to provide a scientific basis for the prevention and control of bacterial cold water disease in rainbow trout.

Abstract:In order to explore the role of miR-137 in the color formation of koi, the precursor sequences of miR-137 in 14 fish species were aligned and constructed phylogenetic tree by maximum likelihood (ML). Besides, The expression levels of miR-137 in different developmental stages and tissues also detected. Then, the target genes of miR-137 was predicted and analyzed by GO and KEGG analysis. In addtion, the luciferase reporter was used to verify the availability of miR-137 with its targets, and the expression levels of miR-137 and target genes in different development stages and tissues were checked and the correlation analysis between them was also conducted. The results showed that the precursor sequence similarity of miR-137 between koi and carp was the highest, and miR-137 sequences exhibited high conservation among all fish species. A great number of predicted target genes enriched in melanogenesis, pigment cell differentiation, pteridine-containing compound metabolic process and so on. Real time PCR results showed the expression of miR-137-3p climbed the peak on 11 dph and rapidly dicreased in the following stage. miR-137 was expressed in kinds of tissues, especially significant in eye and muscle. Besides, the skin and fins, the pigment cell enriched tissues, also had a higher expression and the expression of miR-137 in white tissues was higher than the red. The luciferase reporter analysis certified that miR-137 bound with the mitfa 3＇-UTR to inhibit its expression but did not appeared significant inhibitory effect on sprb, and miR-137 was negatively correlated with the expression of mitfa and sprb in different developmental stages, but not in tissues. All the above results confirmed miR-137 was highly conserved during fish species evolution and displayed correlation with the koi color formation, in which miR-137 might regulate mitfa involving in the body color formation. This study provides basic research data for further exploring the role of miR-137 in koi color formation.

Abstract:In order to determine the pathogenicity of Anguillid herpesvirus (AngHV), an AngHV strain, NA16108, isolated from “mucus sloughing and hemorrhagic septicemia disease” samples was used to study its pathogenesis to juvenile European eel, Anguilla Anguilla. The results showed that the body surface of the AngHV-injected A. anguilla had the symptoms of mucus exfoliation, fin hemorrhages, red head, etc. The diseased A. anguilla had pathological changes of mucus increase and hemorrhages of gill, discoloration of liver and swelling of spleen and kidney, etc. Further histopathological analysis showed that the skin had exfoliation of mucus and mucosa flat epithelial cells, gill had secondary lamellar hyperplasia, blood vessel hemorrhages, swelling and necrosis of respiratory cells, spleen had necrosis and aggregation of melanocytes, and kidney had necrosis wall cells and narrowing lumen of renal tubular, which are consistent with the clinical characteristics of A. anguilla "mucus sloughing and hemorrhagic septicemia disease". The mortality analysis showed that AngHV infected A. anguilla began to die from the 4th day post injection, and the cumulative mortality on the 7th and 14th day reached up to 26.7% and 56.7%, respectively. Quantitative real-time PCR analysis showed that AngHV could be detected in the liver, spleen, kidney, intestine, gill and skin mucus of AngHV infected A. anguilla, and AngHV could be re-isolated by EO cell line from the main internal organs, which indicating that the A. anguilla had a systemic infection of AngHV. The results indicated that AngHV is the pathogenic agent of "mucus sloughing and hemorrhagic septicemia disease", which laid an important foundation for further study on the pathogenesis and prevention and control of the disease.

Abstract:In order to study the regulation of autophagy-related gene 13 (ATG13) and ATG101 in Macrobrachium nipponense under hypoxia stress, the full-length cDNA sequences of ATG13 and ATG101 of M. nipponense were cloned for the first time by RACE PCR through cloning, expounds the cell autophagy genes ATG13 cDNA 2 043 bp (NCBI login id: MT084347), including 211 bp 5' untranslated regions (UTR), 449 bp 3' UTR and 1 383 bp open reading frame (ORF), which encodes 460 amino acids; ATG101 cDNA is 1 051 bp long (NCBI login id: MT084348), including the 5' terminal non-translation region of 18 bp, the 3' UTR of 373 bp and the open reading frame of 660 bp. The open reading frame encodes 219 amino acids. Based on bioinformatics analysis, the amino acid similarity ratio showed that the autophagy gene ATG13 of the biogas shrimp was rich in highly conserved LC3 functional domain (LIR). Phylogenetic tree analysis showed that the ATG13 gene of M. nipponense was closely related to the autophagy related genes of Penaeus vannamei. The results showed that ATG13 and ATG101 were highly expressed in hepatopancreas and brain tissues, but low in muscles. The difference of ATG13 and ATG101 expression in hepatopancreas tissues under hypoxia stress was tracked by real-time fluorescence quantitative PCR (qRT-PCR). The expression of ATG13 and ATG101 in the experimental group was significantly higher than that in the control group at 6h and 12h, but there was no significant difference between the experimental group and the control group at 12 h after the recovery of normoxia, which were similar with M. nipponense TAG13 and ATG101 protein expression abundance using western blot. The results of ultrastructure observation by transmission electron microscope (TEM) showed that autophagic vacuoles began to appear in lysosomes of hepatopancreas after 6 h and 24 h of hypoxia, suggesting that acute hypoxic stress could induce the formation of autophagosomes. The results of this study may provide a theoretical reference for understanding the regulatory mechanism of M. nipponense in response to hypoxic stress.

