Haliotis Asinina Linnaeus Research Articles

The Potential of Donkey’s Ear Abalone (Haliotis asinina Linnaeus, 1758) as an Antibacterial Agent and Its Effect on Blood Cholesterol Reduction in Mice (Mus musculus Linnaeus, 1758)

The Potential of Donkey’s Ear Abalone (Haliotis asinina Linnaeus, 1758) as an Antibacterial Agent and Its Effect on Blood Cholesterol Reduction in Mice (Mus musculus Linnaeus, 1758)

Effect of gonadotropin releasing hormone on the expression of luteinizing hormone and estrogen in the nerve ganglia and ovary of a tropical abalone, Haliotis asinina Linnaeus

Gonadotropin releasing hormone (GnRH) is a peptide brain hormone that is involved in the regulation of reproduction in vertebrates via stimulation of the secretion of the pituitary hormones, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which in their turn stimulate sexual development and sex steroid hormone secretion by the gonads. The tropical abalone, Haliotis asinina, in common with many other invertebrates contains a peptide with a similar structure to GnRH. This study looks at its possible involvement in reproduction by injecting groups of one-year-old female abalone at the mature phase by injecting them with synthetic H. asinina (Has) GnRH at doses of 0, 250 and 500 ng/g and then measuring the amount of material in nerve ganglia, ovary and hemolymph that cross-reacted with enzyme-linked immunosorbent assays (ELISA) for vertebrate LH and steroid, estradiol. Immunohistochemistry, using antibodies for the same two compounds, was also carried out to examine the location of immunoactivity in the tissues of the animals. There were slight (in some cases statistically significant) increases in LH-immunoactivity and estradiol in the hemolymph and tissues. However, this applied to the lower dose only (i.e the dose-response relationship was non-monotonic). Using immunohistochemistry, LH-immunoreactive cells were observed in types 1 and 2 neurosecretory (NS1 and NS2) cells within the cerebral and pleuropedal ganglia of H. asinina. In addition, LH-immunoreactive nerve fiber bundles were strongly detected in both ganglia. The immunoactivity against the estrogen appeared to be localized in the granulated cells within the connective tissue and trabeculae of the mature ovary. There was no positive staining in the cytoplasm of any stage of the germ cells. The interpretation of these findings is presently hindered by the fact that the homologous gene for vertebrate LH has not yet been identified in the genomes of any mollusks (so the cause of the immunostaining is as yet unknown) and also by the fact that mollusks are known to readily absorb steroids from the environment and store them long-term in the form of fatty acid esters. More work, involving identification of the protein that cross-reacts with the LH antiserum and also exclusion of the possibility that the estradiol is of exogenous origin, will have to be carried out before these findings can be used to manipulate reproduction in this species.

The effects of different monospecific benthic diatoms on larval settlement, metamorphosis, survival, and growth of Haliotis asinina Linnaeus in the South China Sea

Settlement, metamorphosis, survival, and growth of Haliotis asinina larvae exposed to settlement surfaces coated with biofilms of four local diatom species (Navicula seminulum,Navicula parva,Nitzschia alexandria, Amphora coffeaeformis) were assessed. After 24 h and 72 h, N. alexandria induced the highest settlement rate (p 0.05) for any diatom treatment, but after 72 h, all diatoms induced a significantly higher metamorphosis rate than the control (p 0.05) in diatom film treatments, relative to control. By day 20, post-larvae survived best on slats with N. alexandria (79.86 %). Survival among treatments was the lowest on slats with N. seminulum (54.91 %), and no live larvae were found in the control. Post-larvae on slats with A. coffeaeformis showed the highest daily growth rate of shell length (DGsl) (87.44 μm d−1). Post-larvae on slats with N alexandria showed the lowest DGsl (55.66 μm d−1). Commercial nursery slats seeded with N. alexandria will result in high and consistent settlement, metamorphosis, and survival, while slats with A. coffeaeformis will ensure sufficient food for rapid growth of the H. asinina post-larvae.

Effects of different diet combinations on the growth of juvenile abalone (Haliotis asinina Linnaeus)

Abalones are common herbivores found throughout temperate and tropical waters; however, the diet composition of juvenile abalones remains unclear. This study aimed to evaluate the effects of four different macroalgae (Gracilaria tenuistipitata, Laminaria japonica, Gelidium japonica, and Sargassum sp.) on the feed intake and feeding rate of juvenile Haliotis asinina Linnaeus (H. asinina), and the effect of these macroalgae on abalone food choice as single or combined diets. Juveniles of H. asinina with mean initial weight and shell length of 5.2±0.9g and 24.2±0.7mm, respectively, were selected, and the experiments lasted for approximately 100 days. In trial 1, there were four treatments, and each supplied with a single macroalgal species with 24h fasting; in trial 2, all four macroalgal species were supplied together with 24h fasting; in trial 3, the juveniles were fasted for an additional 24h before supplying a single diet to explore the effect of the fasting; and in trial 4, different combinations of macroalgae were supplied as diet for biological evaluation of factors, including daily rate of shell increase, weight growth rate, specific growth rate, and feed conversion efficiency. Comparison of different feed intakes, feeding rates, and selection rates suggested that H. asinina juveniles showed different feeding preferences for the different macroalgae. The most consumed diet was G. japonica (red algae), followed by G. tenuistipitata (red algae), and L. japonica (brown algae), and finally, Sargassum sp. (brown algae). The results of trial 4 suggested that mixed feeds had better effects than single diets (P<0.05), and the best diet combination was L. japonica and G. tenuistipitata.

