Search

After being exposed to environmental stimuli during early developmental stages, some organisms may gain or weaken physiological regulating abilities, which would have long-lasting effects on their performance. Environmental hypoxia events can have significant effects on marine organisms, but for breeding programs and other practical applications, it is important to further explore the long-term physiological effects of early hypoxia exposure in economically significant species. In this study, the Pacific abalone Haliotis discus hannaiwas exposed to moderate hypoxia (∼4 mg/L) from zygote to trochophora, and the assessments of hypoxia tolerance were conducted on the grow-out stage. The results revealed that juvenile abalones exposed to hypoxia at the early development stages were more hypoxia-tolerant but with slower weight growth, a phenomenon called the trade-off between growth and survival. These phenotypic effects driven by the hypoxia exposure were explained by strong selection of genes involved in signal transduction, autophagy, apoptosis, and hormone regulation. Moreover, long non-coding RNA regulation plays an important role modulating carry-over effects by controlling DNA replication and repair, signal transduction, myocardial activity, and hormone regulation. This study revealed that the ability to create favorable phenotypic differentiation through genetic selection and/or epigenetic regulation is important for the survival and development of aquatic animals in the face of rapidly changing environmental conditions.

Aquaculture contributes significantly to the global economy and has become the key to global food security and nutrition strategies. In order to supply sustainable and equitable aquatic food, studies on aquaculture genomics, genetics and selective breeding are required. Genomic selection (GS) captures diversity and estimates breeding values based on genome-wide distributed markers enhancing aquaculture production efficiency, sustainability, product quality, and profitability. However, the application of GS in aquaculture is still in its initial stage compared with that in plants and livestock. The complex preprocessing, quality control and postprocessing steps, complicated statistical models, fussy file format conversions between various interfaces and frequent switches among different running environments prevent smooth and large-scale applications. In this study, we have developed AquaGS, an open-source Graphic User Interface (GUI) Genomic Selection pipeline offering click-by-click running from inputting raw data for phenotype and genotype to the final mate allocation scheme. AquaGS is a C++ based application that uses QT to create a GUI and integrates the functions needed for the GS process by calling various programs and specific tools in the background, such as C++, Python, R, PLINK and AlphaMate. AquaGS includes phenotype preprocessing, quality control, testing the significance of effects, breeding value predictions, cross-validation and mating allocation scheme generation, integrated from widely-used standalone methods and tools, such as BLUP, GBLUP, SSBLUP, Bayes A, Bayes B, Bayes Cπ, and Bayesian Lasso model. Additionally, AquaGS includes a mating design module based on optimum contribution selection to avoid inbreeding depression and maximize genetic gains. To accommodate various application scenarios, AquaGS offers a flexible, interactive and customized processing pipeline.

Salinity and dissolved oxygen concentration are two of the most important factors affecting the geographic distribution, survival, and physiological processes of estuarine and mariculture organisms. In this study, the effects of low salinity and hypoxia on survival and physiology were evaluated for two populations of Babylonia areolata, a Thailand population (TT) and a Hainan population (HH), and their reciprocal hybrids TH (TT♀ × HH♂), HT (HH♀ × TT♂). HH was more sensitive to low salinity, with a survival rate close to zero after 54 h of low salinity stress, while the survival rates of the other three populations remained above 50%, and the median lethal times (LT50) of the four populations after 72-h low salinity stress were in the order TT > TH > HT > HH. In addition, comparing the heterosis levels calculated from the 72 h-LT50and the 48-h and 72-h survival rates of TH and HT under low salinity stress, the mid-parent heterosis (HMP) values of the three indicators of TH were 24.56%, 79.56%, and 80.97%, respectively, and the HMPvalues of the corresponding indicators of HT were 19.67%, 70.47%, and −42.88%, respectively. Moreover, with the increase in time under hypoxia, TH and HT began to die, and the survival rates of TH and HT were lower than those of their parental populations. The oxygen consumption rates (OCR) of TH and HT under hypoxic conditions were lower than those of TT and HH. The results showed that the crossbreeding between TT and HH improved the low salinity tolerance of their hybrids but decreased their tolerance to hypoxia. This study provides information concerning this ivory shell hybrid system that could aid in the application of heterosis in ivory shell aquaculture.

