Now showing items 1-9 of 9

    • Article

      Aeromonas hydrophila associated with ulcerative disease epizootic in Laguna de Bay, Philippines 

      AT Llobrera & RQ Gacutan - Aquaculture, 1987 - Elsevier
      Aeromonas hydrophila was consistently associated with necrotic ulcers and lesions in mudfish/snakehead (Ophiocephalus striatus), Thai catfish (Clarias batrachus), crucian carp (Carassius carassius) and goby (Glossogobius giurus) in Laguna de Bay, Philippines, during the months of December 1985 through February 1986. The bacterium was isolated from body lesions and ulcers of all fish examined and rarely from the kidney and liver of carp and catfish. The disease was characterized by hemorrhages, lesions and open necrotic ulcers on the body of the fish, particularly the head (just behind the eyes), the mandible and the maxilla, and the caudal peduncle regions. Erosion of the head bone tissues and the tails was observed in very severe cases. The presence of A. hydrophila is believed to be secondary to some predisposing factors existing in Laguna de Bay.
    • Conference paper

      Antibiotic uptake of the giant freshwater prawn Macrobrachium rosebergii by the osmotic infiltration technique. 

      AT Llobrera & DH Lewis - In JL Maclean, LV Dizon & LV Hosillos (Eds.), The First Asian Fisheries Forum. Proceedings of the First Asian Fisheries Forum, 26-31 May 1986, Manila, Philippines, 1986 - Asian Fisheries Society
      Erythromycin and oxytetracycline uptake by the giant freshwater prawn, Macrobrachium rosenbergii , was evaluated by the two-step osmotic infiltration technique. Test prawns were immersed in 7.5% NaCl conditioning (hyperosmotic) solution for 30 min. then transferred to a freshwater (hypo-osmotic) solution containing 10 mu g/ml of antibiotic. Antibiotic uptake was determined in test and control prawns at 5, 10, 20 and 40 min. Maximum concentration of erythromycin was observed in test prawns 10 min. after exposure, whereas the same concentration was not achieved in control prawns until 40 min. Oxytetracycline uptake was similar in treated and control prawns in that maximum tissue levels were observed after 40 min. in both cases. The uptake of erythromycin was significantly greater in prawns treated for 10 min. than in prawns treated for 5, 20 and 40 min. Osmotic infiltration did not significantly enhance oxytetracycline uptake at all time intervals tested.
    • Article

      Bacteria from seawater used in Penaeus monodon larval cultures 

      AT Llobrera & RQ Gacutan - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Bacteria in the seawater used in P. monodon hatchery operations were isolated on Bachmann's agar. The total plate counts in 25 isolations ranged from 1.0 - 5.0 x 102 to 5.1 -10.0 x 105 cells per ml. Out of 124 isolates, 98 (79 percent) were Gram-positive and 26 (21 percent) were Gram-negative. Micrococcus and Staphylococcus were dominant in the former group, while Acinetobacter, Moraxella, Flavobacterium and Alcaligenes were most numerous in the latter. Twenty-nine of the Gram-positive isolates closely resembled Peptostreptococcus, Planococcus, and Pediococcus.
    • Conference paper

      Current fish disease problems in the Philippines and their economic impact 

      AT Llobrera - 1987
      An account is given of fish disease problems facing the aquaculture industry in the Philippines. The Laguna de Bay fish kills that occurred in December 1985 and February 1986, involving epizootic ulcerative syndrome of bottom dwelling fish species, and the economic impact on the industry are discussed in particular. Soft-shelling disease of giant tiger prawn (Penaeus monodon), gas bubble disease and various other bacterial disease problems are also considered.
    • Article

      Effect of furanace on the development of larval stages of Penaeus monodon Fabricius 

