http://hdl.handle.net/10862/5904 Terminal Report of the Regional Fish Disease Project on “Development of Fish Disease Inspection Methodologies for Artificially-Bred Seeds” Funded by the Government of Japan Trust Fund from 2000 to 2004 2026-04-06T12:59:11Z http://hdl.handle.net/10862/5909 Studies on the experimental transmission model of monodon baculovirus (MBV) and hepatopancreatic parvovirus (HPV) in shrimp (Penaeus monodon) Catap, Elena S.; de la Peña, Leobert D. Nagasawa, Kazuya Series of experiments on the transmission of monodon baculovirus (MBV) and hepatopancreatic parvovirus (HPV) in Penaeus monodon were undertaken. Feeding of MBV-infected carcasses to experimental shrimps resulted to 100% infection at day 4 post-infection as determined by wet-mount technique and histopathology of hepatopancreas. Oral route of infection was also efficient in inducing HPV infection in postlarval P. monodon. Percentage of infection was 100% at 5-7 days post-infection which was also determined using the wet-mount technique, originally developed for MBV, and through histopathology. Further studies on the transmission of HPV showed that age of shrimps is an important factor in its pathogenicity. Results showed that HPV could be transmitted efficiently in postlarval P. monodon, but less efficient in juveniles. No infection was induced among the adult shrimp samples. It was also shown that the oral route of infection is more efficient in transmitting HPV rather than water-borne inclusion bodies. This is the first report of horizontal transmission of HPV in postlarval P. monodon in the Philippines. 2005-03-01T00:00:00Z http://hdl.handle.net/10862/5930 Development of immunological indices for monitoring health status in shrimp (Penaeus monodon) Amar, Edgar C.; Catap, Elena S.; de la Peña, Leobert D. Nagasawa, Kazuya Some hemolymph parameters were determined as non-invasive early-warning indicators of health status in black tiger shrimp (Penaeus monodon). These included total hemocyte count (THC), respiratory burst activity, phenoloxidase activity (PO), plasma total protein, and plasma bactericidal activity. Changes in the above parameters were also determined over a 108 hr duration after exposure to the following treatments: (1) bath administration of an immunostimulant (β-glucan) at a concentration of 0.1 mg/L; (2) intramuscular (IM) injection of 1 × 10⁶ cfu/g Vibrio sp. (PN-9801); and (3) a control (IM injection of phosphate buffered saline). Changes in the above parameters were also monitored for 12 days in shrimps exposed to white spot syndrome virus (WSSV) by IM injection. Results showed that PO activity peaked at 46-98 hr post-exposure and was highest for β-glucan, followed by Vibrio sp. However, observed differences among the treatments were not significant. Peaks in THC responses varied according to the stimuli, ranging between as early as 4 hr in the Vibrio and control, and 48 hr in the β-glucan group. Bactericidal activity of the shrimp plasma exhibited the same pattern as that of THC except that activity peaked at 24 hr for immunostimulated shrimp and at 48 hr for control. Peak inhibition was markedly higher for the Vibrio and β-glucan groups than the control. Respiratory burst activity peaked at 48 hr in all treatments and was highest for bacteria, followed by the control and immunostimulated group. Comparison of histopathological changes of the shrimp lymphoid organ (LO) from the different groups revealed no remarkable changes in the PBS-injected group, which appeared normal up to 48 hr post-exposure. However, degenerative tissue changes occurred progressively in the bacteria-treated group, while some changes resembling that of the bacteria-treated group in shrimp treated with immunostimulant were assumed to be due to enzymatic (PO) reactions. As for WSSV-exposed shrimp, THC, DC, and PO activity showed a sharp decline that are associated with injury and infection. Notwithstanding high variation in individual shrimp responses, the time-course response of shrimp to the variables tested was apparent, which may be useful in detecting differences between different stimuli. As for factors affecting hemocyte responses, THC decreased with decreasing salinity levels and increasing time of exposure to critical dissolved oxygen levels. It also showed an optimum between pH 6.5 and 8, whereas it was fairly constant in shrimps between 3 and 30 g, but increased with bigger-sized (60 g) shrimp. Phenoloxidase activity slightly increased with short exposure to critical DO levels, but decreased with longer exposure time. Salinity had a negative effect on phenoloxidase activity, which decreased as salinity decreased. PO activity had an optimum between pH 6 to 8 while it increased logarithmically with increasing size up to 40 g, after which the increase was asymptotic. In conclusion, the patterns and differences in hemolymph responses among the different groups can be used as indices of certain physiological and pathological conditions in P. monodon. However, since these responses are affected by various factors, assays using these indices as health indicators should be conducted under well-defined conditions. 2005-03-01T00:00:00Z http://hdl.handle.net/10862/5931 Parasites of commercially-important marine fish cultured in the Philippines Cruz-Lacierda, Erlinda R.; Pineda, April Joy T. Nagasawa, Kazuya The commercially-important cultured marine fish, orange-spotted grouper (Epinephelus coioides), mangrove red snapper (Lutjanus argentimaculatus) and rabbitfish (Siganus guttatus), were examined at regular intervals to screen for their associated parasite fauna. Culture and collection sites included hatcheries, earthen ponds and floating cages in Panay Island, Philippines. Wild fish from water supply canals of fishponds, as well as near the vicinity of floating cages, were also collected and examined for parasites. The host-parasite relationship was also determined for some significant parasites. Similar parasite fauna was recovered both in wild and cultured fish indicating that the former is a potential reservoir of these organisms. Most of the parasites recovered are management-related problems and can be prevented through practice of good husbandry and management techniques. 2005-03-01T00:00:00Z http://hdl.handle.net/10862/5918 Prevalence of economically-important viral diseases in wild shrimp (Penaeus monodon) in the Philippines de la Peña, Leobert D.; Lavilla-Pitogo, Celia R.; Villar, Corina Belle R.; Paner, Milagros G. Nagasawa, Kazuya Prevalences of white spot syndrome virus (WSSV) and monodon baculovirus (MBV) were determined using polymerase chain reaction (PCR) as the detection method in wild black tiger shrimp (Penaeus monodon) collected from seven sampling sites in the Philippines. These seven sampling sites are the primary sources of spawners and broodstocks for hatchery use. Samples for PCR comprised DNA extracts from gills for WSSV detection and from hepatopancreas for MBV. As a result, WSSV was detected in shrimp from all sites except Bohol during dry season, and were negative from all sites except Palawan during wet season. However, all the positive shrimp showed no white spots in the carapace. MBV was also detected from all sites except Palawan, Negros Occidental and Bohol during dry and wet seasons, respectively. The prevalences of WSSV and MBV showed seasonal and sex variations, i.e. the prevalence in dry season (April-May) was higher than in wet season (August-October), and the prevalence in female shrimps was higher than in males. A very low prevalence of dual infection with WSSV and MBV was also observed. These results suggest that the viruses have already established in the local marine environment and in wild populations of P. monodon, and spawners collected during dry season could serve as the main source of contamination for vertical transmission of the virus when they spawn. 2005-03-01T00:00:00Z