Will microbial manipulation sustain the ecological balance in shrimp (Penaeus monodon) hatcheries?
MetadataShow full item record
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.
Lavilla-Pitogo, C. R., Albright, L. J., & Paner, M. G. (1998). Will microbial manipulation sustain the ecological balance in shrimp (Penaeus monodon) hatcheries? In T. W. Flegel (Ed.), Advances in Shrimp Biotechnology : Proceedings to the special session on shrimp biotechnology, 5th Asian Fisheries Forum, 11-14 November 1998, Chiengmai, Thailand (pp. 185–192). Bangkok, Thailand: National Center for Genetic Engineering and Biotechnology.
PublisherNational Center for Genetic Engineering and Biotechnology
We thank the International Development Research Centre (IDRC) of Canada for funding the research under Project 3-P-88-1053-02. Sheila Mae Buen provided excellent help with the graphs.
- Conference Proceedings 
Showing items related by title, author, creator and subject.
Bacterial loads in hatcheries and virulence of Vibrio spp. to larvae of the tiger shrimp Penaeus monodon JL Torres - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of AgricultureShrimp hatcheries are high-density systems and are prone to diseases. A small-scale and a large-scale hatchery for the tiger shrimp Penaeus monodon in Iloilo, Philippines were monitored over two months for water quality and shrimp survival. Water quality (water temperature, pH, salinity, dissolved oxygen, and specific gravity) was not significantly different between the two hatcheries. However, the small hatchery seemed to favor survival of eggs to early postlarval stages, whereas the large hatchery favored the survival of late postlarvae. The normal microflora and bacterial loads of tiger shrimp eggs, larvae, postlarvae, and rearing water were determined to identify the dominant bacteria and potential pathogens. Shrimp eggs harbored the lowest heterotrophic bacterial counts. The counts increased from the nauplii to the mysis stages, decreased during the mysis stage, and then gradually increased in the older larvae. Bacterial loads in the rearing water reflected those in raw sea water and reservoir-aged sea water. Vibrio, Pseudomonas, and Aeromonas were not detected in eggs but were found in postlarvae. Ubiquitous in sea water, these bacteria increased with the build-up of organic matter. The bacterial load in the water adversely affected larval survival. Forty bacterial strains were isolated from tiger shrimp eggs, larvae, postlarvae, from the feeds, and from the rearing water. These were tested for biochemical characteristics and segregated into eight groups or genera. Six genera were found in the mysis and five genera in the postlarvae. The Vibrio species were dominant. Only Escherichia spp. were present in feeds, whereas five genera were present in the rearing water. Only Vibrio and Pseudomonas were present in both larvae and water. Moraxella, Aeromonas, and Klebsiella were found in larvae but not in rearing water. Micrococcus and coryneforms were found only in rearing water. Four Vibrio isolates were tested for virulence against shrimp postlarvae at inoculation densities of 102 and 107 cfu/ml. The four Vibrio species caused mortality of postlarvae, and more at the higher inoculation density. The most virulent was Vibrio anguillarum—30% of postlarvae died after 24 h exposure to a bacterial density of 102 cfu/ml, and all larvae died after 48 h at 107 cfu/ml. Shrimp hatcheries must have protocols for hygiene and sanitation and for disease prevention and control.
Level and percentage recovery of resistance to oxytetracycline and oxolinic acid of bacteria from shrimp ponds The bacterial level of the water, sediment and cultured shrimp (Penaeus monodon) from different ponds were determined using a general medium, a presumptive Vibrio medium and a presumptive Pseudomonas–Aeromonas medium. Samples were taken from ponds that had not used any antimicrobial, ponds that had previously used and also ponds that were currently using oxolinic acid (OXA). The bacterial level in the sediment was higher than in the water using all three media. More bacteria existed in the pond system than in the receiving environment. Shrimp hepatopancreas harbored more bacteria than the lymphoid organ. The Vibrio density of the pond and bacterial levels in the shrimp were correlated with the use of the antimicrobial. The Vibrio level of the pond samples and microbial density of shrimps were higher from ponds that had not used any antimicrobials. The percentage recoveries of resistance to oxytetracycline (OTC) and OXA in bacteria from shrimp ponds and cultured shrimps were also determined using Zobell's marine agar, Pseudomonas–Aeromonas selective agar and thiosulfate citrate bile sucrose agar (TCBS) with the addition of either 25 μg/ml OTC or 25 μg/ml OXA. Presumptive Vibrio bacteria and other bacterial taxa recovered from the pond/receiving water/sediment from all three sites showed some degree of resistance to OTC and OXA. However, a higher percentage recovery of strains resistant to OTC than to OXA was observed among the presumptive vibrios and other bacterial taxa. Pseudomonas and Aeromonas bacteria were more resistant to OXA compared with the vibrios. All bacterial taxa resistant to OTC were more readily recovered from the water samples than from the sediment samples. In general, between the samples from the pond and from the receiving environment, a higher percentage of resistant strains was observed in the latter. Higher percentage recovery of bacteria resistant to OXA was observed in shrimp from ponds currently using OXA than those from ponds that had not used any or those that had previously used them. The results of the present study showed that the percentage recovery of resistance reflected the pattern of antimicrobial use.
Anti-luminous Vibrio factors associated with the ‘green water’ grow-out culture of the tiger shrimp Penaeus monodon GD Lio-Po, EM Leaño, MMD Peñaranda, AU Villa-Franco, CD Sombito & NG Guanzon Jr. -
Aquaculture, 2005 - ElsevierThe 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.