Now showing items 1-9 of 9

    • 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.
    • Oral presentation

      Heterotrophic bacteria associated with eggs and larvae of Penaeus indicus in a hatchery system. 

      I Singh, P Laksmanaperumalsamy & D Chandromohan - In Y Taki, JH Primavera & JA Llobrera (Eds.), Proceedings of the First International Conference on the Culture of Penaeid Prawns/Shrimps, 4-7 December 1984, Iloilo City, Philippines, 1985 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Total viable aerobic heterotrophic bacteria (THB) associated with egg, nauplius, zoea, mysis and postlarva of Penaeus indicus and seawater in a hatchery system were estimated for three years from 1981 to 1984. The bacterial population varied from 1.3 × 104 to 8.72 × l07/g in egg, 1.5 × 104 to 6.17 × 107/g in nauplius, 4 × 103 to 3.14 × 107/g in zoea, 1.35 × 106 to 1.25 × 108/g in mysis, 1.6 × 105 to 8.44 × 106/g in postlarva. Water contained a THB population of 1.2 X 105 to 2.8 × 108/100 ml.

      Species of Vibrio, Pseudomonas, Aeromonas, Acineto-bacter, Moraxella, members of the family Enterobac-teriaceae, Micrococcus, Bacillus, and Coryneform group were encountered. Gram-negative bacteria were found to be dominant in all stages and showed an increase from egg (81.3%) to postlarva (92.7%). However such an increase was not recorded in the respective water samples even though gram-negative bacteria were found to be dominant. Vibrio spp. were found in high numbers in postlarvae and it was to be increasing from egg (10.4%) to postlarva (80%). The number of larvae in culture pools gradually declined as the nauplii metamorphosed to postlarvae through zoea and mysis. In general, coincidence of higher percentage of Vibrio spp. and larval mortality was recorded. Physico-chemical factors such as salinity, temperature, pH, oxygen, inorganic phosphorus, organic phosphorus, inorganic nitrogen and organic nitrogen of water did not show much variation in the same set of pools. Relationship between the physico-chemical parameters, bacterial population and the number of larvae is discussed.
    • Oral presentation

      Role of bacteria and meiofauna in the productivity of prawn aquaculture ponds. 

      DJW Moriarty - In Y Taki, JH Primavera & JA Llobrera (Eds.), Proceedings of the First International Conference on the Culture of Penaeid Prawns/Shrimps, 4-7 December 1984, Iloilo City, Philippines, 1985 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Detrital food chains, based on the use of manures and compost have been used in aquaculture for centuries. Heterotrophic bacteria convert organic detritus into protein and thus constitute an important food source in ponds. Bacterial growth rates, and thus productivity, in natural environments can be calculated from the rate of tritiated thymidine incorporation into DNA. Rates of oxygen consumption by bacteria can be estimated from values for production. The tritiated thymidine method has been used to measure bacterial production in aquaculture ponds where a pelleted food was fed to penaeid prawns. It was found that most of the pelleted food was supporting bacterial growth, with bacterial production ranging from 0.43 to 2.1 mgCℓ–1d–1 in the water and 150 to 500 mgC m–2d–1 in the sediment. Bacterial biomass and growth rates were shown to be regulated by meiofauna, which in turn were eaten by the prawns. Primary production was not significant in the ponds. More oxygen was consumed by bacteria in the water column than was produced by photosynthesis of phytoplankton.

      Average shrimp yields at harvest were: chicken manure, 262 kg/ha; cow manure, 218 kg/ha; feed, 387 kg/ha; and control, 160 kg/ha. Average survival for each treatment was 50, 76, 58 and 79%, respectively. The percent yield of P. vannamei: P. stylirostris: P. occidentalis by weight for the four treatments was 85:15:0, 87:13:0, 78:22:0, and 92:9:0, respectively. P. occidentalis suffered 100% mortality during the production period. Average weights of shrimp at harvest were 8.72, 7.32, 12.07, and 5.98 g for the respective treatments. Ratios of average individual weights for P. vannamei: P. stylirostris for the treatments were 2.00:1, 1.99:1 and 2.22:1, respectively. Manures and feed significantly increased yield over the control (P< .0002). Feed significantly increased yield over that of the manures (P < .0001); while yields for manures did not differ (P > .05). Survival was not significantly different among treatments (P > .05).
    • Conference paper

      Selection of probiotics for shrimp and crab hatcheries. 

