Current Articles

Display Method:
2023, 19(1)
Research Paper
Influence of statistical deviation of historical catch on stock assessment: a case study of western Atlantic Thunnus thynnus
FENG Ji, ZHU Jiangfeng, ZHANG Fan, LI Yanan, GENG Zhe
2023, 19(1): 1-11. doi: 10.12131/20220037
Catch data, which is the most basic data for stock assessment, is also most likely to cause reporting and statistical errors. Misreporting is one of the causes for statistical deviation of historical catch, which is currently prevalent in all types of fisheries worldwide. Analyzing the influence of statistical deviation of historical catch on stock assessment based on historical data helps to establish reasonable management objectives, and promote sustainable utilization of fishery resources. In this study, we selected western Atlantic bluefin tuna (Thunnus thynnus) as an example to evaluate the influence of statistical deviation of historical catch on its stock assessment. We carried out a stock assessment by using Age-Structured Assessment Program (Age-Structured Assessment Program, ASAP), and investigated the effects of catch information inaccuracy on the assessment results by setting different levels of statistical deviation of historical catch. The results indicate that the estimated values of fishing mortality (F) and spawning stock biomass (SSB) changed in the same direction with the adjusted catch. With the increase of statistical deviation of catch, the relative difference of biological reference points also increased. The relative deviation rate of F-related biological reference points was less than 1% under all eight assumed statistical deviations of catch. When the statistical deviation of the historical catch was assumed as −20%, the maximum relative difference of SSB-related biological reference points was about 4%. The statistical deviation of catch had a more obvious impact on SSB-related biological reference points than F-related biological reference points. In conclusion, it is suggested to strengthen the source analysis of catch data quality issues, so that the scientific reconstruction of historical fishery data can be conducted to improve the accuracy and reliability of the stock assessment results.
Spatio-temporal distribution of habitat patterns of Scomber japonicus in East China Sea under future climatic conditions
WU Xiaoci, FENG Zhiping, YU Wei
2023, 19(1): 12-21. doi: 10.12131/20220126
To investigate the effects of global climate change on the habitat pattern of Scomber japonicus in the East China Sea and to slow down the adverse effects of climate change on the fishing ground of S. japonicus, based on the water temperature data of 2.5 m (Temp_2.5 m), 25 m (Temp_25 m) and 50 m (Temp_50 m) output by CMIP6 climate model, we analyzed the spatio-temporal changes of the habitat in the East China Sea under three future climatic conditions (SSP126, SSP370 and SSP585). The results show that for SSP126, Temp_2.5 m, Temp_25 m and Temp_50 m showed relatively minor changes. For SSP370 and SSP585, Temp_2.5 m, Temp_25 m and Temp_50 m showed an overall upward trend. The three factors also changed in the spatial distribution during 2015−2020, 2055−2060 and 2095−2100. The habitat suitability index (HSI) on the fishing ground and proportion of suitable habitat of S. japonicus in the East China Sea from 2015 to 2100 showed a similar downward trend under SSP126, SSP370 and SSP585 conditions. However, the proportion of unsuitable habitat area from 2015 to 2100 increased under SSP126, SSP370 and SSP585 conditions. The suitable habitats of S. japonicus were mainly distributed in the waters of 122°E−126°E and 28°N−30°N during 2015−2020, 2055−2060 and 2095−2100, while the unsuitable habitat was mainly distributed in the middle of fishing ground. In addition, the gravity center of suitable habitat of S. japonicus tended to move northward. The results suggest that the global warming is unfavorable for the formation of suitable habitat of S. japonicus in the East China Sea.
