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The small abalone ( Haliotis diversicolor) is a mollusc and was cultured in south of china. Problems such as the decreasing pathogen-resistance and their mass mortality during the summer. The increased immunity of small abalone populations is a key factor in resolving these problems. Thus, the study of immunity-related genes in small abalone has become important. In this study, three bacterial species were initially isolated from small abalone carcasses. The regression of infection was analysed, which revealed that the bacteria species could cause rapid morbidity in small abalone. A QM-like gene ( Hdi QM) was found and bacterial challenge tests showed that Hdi QM gene expression was induced by the bacterial isolates from small abalone carcasses. Therefore, our results implied that Hdi QM was found to be an inflammatory stress-inducible gene associated with pathogen infection, with important functions in small abalone immunity. [ABSTRACT FROM AUTHOR]

The small abalone Haliotis diversicolor is an economically important mollusk that is widely cultivated in Southern China. Gonad precocity may affect the aquaculture of small abalone. Polyamines, which are small cationic molecules essential for cellular proliferation, may affect gonadal development. Ornithine decarboxylase (ODC) and antizyme (AZ) are essential elements of a feedback circuit that regulates cellular polyamines. This paper presents the molecular cloning and characterization of AZ from small abalone. Sequence analysis showed that the cDNA sequence of H. diversicolor AZ (HdiODCAZ) consisted of two overlapping open reading frames (ORFs) and conformed to the +1 frameshift property of the frame. Thin Layer chromatography (TLC) analysis suggested that the expressed protein encoded by +1 ORF2 was the functional AZ that targets ODC to 26S proteasome degradation. The result demonstrated that the expression level of AZ was higher than that of ODC in the ovary of small abalone. In addition, the expression profiles of ODC and AZ at the different development stages of the ovary indicated that these two genes might be involved in the gonadal development of small abalone. [ABSTRACT FROM AUTHOR]

The transcriptional activity of the SARP19- I1 and vdg3- I1 genes increases over tenfold when Haliotis diversicolor larvae shift from the pelagic to benthic lifestyle, signifying the important role of these genes during abalone metamorphosis. In this study, eight paralogous SARP19 genes and six paralogous vdg3 genes were identified from H. diversicolor transcriptomes. Phylogenetic analyses were performed, and the spatio-temporal expression patterns of these genes were separately determined by quantitative polymerase chain reaction (qPCR) and whole mount in situ hybridization (WMISH). Five SARP19 paralogs and five vdg3 paralogs showed at least a tenfold increase in expression after settlement. Among these differentially expressed genes, three SARP19 paralogs and four vdg3 paralogs were verified as being spatially expressed in the digestive glands of newly settled postlarvae. We proposed that a hypothesis of coevolution between the two gene families might explain the similarities in their expression patterns and their phylogenetics. [ABSTRACT FROM AUTHOR]

Background: The abalone Haliotis diversicolor is a good model for study of the settlement and metamorphosis, which are widespread marine ecological phenomena. However, information on the global gene backgrounds and gene expression profiles for the early development of abalones is lacking. Methodology/Principal Findings: In this study, eight non-normalized and multiplex barcode-labeled transcriptomes were sequenced using a 454 GS system to cover the early developmental stages of the abalone H. diversicolor. The assembly generated 35,415 unigenes, of which 7,566 were assigned GO terms. A global gene expression profile containing 636 scaffolds/contigs was constructed and was proven reliable using qPCR evaluation. It indicated that there may be existing dramatic phase transitions. Bioprocesses were proposed, including the 'lock system' in mature eggs, the collagen shells of the trochophore larvae and the development of chambered extracellular matrix (ECM) structures within the earliest postlarvae. Conclusion: This study globally details the first 454 sequencing data for larval stages of H. diversicolor. A basic analysis of the larval transcriptomes and cluster of the gene expression profile indicates that each stage possesses a batch of specific genes that are indispensable during embryonic development, especially during the two-cell, trochophore and early postlarval stages. These data will provide a fundamental resource for future physiological works on abalones, revealing the mechanisms of settlement and metamorphosis at the molecular level. [ABSTRACT FROM AUTHOR]

