Search
Now showing items 1-10 of 21
Production, feeding and storage of Tetraselmis tetrathele paste by electrolytic flocculation
(Springer, 2023-02)
An innovative microalgae harvesting technique using electroflocculation was carried out at different voltage treatments (4, 7, and 9 V) using a fabricated voltage regulator and compared with harvesting by electroflocculation ...
Genomic analysis of Vibrio harveyi strain PH1009, a potential multi-drug resistant pathogen due to acquisition of toxin genes
(Elsevier, 2023-03-25)
In has increasingly been observed that viral and bacterial coinfection frequently occurs among cultured shrimp and this coinfection could exacerbate the disease phenotype. Here, we describe a newly discovered bacterial strain, Vibrio harveyi PH1009 collected from Masbate Island, Philippines that was found to be co-infecting with the White Spot Syndrome virus a sample of black tiger prawn, Penaeus monodon. The genome of V. harveyi PH1009 was sequenced, assembled, and annotated. Average Nucleotide identity calculation with Vibrio harveyi strains confirmed its taxonomic identity. It is a potential multi-drug and multi-heavy metal resistant strain based on the multiple antibiotic and heavy metal resistance determinants annotated on its genome. Two prophage regions were identified in its genome. One contained genes for Zona occludens toxin (Zot) and Accessory cholera toxin (Ace), essential toxins of toxigenic V. cholerae strains apart from CTX toxins. Pan-genome analysis of V. harveyi strains, including PH1009, revealed an “open” pan-genome for V. harveyi and a core genome mainly composed of genes necessary for growth and metabolism. Phylogenetic tree based on the core genome alignment revealed that PH1009 was closest to strains QT520, CAIM 1754, and 823tez1. Published virulence factors present on the strain QT520 suggest similar pathogenicity with PH1009. However, PH1009 Zot was not found on related strains but was present in strains HENC-01 and CAIM 148. Most unique genes found in the PH1009 strain were identified as hypothetical proteins. Further annotation showed that several of these hypothetical proteins were phage transposases, integrases, and transcription regulators, implying the role of bacteriophages in the distinct genomic features of the PH1009 genome. The PH1009 genome will serve as a valuable genomic resource for comparative genomic studies and in understanding the disease mechanism of the Vibrio harveyi species....
Inclusion of live mud polychaete (Marphysa iloiloensis) in the feeding regime improved the hatchery performance of domesticated Indian white shrimp (Penaeus indicus)
(Elsevier, 2023-03-07)
A 60-day feeding trial was conducted to evaluate the effect of inclusion frequency of hatchery-bred mud polychaete, Marphysa iloiloensis, as part of a combination diet on the reproductive performance and larval quality of ...
Effect of size grading on growth of yellow Pacific shortfin eel (Anguilla bicolor pacifica)
(Wiley, 2023-03-22)
Heterogeneous growth, which is common among farmed fish, can be remedied by size grading. This study focused on whether the size grading process, which is commonly practiced in aquaculture, improves the subsequent growth ...
Molluscan aquaculture in the Philippines: A review
(Springer, 2023-04-25)
Molluscs are among the most valuable resources of the Philippines, an archipelagic country of 7,107 islands bounded by 36,000 km of coastline and 26.6 million ha of coastal waters. In 2020, production from mussels and ...
Estimating the economic benefits and costs of conserving marine protected area in San Jose, Antique, Philippines
(Silliman University, 2023-03-27)
The establishment of marine protected areas (MPAs) in the Philippines becomes a priority management strategy to conserve marine biodiversity and address the problem of declining marine resources. Economic studies can be a ...
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....
Effect of diet isotopic ratios on the \(\mathsf{\delta^{13}C}\) and \(\mathsf{\delta^{15}N}\) signatures of scallop-gut contents in a natural setting
(The Plankton Society of Japan, 2023)
The relationship between diet isotopic signatures and the extent of the tissue-diet isotope fractionation factors have been shown previously in controlled feeding studies, but this relationship remains poorly resolved for ...
Comparison of reproductive aspects of the tropical eel Anguilla bicolor (McClelland 1884) in freshwater and estuarine habitats
(Marine Science Department, Diponegoro University, 2023-09-07)
The tropical anguillid eel, Anguilla bicolor McClelland, experiences significant growth up to the adult size in both freshwater and estuarine ecosystems, encountering salinity gradients that may impact their reproduction. ...
Bacterial diseases of tilapia, their zoonotic potential and risk of antimicrobial resistance
(Wiley, 2023-03-05)
Tilapia culture is an important source of income and nutrition to many rural families. Since 2000, the production of tilapia increased and reached domestic and global markets. Major farmed species is Nile tilapia (Oreochromis ...