Study on habitat suitability of Coilia mystus in Pearl River Estuary, China
XIE Yufang, WU Peng, LIU Yong, XIAO Yayuan, TANG Guanglong, WANG Teng, LIN Lin, LI Chunhou
2023, 19(1): 22-29. doi: 10.12131/20220029
Exploring the habitat suitability of Coilia mystus, a migratory fish in the Pearl River estuary, can provide a scientific basis for the protection and utilization of fishery resources of C. mystus. Based on the date collected by the bottom-trawl in the Pearl River Estuary during winter in 2019 and summer in 2020, we constructed the habitat suitability index (HSI) model of C. mystus, taking the water depth, bottom salinity, bottom temperature, as well as bottom dissolved oxygen as indicator environment indicators. The analytic hierarchy process (AHP) was used to calculate the weight of the indicators. The arithmetic mean (AMM) and the geometric mean (GMM) were used to build a model. Then a suitability curve was developed and the HSI of C. mystus was calculated. Results show that the optimal bottom salinities for C. mystus in the Pearl River Estuary in winter and summer were 21.03‰−30.55‰ and 20.25‰−25.82‰, respectively; the mass concentrations of suitable dissolved oxygen were 6.79–7.28 and 3.85–4.01 mg·L−1, respectively; the suitable water depths were 11.69–20.10 and 7.80–9.23 m, respectively; the suitable bottom temperatures were 19.84–19.95 and 28.36–29.44 ℃, respectively. The sites with HSI value greater than 0.5 accounted for 17.39% of the total survey sites. The study shows that the suitability of C. mystus was low, and its suitable habitats in the Pearl River Estuary are mainly located in the Sousa chinensis Nature Reserve in the Neilingding sea area.
Ecological health assessment of Cyprinus carpio and Leiocassis longirostris national aquatic germplasm resources reserve in Huaihe River
WANG Dongwei, CHEN Yongjin, FANG Di'an, ZHOU Yanfeng
2023, 19(1): 30-38. doi: 10.12131/20220109
Evaluation of water ecological health status helps to judge the effectiveness of water ecological restoration, which is an effective means of water environment management. In order to explore the water ecological health status of Cyprinus carpio and Leiocassis longirostris national aquatic germplasm resources reserve in Huaihe River, according to the survey results of phytoplankton community structure in 2020 and combined with the morphological functional group classification, we constructed the ecological health evaluation system of the reserve based on the biological integrity index of phytoplankton. Besides, we carried out the Mann-Whitney non-parametric test and correlation analysis of the candidate parameters to determine the final evaluation parameters, and used the ratio method to determine the grading evaluation standard for the evaluation of the health status of the reserve water. The results show that the evolution trend of dominant functional groups of phytoplankton was III+IV+V (Spring)→III+IV+V+VI (Summer)→V+VI (Autumn)→IV+V+VI (Winter). Except that the dominant functional groups in the core area were III+ IV+V+VI, the dominant functional groups of the experimental area, the Guo river and the Huaihe River were III+IV+V+VI. 68.06% of the sampling sites in the reserve were evaluated as "average" or above, indicating that the overall water ecological health status was good. Specifically, the temporal pattern of winter was better than autumn, followed by summer, and the worst was in spring; the spatial pattern of Huaihe River mainstream was better than Guohe River, and the experimental area was better than the core area.
Study on lipid accumulation and contribution to reproductive energy in female Illex argentinus
SONG Wei, ZANG Na, FENG Yixuan, LIN Dongming
2023, 19(1): 39-47. doi: 10.12131/20210348
To explore the accumulation of tissue lipid and its contribution to reproductive energy during gonadal development of Illex argentinus has important theoretical value for understanding its reproductive investment strategy, as well as the sustainable development and utilization of this resource. By using tissue energy density measurement technology and lipid extraction technology, we measured and analyzed the energy density of mantle soma, digestive gland, ovary and oviduct eggs of female I. argentinus before and after degreasing, as well as the lipid mass fraction, lipid energy and proportion of each tissue. Results indicate that the energy density of all tissues decreased significantly after lipid extraction. During the maturation, female I. argentinus maintained a relative stable level of the lipid mass fraction and percentage of lipid energy in mantle soma and oviduct eggs. However, there was a significant decreasing trend in the lipid mass fraction and percentage of lipid energy in the digestive gland but an increasing trend in the ovary (Maximum in Phase IV) along with maturation. Furthermore, Pearson's r analysis indicates that there was a significantly negative relationship in the lipid mass fraction, lipid energy and percentage of lipid energy between gonadal tissues (Combination of ovary and oviduct eggs) and digestive gland, but without a significant relationship between gonadal tissues and mantle soma. In summary, female I. argentinus exhibits tissue-specific lipid content and lipid energy accumulation. The lipid content has a significant contribution to the reproductive energy, and lipids in the gonadal tissues are significantly correlated with lipids in the digestive gland, which further proves that energy allocation to reproduction in I. argentinus mainly depends on the income resources.
