Histology of Asian Seabass (Lates Calcarifer) and histopathology associated with viral infections | |
| Author | Garud, Pradnya Rajendra |
| Call Number | AIT Thesis no.AQ-23-01 |
| Subject(s) | Fishes--Histology Fishes--Diseases Giant perch Seabass |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Aquaculture and Aquatic Resources Management |
| Publisher | Asian Institute of Technology |
| Abstract | Asian seabass (Lates calcarifer) is prized as a commercially important and valuable food fish most farmed in Asia and Australia. Previous studies on histology reported the morpho histological features of the gut, musculature, and lymphoid organs; however, there is a lack of comprehensive reference point for the appearance and normal state of cell and tissue structures. So far, the focus has been on the cytopathological conditions of Asian seabass. In consideration of this, the present study attempted to elucidate the histological featured atlas for juvenile Asian seabass which would greatly enhance the comprehension of histology and serve as the foundation to build up an ichthyopathology knowledge base for observation of cytological tissue patterns. Through routine histological analysis (H&E), the morphology and cellular organization of the gills, integument, spleen, liver, kidney, heart, eye, and gut were examined in detail. The results revealed distinct structural features of each organ system, highlighting their unique functions in the Asian seabass. Mucus cells were evident in the skin and gills of Asian seabass, while mucus-secreting goblet cells were present throughout the alimentary canal. The histological examination of the alimentary canal wall of the Asian seabass indicated the presence of four characteristic layers namely; mucosa, submucosa, muscularis, and serosa. The lamina propria of the posterior intestine demonstrated the presence of prominent gut-associated lymphoid tissue (GALT) in the form of lymphoid aggregates was observed. Clusters of pyramidal acinar cells were present in the exocrine pancreatic tissue and cytoplasm filled with secretory zymogen granules, which defined its active feeding nature. The histology of the spleen and kidney, revealed them to be rich sources of melanomarcophage centers and active hematopoietic organs. The stratified epithelium of gill arch mucosa consisted of numerous rodlet and mucus cells, although different cell types such as chloride cells, mucus cells, epithelial cells, and alternating pillar cells were notably observed in the filament epithelium. Neck cells in the kidney nephron were found to be densely packed, next to the glomerulus. Histologically, the eyes of Asian seabass followed general structural organization, and similar retinal layers were organized as in higher vertebrates. Histopathology of infected Asian seabass associated with viral infections was also studied. Pathognomonic lesions such as basophilic megalocytes in SDDV, basophilic hypertrophied cells (BHC) in ISKNV, cell vacuolization in NNV, and basophilic intranuclear inclusion bodies (BIB) in the LCHV-infected barramundi were examined. In its entirety, our study advances knowledge of normal tissue components, enabling the fish farmers to select good quality seeds and thereby promptly highlighting the problems to alleviate the negative impacts of diseases on barramundi aquaculture. Furthermore, histology can inform strategies for improving the growth and health of Asian seabass. |
| Year | 2023 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Ha, Thanh Dong;Salin, Krishna R. (Co-Chairperson); |
| Examination Committee(s) | Zulfiqar, Farad;Lumpan Poolsawat; |
| Scholarship Donor(s) | AIT Scholarships; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2023 |