皱纹盘鲍消化道粘液细胞的类型与分布

采用阿新兰—过碘酸雪夫氏反应 (AB -PAS)染色方法显微观察和分析了皱纹盘鲍成贝消化道粘液细胞的类型与分布。据所显示颜色的不同 ,将粘液细胞分为Ⅰ—Ⅳ 4种类型 :分别呈红色、蓝色、紫红色和蓝紫色。口区唇上皮分布有大量粘液细胞 ,以Ⅱ型为主 ,另有少量Ⅳ型 ,主要为杯形并多为大型细胞。口球上皮及齿舌囊上皮粘液细胞分布密度高 ,以Ⅱ型为主 ,Ⅳ型次之。食道前段上皮有大量粘液细胞分布 ,中段和后段粘液细胞逐步减少 ,主要为Ⅱ型。肠各段上皮均有粘液细胞分布 ,但下行肠道比上行肠的粘液细胞相对多些 ,也以Ⅱ型为主 ,多为杯形和近圆形。直肠内、外上皮均有大量Ⅱ型粘液细胞分布 ,近圆形的较多。在嗉囊、胃盲囊和胃未见明显着色的粘液细胞     

Genetic variability of cultured populations of the Pacific abalone (Haliotis discus hannai Ino) in China based on microsatellites

The genetic diversity of cultured populations of the Pacific abalone (Haliotis discus hannai Ino) from northern China was analysed using seven microsatellite markers. The microsatellite loci were polymorphic for all the populations, with an average of 8.7 alleles per locus (range 8.0–9.4). The mean observed and expected heterozygosities were 0.547 (range 0.500–0.596) and 0.774 (range 0.754–0.787) respectively. The allelic diversity in terms of number of alleles per locus was considerably lower than that previously found in wild populations (range 21.8–23.0), indicating that bottleneck effects occurred when each population was founded. Significant genetic differentiation among the five cultured populations was shown using F_st and R_st values, and pairwise comparison based on allelic distribution. A neighbour‐joining analysis of the genetic distance did not show a consistent relationship between the geographic and the genetic distances, suggesting the existence of exchanges of breeds and eggs between the hatcheries. The results obtained in this study are useful for a number of areas of interest for fisheries management and the aquaculture industry, especially with regard to breeding programmes.     

Effects of the initial size, stocking density and sorting on the growth of juvenile Pacific abalone, Haliotis discus hannai Ino

During winter months, a novel overwintering mode of transferring juvenile abalones to open seawaters in southern China rather than keeping them in closed land-based nursery systems in northern China is a popular practice. The initial size, stocking density and sorting are among the first considerations when establishing an abalone culture system. This study aimed to investigate the effects of these factors on the growth of juvenile Pacific abalone, Haliotis discus hannai Ino, during overwintering. Juvenile abalones were reared in multi-tier basket form for overwintering in open seawaters in southern China for 106 days. The daily growth rates (DGRs) in the shell length of all experimental groups ranged from 67.08 to 135.75 μm day⁻¹, while the specific growth rates (SGRs) were 0.2447–0.3259% day⁻¹. Variance analysis indicated that both DGRs and SGRs in shell length were significantly affected by the initial body size and stocking density. Furthermore, the effects of stocking density on DGRs and SGRs varied with the initial size. However, sorting abalones according to their initial sizes may not be necessary in practice as sorting did not alter growth significantly at all densities in this study. Factors potentially affecting abalone growth such as genetic control and intraspecific competition were discussed.     

磁化水对皱纹盘鲍生长影响的研究

水在磁场中可以被磁能活化,使水分子缔结链变小,活性增加。小分子水的渗透力、溶解力强,更容易穿过细胞膜,促进机体新陈代谢。本试验利用永磁铁使海水磁化激活,饲养皱纹盘鲍,试验结果显示,壳长2．0～2．5cm的幼鲍在三个月内增长率提高了1．3～1．6％,增重率提高了7％;饵料系数降低了1．7～2．1％;成活率提高了2．4～3．0％。     

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.     

皱纹盘鲍与光棘球海胆越冬期筏式混养的初步研究

实验分越冬前期和越冬后期两个阶段进行。越冬前期鲍与海胆在生长方面的结果无显著差异,但混养可防止苔藓虫的附着,海胆的混养效果以２０个／格略好;越冬后期海胆混养的密度则以５个－１０个／格为最佳,混养可有效地防止多种敌害生物附着。     

Influence of 18:2n‐6/20:5n‐3 ratio in diets on growth and fatty acid composition of juvenile abalone,Haliotis discus hannai Ino

A 120‐day feeding trial was conducted to examine the effects of the ratio of dietary linoleic acid (LA, 18:2n‐6) to eicosapentaenoic acid (EPA, 20:5n‐3) on the growth and fatty acid composition of juvenile Haliotis discus hannai (initial shell length 10.23 ± 1.48 mm; initial body weight 0.13 ± 0.05 g) in a recirculation water system. Five semipurified diets with 35 g kg^?1 total lipid were formulated to contain graded LA/EPA ratios (1 : 0, 0.75 : 0.25, 0.5 : 0.5, 0.25 : 0.75, and 0 : 1, respectively). Twenty‐five juveniles were stocked in a rearing unit, a plastic basket (20 × 20 × 10 cm), as a replicate, and there were three replicates for each dietary treatment. The results showed that abalone survival rates were generally high (90.1–98.3%) and independent of the dietary treatments. However, abalone growth was significantly affected by LA/EPA ratio (P < 0.05). The LA/EPA ratio of 0.25 : 0.75 (Diet 4) produced the highest weight gain rate (WGR, 416.3%), closely followed by the ratio of 0 : 1 (Diet 5, 412.9%), the ratio of 0.5 : 0.5 (Diet 3, 399.7%) and the ratio of 0.75 : 0.25 (Diet 2, 372.1%), but no significant differences were observed among these treatments. The abalone fed the diet without 20:5n‐3 (Diet 1) had the lowest WGR (Diet 1, 363.8%), which was significantly lower than that of Diet 4. Fatty acid profiles in abalone body reflected those of dietary lipids, especially for the polyunsaturated fatty acids. The contents of arachidonic acid (AA; 20:4n‐6) in abalone tissues were positively correlated with dietary level of 18:2n‐6 (P < 0.05). Similar correlation was also observed between the level of docosahexaenoic acid (DHA, 22:6n‐3) in abalone tissues and the level of dietary EPA. It is suggested that abalone, H. discus hannai, have the capacity to synthesize 20:4n‐6 from 18:2n‐6, and maybe 22:6n‐3 from 20:5n‐3.