      RQ Gacutan & AT Llobrera - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Zoea 2 (Z2), Mysis 1 (M1) and Postlarva 1 (P1) of P. monodon artificially spawned in closed-system concrete hatchery tanks were bioassayed for their tolerance to the antibiotic furanace. The setup consisted of four 20-liter capacity plastic basins previously conditioned for 15 days with freshwater in full sunlight. During the experiment, each basin was filled with 5 liters of seawater to which was added filtered Chaetoceros and Brachionus to give densities of 5 . 0-7 . 5 x 10-4 cells/ml and 10-20 individuals/ml, respectively. The following are the properties of the water used throughout the experiments: salinity, 26-32%; pH, 7 . 3-8 . 4; temperature, 25-30 degree C; dissolved oxygen, 4 . 5-8 . 4 ppm; nitrite, 0 . 36-0 . 99 ppm; and ammonia, 0 . 10-0 . 30 ppm. To each basin were added 50 healthy larvae of specific stages of P. monodon. After an initial acclimation of one hour in the medium, preweighed amounts of the antibiotic were added and thoroughly dissolved. The concentrations tested were 1 . 0, 2 . 0 and 3 . 0 ppm. One basin always served as control. After 24 hours of exposure, the surviving population in each basin was counted. The survivors were then examined thoroughly under the microscope for unusual behavior and morphological defects brought about by the exposure. To minimize wide variations in the medium as a result of feeding and other manipulations, the systems were all prepared at 9:00 a.m. each time, and the feeds on two instances, one at 5:00 p.m. and another at 5:00 a.m. Fifteen trials conducted with Z2 showed survival ranges of 68% to 98% with a mean of 77 . 6% in the controls; 32% to 94% with a mean of 65 . 7% at 1 ppm, and 0% to 56% with a mean of 36.5% at 2 ppm. There were no survivors at 3 ppm. Interpolation from the survival-dose curve gave a 24-hr LC50 of approximately 1.6 ppm.
    • Conference paper

      Effects of furanace on the development of larval stages of Penaeus monodon Fabricius 

      RQ Gacutan, AT Llobrera & MCL Baticados - In Proceedings of the Second Biennial Crustacean Health Workshop, 1977 April 20-22, Galveston, Texas, 1979 - Sea Grant College Program, Texas A&M University
      Successful molts and morphological defects in P. monodon zoeae (Z1, Z2, Z3) resulting from a 24-h exposure to 1.0 and 2.0 mg/L furanace in baths of 1.0 and 2.0 mg/L were quantified. Molting was delayed in Z1, but not in Z2 and Z3 at 1.0 mg/L; considerably delayed in all sub-stages at 2.0 mg/L. Morphological defects in the telson, carapace, uropods and pereiopods were observed in high frequency in Z3 after the exposure. These abnormalities did not result in 1.0 mg/L. In Z2, a 6-h exposure is deemed optimum for bath in 1.0 mg/L as gauged from higher survival of larvae after 96 h.
    • Conference paper

      Effects of storage on the microbial quality of slipper oysters, Crassostrea iredalei 

      AT Llobrera, ML Bulalacao & N Suñaz - In JL Maclean, LB Dizon & LV Hosillos (Eds.), The First Asian Fisheries Forum. Proceedings of the First Asian Fisheries Forum, 26-31 May 1986, Manila, Philippines, 1986 - Asian Fisheries Society
      The effects of storage on the microbial quality of slipper oysters, Crassostrea iredalei, were examined. Oysters were stored at room temperature (24°C), under a blanket of ice (3-4 C), chilled (4-C) and frozen (-25°C) until they spoiled. The shelf life of oysters stored at room temperature was only two days. Oysters held under a blanket of ice had a shelf life of 14 days and chilled oysters, 22 days. Frozen oysters remained in good condition over the 64 day storage period.

      The initial total aerobic bacterial count of oysters was 105cfu/g. Counts for frozen oysters decreased by 1 log (104) while counts for oysters stored at other temperatures increased by 2-4 log (107-109). Bacterial typing of 50 randomly-picked colonies made every four days showed Pseudomonas to be the predominant spoilage organism. Total and fecal coliform counts did not increase even for oysters held at room temperature. Typical Staphylococcus aureaus colonies were isolated but were shown to be non-pathogenic by the coagulase test. Analyses for the presence of other organisms of public health concern revealed that Salmonella, Shigella, Vibrio cholerae, V. parahaemolyticus, Lactose + Vibrios (V. vulnificus) and fecal streptococci were present in very low or undetectable levels. Thus, hazards or risks associated with these organisms may be considered minimal.
    • Conference paper

      A suctorean parasite of Penaeus monodon larvae 

      RQ Gacutan, AT Llobrera, CB Santiago, PJ Gutierrez & G Lio-Po - In Proceedings of the Second Biennial Crustacean Health Workshop, 1977 April 20-22, Galveston, Texas, 1979 - Sea Grant College Program, Texas A&M University
      A pathogenic suctorean, identified as Ephelota gemmipara was observed in P. monodon larvae spawned and reared in tanks. Commonly found to inhabit hydroid colonies, E. gemmipara has a stalked body with two types of tentacles, the sucking and piercing types, and was observed to reproduce by multiple exogenous budding.
    • Article

      A suctorean parasite of Penaeus monodon larvae 

      RQ Gacutan, AT Llobrera, CB Santiago, PJ Gutierrez & G Lio - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A new disease caused by a suctorean has been observed in tank-spawned and reared P. monodon larvae. Identification of the etiologic agent pointed to Ephelota gemmipara R. Hertwig, a species commonly found to inhabit hydroid colonies.