Background: Ginsenoside Rg1 (Rg1) is the main active compound of ginseng herbs. Objective: The aim of this study is to develop a rapid, selective and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to determine the levels of Rg1 in rat plasma and investigate the pharmacokinetics and bioavailability of Rg1 in rats. Methods: Chromatographic separation was achieved on an UHPLC-MS/MS system with an UPLC BEH C18 column using an elution gradient of a mixture of acetonitrile and water (with 0.1% formic acid). The analytes were quantitatively determined by negative-mode electrospray tandem MS. Results: The linearity of the calibration curve was from 2 to 1,000 ng/mL (r ≥ 0.9956), and the lower limit of quantification was 2 ng/mL. The inter-day and intra-day precision were both lower than 12.0%, and the accuracy ranged from 90.6 to 109.7%. The recovery of the targets was higher than 87.0%, and the matrix effect at three different analyte concentrations were from 89.0 to 97.2%. The bioavailability of Rg1 was only 6.1% due to a poor oral absorption. Conclusion: This new quantitative method was found to be sensitive, rapid and selective, and was successfully used to study the pharmacokinetics of Rg1 after intravenous and oral administration in rats.

Curcumin (CUR), as a natural and innocuous phytogenic compounds, is regarded as a multifunctional feed additive with growth-promoting and immunostimulant potential in aquaculture. The effects of dietary CUR on the survival and growth of the abalone (Haliotis discus hannai) were evaluated by measuring growth, hematological parameters, and the abundance and diversity of gut flora. A total of 720 abalones (shell length: 59.69 ± 0.15 mm, body weight: 24.80 ± 0.20 g) were randomly distributed into six group (six replicates each group), fed six diets containing 0, 0.05, 0.1, 0.2, 0.4, and 0.8 g/kg of CUR for 100 days. Results indicated that CUR supplementation at 0.1–0.4 g/kg diet improved the growth performance. When the addition of CUR was greater than 0.1 g/kg, the activities of catalase, superoxide dismutase, glutathione peroxidase and total antioxidant capacity in the serum and hepatopancreas were significantly increased, while the contents of malondialdehyde were significantly reduced (P < 0.05). After infection with Vibrio harveyiAP37, the survival rate in all CUR supplementation groups were significantly higher than the control group (P < 0.05), and the highest values of the total hemocyte count, reactive oxygen species, and phagocytic activity were recorded in CUR 0.1 group. In addition, supplementation of the diet with 0.1 g/kg CUR decreased the gut microbial diversity indices and increased the abundance of potentially beneficial genera including Mycoplasma(26.82%), Psychrilyobacter (23.62%) and Vibrio(21.44%). In conclusion, addition of 0.1 g/kg of CUR to the diet not only improved the survival, growth, feed utilization, and regulated gut flora composition of abalone, but also effectively enhanced their antioxidant capacity, cellular immunity and resistance to V. harveyiAP37 infection. Therefore, CUR may be a useful feed additive for abalone aquaculture.

AbstractThe small abalone Haliotis diversicoloris an economically important shellfish species in southern China. Wild (Japanese, Guangdong, and Hainan) and cultured (Taiwanese and Vietnamese) subpopulations of small abalone were examined using seven microsatellite loci to assess the levels of genetic diversity and the degree of genetic differentiation among them. These seven microsatellite markers showed a high level of polymorphism. A total of 209 alleles were detected, with an average of 29.86 alleles per locus among the five subpopulations. The average observed heterozygosities per locus ranged from 0.733 in the Japanese subpopulation to 0.804 in the Hainan subpopulation, while the average expected heterozygosities per locus ranged from 0.909 in the Vietnamese subpopulation to 0.940 in the Guangdong subpopulation. Values for the differentiation index Destvaried from 0.1071 to 0.4020 among different subpopulations. The values for genetic distance (DA) ranged from 0.244 to 0.409, with an average of 0.294. Both Destand DAshowed that the largest distance was between the Japanese and Vietnamese subpopulations. Principal coordinate analysis was performed for all subpopulations and loci using genetic distance to summarize genetic relationships. The analysis indicated a grouping of the three wild subpopulations (Japanese, Guangdong, and Hainan). The Vietnamese subpopulation was plotted separately from others. The information on the genetic variation and differentiation in the wild and cultured subpopulations obtained in this study is useful for the development of guidelines for genetic breeding programs for small abalone.Received November 8, 2010; accepted February 22, 2011

