Studies On The Morphology And Histology Of Organ And Nutrients Evaluation Of Liza Haematocheila Pond Culture In Guangdong Province

Experiment1:The histological，surface and internal fine structures of gill filaments of Lizahaematocheila were investigated using light，scanning and transmission electronmicroscopy. The results showed that there were4pairs of holobranch，each gillfilament included branchial arch、primary filament、secondary filament and gill raker.The surface structure and ultrastructure of gill filaments and secondary gill lamellaeof Liza haematocheila were similar to those of other teleosts.The surface of primaryfilament had various features such as regular or irregular circular microridges,indentations, micropits and crevices.The primary filaments were divided intorespiratory area and non-respiratory area.The respiratory area of filaments was folded,and its epithelial cells had no microridge but folded surface. Various features such asindentations， micropits and crevices were present on non-respiratory area offilaments,and its epithelial cells had regular fingerprint shape microridges.Thesecondary filaments,the main respiratory,were consisted of basementmembranes,epithelial cells,endothelial cells,pillar cells and capillary vessels.Chloridecells were frequently found in primary filament and secondary filament,and they oftenseemed to be open at the surface between adjacent epithelial cells.The average valueof total respiratory area and relative respiratory area of the Liza haematocheila was59.99±34.51cm²,5.80±2.19cm²Â·g^-1, respectively. The close relationship between thestructure of fish gill and its function of Liza haematocheila was discussed.Experiment2:The morphology and histology of the digestive thract of Liza haematocheilawere investigated by the methods of anatomy, tissue sections and opticalmicroscopy.The results showed that the digestive tract of Liza haematocheila wascomposed of buccal-pharynxcavity,esophagus, stomach and intestine,and the intestinewas composed of foregut, mid-intestine and hindgut. The organization structure of digestive of Liza haematocheila divided into four layers: mucosa, submucosa,musclelayer and serosa. Gastrointestinal wall.The mucosa located in the inner ofgastrointestinal wall, which was mainly composed of the mucosal epithelium andlamina propria.It was loose connective tissue in the submucosa, which containedvasculars,nerves and lymphoid tissue.Muscle layer was dense,which was longitudinallayers of striated muscle in the outer layer of muscle,the inner layer was circularlayers of striated muscle.The outer surface of the digestive tract was covered by a thinlayer of serosa.The differences between the various parts of the digestive tract mainlyshowed the type of folds and epithelial cells，the structure of the muscularis，the typeof muscle tissue and the number of goblet cells.The adaptive relationship betweenmicrostructure of the digestive tract and feeding habit was discussed in this paper.These characteristics made Liza haematocheila had typical habits of omnivorous fish,which was beneficial to food fully digested and absorbed in the intestinal tract.Experiment3:The Microscopic and internal fine structure of the kidney in Liza haematocheila wasobserved using light and transmission electron microscopy （TEM） technique. Resultsshow that the renal corpuscle is composed of Glomerular and Renal capsule，meanmacroaxis diameter and brachyaxis diameter of renal corpuscle are51μm （46～55μm，n=10tail）and33μm（26～39μm，n=10tail）,respectively. There are manypodocytes in renal capsule which have many foot processes sticking to the inner basemembrane. They are quite near capillaries and this indicates that podocyte might playan important role in crude urine producing. Based on the morphology and structure ofepidermic cells，renal tubules are divided into4parts which are neck segment（NS），the first proximal segment（PⅠ），the second proximal segment（PⅡ）and collectingsegment（CS）,which are different from various species. The Neck segment （NS） cellsare cubical epithelium，and there are abundant brush borders at the margo liber of thefirst proximal segment （PⅠ） and the second proximal segment （PⅡ）. Theultrastructure illuminates that the first proximal segment is the most significant part toreabsorb crude urine.Experiment4:The experiment dealt with the basic components （moisture, crude protein, crudefat and ash）,amino acids、fatty acids and mineral elements of pond cultured Lizahaematocheila in Guangdong,also analyze and evaluate the nutritional quality of L. haematocheila. The results showed that contents of moisture, crude protein,crudefat,ash of the fish muscles were76.9%,20.2%,1.2%and1.13%, respectively. Thetotal percentage of18amino acids and8essential amino acids were19.43%and8.77%in the wet muscle samples, respectively. The percentage of essential aminoacids in the total amino acids was45.14%, and the ratio of essential amino acids andnon-essential amino acids was97.23%. Apparently, the two ratios in the muscle of L.haematocheila were in accord with the standard of FAO/WHO （40%,60%）.According to amino acids score（AAS） and chemical score （CS）,the first limitingamino acid was valine and the second limiting amino acid was methionine+cystinein the muscle of L.haematocheila,with an essential amino acid indice （EAAI） of61.56. Twenty-two fatty acids were found in the dried muscle samples and the ratio ofunsaturated fatty acids and saturated fatty acids was3∶1. The content of EPA+DHA was5.92%in the dried sample, which was higher than some other economicfishes. The composition of trace elements in the muscles of L.haematocheila wasreasonable. In general, L.haematocheila are euryhaline fish species with balancednutrition and relatively high nutritional value with a good prospect in terms ofdevelopment and extension.