Effects of elevated pCO2 on the early development of the commercially important gastropod,Ezo abalone Haliotis discus hannai

We used an up‐to‐date, a high accuracy CO₂ manipulation system to investigate the sensitivity of organisms to CO₂ acidification, rearing marine calcifiers under elevated CO₂ in running water. We evaluated the effects of elevated partial pressures of carbon dioxide (pCO₂) in seawater on larvae of the commercially important marine gastropod Ezo abalone Haliotis discus hannai. In larval Ezo abalone, no effect of exposure to <1100 μatm pCO₂ seawater was observed in fertilization, malformation, or mortality rates until 15 h after fertilization. However, compared to control larvae in seawater (450 or 500 μatm pCO₂), the fertilization rate and the hatching rate (15 h after fertilization) decreased with increased pCO₂ exposure (1650 and 2150 μatm pCO₂) and the malformation rate increased significantly, with the larval shell length being smaller 75 h after hatching. These results suggest that ocean acidification will potentially impact the marine population of Ezo abalone as a human food source in the future.     

Effects of artificial selection practices on loss of genetic diversity in the Pacific abalone,Haliotis discus hannai

The Pacific abalone, Haliotis discus hannai Ino, is one of most important aquaculture species in China. Artificial selection has been the common and inevitable approach in breeding. In present study, the effect of artificial selection on the genetic structure of two abalone lines (JJ selection strain, three successive selection lines based on the fast‐growing trait, which was named JJF0, JJF1, JJF2, and JJF3; and R selection strain, the offspring of the red shell colored variants) were evaluated using 10 microsatellites. Loci showed from low to high polymorphism, with the number of alleles (A) ranging from 2 to 18 in each population. The mean observed (H_o) and expected heterozygosities (H_e) were 0.650 ± 0.022 and 0.711 ± 0.018, respectively. In selection strain JJ, the values for most diversity genetic indexes (A_e, the number of effective alleles, H_o and H_e) decreased from JJF0 to JJF3. Meanwhile, compared to JJ line, the genetic diversity estimates of R were close to those of JJF3. Nei's genetic distance ranged from 0.20357 to 0.51346. The unweighted pair group method with arithmetic mean tree based on Nei's genetic distance also showed that the control Japan population and JJF0 formed to a cluster firstly, which were subsequently grouped together with JJF1, JJF2, JJF3, whereas the R was isolated from the rest of the populations. Analysis of genetic information indicated that genetic diversity was lost with artificial selection practices. Mechanisms underlying the maintenance of an acceptable level of genetic diversity while pursuing economic interests should be conducted in future research studies.     

The potential for utilizing fouling macroalgae as feed for abalone Haliotis discus hannai

In order to assess the potential of utilizing fouling macroalgae as feed for abalone Haliotis discus hannai, the species, biomass and total stock of fouling macroalgae attached on the aquaculture facility‐lines were investigated and assessed at Sungo Bay, China, in August 2007. The nutritional value of four fouling macroalgae (Codium fragile, Sargassum muticum, Ulva pertusa and Laminaria japonica) and one cultured macroalgae (Gracilaria lemaneiformis) as the diet of abalone was assessed by analysis of the chemical composition of the macroalgae and by measuring bioavailability and digestibility to abalone H. discus hannai under laboratory conditions in August 2007. The results showed that the biomass of fouling macroalgae at the two sites was 243.61 ± 26.23 and 1078.15 ± 50.28 g m^?1 respectively. The contents of protein of G. lemaneiformis and C. fragile were 18.30% and 17.60%, respectively, which were significantly higher than the others. The five macroalgae were accepted by the abalone, and growth energies (P) and growth efficiency (%) were positive. However, significant differences were found among the different macroalgae. The growth efficiencies of abalone show a negative relationship with the levels of dietary lipid and a positive relationship with the protein contents. These results suggest that fouling macroalgae have a great potential to be used as diets of abalone.     

Mining expressed sequences for single nucleotide polymorphisms in Pacific abalone Haliotis discus hannai

Although single nucleotide polymorphisms (SNPs) are important resources for population genetics, pedigree analysis and genomic mapping, such loci have not been reported in Pacific abalone so far. In this study, a bioinformatics strategy was adopted to discover SNPs within the expressed sequences (ESTs) of Pacific abalone, Haliotis discus hannai , and furthermore, polymerase chain reaction direct sequencing (PCR-DS) and allele-specific PCR (AS-PCR) were used for SNPs detection and genotype scoring respectively. A total of 5893 ESTs were assembled and 302 putative SNPs were identified. The average density of SNPs in ESTs was 1%. Fifty-two sets of sequencing primers were designed from SNPs flanking ESTs to amplify the genomic DNA, and 13 could generate products of expected size. Polymerase chain reaction direct sequencing of the amplification products from pooled DNA samples revealed 40 polymorphic SNP loci. Using a modified tetra-primer AS-PCR, seven mitochondrial and six nuclear SNPs were typed and characterized among 37 wild abalones. In conclusion, it is feasible to discover SNPs from number limited ESTs and the AS-PCR as a simple, robust and reliable assay could be a primary method for small- and medium-scale SNPs detection in abalones as well as other non-model organisms.     