The small abalone Haliotis diversicoloris an economically important shellfish species in southern China. Wild (Japanese, Guangdong, and Hainan) and cultured (Taiwanese and Vietnamese) subpopulations of small abalone were examined using seven microsatellite loci to assess the levels of genetic diversity and the degree of genetic differentiation among them. These seven microsatellite markers showed a high level of polymorphism. A total of 209 alleles were detected, with an average of 29.86 alleles per locus among the five subpopulations. The average observed heterozygosities per locus ranged from 0.733 in the Japanese subpopulation to 0.804 in the Hainan subpopulation, while the average expected heterozygosities per locus ranged from 0.909 in the Vietnamese subpopulation to 0.940 in the Guangdong subpopulation. Values for the differentiation index Destvaried from 0.1071 to 0.4020 among different subpopulations. The values for genetic distance (DA) ranged from 0.244 to 0.409, with an average of 0.294. Both Destand DAshowed that the largest distance was between the Japanese and Vietnamese subpopulations. Principal coordinate analysis was performed for all subpopulations and loci using genetic distance to summarize genetic relationships. The analysis indicated a grouping of the three wild subpopulations (Japanese, Guangdong, and Hainan). The Vietnamese subpopulation was plotted separately from others. The information on the genetic variation and differentiation in the wild and cultured subpopulations obtained in this study is useful for the development of guidelines for genetic breeding programs for small abalone.

•The effectiveness of 6-DMAP and CB in inducing autotriploid larvae in H. discus hannaihas been improved.•The induction of allotriploid larvae (H. discus hannai♀ × H. fulgens♂) via chemical method was firstly conducted.•The relatively high rates (91.66–100.00 %) of autotriploid and alloptriploid were obtained using optimal parameters.

Evident survival heterosis exists in the hybrid (HdDY) of two Haliotis diversicolorgeographic genotypes (maternal genotype HdTW and paternal genotype HdJP). To explore the physiological basis underlying the heterosis, we compared the survival rate, cardiac performance, oxygen consumption rate, and ammonia excretion rate of the three H. diversicolorgenotypes at the low temperature. After one year of cultivation in the abalone farm, the survival rates of HdTW, HdJP, and HdDY were 27.76%, 86.90%, and 88.57%, respectively. The 50% lethal low temperature (LLT50) of HdTW was higher than HdJP and HdDY. During low-temperature exposure, the abalone’s heartbeat variation pattern appeared as three stages: the heartbeat decreasing stage, arrhythmia stage, and cardiac recovery stage. Four cardiac indices were developed to compare the three genotypes’ cardiac differences: the low-temperature heartbeat decreasing rate (LDR), cardiac arrhythmia temperature (CAT), low-temperature heartbeat recovering rate (LRR), and cardiac recovery time (CRT). HdTW had lower LDR and higher CAT than HdJP and HdDY, while HdJP had lower LRR and higher CRT than HdTW and HdDY, suggesting the hybrid’s cardiac function is parent-like in low-temperature tolerance and mother-like in low-temperature recovery. Meanwhile, the heart rates of HdJP and HdDY were always higher than HdTW at both normal temperature (20 °C) and low temperature (12 °C). The oxygen consumption rate and ammonia excretion rate of HdJP and HdDY were also higher than HdTW after low-temperature exposure. The results indicate the hybrid’s advantageous respiratory and metabolic functions at low temperatures, which could be a vital physiological mechanism of the hybrid’s survival heterosis. This study elucidates the cardiac and respiratory metabolic differences among different abalone genotypes at low temperatures, which may help us understand the physiological basis of mollusks’ low-temperature tolerance. The evaluation protocol and indices developed in this study could be helpful in mollusks’ physiological researches, such as the low-temperature tolerance heterosis, low-temperature adaption, and habitat differentiation.