Existence of APGWamide in the testis and its induction of spermiation in Haliotis asinina Linnaeus

Immunolocalization by using rabbit polyclonal antibody against APGWamide demonstrated that there was APGWamide immunoreactivity (APGW-ir) in the varicosed nerve fibers in the capsule, connective tissue and trabeculae of the testis whereas there was no APGW-ir in the ovary of sexually mature broodstocks of Haliotis asinina. In vivo bioassay, by injecting APGWamide into foot muscle of mature males and females (age over 24 months), showed that most males (87.50%) injected with 200 μl of 10 − 3 M APGWamide (170 μg APGWamide/animal) could be induced to spermiate whereas fewer males (43.75%) injected with 200 μl of 10 − 6 M APGWamide (0.17 μg APGWamide/animal) could spermiate. Following injection with 10 − 3 M, 53% of males spawned within 3 to 4 h, while the remaining males spawned within 2 to 3 h. The former tended to release more sperm at the range of 1.04 to 2 × 10 9, and the latter at the range 3.62 × 10 7 to 2.07 × 10 8 cells, respectively, and that the sperm of the former group appeared to be more motile. Following the injection of 10 − 6 M, all inducible males spawned within 2–3 h, and 43% of spawned males have sperm around 2 × 10 9, while 57% have fewer sperm number ranging from 2.75 × 10 7 to 9.94 × 10 8 cells. In contrast to males, none of the mature females with ripen ovary could be induced to ovulate. These data suggest that APGWamide is an important signaling molecule that plays a role in the male reproductive process that could be used to induce spermiation.

Changes in the quality of abalone (Haliotis asinina Linnaeus) packaged under atmospheric air, vacuum and modified atmosphere

AbstractChanges in the quality of abalone (Haliotis asinina Linnaeus) meat packaged under modified atmosphere (MA) of 40% CO2/30% O2/30% N2, vacuum and atmospheric air in polyvinylidene chloride (PVDC)/nylon/oriented polypropylene (OPP) pouches, and stored at 2 ± 1°C were investigated. Biochemical indices, such as pH, total volatile basic nitrogen (TVB‐N), and trimethylamine (TMA) and sensory evaluation, as well as total plate counts of packaged abalone meat were determined periodically. TMA was not affected by the packaging conditions, and remained low during storage periods. A decrease in pH of the MA packaged abalones during the storage reflected the apparent absorption of CO2. The content of TVB‐N slowly increased in the MA packaged abalone, whereas those stored in atmospheric air markedly increased during the storage. The sensory quality of MA packaged abalones was shown to be acceptable up to 15 days, while atmospheric and vacuum‐packaged abalones were not acceptable after 3 days of storage. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Egg-laying-hormone immunoreactivity in the neural ganglia and ovary of Haliotis asinina Linnaeus

Immunoreactivity against the abalone egg-laying hormone (aELH) was detected in the fine granules of type 1 and 2 neurosecretory (NS) cells, neurites in the neuropil, and blood sinuses in the connective tissue sheath of the cerebral, pleuropedal, and visceral ganglia of the tropical abalone, Haliotis asinina Linnaeus. The number of positive NS cells, and the intensity of staining in the ganglia, varied and might be related to the stage of ovarian cycle. At any stage, positive cells were most numerous in the pleuropedal, and least numerous in the visceral ganglion. In addition, several cells of the statocyst and associated nerves also exhibited the immunoreactivity. In the ovary, the most intense reactivity was detected in the follicular and granular cells adjacent to mature oocytes, in the trabeculae and the ovarian capsule. The cytoplasm of mature oocytes was also moderately stained. The results indicate that the cerebral, pleuropedal, and visceral ganglia are the main sites of aELH-producing cells. The ovary may also produce aELH locally.

Induction of larval settlement and metamorphosis in the donkey-ear abalone, Haliotis asinina Linnaeus, by chemical cues

The effects of the chemical inducers, gamma-aminobutyric acid (GABA) and potassium chloride (KCl), on the larval settlement and metamorphosis of the donkey-ear abalone, Haliotis asinina, was investigated. H. asinina larvae (5–6 h post-hatch) were exposed to a range of GABA (0.125–2.00 μM) and KCl (1.00–12.00 mM) concentrations for 72 h. Results of the dose response experiments showed that settlement and metamorphosis vary according to the dose levels of the inducer compounds. Under controlled laboratory conditions, 0.45–0.50 μM and 6.0 mM seemed to be the optima for GABA and KCl, respectively, as these concentrations elicited the greatest number of postlarvae that metamorphosed, settled or survived. However, GABA generally promoted better attachment and metamorphic response as well as survival than KCl in H. asinina postlarvae.