Abalone animals are import models for the study of the early development of marine invertebrates. However, systematical evaluations of internal control genes (ICG) have seldomly been performed. In this study, ten candidate genes were cloned and surveyed for their stability throughout the early developmental period of H. diversicolor using qPCR. In a period from fertilized egg to postlarva, three genes, Y-box protein 1 (YB1), ornithine decarboxylase antizyme 1 (OAZ1) and eukaryotic translation initiation factor 5A (EIF5A), were found to be the most stable and could be used as ICGs. It is suggested that using two genes jointly, such as YB1 and OAZ1, could be sufficiently reliable to normalize the temporal dynamics of other genes. Normalized by YB1/OAZ1, some rough features of early development of a small abalone were characterized. This is the first report of the temporal dynamics of metabolic activities and overall mRNA abundance of abalone animals in early stages. It is also the first time the multi-functional gene YB1 has been described as an internal control for early developmental biology studies. Phylogeny and function of YB1 are further discussed [ABSTRACT FROM AUTHOR]

The aquaculture industry of small abalone Haliotis diversicolor in southern China is now close to collapse because of high mortality at the grow-out stage. To examine if survival and growth (shell length increase) could be improved by cross breeding among populations, a 3 × 3 complete diallel cross was conducted among three populations from Japan (A), Taiwan (B) and Vietnam (C). Performances in growth rate and survival at early juvenile, later juvenile and grow-out stages were compared among the six reciprocal cross lines and three parental lines. Magnitude of heterosis for survival and growth varied among cross lines in the three growing stages. As to mid-parent heterosis, HAB was significantly ( P<0.01) higher than HAC and HBC at all three growing stages for both growth and survival, and all mid-parent heterosis fell between the two corresponding single-parent heterosis. HAB was 6.84% for shell length and 69.09% for survival at Day 420. Our results of high survival heterosis in line AB and line BA show that crossbreeding between different populations can benefit the small abalone breeding programs and the industry. [ABSTRACT FROM AUTHOR]

Two trials were conducted to determine the optimal replacement level of rice bran meal (RBM) as a substitute for kelp meal (KM) in the diet of the hybrid abalone Haliotis discus hannai ♀ × H. fulgens ♂. This study also investigated whether betaine as an attractant supplementation could be used to facilitate RBM as a replacement for KM. In Trial 1, RBM was used to replace 25%, 50%, and 100% of the dietary KM (RBM25, RBM50, and RBM100, respectively) based on a diet containing 30% KM (Con). In Trial 2, RBM50 was the same as in Trial 1, and betaine was supplemented in RBM50 at 0.2% (B1), 0.4% (B2), and 0.8% (B3) in the diets. Abalone (weight approximately 4 g) were randomly assigned to four groups replicated in triplicate (60 abalone/replicate). The abalone were fed the experimental diets for 10 weeks. In Trial 1, compared to the Con group, no significant differences were observed in final weight (FW), final shell length (FSL), specific growth rate (SGR), or daily increment in shell length (DISL) at 25% KM replacement by RBM. However, 50% KM replacement significantly reduced the FW, FSL, SGR, and DISL compared to the Con group. There were no significant differences in the proximate composition of the soft body tissues of the abalone. In Trial 2, growth performance parameters of the hybrid abalone were significantly improved with increasing levels of betaine in the diets compared to those fed diet RBM50, reaching the maximum value in the B2 group. Consistent with the feed intake results, the hormone concentrations of neuropeptide Y (NPY) and orexins in the digestive gland and cerebral ganglia of abalone were significantly increased when the supplementation level of betaine in the diets was increased to 0.2%. However, no apparent impacts were observed on NPY or orexin concentrations among the B1, B2, and B3 groups. Finally, we suggest 0.4% betaine supplementation along with replacing 50% of the KM with RBM in the hybrid abalone diet. The optimal diet is a cost-effective alternative feed formulation that can reduce the dependence on KM for abalone production in China. This study also demonstrates the potential of betaine as a feed attractant in abalone aquaculture. • 25% kelp meal (KM) can be replaced by rice bran meal (RBM) without obvious adverse impacts on the growth performance of the hybrid abalone. • The addition of 0.4% betaine in diets increased the replacement level of KM by RBM to 50% without negatively affecting the growth performance of the hybrid abalone. • Development of such diets will significantly reduce feed cost and reliance on KM for abalone feed company in China. [ABSTRACT FROM AUTHOR]

