Now showing items 1-4 of 4

    • Article

      Parasites of window-pane oyster (Placuna placenta Linnaeus, 1758) from Trapiche, Oton in west central Philippines 

      G Erazo-Pagador - The Philippine Agricultural Scientist, 2015 - College of Agriculture, University of the Philippines Los Baños
      Parasitology of edible and commercially valuable window-pane oysters (Placuna placenta L.) using gross macroscopic examination and histology was conducted. To screen for the presence of parasites, wild oysters were collected monthly from January 2008 to December 2008 from Trapiche, Oton in west central Philippines. Thirty live adult oysters with shell length (SL) of 52-89 mm were hand-picked monthly. Gross observation showed the presence of pea crabs (Pinnotheres sp.) in the mantle cavity of the oysters. The overall prevalence and intensity of P. placenta with pea crabs were 4.44% and 1, respectively. Histological examination revealed the occurrence of Tylocephalum sp. (prevalence and intensity of the parasites were 1.66 % and 0.5, respectively) in connective tissues around the digestive gland. Tylocephalum sp. was found surrounded by hemocytic infiltration. Ciliates (Ancistroma sp.) were also observed in the gills with overall prevalence of 38.83% and intensity of 7.51. Larval stages of trematodes of Bucephalus sp. (prevalence, 18.83%; intensity of 1.5) were found in the connective tissues of the female gonad. The study presents a documentation of parasites of P. placenta in the Philippines.
    • Conference paper

      Parasitic caligid copepods of farmed marine fishes in the Philippines 

      ER Cruz-Lacierda, G Erazo-Pagador, A Yamamoto & K Nagasawa - In MG Bondad-Reantaso, JB Jones, F Corsin & A Takashi (Eds.), Diseases in Asian Aquaculture VII: Proceedings of the Seventh Symposium on Diseases in Asian Aquaculture, Taipei, Taiwan 20-26 June 2008, 2011 - Fish Health Section, Asian Fisheries Society
      Recently, heavy infestation of caligid copepods occurred among farmed rabbitfish Siganus guttatus, pompano Trachinotus blochii and sea bass Lates calcarifer in the Philippines. In S. guttatus broodstock, Caligus epidemicus, Pseudocaligus uniartus and Lepeophtheirus sigani concurrently caused severe erosion and hemorrhaging of the body surface, fins and eyes of affected fish occurring at 95.78%, 1.52% and 0.70% of the parasite load, respectively, and with associated mortality of the host fish. In marketable-sized T. blochii, L. spinifer caused body lesions that considerably reduced the market value of harvested fish. In L. calcarifer juveniles, infestation with C. epidemicus resulted to loss of appetite, lethargy and stunted growth of affected fish. Because of its pathogenicity, low host specificity and tolerance to brackish water, C. epidemicus poses the highest threat to farmed marine fish in the Philippines. Lates calcarifer and T. blochii are new host records for C. epidemicus and L. spinifer, respectively. This is also the first record of L. spinifer in the Philippines.
    • Article

      A parasitological survey of slipper-cupped oysters (Crassostrea iredalei, Faustino, 1932) in the Philippines 

      G Erazo-Pagador - Journal of Shellfish Research, 2010 - National Shellfisheries Association
      This paper describes the first screening in the Philippines of slipper-cupped oysters (Crassostrea iredalei) for the presence of parasites. Slipper-cupped oysters were sampled at 2 sites in Ivisan, Capiz, from September to December 2007. Macroscopical and histological analyses were carried out in oyster tissues. Histological examination showed gregarine protozoan Nematopsis sp. as the most prevalent parasite (71.33% and 65.0%) at 2 sites with a moderate intensity of infection. Tylocephalum sp. cestode was found in the connective tissue around the digestive gland, with a prevalence of 60% and 52.3% in 2 sites, with a moderate intensity of infection. Digenean trematodes had a 37.80% prevalence at site 1 and a 22.45% prevalence at site 2. Ciliates were also observed with a prevalence of 18.75% (site 1) and 13% (site 2). The observed infection of oysters had no apparent effect on oyster production at these sites maybe due to low infestation levels or to the fact that the parasites have no pathological effect.
    • Article

      Rapid wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid 

      G Erazo-Pagador & MS Din - The Israeli Journal of Aquaculture-Bamidgeh, 2001 - Society of Israeli Aquaculture and Marine Biotechnology
      Wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid was studied under laboratory conditions. Fish weighing approximately 80-110 g were stocked in 500 l aquaria in a static water system and fed one of five test diets containing different levels of microencapsulated ascorbic acid (0, 0.06, 0.10, 0.30 and 0.70 g AsA/100 g feed). After two weeks, all experimental fish were wounded by making a 1 x 1 cm dorso-lateral incision above the lateral line of the fish. Wounded tissues were sampled for histopathological analysis 4, 8, 24, 48 and 96 hours, 6, 8, 10, 12 and 14 days after making the incision. There were significant differences in weight gain, specific growth rate (SGR) and feed conversion ratio among the dietary treatments. Weight gain and SGR of fish fed the ascorbic acid free diet were lower than those of fish fed diets supplemented with ascorbic acid. The wound healing response showed a direct correlation to ascorbate level in the diet. Fibroblasts were present at 96 h irrespective of the ascorbic acid level. As 14 days, fish fed no ascorbic acid had some regeneration of muscle tissues, whereas fish fed diets containing supplemental ascorbic acid had a normal epidermis, dermis and muscle structure. There was no mortality during the experimental period, and fish fed ascorbic acid free diets did not exhibit any deficiency signs. Results of this study indicate that about 0.10-0.70 g AsA/100 g feed is needed for wound repair in African catfish.