Heavy metal enrichment characteristics and risk assessment of typical fishes in tropical seagrass beds
JIANG Rui, WU Yunchao, HUANG Xiaoping, LIU Songlin, CHEN Qiming
2023, 19(1): 48-57. doi: 10.12131/20220118
The ingestion of seagrass by herbivorous fish will affect the transfer process of metal elements in seagrass beds, and the accumulation of heavy metals will cause human ingestion risks. Taking two typical fish species (Siganus guttatus and S. fuscessens) eating seagrasses in two tropical seagrass beds as main research objects, we determined the enrichment of heavy metals and their contamination, and assessed the dietary exposure risk in seagrass bed environment and fishes. Then we further explored the transfer characteristics of heavy metals in seagrass bed ecosystems. The results show that the contents of Cu, Cd, Zn and Pb in fish muscles were at a low level. There are significant positive correlations between Cu and Pb, and between Zn and CD. The enrichment effects of Zn and Cu were greater than those of Cd and Pb, but only Zn showed an potential enrichment effect in these two fish muscles. The Zn contents in these two fishes showed a serious pollution risk, while Pb contents showed slight pollution, but the contents of Cu and Cd were at a normal risk level. Eating these two fishes has little health risk. Due to the different growth rates and food sources, the content, pollution and enrichment of heavy metals in S. fuscessens are slightly higher than those in S. guttatus. The contents and enrichment of heavy metals in seagrass beds are generally higher than those in fishes. The accumulation of heavy metals mainly occurs in seagrass, and the heavy metal content in fish decreases with higher trophic levels.
Comparison and optimization of total phosphorus determination method in mariculture tailwater
LIU Yan, TONG Fei, CHEN Pimao, YUAN Huarong, FENG Xue
2023, 19(1): 58-66. doi: 10.12131/20220056
In order to improve the efficiency of the determination of total phosphorus (TP) in the mariculture tailwater, we determined the TP content by microplate reader instead of spectrophotometer in mariculture tailwater, and optimized the digestion method of TP, the type of microwell plate and the amount of sample. The results show that there was no significant difference between 60 min of digestion using a temperature-controlled heating plate and 30 min of digestion using an autoclave (P>0.05). The sensitivity of the assay was better than those of the other experimental groups (200 µL for 96-well plate, 200 µL for 96-well quartz plate, 200 and 500 µL for 48-well plate, 500 µL and 1 mL for 24-well plate) when using a 48-well plate with 1 mL of sample. The linear correlation between phosphate concentration and absorbance was the best (R2=0.999 9) for the 48-well plate with 1 mL and the 96-well plate spiked with 200 µL. The accuracy and precision validation of TP determination in mariculture tailwater showed that the relative error (RE) and relative standard deviation (RSD) of the 48-well plate spiked with 1 mL were higher than those of the other experimental groups (96-well plate 200 µL, 96-well quartz plate 200 µL, 48-well plate 200 µL and 500 µL, 24-well plate 500 µL and 1 mL). The recoveries of disodium glycerophosphate (β-GLP) and sodium hexametaphosphate (SHMP) were 98.2%−99.6% and 93.4%−97.1%, respectively, and the limit of quantification (LOQ) of TP were 0.25 µmol·L−1; the RE and RSD of 96-well ELISA plate spiked with 200 µL were −14.03%−0.21% and 2.63%−14.23%, respectively, and the recoveries for β-GLP and SHM were 94.7%−99.0% and 88.9%−97.3%, respectively, and the LOQ of TP was 0.55 µmol·L−1. At TP concentration of 0.55−6.4 µmol·L−1, the accuracy and precision of the two optimized methods meet the determination requirements and can be used for the determination of TP in mariculture tailwater.
