Studies On Breeding Biology Of Epinephelus Septemfasciatus And Histologic Biology Of Cheilinus Undulatus

Experiment 1: Effects of environmental factors on the spermatozoa vitality of Epinephelus septemfasciatusThe effects of salinities and temperatures on the spermatozoa vitality, and cryopreservation of the spermatozoa of Epinephelus septemfasciatus were investigated. The results showed that the spermatozoa vitality was highest under the condition of salinity 30 and water temperature of 22.8℃, with the longest eddying time of 33.99 min. Quadratic function correlations were found between eddying time of spermatozoa and both salinity and temperature, as well as between total active time and both that. The motility of spermatozoa were inhibited reversibly in low-salinity (<15 ppt) and freshwater. Strong vitality of spermatozoa was kept for longer than one week preserved in low temperature below 4℃. Survival rate of spermatozoa cryopreservation were over 10% with the optimal activated salinity of 25.Experiment 2: Ultrastructure of spermatozoa in Epinephelus septemfasciatusUltrastructure of spermatozoa of E. septemfasciatus was investigated using transmission electron microscopes. The spermatozoa consists of two parts: the head and the tail (flagellum), no mid-piece. The spermatozoa of E. septemfasciatus are acrosome less. A large spherical nucleus, covered with nuclear membrane, is located at the front part of the head and about its 1/3. The high electron density chromatin are the main components of nucleus, with several low electron density vesicles in it. There is little space between the plasma membrane and nuclear membrane at the front part of head. The implantation fossa is located in the posterior end of the nucleus. Proximal centriole and intercentriolar body are located in implantation fossa. The posterior end of the head is a large sleeve, which is about 2/3 of the head. The sleeve contains centriolar complex, several mitochondria and vesicles. At the mid-part of the sleeve, there is a sleeve carve, out of which the thin and long tail stretches. The tail with only a little cytoplasm is thin and long. The axoneme between the end of the base body and the head of the tail is"9+0".The 9 doublet of the axoneme, the central structure of the tail, is connected to the 9 strips of the posterior end of the basal body. The flagellar tail is the conventional"9+2"axoneme.Experiment 3: Morphological development of larvae and juvenile Epinephelus septemfasciatusThe morphological characteristics of early development of Epinephelus septemfascitus were observed, surveyed and described during July and August 2009. The results showed that the total length of newly hatched larvae was (1.3606±0.0091) mm. A large yolk sac of newly hatched larvae, located at the abdomen, was elliptic, and its major axis was (0.8602±0.0151) mm, minor axis (0.5814±0.0162) mm. The diameter of the spherical oil droplet was (0.1258±0.0065) mm. At the water salinity of 29-31 and temperature of 23.0-26.5℃, the yolk sac of the larvae was disappeared 4days after hatching, and the larvae began to eat. It was the time for beginning to the development of organs during 4-12 days after hatching, and at that time the larvae grew very slowly, the larvae grew fast obviously 21 days after hatching. The second spine of dorsal fin and the first spine of ventral fin appeared at 19 days after hatching. The growth and configuration of the second spine of dorsal fin and the first spine of ventral fin is the most remarkable characteristics during early development of E. septemfaciatus. Highly significant exponential function correlated between days after hatching and total length, body length, body height, pre-anal length, eye diameter, weight. The ratio of body length to height was undulated slightly, a few days latter after hatching the ratio kept stable.Experiment 4: Microstructure of peripheral blood cells and biochemical indices of Cheilinus undulatusThe peripheral blood cells of C. undulatus were morphologically described used the double dyed method of Wright's and Giemsa. The serum biochemical indices of C. undulatus were also studied. The results shows that the erythrocyte and leucocyte concentration in the blood were (3.15±0.79)×10¹²/L and (1.42±0.71)×10¹⁰/L, respectively. The number of erythrocyte was much larger than the leucocyte in the blood. The sizes of the different type blood cells were also measured. On the stained smears, five major cell types were recognized: erythrocyte, neutrophil, monocyte, lymphocyte and thrombocyte. The eosinophilic granulocyte and basophilic granulocyte were not found in smears, instead, some nuclear shadow of erythrocytes, immature erythrocytes, direct dividing and dissolving erythrocytes were easily found. Among these cells, the size from large to small follows the order of monocyte, neutrophil, erythrocyte, large lymphocyte, thrombocyte and small lymphlcyte. The most of the indices were different from the normal ranges of human, but it's recently the same as other teleosteans. Experiment 5: Light, Scanning and Transmission Electron Microscopical Observation of Gill Filaments of Cheilinus undulatusThe histological, surface and internal fine structures of gill filaments of Cheilinus undulatus were investigated using light, scanning and transmission electron microscopy. The results showed that there were 3 pairs of holobranch,1 pair of hemibranch and 1 pair of pseudobranchia. The comb primary filaments lined on the gill arches closely. Many secondary gill lamellae arranged closely on two sides of each filament, and inlaid each other. The blood system of filament was consisted by afferent artery, efferent artery and capillary vessel nets. Various features such as indentations, micropits and crevices were present on non-respiratory surface of filaments. The respiratory surface of filaments were fold. The filaments were covered by epithelia cells, which had different surface features in different areas. It had regular fingerprint shape microridges in non-respiratory surface, no microridge but folded surface in respiratory area and irregular microredges in the transition region. There were many holes among the non-respiratory surface. Chloride cells and mucous cells were observed and many mitochondria and excretion vesicles distributed in chloride cells. Secondary filaments was consisted by epithelia cells, basement membranes, endothelial cells and pillar cells. These structures formed the water-blood barrier. The close relationship between the structure of fish gill and its function were discussed.Experiment 6: Morphology and histology of the digestive tract in Cheilinus undulatusThe morphology and histology of the digestive tract of Cheilinus undulatus were investigated by the methods of anatomy, tissue sections and optical microscopy. The results showed that the digestive tract of C. undulatus was composed of buccal-pharynx cavity, esophagus, stomach and intestine. There were jaw teeth and pharyngeal teeth in the large buccal-pharynx cavity. The esophagus was very coarse and short. The stomach shaped as"I"and swelled. There was no pyloric caeca at the pyloric stomach. The intestine was very short, and it included anterior intestine, posterior intestine and rectum. The intestinal coefficient was about 3.05. It was full of microvilli in the cavity all over the digestive tract. The wall of the digestive divided into four layers: mucosa, submucosa, muscle layer and serosa. The epithelium of the digestive tract was composed of simple columnar cells, in which goblet cells were distributed. It was loose connective tissue in the submucosa. It was circular layers of striated muscle in the inner layer of muscle, the outer layer was longitudinal layers of striated muscle. The nerve plexuses distributed in the muscle layer between the circular layer and the longitudinal layer. The outer surface of the digestive tract was covered by a thin layer of serosa.