      CR Lavilla-Pitogo, DD Catedral, SAG Pedrajas & LD De la Peña - In Disease Control in Fish and Shrimp Aquaculture in Southeast Asia – Diagnosis and Husbandry Techniques: Proceedings … Aquaculture in Southeast Asia – Diagnosis and Husbandry Techniques, 4-6 December 2001, Iloilo City, Philippines, 2002 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A study aimed at obtaining a biological control agent against bacterial diseases, specifically luminescent vibriosis, of hatchery-reared shrimps and crabs was done to find an alternative for chemotherapy as a disease prevention and control method. Bacteria were isolated from crustacean rearing environments where luminescent vibrosis was not observed, from natural food, and from various feed ingredients. From hundreds of purified strains, 80 bacterial isolates were tested in one-on-one mixed cultures in seawater for their ability to suppress the growth of luminescent Vibrio harveyi. Of the 10 isolates exhibiting that capability, two strains were further studied: C1 from chlorella culture and P9 from a commercial probiotic preparation. However, due to the indigenous nature of C1 strain from the unicellular alga Chlorella sp. and the ease in distinguishing it from other bacteria owing to its colony morphology, more tests were done on C1 strain. To determine the suitability of C1, and to some extent P9, as biocontrol bacteria, their pathogenicity against crab larvae and shrimp postlarvae, and their ability to become associated or incorporated into the larvae were determined. Incorporation into the rotifer, Brachionus, was also tested. Due to the positive results obtained in the incorporation experiments, the growth of strain C1 in microbiological media and unrefined media prepared from agricultural by-products was also tested.
    • Conference paper

      Siderophore detection among bacteria associated with the epizootic ulcerative syndrome (EUS) 

      EM Leaño, GD Lio-Po & LA Dureza - In M Shariff, JR Arthur & RP Subasinghe (Eds.), Diseases in Asian Aquaculture II : Proceedings of the Second Symposium on Diseases in Asian Aquaculture, 25-29 October 1993, Phuket, Thailand, 1995 - Fish Health Section, Asian Fisheries Society
      Sixteen isolates of Aeromonas hydrophila andone isolate each of Aeromonas sp. n., Aquaspirillum sp., Pseudomonas sp., and Streptococcus sp., isolated from normal, apparently normal and epizootic ulcerative syndrome (EUS)-affected fish were screened for siderophore production at 20, 25, 30, and 37oC. results showed that siderophore production of A. hydrophila and Aeromonas sp. n. isolates decreased with increasing temperature. Among A. hydrophila isolates, 81.2% produced siderophore at 20oC, 50% at 25 and 30oC, and only 37.5 at 37oC. In contrast, Aquaspirillum sp., Pseudomonas ep., and Streptococcus sp., showed higher production of siderophore at 30 and 37oC.
    • Conference paper

      Studies on the efficacy of Sarafin® (sarafloxacin hydrochloride) on vibrios associated with vibriosis in black tiger shrimp (Penaeus monodon) 

      RV Pakingking Jr. - In CR Lavilla-Pitogo & ER Cruz-Lacierda (Eds.), Diseases in Asian Aquaculture IV. Proceedings of the Fourth Symposium on Diseases in Asian Aquaculture, 22-26 November 1999, Cebu City, Philippines, 2002 - Fish Health Section, Asian Fisheries Society
    • Conference paper

      Studies on the sources of luminescent Vibrio harveyi in Penaeus monodon hatcheries 

      CR Lavilla-Pitogo, LJ Albright, MG Paner & NA Suñaz - In M Shariff, RP Subasinghe & JR Arthur (Eds.), Diseases in Asian Aquaculture I. Proceedings of the First Symposium on Diseases in Asian Aquaculture, 26-29 November 1990, Bali, Indonesia, 1992 - Asian Fisheries Society, Fish Health Section
      One of the major problems in the otherwise highly successful Penaeus monodon hatchery industry in the Philippines is the occurrence of luminescent bacterial disease due to Vibrio harveyi. The possible sources of the bacteria were investigated. Eggs within the ovaries of stage III and IV wild-caught and ablated female P. monodon harbour no bacteria. On the other hand, the midgut contents of these spawners, as well as of pond-reared juveniles, contained numerous luminescent bacteria. Plate counts of the exoskeleton from all sampled females revealed that V. harveyi is a minor component of the exoskeleton-associated flora. Scanning electron microscopy of the exoskeleton showed no significant attached populations. The bacterial loads of Chaetoceros calcitrans, a marine diatom, and Artemia salina nauplii were likewise estimated. C. calcitrans did not harbour V. harveyi at any phase of its growth. Twenty-four-hour-old A. salina appeared to have no resident V. harveyi, but its culture water contained small populations of these bacteria. These data show that the main source of the luminescent bacteria is the midgut contents of the mother, which are shed into the water almost simultaneously with the eggs during spawning.
    • Conference paper

      Transferable drug resistance plasmids in fish-pathogenic bacteria. 