Effect of five factors on removing ammonia nitrogen and nitrite by Rhodococcus ruber HDRR2Y fermentation
XU Yu, HU Xiaojuan, ZHANG Song, XU Wujie, SU Haochang, WEN Guoliang, CAO Yucheng
2023, 19(1): 67-74. doi: 10.12131/20220044
The bacteria Rhodococcus ruber is usually used in waste water and sewage treatment. In order to discuss the effect of environmental factors on R. ruber HDRR2Y's removing ammonia nitrogen and nitrite, we added the culture medium of R. ruber strain HDRR2Y to the aquaculture water containing high concentration of ammonia nitrogen (NH4 +-N) and nitrite (NO2 -N), and observed the changes of ammonia nitrogen and nitrite concentrations by the national standard method, so as to investigate the effect of the culture medium on the removal of ammonia nitrogen and nitrite. In addition, we carried out the Plackett-Burman experimental design according to five factors: temperature, rotating speed, salinity, inoculum amount, substrate (Ammonia nitrogen and nitrite) concentration, to explore the effect of these factors on the removal of ammonia nitrogen and nitrite by R. ruber. The results show that during the fermentation process, the mass concentration of strain HDRR2Y increased from 5×104 CFU·mL−1 to 4.08×109 CFU·mL−1 in the initial 36 h. After adding the culture medium, the mass concentration of ammonia nitrogen decreased from 15 mg·L−1 to 5.56 mg·L−1, with a removal rate of 62.96%, and that of nitrite decreased from 15 mg·L−1 to 6.95 mg·L−1, with a removal rate of 59.37%. Among the five factors, temperature and ammonia nitrogen concentration had the most significant effects on the removal of ammonia nitrogen by strain HDRR2Y (P<0.05) (Temperature>ammonia nitrogen concentration>rotation speed>biomass>salinity). Temperature and rotating speed were the two most significant factors affecting the removal of nitrite (P<0.05) (Temperature>rotating speed>salinity>nitrite concentration>bacterial count). It is showed that the culture medium of strain HDRR2Y is good for removing ammonia nitrogen and nitrite, and temperature is the most significant factor affecting the efficiency of HDRR2Y in removing ammonia nitrogen and nitrite.
Establishment of reverse transcription droplet digital PCR assay for detection of Tilapia Lake Virus
LI Min, LI Yongfu, HUANG Yuhao, CHEN Zhuojun, MO Zuanlan, ZHONG Qunfang, LI Benwang, ZHANG Xianpeng
2023, 19(1): 75-85. doi: 10.12131/20220184
To establish an assay of reverse transcription droplet digital PCR (RT-ddPCR) for Tilapia Lake Virus (TiLV), we designed a pair of specific primers and probe based on the conserved region of TiLV segment 3 and evaluated the specificity, sensitivity and repeatability of this method. The structured standard curve was evaluated by using TiLV-cDNA as a template. Finally, the samples were tested. When the concentrations of primers and probes were 500 and 300 nmol·L−1 and the annealing temperature was 54.2 ℃, the established TiLV RT-ddPCR amplification reaction efficiency was the highest, the distribution boundary of the positive and negative droplets was the most obvious, and the average copy number was higher. The RT-ddPCR of TiLV had a lower limit of detection with 2 copies·μL−1 and showed a good linear relationship between 1–90 000 copies·μL−1 (Correlation coefficient R2=0.995 8). There was no amplification reaction to other viruses in aquatic animals. The CV of ddPCR for TiLV-cDNA was 4.86%. There was no cross reaction with the positive samples of other five common aquatic animal disease viruses [Carp edema virus (CEV), Koi herpesvirus (KHV), Grass carp reovirus (GCV), Cyprinid herpesvirus 2 (CyHV-2), Red sea bream iridovirus (RSIV)]. Among the 53 detected samples, 48 were negative, three of five proficiency testing samples were positive, consistent with satisfactory previous proficiency testing results.
