Now showing items 1-5 of 5

    • Article

      Acute toxicity of potassium permanganate to milkfish fingerlings, Chanos chanos 

      ER Cruz & CT Tamse - Bulletin of Environmental Contamination and Toxicology, 1989 - Springer Verlag
      Potassium permanganate (KMnO4) is a strong oxidizing agent and is commonly used in aquatic systems to improve available oxygen, treat infectious diseases and parasites, detoxify fish poisons, and control algae. The following study was undertaken to determine the 24- and 96-h median lethal concentration (LC50) of milk fish (Chanos chanos)) fingerlings to KMnO4. The study was also designed to evaluate the histopathological response of fish tissues to KMnO4 but was reported in another paper (Cruz and Tamse 1986).
    • Technical Report

      Artificial fertilization of eggs and early development of the milkfish Chanos chanos (Forskal) 

      H Chaudhuri, JV Juario, JH Primavera, R Mateo, R Samson, ER Cruz, EO Jarabejo & JT Canto Jr. - In Induced spawning, artificial fertilization of eggs and larval rearing of the milkfish Chanos chanos (Forskal) in the Philippines, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Technical report / SEAFDEC Aquaculture Department; 4
      Hydrated eggs obtained from a female milkfish were artificially fertilized with the milt collected from a male injected with acetone-dried pituitaries of salmon. The fertilized eggs (1.1 to 1.25 mm in diameter) developed normally in seawater in basins and Petri dishes at a salinity of 30-34 ppt and successfully hatched in 25 to 28½ hours at a temperature of 26.4-29.9°C. The yolk was completely absorbed in about 2½ days and at this period many postlarvae died. A few larvae were reared up to 5 days but all died within 6 days. Effects of feeding the postlarvae from the third day with freshly hatched trochophore larvae of oysters obtained from eggs artificially fertilized in the laboratory could not be ascertained.
    • Article

      The effects of iron compounds on the virulence of Vibrio anguillarum in Japanese eels and ayu 

      T Nakai, T Kanno, ER Cruz & K Muroga - Fish Pathology, 1987 - Japanese Society of Fish Pathology
      When Japanese eels (Anguilla japonica) were injected intramuscularly (IM) with ferric ammonium citrate (FAC) at a sublethal dose of 10 µg/g and followed by IM-injection with various doses of Vibrio anguillarum, FAC injection enhanced greatly the virulence of the pathogen to eels, lowering the LD50 value from 107.9 to 104.2 CFU/100 g. Similar effects were obtained with ferrous sulfate and ferric chloride in eels. However, such a virulence-enhancing effect of FAC was scarcely observed in ayu (Plecoglossus altivelis), which has high susceptibility to the pathogen by nature. It was also found that addition of FAC (10 µg/ml) in fish sera accelerated the bacterial growth in vitro but the effect was much greater in eel serum than in ayu serum. The results of these in vivo and in vitro experiments demonstrated that the availability of free iron in host fish would have a significant influence on the pathogenesis of V. anguillarum infection.
    • Article

      Histopathological response of milkfish Chanos chanos Forsskal fingerlings to potassium permanganate 

      ER Cruz & CT Tamse - Fish Pathology, 1986 - Japanese Society of Fish Pathology
      Static 96 h bioassays were conducted on milkfish fingerlings at concentrations ranging from 1.00 to 1.80 mg/l KMnO4. Histopathological analyses of gills, liver, and kidney tissues revealed significant changes even in non-lethal concentrations tested. Damage became severe with increasing concentration and longer exposure to the chemical. Partial to complete recovery was observed in gills, liver, and kidney cells of fish exposed to KMnO4 for 96 h and then maintained in KMnO4-free seawater for 240 h.
    • Article

      Tolerance level and histopathological response of milkfish (Chanos chanos) fingerlings to formalin 

      ER Cruz & CL Pitogo - Aquaculture, 1989 - Elsevier
      Static 96-h bioassays were conducted on milkfish (Chanos chanos ) fingerlings with formalin at concentrations ranging from 50 to 500 ppm. The 24-, 48-, 72-, and 96-h median lethal concentration values (LC50) were 322, 260, 241, and 232 ppm formalin, respectively. Histological analyses of gills, liver, and kidney tissues revealed significant pathological changes even with the sublethal concentrations. The intensity of cell damage increased with increasing concentration and exposure to the chemical. Formalin treatments caused hyperplasia, epithelial separation, and necrosis in the gills; cloudy swelling, hemorrhage, deposition of pigments, and necrosis in liver parenchyma; and degeneration of renal tubules. Partial recovery of tissue was observed in fish after 10 days in formalin-free seawater.