In this study, the optimal dietary protein levels for adult hybrid abalone (H. discus hannai♀ × H. fulgens♂) were evaluated at two representative temperatures, and the interactive influences of dietary protein and water temperature on abalone meat quality were examined. Six isoenergetic and isolipidic diets containing graded levels of protein (15%, 20%, 25%, 30%, 35%, and 40%) were fed to the hybrid abalone for 90 days. Based on the specific growth rate, the optimum dietary protein levels for adult hybrid abalone using a quadratic curve model were estimated to be 28.07% and 26.47% of the diet at 23 °C (optimum temperature) and 27 °C (high temperature), respectively. The amount of crude protein in the abalone body increased linearly with the dietary protein levels and water temperature. Antioxidation enzyme activities of abalone muscle, including GPx and GST were significantly affected by the interaction of dietary protein levels and water temperature. As for texture analysis, the abalone kept at 23 °C exhibited higher meat hardness than those fed the same diets at 27 °C. The n-3 PUFAs (particularly DHA and EPA) in abalone meat were significantly influenced by dietary protein levels, and the highest content was observed in the 30% dietary protein group. These levels were not affected by water temperature. In addition, higher dietary protein levels and water temperatures increased the total contents of free amino acids and flavor amino acids (Asp + Glu + Gly + Ala + Arg + Tau). The cooking loss of abalone meat was reduced with increased protein levels and was significantly lower in the 23 °C group, along with a higher meat postmortem pH value. The collagen fiber ratio and collagen content of abalone meat were higher in the 23 °C group. In summary, for multiple diet feeding strategies in practical production of abalone aquaculture, the balance between the seasonally specific feeds cost benefits and the abalone meat quality should be carefully evaluated. • The optimum dietary protein levels of adult hybrid abalone were estimated to be 28.07% and 26.47% of the diet by the quadratic curve model at 23 °C (optimum temperature) and 27 °C (high temperature), respectively. • Beyond 30% dietary protein, the growth performance declined, but relatively increased the nutritional, flavor quality, and hardness of abalone meat at both water temperatures. [ABSTRACT FROM AUTHOR]

In commercial aquaculture, the phenomena of diet conversion and water temperature fluctuation commonly occur in abalone farming. The meat quality of abalone is affected by diet and temperature, and this in turn directly influences consumer acceptance of abalone products and financial returns to producers. The aim of this study was to investigate the impacts of diet (Gracilaria lemaneiformis vs artificial feed) and water temperature (low, 19 °C and high, 27 °C) on growth performance, nutritional value, flavor, and sensory quality of abalone. The results showed that artificial feed led to increases in growth, content of body protein, total free amino acids (TAA), delicious amino acids (DAA), volatile compounds (alcohols, acids, aromatic compounds, and esters), and sensory quality (hardness) of abalone meat. High temperature significantly decreased the growth, body moisture, n-3 polyunsaturated fatty acids, and hardness but increased the contents of DAA, TAA, alcohols, acids, and aromatic compounds in abalone meat. Our study suggests that high temperature significantly decreases the growth and nutritional value of abalone muscle but does provide a different mouthfeel and flavor for consumers, and nutrition-balanced artificial feed as the diet at a low water temperature maximizes the growth of abalone without sacrificing meat quality. The results may help to formulate an optimal feed strategy for farming industries throughout the abalone culture period, thereby allowing farmers to harvest premium quality abalone and elevate the market value of abalone products. • In commercial aquaculture, the phenomena of diet conversion and water temperature fluctuation commonly occur in abalone farming. • High temperature significantly decreases the growth and nutritional value of abalone muscle but does provide a different mouthfeel and flavor for consumers. • Artificial feed as the diet at a low water temperature maximizes the growth of abalone without sacrificing meat quality. [ABSTRACT FROM AUTHOR]

Abstract: Pedal mucus is important for locomotion, protection and signal transmission in the Gastropoda. It also provides nutrients and a habitat for microbes. In this study, we examined the effects of pedal mucus and the mucus trail of the small abalone, Haliotis diversicolor, on bacterial growth, attachment, biofilm formation and community structure. The results showed that pedal mucus enhanced the growth of bacteria, and that more opportunistic pathogens attached to a substrate covered with pedal mucus (for Vibrio alginolyticus, the cell density was up to 5 times higher than on a clean substrate). During microplate assay, when pedal mucus was added as the sole nutrient source, V. alginolyticus formed a biofilm, but few cells grew on the bottom of the wells if no mucus was added. Under flow-cell culture conditions, differently structured biofilms were formed in the clean and pedal mucus conditioned glass slides. The mucus trail induced a heterogeneous biofilm with cell clusters. Moreover, pedal mucus could support much more CFUs than the clean substrates. Using denatured gradient gel electrophoresis comparison of the bacterial community on a clean substrate and in the mucus trail, we found several specific species in the latter. At least one species, Klebsiella pneumoniae, is potentially harmful to the small abalone. In summary, the pedal mucus of Haliotis diversicolor enriched bacterial occurrence, including some pathogens, which deserves to be considered in high density culture conditions. [Copyright &y& Elsevier]