Genetic diversity and population structure of Gymnocypris przewalskii based on SNP markers
LUO Hui, FANG Di'an, HE Miao, MAO Chengcheng, KUANG Zhen, QI Hongfang, XU Dongpo
2023, 19(1): 86-96. doi: 10.12131/20220091
To investigate the genetic diversity and genetic differentiation of natural resources of Gymnocypris przewalskii, and provide references for its conservation measures, we collected 72 individuals of G. przewalskii from six natural populations in Qinghai Lake to analyze the genomic SNP and genetic characteristics by using simplified genome sequencing. Altogether 1 600 061SNP markers were obtained, and 45 266 high-quality SNP loci were screened for genetic analysis after filtering. The average Pi diversity index was 0.317 0–0.327 4. The average observed heterozygosity (Ho) and expected heterozygosity (He) were 0.459 4–0.482 3 and 0.336 7–0.344 4, respectively. The genetic distance (D) was 0.018 4–0.023 3 and the genetic differentiation index (Fst) were not significant (P>0.05). AMOVA analysis shows that the genetic variation was 102.37% within populations. Further-more, both population structure and phylogenetic tree analysis show that the six G. przewalskii populations clustered into one glade with similar genetic structure. In contrast, the genetic structure obtained from DAPC analysis was relatively clearer, showing that the Haergai, Heima and Shaliu River populations cross-clustered with each other, while the remaining three populations clustered into three other branches. In conclusion, the observed heterozygosity of the six geographic populations was higher than the expected value, with a homogeneous population structure.
Effects of dietary supplementation with powder of Antarctic krill (Euphausia superba) on growth performance, body composition and color of Litopenaeus vannamei
LI Wenheng, WANG Haitao, SHAN Hongwei, GAO Chang, LI Jiqing
2023, 19(1): 97-105. doi: 10.12131/20220074
To determine the application effect of Euphausia superba powder (PE) in shrimp culture, we designed five groups [S0 group (No PE supplementation), S5 group, S10 group, S15 group, and S20 group (5%, 10%, 15% and 20% PE supplemented to the feed, respectively)] for a 35-day experiment on Litopenaeus vannamei [Body mass of (7.27±0.88) g]. The effect of dietary supplementation with PE on the growth performance, body composition and color of L. vannamei were evaluated. The results show that: 1) PE supplementation improved the survival rate (SR) of L. vannamei significantly (P<0.05), and the final body mass (FBW), weight gain rate (WGR) and specific growth rate (SGR) of L. vannamei in S15 group were significantly higher compared with the other groups (P<0.05). 2) With the increase of PE supplementation, the crude fat content of L. vannamei increased gradually, and those in S10 group, S15 group and S20 group were significantly higher than that in S0 group (P<0.05). Additionally, the brightness (L*) of the cephalothorax and the yellowness (b*) of the carapace of L. vannamei decreased gradually, which were significantly lower than those in S0 group (P<0.05). 3) PE supplementation to the feed increased the astaxanthin content in the hepatopancreas and crustacean of L. vannamei significantly (P<0.05), and the effect was positively associated with PE supplementation. The expression level of the LVPBP75 related to body color was also positively correlated with PE supplementation. The results indicate that dietary supplementation with PE, especially with 15% PE, can improve the growth, astaxanthin content, body color as well as expression level of LVPBP75 of L. vannamei.
Effects of Bacillus on growth, survival, immunity and digestive enzyme activities of Babylonia areolata
ZHANG Yuwei, ZHAO Wang, DENG Zhenghua, HUANG Xingmei, WEN Weigeng, SUN Jingfeng, WANG Ruixuan
2023, 19(1): 106-115. doi: 10.12131/20220060
In order to explore whether Bacillus can replace antibiotics in the culture of Babylonia areolata, during the growth and development of B. areolata from early veliger larva to juvenile, we used Bacillus (B. coagulans, B. licheniformis) and antibiotics (sulfamethoxazole) for artificial regulation to study their effects on the growth, survival, immune and digestive enzyme activities of B. areolata. The results show that Bacillus and sulfamethoxazole promoted the growth of each trait index of B. areolata, and the difference among them was not significant (P>0.05). The survival rate of the Bacillus group was significantly higher than that of the control group and the sulfamethoxazole group in the later veliger larva stage (P<0.05). The activities of AKP, ACP, CAT, POD, GSH-Px, SOD, LPS and AMS, and MDA molality and T-AOC in Bacillus group were higher than those in the control group and the sulfamethoxazole group. The results show that appropriate use of Bacillus (B. coagulans and B. licheniformis) during the seedling breeding of B. areolata can improve the immunity and disease resistance of the body, increase the activity of digestive enzymes, promote the growth of larvae and improve the survival rate, and the effect is better than that of sulfamethoxazole.