Ultrastructure of female germ cells in Haliotis asinina Linnaeus

Summary Germ cells in the ovary of H. asinina are divided into six stages: oogonia and five stages of oocytes. The oogonium is a scallop-shaped cell 8–10 μm in diameter, closely adhered to a trabecula. Its nucleus exhibits small blocks of heterochromatin along the nuclear envelope and a small nucleolus. The cytoplasm contains abundant ribosomes. The stage I oocyte is a round cell 12–25 μm in diameter. Its nucleus contains numerous lampbrush chromosomes consisting of chromatin fibers with three sizes, i.e., 100–200,40-60 and 7–12 nm in diameter. The cytoplasm has numerous mitochondria, few rough endoplasmic reticulum, and abundant ribosomes. The stage II oocyte is a round cell 25–35 μm in diameter. Its nucleus exhibits increasingly decondensed chromatin and a nucleolus, and the nuclear envelope exhibits numerous nuclear pores. The cytoplasm contains numerous and well-developed Golgi bodies, rough endoplasmic recticulum and abundant ribosomes. There are two types of secretory granules: both have a spherical shape, 350–450 nm in diameter, with an electron-dense and electron-lucent matrix, respectively. The stage III oocyte is a pear-shaped cell about 35x70 μm in size. Lampbrush chromosomes are almost completely unraveled. The two types of secretory granules are greater in number and cluster around the Golgi bodies. Larger and more electron-dense ovoid-shaped yolk granules start to appear. The stage IV oocyte is a flask-shaped cell about 50x80 μm in size. Its nucleus contains completely decondensed chromatin and a highly enlarged nucleolus. The cytoplasm is filled with lipid droplets (1.5–3 μm in diameter) and yolk granules (1.5–2.5 μm in diameter). The vitelline-cum-jelly coat starts to develop, and could be derived from the first type of secretory granules which are translocated to be exocytosed at the plasma membrane. The stage V oocyte is similar to the stage IV oocyte except its vitelline-jelly coat achieves maximum thickness and appears fibrous in comparison to the amorphous appearance at stage IV.

Ultrastructure of the differentiating male germ cells in Haliotis asinina Linnaeus

Summary Male germ cells in the testis of H. asinina can be divided into 14 stages based on the ultra-structure and patterns of chromatin condensation. The spermatogonium is a spherical or oval-shaped cell with diameter about 8 μm. Its nucleus contains mostly euchromatin with only a thin rim of heterochromatin along the inner facet of the nuclear envelope. Primary spermatocytes (PrSc) are divided into six stages, i.e., leptotene (LSc), zygotene (ZSc), pachytene (PSc), diplotene (DSc), diakinesis (DiSc) and metaphase (MSc). The early cells are round and become increasingly larger, ranging in size from 12 to 14 um from LSc to PSc; then their sizes gradually decrease from 10 to 7 μn from DSc to MSc. LSc contains small blocks of heterochromatin that are scattered throughout the nucleus. These heterochromatin blocks are increasingly thickened and lengthened in ZSc, and achieve their maximum sizes in PSc. DSc decreases in size, resulting in the close clumping of chromatin blocks; while in DiSc and MSc long and large blocks of chromosomes are formed and then move to be aligned along the equatorial region. In the nuclei of all stages of PrSc, heterochromatin blocks are formed by the tight aggregation of 30 nm chromatin fibers. The secondary spermatocyte (SSc) is a round cell about 8 μm in diameter. They are aligned in rows that separate spermatids from primary spermatocytes. Their nuclei contain criss-crossing chromatin cords in a reticulate pattern, whose individual 30 nm fibers are loosely packed. All spermatids are freed from the epithelium, and can be divided into four stages: St1 is a large round cell (about 5–6 μm), and its nucleus contains evenly dispersed 30 nm chromatin fibers. In St2 the nucleus decreases in size by a half and becomes oval; thus the chromatin fibers are packed closer together, particularly around the axis of condensation. In St3 the nucleus is elongated with individual chromatin fibers enlarged to about 40 nm in cross section, and they are packed tightly together. In St4 (about 3x2 μm) the nucleus is increasingly elongated with the acrosome covering the anterior pole. Individual chromatin fibers are enlarged to 60 nm and appear in cross-section as closely aligned dense granules. The spermatozoon has a cone-shaped head (about 3 x 1.5 μm) that contains completely condensed chromatin covered by the cup-shaped acrosome with the subacrosomal core. Each spermatozoon has globular mito-chondria surrounding a pair of centrioles at the neck region and the tail consists of the axonemal microtubules surrounded by the plasma membrane.