Abstract:Litopenaeus vannamei is the largest economic shrimp breed in the world at present. However, with the expansion of shrimp culture, diseases and other problems are exposed gradually. Shrimp culture industry was affected seriously by diseases all over the world. Shrimp belongs to invertebrate, and has no typical acquired immune system. They mainly rely on the innate immune system for defense and protection when pathogens invade. In innate immune response, crustaceans recognize non-self components through pattern recognition receptors (PRRs). The components recognized by PRRs are mainly constitutive and conserved polysaccharide molecules on the surface of microorganisms, which are not produced by eukaryotic cell hosts and are necessary for the survival of pathogenic microorganisms. They are called pathogen associated molecular patterns (PAMPs). The recognition and binding of PRRs to PAMPs is the beginning of humoral immunity. The recognition of PRRS to pathogens can directly or indirectly activate proteases, hemocytes and intracellular signal pathways related to humoral immunity. A variety of immune defense reactions were triggered. It produce antibacterial substances and effective molecules to inhibit and eliminate pathogens. As a pattern recognition receptor and terminal effector, C-type lectin participates in the process of “non self” recognition and elimination of invasive pathogens, which is crucial in the innate immune defense mechanism of crustaceans. In this study, a novel C-type lectin gene (LvLc2, GenBank accession number: KR020738) was cloned from hemocytes of Litopenaeus vannamei according to our previous transcriptome results. Bioinformatics analysis showed that the ORF region of LvLc2 gene was 465 bp encoding 154 aa with 11 bp 5'-UTR and 126 bp 3'-UTR. The predicted molecular weight was 17.16 ku and the theoretical isoelectric point was 4.54. The deduced amino acid sequence contained a signal peptide sequence with 17 amino acids at the amino end and a conserved carbohydrate recognition domain (CRD) at the carboxyl end. LvLc2 gene was expressed in different tissues of L. vannamei. The main expression was in intestine, followed by stomach, hepatopancrease, hemocytes, and the lowest expression level was in muscle. After shrimps were challenged by LPS and PGN, the expression profiles of LvLc2 gene were analyzed by qPCR. Different pathogen-associated molecular patterns (PAMP) could induce response changes of LvLc2 gene after stimulation, which indicated that it had a potential broad-spectrum response pattern. At the same time, it had different expression profiles for different pathogens, which showed the differences of recognition, combination and indirect immune effects. The research of its characterization and function are helpful to better understand the mechanism of shrimp C-type lectin during the process of pathogen infection.

Abstract:To explore mechanism and feasibility of “lock in freshness” of farmed fish chilled products, Takifugu rubripes farmed was taken as raw material. The experiment is performed in two post mortem stages, including a quality determination period（QDP）corresponding to on-site handling and post quality determination period (P-QDP）corresponding to the ice storage. The delayed effect of the QDP chilling treatment on the P-QDP was investigated. On-site handling were carried out using humane slaughter followed by instant bleeding in -1℃ sea water with 20 minutes, gutted and rinsed fish were individually wrapped and storaged with flake ice surrendered. Meanwhile, the Control group as chilling-free was compared to the Treatment group with chilling at the QDP. The chilled Takifugu rubripes postmortem biochemical metabolism was measured by rigor index, pH, lactic acid content, ATP and ATP-related compounds and K-Value. Meanwhile, the quality was performed and analyzed by muscle ultrastructural changes in two treatments. Result showed that Treatment temperature after chilling in quality determination period dropped rapidly from 10.9℃ to 2.7℃ in 20 minutes, which has a significantly effective of chilling. Treatment temperature was increased dramatically from 2.7℃ to 8.5℃ in 1 hour because of the special strengthening washing body process of Takifugu rubripes after processed. And the fish temperature was reduced to 0.5℃ after 12h iced storage. The delayed effect of the QDP chilling treatment on the P-QDP can be clearly observed by the muscle ultrastructural. Regardless of the Treatment or the Control, in subsequent chilling storage, muscle tissue degraded gradually. Notable, distinct difference can be observed between the Treatment and the Control. The phenomenon of cell structure degraded of the Control was occurred compared with the Treatment in day 0. And intermyofibrillar spaces increased were occurred. Sarcomeres were non-parallel and swollen sarcoplasmic reticulum was obviously. Especially in day 4, sarcomeres were altered significant, mainly at the Z-line and I-band level disruptions. Structure was obscured and destroyed more significantly than the Treatment. But the results showed that traditional biochemical indictors could not be detected sensitive difference of the two treatments. The Treatment biochemical metabolism rate was keep pace with the Control: the rigor mortis progression was similar and rigor state was maintained 4-5 days. Lactate acid, pH, nucleotide metabolism rate and K-value had no significant difference, and K-value was 15% in 8th chilling storage. In conclusion, there was a quality determination period after fish captured, which had the delayed effect of chilled fish quality on the post quality determination period. The degradation of muscle cell could be prolonged by QDP-chilling, which had significant effect of “lock in freshness” on quality of chilled fish. In this way, the image of seafood quality of domestic fisheries could be improved fundamentally, providing significant practical value in China.