Effects of egg product on growth performance, muscle nutrients,  and intestinal microflora of Procambarus clarkii
XIAO Wenfu, HU Bing, CUI Xuehai, CAO Manxia, YAO Haihang, LI Peng, YU Lijuan, YUAN Hanwen, GAO Weihua, TIAN Juan
2023, 19(1): 116-127. doi: 10.12131/20220128

To evaluate the application effect of spray-dried egg product in the diet of Procambarus clarkii, we formulated five isonitrogenous and isoenergetic diets containing 0% (Control group), 2.0%, 4.0%, 6.0% and 8.0% spray-dried egg product, which replaced 0% (CON), 25% (R1), 50% (R2), 75% (R3) and 100% (R4) fishmeal, respectively, to feed the shrimps [Initial body mass (9.02±0.12) g] for six weeks. The results show that there were no significant differences in the specific growth rate, feed conversion ratio, feeding rate, survival rate and hepatosomatic index among all the groups (P>0.05). The weight gain rate in R4 group decreased significantly compared with the CON group (P<0.05). The contents of crude protein, essential amino acid and total amino acid in abdominal muscle in R4 group increased significantly compared with the CON group (P<0.05). The contents of crude fat and ash in muscle in R2, R3 and R4 groups were significantly higher than those in the CON group (P<0.05). There were no significant differences in the contents of 17 hydrolyzed amino acids in muscle among all the groups (P>0.05). Compared with the CON group, the intestinal protease activities increased significantly but the amylase activities decreased significantly in egg product supplementation groups, and the intestinal lipase activity increased significantly in R3 and R4 groups (P<0.05). The serum alkaline phosphatase activity and total protein content in R2, R3 and R4 groups increased significantly than those in the CON group (P<0.05). The bacterial abundances of Clostridium sensu stricto and Lysobacter in R3 group were significantly higher than those of the other groups, while the bacterial abundance of Streptococcus in R4 group was significantly higher than that of the other groups (P<0.05). In conclusion, when the diet of P. clarkii contains 6% fishmeal, the spray-dried egg product can replace 75% fishmeal.

Comparative analysis of nutritional composition of muscle from Siganus oramin living in different habitats
YANG Yukai, HUANG Xiaolin, SHU Hu, LIN Heizhao, WANG Lan, XUN Pengwei, YU Wei, HUANG Zhong, LI Tao
2023, 19(1): 128-135. doi: 10.12131/20210345
To provide basic data for the production of Siganus oramin formula feed, we measured the general nutritional composition, amino acids and fatty acids in the muscle of S. oramin from industrial farming, high pond farming and the wild by biochemical analysis, investigated the effects of habitat on the muscle the nutrition and quality of S. oramin. The results show that compared with the wild fish, the contents of crude protein and crude lipid were higher but those of ash and moisture were lower in the muscle of the farmed fish, and the crude fat content in the industrial farmed fish was significantly higher than that of the other groups (P<0.05). Moreover, there were 17 common amino acids in the three kinds of fishes. Among them the glutamate content was the highest. For essential amino acids (EAA), lysine had the highest content. The essential amino acid index (EAAI) was highest in high pond farmed fish but lowest in the wild fish. Furthermore, there were 26 species fatty acids in the two kinds of farmed fish but only 24 species were found in the wild fish. The contents of polyunsaturated fatty acids (PUFA), n-6 series C18:2n6c were highest in the two farmed fishes, while those of the C22:6n3 (DHA) and C20:5n3 (EPA) of n-3 series were significantly higher in the wild fish. The ratio of n-3/n-6 and the content of DHA+EPA in the wild fish were significantly different from the two farmed fishes (P<0.05). Thus, it is revealed that the farmed S. oramin's nutrition and flavor are better than the wild ones, but they lack n-3 PUFA such as DHA and EPA.