      T Aoki - In JR Arthur, CR Lavilla-Pitogo & RP Subasinghe (Eds.), Use of Chemicals in Aquaculture in Asia : Proceedings of the Meeting on the Use of Chemicals in Aquaculture in Asia 20-22 May 1996, Tigbauan, Iloilo, Philippines, 2000 - Aquaculture Department, SEAFDEC
      Chemotherapeutic agents have been developed for treating bacterial infections and have been widely used for cultured fish for the last 30 years in Japan. The extensive use of chemotherapeutants has resulted in an increase in the occurrence of drug resistance in fish-pathogenic bacteria and also in the bacterial flora of the intestinal tract of cultured fish. The kinds of chemotherapeutants used are correlated with the occurrence of the corresponding drug-resistant genes in fish-pathogenic bacteria. Almost all multiple-drug resistant strains are carried on the transferable R plasmid, although resistance in fish pathogens to nitrofuran derivatives and pyridonecarboxylic acids is associated with a chromosomal gene. The DNA sequences of R plasmids generally differ depending on the species of fish pathogen. Exceptions are the R plasmids of Aeromonas hydrophila and A. salmonicida, which have the same resistance markers as chloramphenicol, streptomycin, and sulfonamides (SA); and the R plasmids of A. hydrophila and Edwardsiella tarda, which have the same resistance markers as SA and tetracycline. The fish pathogens A. hydrophila, A. salmonicida, E. tarda, Enterococcus seriolicida, Pasteurella piscicida, and Vibrio anguillarum are all widely distributed in fish farms in various areas, and within each species the R plasmid has an identical DNA sequence. The chloramphenicol resistance (cat) gene of the R plasmid from Gram-negative bacteria was classified into CAT I, II, III, and IV according to the DNA sequence. The cat gene of P. piscicida was classified as CAT I, those of A. salmonicida and E. tarda were classified as CAT II, and that of V. anguillarum was classified as CAT II or IV, depending on the time the strains were isolated. The tetracycline-resistance determinants (Tet), which occur in six classes (Tet A through Tet G), were class D in the R plasmids obtained from strains of V. anguillarum that were isolated from 1989 to 1991. The Tet for strains of V. anguillarum isolated from 1973 to 1977 was classified as Tet B, while for strains isolated from 1980 to 1983 it was classified as Tet G.
    • Conference paper

      Will microbial manipulation sustain the ecological balance in shrimp (Penaeus monodon) hatcheries? 

      CR Lavilla-Pitogo, LJ Albright & MG Paner - In TW Flegel (Ed.), Advances in Shrimp Biotechnology : Proceedings to the special session on shrimp biotechnology, 5th Asian Fisheries Forum, 11-14 November 1998, Chiengmai, Thailand, 1998 - National Center for Genetic Engineering and Biotechnology
      A shift in preferred methods employed to contain bacterial diseases in the hatchery phase of shrimp culture has resulted largely from the unsuccessful control by and deleterious effects of chemotherapy. Manipulation of hatchery microbial ecology has gained popularity, but for successful implementation, this niche-filling approach requires a thorough understanding of the epidemiology of bacterial diseases in the hatchery. This study examined the responses of Vibrio harveyi populations, (associated with luminescent vibriosis in shrimp larvae) to various physico-chemical factors and various hatchery components. Results showed that V. harveyi had a wider range of tolerance to environmental parameters than larvae of Penaeus monodon, such that control measures based on manipulation of these parameters might not be feasible. However, it was evident from the results that there were components in the shrimp hatchery environment that could be manipulated to control high populations of V. harveyi. The natural microflora of seawater, as well as the microbial flora associated with the diatoms Skeletonema costatum and Chaetoceros calcitrans negatively affected the survival of V. harveyi in experimental mixed cultures. The successful manipulation of such benign microbial components to compete with and exclude potential pathogens is necessary to sustain ecological balance in the shrimp hatchery environment.