Now showing items 1-4 of 4

    • Article

      Anti-luminous Vibrio factors associated with the ‘green water’ grow-out culture of the tiger shrimp Penaeus monodon 

      The ability of the “green water” grow-out culture of the tiger shrimp Penaeus monodon to prevent outbreaks of Luminous Vibriosis was investigated by screening associated isolates of bacteria, fungi, phytoplankton and fish skin mucus for anti-luminous Vibrio metabolites. Among the 85 bacterial isolates tested, 63 (74%) caused +∼+++ inhibition of the Vibrio harveyi pathogen after 24–48 h co-cultivation. The variation in growth inhibition rates of +, ++, and +++ were demonstrated by 15 (18%), 13 (15%), and 28 (33%) isolates, respectively, 24 h after treatment. Eight bacterial isolates showed consistently sustained maximum inhibition of luminous Vibrio after 24 to 48 h exposure. The majority of these luminous Vibrio inhibiting bacterial isolates were obtained from tilapia mucus and gut. In tests with fungi, 4 of 20 (20%) yeast isolates showed intracellular metabolites inhibitory to luminous Vibrio. Among filamentous fungi, 5 of 45 (11%) isolates yielded intracellular metabolites while 3 of 41 (7%) isolates had extracellular metabolites inhibitory to luminous Vibrio. These fungal isolates were identified as Rhodotorula sp., Saccharomyces sp., Candida sp., Penicillium sp., mycelia sterilia, and two unidentified species. The microalgae, Chaetoceros calcitrans and Nitzchia sp., consistently demonstrated complete inhibition of luminous Vibrio from 24 h and 48 h post exposure, respectively, and during the 7-day experiment. Leptolyngbia sp. caused a 94–100% reduction of the luminous Vibrio population from 104 to 101 cfu/ml 24 h post exposure which was sustained throughout the 10-day observation period. In contrast, the inhibitory effects of Skeletonema costatum on luminous Vibrio was bacteriostatic throughout the 7-day exposure while Nannochlorum sp. did not significantly inhibit luminous Vibrio. The skin mucus of jewel tilapia, Tilapia hornorum, had no resident luminous bacteria and inhibited this bacterial pathogen in 6–48 h, which was proportionate to the 103 and 105 cfu/ml test concentrations of luminous Vibrio. This study provides a scientific explanation that the effectiveness of the “green water” culture of tiger shrimp (P. monodon) in preventing outbreaks of luminous Vibriosis among P. monodon juveniles in grow-out ponds can be attributed to the presence of anti-luminous Vibrio factors in the bacterial, fungal, phytoplankton microbiota and the skin mucus of tilapia associated with this novel technique of shrimp culture.
    • Article | Short communication

      Bacteria associated with infection at hormone-implantation sites among milkfish, Chanos chanos (Forsskal), adults 

      G Lio-Po, C Pitogo & C Marte - Journal of Fish Diseases, 1986 - Blackwell Publishing
      SEAFDEC Contribution No. 164. Paper presented at the Second International Warmwater Fish Conference at Laie, Hawaii, 5–8 February 1985.
    • Article

      Pathogenicity of the epizootic ulcerative syndrome (EUS)-associated rhabdovirus to snakehead Ophicephalus striatus 

      GD Lio-Po, LJ Albright, GS Traxler & EM Leaño - Fish Pathology, 2001 - Japanese Society of Fish Pathology
      The rhabdoviruses isolated from EUS-affected snakeheads in the Philippines was tested for pathogenicity to healthy, naive snakehead Ophicephalus striatus fry, fingerlings and juveniles. Virus exposure of naive snakehead fry and fingerlings by bath at 20-22.5°C resulted in significant mortalities (p<0.01) with no apparent lesions. Naive snakehead juveniles when injected intramuscularly (IM) with the EUS-associated rhabdovirus at ambient water temperature (28-32°C) did not develop any lesion. However, similarly treated snakehead juveniles at 20-22.5°C developed dermal lesions 3-5 days following treatment. The lesions progressed from slight to moderately advanced lesions by days 10-12 but not to deep ulcers as exhibited by naturally EUS-affected snakeheads. Mean mortalities were higher in the virus-injected fish (72%) compared to those in controls (33%). Moreover, the virus was reisolated from fish in the 20-22.5°C treatment but not from fish in the 28-32°C treatment. Virus from infected tissue filtrate and the virus passaged 3 or 4 times induced similar dermal lesions if the rhabdovirus concentration was 103 TCID50/fish or higher. When administered orally, by bath, by intraperitoneal (IP), IM and subdermal injections to snakehead juveniles, only the latter two viral routes induced dermal lesions. However, IP injection of the rhabdovirus caused 75% mortalities but none in control fish. The results demonstrate the pathogenicity of the rhabdovirus isolates to naive snakeheads at low (20-22.5°C) rearing water temperatures.
    • Book chapter

      Preface - Health Management in Aquaculture 

      GD Lio-Po, CR Lavilla & ER Cruz-Lacierda - In GD Lio-Po, CR Lavilla & ER Cruz-Lacierda (Eds.), Health Management in Aquaculture, 2001 - Aquaculture Department, Southeast Asian Fisheries Development Center