Anesthetic effect and tissue oxidative injury for Litopenaeus vannamei by two anesthetics
WEI Zhengkun, DONG Hongbiao, ZHAO Wen, CHEN Fei, ZHANG Chuanxiang, CHEN Jian, GONG Baohua, ZHU Changbo, ZHANG Jiasong
2023, 19(1): 136-146. doi: 10.12131/20220070
To provide references for the application of two anesthetics in Litopenaeus vannamei, we studied the anesthetic effects of eugenol (20, 30, 40, 60, 80, 100, 120, 140, 160 mg·L−1) and MS-222 (800, 900, 1 000, 1 100, 1 200, 1 300, 1 400, 1 500, 1 600 mg·L−1) on L. vannamei with body mass of (14±3) g. Besides, we tested the secondary stress injury on the physiological functions and pathomorphologic changes by the two anesthetics. The results show that: 1) Eugenol of 80 mg·L−1and MS-222 of 1 400 mg·L−1 induced L. vannamei to enter the stage of deep anesthetic within 3 min, and return to the normal stage within 5 min. 2) The gills and hepatopancreas of L. vannamei were injured by the two anesthetics, and the antioxidant indexes of gills in the eugenol group reached the maximum value earlier than the MS-222 group. The Caspase-3 activity in the eugenol group decreased significantly after anesthesia recovery of 6 h, while that in the MS-222 group increased significantly (P<0.05). The Na+/K+-ATPase activity in both the groups decreased significantly (P<0.05). Pathomorphologic analysis shows that the two anesthetics could cause deformation or lysis of gills and hepatopancreas, and the eugenol group could recover after anesthesia recovery of 6 h. In conclusion, eugenol and MS-222 have anesthetic effects on L. vannamei, but the concentration of MS-222 is higher and the secondary stress damage to the body is more serious.
Study on distribution characteristics and storage variation of semicarbazide in Macrobrachium rosenbergii
GAO Fangfang, WANG Di, CHEN Shengjun, DENG Jianchao, FENG Yang, PAN Chuang, LI Chunsheng
2023, 19(1): 147-154. doi: 10.12131/20220138
Semicarbazide (SEM) is a toxic substance, which is a marker residue to determine whether Nitrofurazone is used illegally or not. To explore the detection of SEM in Crustacean aquatic products, we detected the SEM content of M. rosenbergii by High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS). The results show that SEM was detected in different parts of M. rosenbergii, higher in the cephalothorax and shrimp shell [Average: (32.02±3.75) and (26.85±13.90) μg·kg−1], but lower in the muscle and liver [Average: (1.35±0.67) and (5.56±0.87) μg·kg−1], and all exceeded the residue limit standards in China (1 μg·kg−1). The SEM content in the shrimp shell and shrimp meat increased with the prolongation of storage time, but that in the shrimp shell was higher than 1.0 μg·kg−1. Different storage temperatures had a little effect on the SEM content of M. rosenbergii. Therefore, when taking SEM as a marker for Nitrofurazone residue detection of M. rosenbergii, the detection time and background content factors should be considered so as to avoid false judgment; and in order to ensure the authenticity and accuracy of the test results, the crushed shell should be avoided in preparing samples.