Abstract:In order to explore the changes in protein expression of large yellow croaker under high temperature stress, tandem mass tag（TMT）combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to perform proteome analysis on the liver tissues between the high temperature tolerance group and the high temperature sensitive group of large yellow croaker. A total of 3 369 proteins were identified, of which 687 were differentially expressed proteins, including 281 up-regulated proteins and 406 down-regulated proteins. 13 randomly selected proteins were validated with parallel reaction monitoring (PRM) assays, which showed that they were consistent with the TMT-labeled proteome analysis results. Subsequently，through bioinformatics analysis and found that high temperature stress has a significant impact on the protein folding and energy metabolism of large yellow croaker. Among them, heat shock proteins 70, calreticulin, glucose-regulated protein and pyruvate kinase play an important role in the response to high temperature stress, This study is helpful to further analyze the high temperature adaptation mechanism of large yellow croaker, and provides reference for breeding high temperature resistant species of large yellow croaker.

Abstract:The study of the relationship between fishery organisms and water temperature is an important part of fishery scientific research, and the analysis of the suitable water temperature range of fish is an important aspect of this content. In this study, based on the distribution data of hairtail resources obtained from a large-scale survey in four quarters from 2014 to 2015, the water temperature range analysis method was improved on the basis of previous studies to avoid some subjective factors in the analysis. a new biological subject temperature range analysis method is created and compared with the traditional frequency method and the previous biological subject method. The results show that the proportion of sites covered by the frequency method is relatively good, but the biomass coverage rate is relatively poor; in the previous biological main body method, the cumulative biomass coverage rate was the highest, and the site coverage rate was also relatively good. the disadvantage is that there are many subjective factors added in the operation process, and the distribution range is discontinuous and contains individual narrow range. In the new method, because its temperature range is relatively concentrated and short, the coverage of the site and biomass is not very high, but the biomass density in the determined temperature range is the highest, and the minimum range which can accommodate the most biomass is found. and the distribution range is continuously concentrated. The characteristics of the biological spatial distribution will directly affect the results of the temperature range analysis method, for example, the aggregation degree of the spatial distribution of the belt fish is obviously lower than that of the small yellow croaker, that is, the spatial distribution of the belt fish is relatively uniform. as a result, one of the branches of the frequency distribution is consistent with its biological main body distribution, while the small yellow croaker has no such results, and there is a great difference between its frequency distribution and biomass distribution. The analysis also found that the populations with higher biomass are generally distributed in the waters with higher water temperature, which may be related to the good nutritional status of the population and the demand for rapid growth. The uneven distribution and aggregation in biological space may be related to the food needs and predation characteristics of species. According to the temporal and spatial distribution characteristics of the high biomass population of hairtail, it is analyzed and inferred that the population may correspond to the reproductive fish schools of spring and summer and autumn.

