UPV Digital RepositoryUPV-DRUniversity of the Philippines Visayas
 

UPV Theses and Dissertations

Permanent URI for this communityhttps://hdl.handle.net/20.500.14583/10

Browse

Filters

2003 - 20042

Settings

Committee Chair: search.filters.chair.Tayo, GilmaDegree: search.filters.degree.Bachelor of Science in Biology

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Effect of salinity on the embryonic development of Portunus pelagicus and Charybdis feriatus eggs
    Alba, Kristine Margaret A. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2003-03)
    The effect of salinity on the embryonic development of Portunus pelagicus and Charybdis feriatus was studied. The five different salinity levels used were 15 ppt, 25 ppt, 35 ppt, 45 ppt, and control (33-35 ppt) to compare their effect on the embryonic development of both species. One thousand newly spawned crab eggs were incubated in vitro in 4-L Nalgene fiberglass containers with 3-L of water at different salinity levels. Mild aeration that allows movement of eggs within the water column was provided. There were three replicates per treatment. Embryonic development of eggs (30 eggs were taken in every salinity level) was monitored daily up to hatching. The newly hatched larvae were then collected and counted. Results showed that during the incubation period, the most advanced stage of embryonic development for Portunus pelagicus was at 33-35 ppt and for Charybdis feriatus was at 35 ppt. There was normal embryonic development and hatching at 35 ppt, 45 ppt, and control (33-35 ppt) for Portunus pelagicus and at 15 ppt, 25 ppt, 35 ppt, 45 ppt, and control (33-35 ppt) for Charybdis feriatus. Eggs that were incubated at 15 ppt and 25 ppt for Portunus pelagicus died. There was normal embryonic development in both species when incubated at 45 ppt. Hatching rate for Portunus pelagicus at control (33-35 ppt) was 34.1 %, at 35 ppt was 16.1 %, and at 45 ppt was 5.8 %. Hatching rate for Charybdis feriatus at 35 ppt was 52.5 %, at control (33-35 ppt) was 21.2 %, at 45 ppt was 12.8 %, at 25 ppt was 6.7 %, and at 15 ppt was 0.3 %. To summarize, embryo of Charybdis feriatus eggs can withstand a wider range of salinity: from a low salinity of 15 ppt to a high salinity of 45 ppt, that makes them a euryhaline species. On the other hand, Portunus pelagicus cannot support embryonic development at lower salinities of 15 and 25 ppt that makes them a stenohaline species.
  • Thumbnail Image
    Item
    Histopathology of the gill, abdomen, and lymphoid organ of giant black tiger shrimp (Penaeus monodon) infected with white spot syndrome virus (WSSV)
    Apines, John S. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2004-03)
    Histological changes in giant black tiger shrimp, Penaeus monodon, were investigated at various time intervals after injection with white spot syndrome virus (WSSV). After infection with the virus, mortalities were observed. Gills, abdomen, and lymphoid organ (LO) were then dissected and subjected to histological examination. The study revealed that the lymphoid organ was the most severely damaged compared to the gills and abdomen. The abdomen, although low in prevalence, was one of the target organs of the virus. Light microscopy showed the aggregation of hemocytes in the abdominal muscles of the shrimp. The infected shrimp were found to have a high prevalence of apoptotic cells. The results of this study supported the earlier findings that cell death in viral infection may have resulted mainly from apoptosis and that increasing numbers of apoptotic cells probably caused the death in WSSV-infected shrimp. Moribund shrimp had extensive deterioration of vital tissues such as the gills and lymphoid organs, thus affecting vital processes in the shrimp body. Gross signs of lethargy and weakness were observed in the moribund shrimps. Hemocyte aggregation, as well as formation of spheroids, were observed in the hemal sinuses of the LO, the abdominal region and the gills. The results are discussed in relation to the hypotheses of acquired tolerance and quasi-immune response in shrimp.