Study on tyrosinase inhibitory activity and Cu2+ binding activity of tilapia skin peptides
SONG Yuqiong, HU Xiao, XIANG Huan, CHEN Shengjun, LI Laihao, YANG Xianqing, WU Yanyan, MA Haixia
2023, 19(1): 155-164. doi: 10.12131/20220097
To find out whether the tilapia (Oreochromis) skin collagen peptides can effectively inhibit melanin production, we used enzymatic method to prepare the tilapia skin tyrosinase (TYR) inhibitory peptides (TSTIP) and studied the relevance between TYR inhibitory activity and Cu2+ binding activity. The results show that the product of tilapia skin hydrolyzed by alcalase for 4 h exhibited both the highest TYR inhibitory activity and Cu2+ binding activity, which were significantly positively correlated (R=0.856). When TSTIP was bound to Cu2+ or tyrosinase, the intrinsic fluorescence absorption had a consistent decreasing trend, but the UV absorption increased and the maximum absorption wavelength had a red shift. For FTIR results, TYR and Cu2+ bound to TSTIP mainly by carbonyl and amino groups. Circular dichroism shows that the β-turn and random curl contents of the two conjugates decreased relatively, while the β-fold content increased relatively, which was more obvious for TSTIP-Cu2+ conjugate. In conclusion, the structural change of TSTIP-TYR is similar with that of TSTIP-Cu2+ conjugate, which indicates that TSTIP can inhibit TYR's activity by binding to its Cu2+ active site.
Research Notes
Morphological development and growth of larvae, juvenile and young red saddleback clownfish (Amphiprion ephippium)
LI Tao, HUANG Xiaolin, YANG Yukai, LIN Heizhao, HU Jing, PENG Jiacheng, HUANG Zhong, YU Wei
2023, 19(1): 165-172. doi: 10.12131/20220059
In order to study the early developmental characteristics of red saddleback clownfish (Amphiprion ephippium), and provide a theoretical reference for its breeding, we had continuously observed and analyzed the morphological and growth characteristics of larvae, juveniles and young individuals. The body of 0 dah (Days after hatching) individuals (Total length 4.472‒6.152 mm) was translucent with obvious fin membrane, only a small part of yolk sac remaining, and feeding had been started. For 7 dah individuals (Total length 5.213‒12.985 mm), the fin membrane disappeared, and the development of each fin basically completed and the bands began to appear on the head, entering into juvenile stage. Then bands began to appear in the middle of the body and fully formed on the head. For 23 dah individuals (Total length>7.652 mm), the whole body was covered by scales, and the bands in the middle of the body extended to the abdomen, with yellow fins, and the trunk was mainly red pigment and yellow pigment, entering young fish stage. For 28 dah individuals, the middle band fully formed, then the bands gradually disappeared from the middle. For 130 dah individuals, the middle band disappeared completely, while the head band disappeared completely until about 160 dah. At this time, the shape and body color of young fish were the same with that of adult fish. In general, the growth of larval, juvenile and young A. ephippium showed a trend of slow-rapid-slow trend with the increase of age. The formation and disappearance of white band on the head and middle part of the body were the most obvious features during the early development stage of A. ephippium.
Study on relationship between body mass and blood indexes of juvenile Thunnus albacares
LIU Hongyan, FU Zhengyi, YU Gang, MA Zhenhua
2023, 19(1): 173-178. doi: 10.12131/20220077
In order to study the basic blood indexes of artificially bred yellowfin tuna (Thunnus albacares), we determined the concentrations or activities of albumin, triglyceride, total cholesterol, transaminase, lysozyme and phosphatase in its serum (W1: 400−900 g; W2: 900−1 400 g; W3: 1 400−1 900 g) with different body mass. The results show that there were significant differences among the albumin, triglyceride and aspertate aminotransferase groups (P<0.05). The glutamic pyruvic transaminase activity and total cholesterol concentration in W2 group were significantly lower than those in the other two groups (P<0.05). The decending order of the concentrations of albumin, triglyceride and total cholesterol was W3>W1>W2. There was no significant difference in the alkaline phosphatase activity among the groups (P>0.05). The acid phosphatase activity in W1 group was significantly higher than that in the other two groups (P<0.05), and the lysozyme concentration in W1 group was not significantly different from that in the other two groups (P>0.05). The results reveal that there were differences in the blood indexes among the three groups of different mass; the difference between W2 group and the other two groups was greater, and the difference between W1 group and W3 group was smaller.