Abstract:The rheotaxis behaviour and Swimming metabolic characteristics of three familiar species of fish (Carassius auratus, Siniperca knerii, Tachysurus fulvidraco) from Yuanshui River by hydropower cascade development were tested using self-manufactured fish swimming ability and metabolic apparatus by adjusting water velocity on the laboratory. The results showed that The relative induction velocity of Carassius auratus, Siniperca knerii, and Tachysurus fulvidraco were, respectively, 0.79±0.14BL/s,1.16±0.07BL/s and 0.75±0.09BL/s. The relative preferred velocity of the three fish were, respectively, 2.31±0.11BL/s,1.86±0.04BL/s and 1.60±0.03BL/s.The critical swimming speed were respectively, 3.43±0.37BL/s, 2.58±0.32BL/s and 2.68±0.13BL/s. The relative preferred velocity, critical swimming speed , RF (respiratory frequency)and OCR(oxygen consumption rate) of Tachysurus fulvidraco were significantly lower than those of the two other fish (P < 0.05). At different flow rates, the RF, TBF(tail beat frequency) and OCR of the three species of fish all showed the same trend of first increasing and then decreasing. With the increase of flow rate, the RF of all fishes had peak value at the flow rate of 3BL/s. Carassius auratus and Siniperca knerii had the highest TBF and OCR value in 2 BL/s group, while that of Tachysurus fulvidraco was in 1.5 BL/s group. The rheotaxis rate of Carassius auratus increased from 64.1% in the static water group to 100% in 4 BL/s group, while that of Siniperca knerii and Tachysurus fulvidraco increased from 60.2% and 58.9% in the static water group to 100% in 2-3 BL/s groups. The swimming states of the three species of fish were obviously affected by the current velocity. In the static water group, the swimming states of Carassius auratus were mainly in “moving forward against the current” and “downstream”,while Siniperca knerii in static water group and most of the flow rates groups were in fixed station against the current. Tachysurus fulvidraco in static water group and lower flow rates groups （<1BL/s）were also mainly in fixed station against the current. With the increase of the current velocity, the proportion of fixed station against the current greatly decreased, while that of “moving backward against the current ” increased. The results provided the reference on the environment adaptability and evolution of movement modes of fish from Yuanshui River by the cascade hydropower development.

Abstract:Shell and pearl are highly ordered biominerals formed by calcium carbonate under the control of organic matrix，composed of shell matrix proteins, sugars and lipids. Shell matrix proteins play significant roles in the formation of shells and pearls. It is very important to study the matrix proteins of Hyriopsis cumingii for revealing the formation mechanism of pearls and cultivating high quality pearls.In this paper, 26 matrix proteins related to the formation of the cuticle, prism layer and nacreous layer of Hyriopsis cumingii were introduced. The structural characteristics of these matrix proteins were analyzed, including the amino acid composition, primary structure and advanced structure. The roles of these matrix proteins in biomineralization were also introduced, including participating in the deposition of calcium carbonate, the formation of organic framework, the regulation of crystal morphology, the regulation of shell coloring and the correlation with pearl weight.

Abstract:Deep-sea cage is a new type of aquaculture model，which has the advantages of advanced technology, environmentally friendly, and high quality of the fish farmed by it. Therefore, it plays an important role in promoting green development of aquaculture. Based on the introduction of the development of common cage and offshore cage in China and of deep-sea cage in other countries, this paper summarizes the development before and after 2017, the research progress, and the future development prospect of deep-sea cage in China. It is to serve as guidance to development of deep-sea cage aquaculture. The future of deep-sea cage farming is promising, while there is still a long way to go.

Abstract:To dertimine the optimal microalgae diet for massive clam culture, this experiment was conducted to investigate the effects of different microalgae diets (Cyclotella sp., Chlorella sp., Scenedesmus dimorphus, monosporidium contortum, and mixed four microalgae) on the growth, pearl producing function, nutrition composition and shell nacre color of Hyriopsis cumingii, using a single factor experiment method. The results showed that the growth of the clam was significantly different with different microalgae diets. The growth rate of weight, shell length, shell width and shell height of Hyriopsis cumingii was the highest when fed by Cyclotella sp., Scenedesmus dimorphus came second, with its growth rate of shell length slightly higher than Cyclotella sp., but no significantly difference (P>0.05). The growths of the mussel for the groups of Chlorella sp., Monoraphidium contortum and mixed algae group were poor. The highest production gain of pearl was 16.23%±1.23% when fed by Cyclotella sp., significantly higher than other four groups (P<0.05). The perfect round pearls rate in Cyclotella sp. and Scenedesmus dimorphus groups was significantly higher than in Monoraphidium contortum group (P<0.05). The trace element content of the foot and mantle was significantly affected by diet (P < 0.05). The highest Ca content of foot was observed in mussels fed Cyclotella sp. (12637.3±624.39 mg/kg), It is significant effect on shell nacre color (P<0.05). Lowest brightness of shell nacre color came with Cyclotella sp., together with smallest chromatic aberration, and higher saturation. For the mixed algae group, the highest brightness of shell nacre color and chromatic aberration, and the lowest saturation were found (P<0.05). The brightness, chromatic aberration and saturation of the Scenedesmus dimorphus group were all at intermediate levels. In conclusion, Cyclotella sp. may be the best diet choice for intensive Hyriopsis cumingii, and followed by Scenedesmus dimorphus.