皱纹盘鲍副肌球蛋白的分离纯化及初步性质研究

为了研究鲍鱼肌原纤维中副肌球蛋白(PM)的性质,以皱纹盘鲍为原料,采用硫酸铵盐析和羟基磷灰石柱层析相结合的方法,从肌肉中纯化得到PM。利用肽质量指纹图谱测定其内部肽片段氨基酸序列;采用双向电泳测定其等电点;用圆二色谱研究其二级结构特征,进一步利用红外光谱对其官能团进行表征。SDS-PAGE结果显示,PM分子量约为97.0 ku。肽质量指纹图谱分析获得36条肽段共403个氨基酸残基,与盘鲍和太平洋牡蛎PM的一致性分别为99.7%和72.0%,表明纯化蛋白确为PM。双向电泳测得PM等电点约为5.4,证明其为一种酸性蛋白。圆二色谱结果显示,PM溶液在192 nm处有一正吸收峰,在208和223 nm处各有一负吸收峰,具有典型α-螺旋结构的特征谱峰型;其热变性温度为58.1°C。红外光谱分析结果进一步证实,PM具有完整的α螺旋结构。对鲍鱼PM理化特性进行研究,可为鲍鱼质构相关研究及鲍鱼制品深加工提供一定的理论基础。     

Supplementary oxygen and temperature management during live transportation of greenlip abalone, Haliotis laevigata (Donovan, 1808)

Live greenlip abalone, Haliotis laevigata , are highly valued in Australian export markets with demand increasingly being met with cultured stock. Live transportation of abalone requires the maintenance of favourable conditions within transport containers for periods exceeding 35 h. We examined the combined effects of temperature regulation (ice provision) and of supplemental oxygen (60% and 100% concentrations) on mortality rates of abalone over 7 days following a 35-h simulated live-transport experiment. We also examined the physiological condition of greenlip abalone (oxygen consumption rate, haemolymph pH and weight) during the simulation experiment. The provision of ice and supplementary oxygen reduced abalone mortalities. Omission of ice and supplementary oxygen during the transport simulation resulted in mortality rates ranging from 70% to 100%. The addition of ice to containers with ambient oxygen concentrations decreased average mortality rates by 50%. While supplementary oxygen further reduced these rates, the provision of both ice and 100% oxygen was by far the most effective combination, reducing mortalities to between 2% and 6%. Supplementary oxygen increased oxygen consumption rates of abalone above those transported at ambient oxygen concentrations. Live-transport decreased haemolymph pH in all treatments but was most pronounced in treatments without ice or supplementary oxygen. On average, abalone lost 7–13% of their weight during the simulation but this loss was independent of transport treatment.     

Growth performance of disk abalone Haliotis discus hannai in pilot- and commercial-scale recirculating aquaculture systems

The study investigated the growth performance of abalone from juvenile to marketable size in a commercial-scale recirculating aquaculture system. The rearing system consisted of 12 raceways (4.0 × 0.8 × 0.6 m) with a protein skimmer and a submerged biofilter for juveniles and 10 raceways (6.6 × 1.3 × 0.6 m) with a protein skimmer and a trickling biofilter for on-growing. Sea mustard (Undaria pinnatifida) and kelp (Laminaria japonica) were fed to the abalone. The total weight of abalone in the recirculating aquaculture system at the juvenile stage increased from 22.0 kg (average shell length 24.5 mm) to 75.5 kg (average shell length 42.5 mm) after 180 days. Feed conversion ratios increased slightly from 13.7 for the first 90 days to 16.3 thereafter. The shell growth rate of juvenile abalone between 24.5 mm and 34.8 mm was 3.4 mm month⁻¹, while for juveniles between 34.8 mm and 42.5 mm it was 2.6 mm month⁻¹. The total weight of abalone in the recirculating aquaculture system for the on-growing stage increased from 100.0 kg (average shell length 44.0 mm) to 433.3 kg (average shell length 72.7 mm) after 570 days. The feed conversion ratios for the first 173 days, the next 320 days, and the last 570 days were 19.6, 22.1, and 24.8, respectively. The growth rate of the average shell length during the on-growing period was 1.5 mm month⁻¹. Total ammonia nitrogen (TAN) concentrations were stabilized below 0.12 mg l⁻¹ in the juvenile recirculating system and 0.14 mg l⁻¹ in the on-growing recirculating system after conditioning of the biofilters.     

