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Lime application to condition soil to pH 11 controls growth of harmful vibrios and WSSV
(European Association of Fish Pathologists, 2023-05-26)
Shrimp farming has been devastated by several diseases. Disease outbreaks can be prevented by optimising environmental conditions or by eliminating risks factors including carrier organisms. These can be achieved through proper pond preparation. One important step in pond preparation is the application of hydrated lime.
This paper describes the effect of hydrated lime application to condition pond soil to pH 11 on the pond ecosystem, more specifically on soil pH and biota. The experiment was done using three 600 m<sup>2</sup> brackish water ponds. After hydrated lime application, the wet soil pH on the 1<sup>st</sup>-8<sup>th</sup> day was significantly higher (P<0.05) compared to the pH before liming to pH 11, and flushing after flooding for 24 h. Soil pH of 11 was observed 24-48h after lime application. Moreover, unwanted species like crabs and fish were found dead. Liming to pH 11 negatively affects the counts of green vibrio colonies thereby decreasing the percentage of green vibrios (PGV). In another experiment, three 750m<sup>2</sup> earthen ponds were used. The pond soils were previously positive for the Whitespot Syndrome Virus (WSSV), hydrated lime were applied to bring the pond soil pH to 11. After lime application, WSSV was not detected in the pond soils.
Results showed that increasing the soil pH to ≥11 positively affects the pond ecosystem. Liming encourages the proliferation of yellow vibrios and the eradication of carrier species (i.e. crabs) as well as predators (i.e. fish) in the ponds. Furthermore, liming to pH 11 may also eradicate White spot virus from the pond sediment. To implement a 1-unit increase in wet pH, hydrated lime should be applied at 2T/ha....
In vitro and in vivo evaluation of the efficacies of commercial probiotics and disinfectant against acute hepatopancreatic necrosis disease and luminescent vibriosis in Litopenaeus vannamei
(Elsevier, 2024-05)
The bioactivities of two commercially available probiotics and one chemical disinfectant were tested against strains of Vibrio parahaemolyticus (VP<sub>AHPND</sub>) and V. harveyi. This study aimed to determine shrimp pathogenic Vibrios' in vitro and in vivo sensitivities to commercial probiotics and a chemical disinfectant. The probiotics and disinfectant were tested first in vitro, followed by the in vivo trials. Results showed that upon administration of probiotics either through diet or adding into the tank water, the survivability of shrimp was increased during challenge with VP<sub>AHPND</sub> and V. harveyi. Also, the disinfectant was tested against the same pathogens and showed positive bactericidal effects at 2500 ppm and 5000 ppm. The present findings suggest that adding probiotics to the rearing water or the shrimp feeds effectively prevents infection by lowering the load of pathogenic bacteria. In comparison, the effectiveness of the disinfectant (PUR) depends on its appropriate concentration and timing of application. It is not only limited to rearing water but is also applicable for decontaminating pond liners, tanks, and other paraphernalia....
Complete genome sequence of Vibrio parahaemolyticus strain PH1273, isolated from aquacultured shrimp in the Philippines
(American Society for Microbiology, 2023-10-19)
We announce the complete genome sequence of Vibrio parahaemolyticus strain PH1273. This strain was collected from a Penaeus vannamei pond in the Philippines in 2015. Genome analysis revealed that it lacks the gene pirAB ...
Series: JIRCAS Working Report; No. 44
Analysis of the sustainability of extensive and intensive methods in brackish water fishpond culture primarily producing shrimp in three Southeast Asian countries
(Japan International Research Center for Agricultural Sciences, 2006)
This study is an investigation of the aquaculture methods used in brackish water fishpond culture mainly producing shrimp in the Philippines, Thailand and Malaysia. Extensive methods are practiced in the Philippines and ...