Now showing items 1-5 of 5

    • Conference paper

      Aeromonas hydrophila in the epizootic ulcerative syndrome (EUS) of snakehead, Ophicephalus striatus, and catfish, Clarias batrachus: quantitative estimation in natural infection and experimental induction of dermo-muscular necrotic lesion 

      Snakehead (Ophicephalus striatus) and catfish (Clarias batraclus) with the Epizootic Ulcerative Syndrome (EUS) were sampled for bacteria. Total bacterial counts of skin and muscle/dermal lesions revealed mean colony forming units (CFU) per gram tissue of 1.22 x 103, 1.40 x 105, 5.31 x 195 and 1.14 x 107 in apparently normal, slightly lesioned, moderately lesioned and severely lesioned snakehead samples, respectively. In catfish, mean CFU per gram tissue were 4.30 x 104 and 2.00 x 105 in apparently normal and slightly lesioned specimens, respectively. Kidney samples likewise revealed the presence of bacteria. Bacteria isolated on trypticase soy agar and Rimler-Shotts medium were predominantly Aeromonas hydrophila occurring in 90% of snakeheads and in 33% of catfish specimens. Infection experiments of A. hydrophila injected intramuscularly into healthy snakehead and catfish induced dermo-muscular necrotic lesions. A dose of at least 106 cells of A. hydrophila was required to induce EUS-like lesions in snakehead and catfish at 21-25 degree C in 24-96 h.
    • Article

      In vitro effects of fungicides on the fungus Haliphthoros philippinensis 

      GD Lio-Po, MCL Baticados, CR Lavilla & MEG Sanvictores - SEAFDEC Aquaculture Department Quarterly Research Report, 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Pure cultures of Haliphthoros philippinensis, isolated from infected Penaeus monodon larvae, were exposed for 24 hours to varying concentrations of antifungal agents. The efficiency of each agent to inhibit sporulation and mycelial growth was measured. Effects on P. monodon eggs and larvae were also investigated. It is concluded that preliminary bioassay of larval tolerance to the suggested effective doses should always be made prior to prophylaxix or therapeutic applications.
    • Article

      In-vitro effect of fungicides on hyphal growth and sporogenesis of Lagenidium sp. isolated from Penaeus monodon larvae and Scylla serrata eggs 

      GD Lio-Po, MEG Sanvictores, MCL Baticados & CR Lavilla - SEAFDEC Aquaculture Department Quarterly Research Report, 1980 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The sensitivity of Lagenidium, isolated from Penaeus monodon, Scylla serrata , to 34 antimycotics was determined. Effects on the development of vesicles, zoospores and mycelial growth were evaluated. Although mycoidal levels of the chemicals tested will be ideal for lethal treatment on control of the fungus, the high dose required may be lethal to the host, thus the use of mycostatic concentrations is more practical. Treatments of rearing water containing larvae, adult shrimps or crabs should be done only after preliminary tolerance experiments using at least the mycostatic dose prove to be safe for the hosts. Mycocidal doses can be used for determining disinfection doses of equipment and facilities used in rearing procedures as well as for destroying batches of infected larvae.
    • Book

      Recommended practices for disease prevention in prawn and shrimp hatcheries 

      GD Lio-Po, RD Fernandez, ER Cruz, MCL Baticados & AT Llobrera - 1989 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension pamphlet / SEAFDEC Aquaculture Department; No. 3
      Disease in prawn is any abnormal condition which may affect adversely the appearance, growth, and function of the animal. It may or may not result in mortalities. Disease outbreaks occur commonly in different culture systems such as hatcheries and grow-out ponds.

      Disease develops through the interaction of the prawn (the host), the causal agent (the pathogen), and the environment. In the presence of a susceptible host, a pathogen and predisposing environmental conditions (poor water quality, inadequate food, frequent handling, overstocking), disease is very likely to occur. Improved environmental conditions, healthy prawns and absence of disease agents would therefore lessen the chance of a disease outbreak.

      The causal agents may be pathogenic organisms (viruses, bacteria, fungi, protozoa, helminths, microcrustaceans) or nonpathogenic adverse environmental conditions (extreme temperatures, low oxygen levels, chemical poisons). Living disease agents cause infectious disease which generally result in gradual mortalities. Non-living disease agents cause non-infectious diseases that result in sudden mass mortalities.

      The environment determines the balance between the prawn as host and the disease agent. Microorganisms are always present in the water and some of them cause disease only when the prawn has been weakened through exposure to stressful environmental conditions.

      Hatchery personnel should realize that they themselves could transmit disease through their contaminated hands, clothing, and footwear. Equipment such as water pumps, blowers, pipes, and materials such as scoop nets, water hoses, pails, glasswares are also possible carriers of disease agents. Spawners, live natural food like diatoms, rotifers and brine shrimp, and artificial diets could also be vehicles of disease transmission.

      The prawn culturist, thus, must be able to manage the environment and make it favorable for the prawn. Hatchery management should, therefore, include operation procedures that will reduce the possibility of disease development during larval rearing. This manual recommends practices for disease prevention to prawn hatchery operators and technicians.
    • Article

      Toxicity of malachite green to the larvae of Penaeus monodon Fabricius 

      GD Lio-Po, CR Lavilla & A Trillo-Llobrera - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A study was undertaken examining the effect of malachite green on the development and survival of the zoeae, mysis and post-larvae of Penaeus monodon. Sensitivity varied with the different larval stages; the zoeae appeared to be the least tolerant. The prophylactic potentials of malachite green in the control of Lagenidiumand Zoothamnium infesting P. monodon larvae are considered briefly. Toxicity risks may be reduced by application between ecdyses or by the removal of the dye by filtration through activated carbon.