Genetic characterization and gonad development of artificially produced interspecific hybrids of the abalones, Haliotis discus discus Reeve, Haliotis gigantea Gmelin and Haliotis madaka Habe

Hybridization among abalone species has been suggested as a possible means to increase their growth rates for aquaculture. As a first step to test the usefulness of the hybrids of Japanese abalone species (Haliotis discus discus, Haliotis gigantea and Haliotis madaka) for aquaculture, we characterized the genetic background and gonad development of hybrids that were produced by artificial insemination. The hybrid status of the resulting offspring was confirmed by assaying 14 allozymes and by RFLP analysis of the 16s rRNA and cytochrome oxidase I (COI) regions of mtDNA using 13 restriction enzymes. Histological examination of the gonads of the hybrids was conducted in comparison with those of the parental species. Cross‐breeding among the three species was conducted successfully in all combinations although with lower fertilization rates (means of 1.3–60.8%) than the parental species (34.3–90%). Crosses between H. discus discus and H. madaka had higher fertilization rates (22.4–60.8%) than those involving H. gigantea (1.3–19.9%). The hybrids were ascertained by the presence of both parental genotypes at the LDH‐A, ME‐A, MDH‐A and GPI loci. The maternal origin of the hybrid mtDNA was confirmed by digestion with DdeI, TaqI, HpaII of the COI region. No polymorphism was observed in the 16S rRNA region. The hybrids had gonadal development and maturity stages similar to the parental species up to fully mature oocytes and sperm. They spawned upon stimulation and produced viable offspring with high fertilization rates and successful development to the juvenile stage in back‐ and homologous hybrid crosses.     

三沙湾夏季大型底栖动物群落结构及其和水产养殖活动关系

为了解三沙湾大型底栖动物群落结构以及区域内水产养殖活动对其产生的影响,依据2016年夏季采集的样品数据,分析底栖群落结构、群落与环境因子的相关性以及典型群落参数在不同类型水域(鱼类网箱、海带吊绳、鲍鱼筏式养殖水域和自然水域)间的差异。结果表明,三沙湾共发现大型底栖动物6门75种,群落丰度和生物量均值分别为371.34个·m^-2和21.82 g·m^-2。其中,丝异须虫(Heteromastus filiformis)、不倒翁虫(Sternaspis scutata)、欧努菲虫(Onuphis eremita)、索沙蚕属一种(Lumbrineris sp.)和角海蛹(Ophelina acuminata)等多毛纲动物为数量优势物种,常在鲍鱼筏式和鱼类网箱养殖水域形成较高种群数量。物种数(N)、丰度(S)、生物量(B)和Shannon-Wiener多样性(H′)、Pielou均匀度指数(J′)、Margalef丰富度指数(d)等群落参数在不同水域之间无显著差异(P>0.05)。聚类分析结果显示,区域内群落空间异质性较高,空间差异未反映出水域类型的差别。水深、底层水体温度和盐度、沉积物含水率、粉砂-黏粒比例、总氮含量以及总有机碳含量等环境因子和群落相关性较强。综上,三沙湾底栖群落在群落参数方面与我国沿海温带水域相似,但群落的物种组成和较高的空间异质性较为独特;物种组成可表征网箱养殖活动的底栖生态效应。     

投喂鲍内脏多糖对罗非鱼肠道菌群结构的影响

利用PCR-DGGE和Illumina测序技术研究了罗非鱼(Oreochromisniloticus)肠道菌群结构及饲喂鲍内脏多糖后罗非鱼肠道菌群的动态变化。在罗非鱼肠道中检测到13个门的细菌,其中梭杆菌门(Fusobacteria,77.84%)为优势菌门,拟杆菌门(Bacteroidetes, 8.59%)、衣原体门(Chlamydiae, 6.18%)、变形菌门(Proteobacteria, 5.84%)和放线菌门(Actinobacteria, 1.20%)为次优势菌门,还检测到Saccharibacteria等8个菌门和一些未知类群。在属的水平上,优势菌属为鲸杆菌属(Cetobacterium)、Neochlamydia、邻单胞菌属(Plesiomonas)和不动杆菌属(Acinetobacter),分别占77.84%、5.796%、2.64%和1.13%,还有一个紫单胞菌科(Porphyromonadaceae)的未知属,占8.29%。此外还有分枝杆菌属(Mycobacterium)等6个菌属和一些未知属。投喂添加鲍多糖的饲料对罗非鱼肠道微生物的构成造成了明显影响,饲喂鲍多糖的处理组和饲喂普通饲料的对照组样品分别聚为两大类。投喂添加鲍多糖饲料后,放线菌门、Saccharibacteria、疣微菌门和TM6_Dependentiae的丰度显著下调;在属的水平上,邻单胞菌属、鲸杆菌属的丰度上调;Neochlamydia、不动杆菌属、分枝杆菌属、Alsobacter、Aquicella、假单胞菌属、气单胞菌属、Alpinimonas等属的丰度下调。其中分枝杆菌属、Alsobacter、Aquicella和邻单胞菌属的丰度与对照差异显著(P0.05)。在种水平上,一些潜在致病菌,如鲍曼不动杆菌(Acinetobabacterbaumannii)、龟分枝杆菌(Mycobacteriumabscessus)、Aeromonas sharmana、耐酪酸冢村菌(Tsukamurella tyrosinosolvens)、铜绿色假单胞菌(Pseudomonas aeruginosa)等的丰度下调,其中龟分枝杆菌和耐酪酸冢村菌与对照差异显著(P0.05),而鲸杆菌属等有益菌的丰度上调。本研究从肠道微生物的角度来研究鲍内脏多糖对宿主的影响,为海洋生物活性物质的功效评价提供了新思路,也为鲍内脏活性物质的开发利用、益生元的研制等奠定理论基础。