Sudewi Sudewi
Institute for Mariculture Research and Fisheries Extension, Gondol

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EXPERIMENTAL INFECTIONS OF MILKY HEMOLYMPH DISEASE IN SPINY LOBSTER Panulirus homarus Sudewi Sudewi; Zeny Widiastuti; Bejo Slamet; Ketut Mahardika
Indonesian Aquaculture Journal Vol 13, No 1 (2018): (June, 2018)
Publisher : Center for Fisheries Research, Agency for Marine and Fisheries Research and Human Resource

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (477.926 KB) | DOI: 10.15578/iaj.13.1.2018.31-40

Abstract

Milky hemolymph disease of spiny lobster (MHD-SL) is categorized as the most destructive disease in farming spiny lobster. Therefore, it is required to investigate the routes of milky disease infection in spiny lobster as a basic knowledge in order to prevent milky disease transmission. The aim of the present study was to perform an experimental infection of milky disease in spiny lobster Panulirus homarus. Experimental infection of milky disease was carried out by several modes of infection which were injection, immersion and per os exposure. Injection of each 0.2 mL undiluted and diluted hemolymph from the diseased lobster resulted in a cumulative mortality of 100% at 15 days post-infection (dpi), and 75% at 16 dpi, respectively. Experimental infection through water immersion caused in a cumulative mortality of 50% at 7 dpi. In contrast, no mortality was observed in per os exposure as well as in control groups. Results of this experimental study provided evidence for horizontal transmission of MHD-SL among P. homarus. Histopathological analysis exhibited that there were masses of Rickettsia-like bacteria (RLB) in the connective tissues of the gill, hepatopancreas, gonad, midgut, and muscle tissues of the affected lobsters. Mass of RLB was not only found in the moribund lobsters but also in the surviving lobsters with milky hemolymph appearance.
IDENTIFICATION AND LIFE CYCLE OF MARINE LEECH ISOLATED FROM CULTURED HYBRID GROUPER IN THE NORTHERN BALI WATERS OF INDONESIA Ketut Mahardika; Indah Mastuti; Sudewi Sudewi; Zafran Zafran
Indonesian Aquaculture Journal Vol 13, No 1 (2018): (June, 2018)
Publisher : Center for Fisheries Research, Agency for Marine and Fisheries Research and Human Resource

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1106.169 KB) | DOI: 10.15578/iaj.13.1.2018.41-49

Abstract

The aims of this study were to identify and to determine life cycle of marine leech isolated from cultured hybrid grouper “cantik” (Epinephelus fuscoguttatus fx E. polyphekadion m) in the northern Bali waters of Indonesia under laboratory conditions. Observation of the life cycle of the marine leech was done using petri-dishes (9 cm in diameter) arranged into two groups. In group-1, a petri-dish was filled with sterile seawater (with water exchange of 50%-60% every two days) and in group-2, a petri-dish was filled with continuous running water. DNA sequence was aligned with the sequences from GenBank by BLAST program. Results of similarity index with GenBank sequence exhibited that the nucleic acid of the marine leech isolated from the hybrid grouper “cantik” showed high similarity (99%) with Zeylanicobdella arugamensis. One adult leech could produce 1-63 eggs. The eggs were developed into morula, blastula, and gastrula within five days. The early phase of the embryo with daily water exchange treatment started on day-6 and hatched into larvae on day-10. The eggs incubated with continuous running water had hatched faster (eight days). However, not all eggs hatched at the same time. Some of the eggs hatched 1-3 days after the first one. Hatching rate of eggs varied from 2.70% to 100%. The newly hatched Z. arugamensis larva has transparent color and length of 1.0-1.5 mm. On day-6, Z. arugamensis larvae were already seen attaching to the body of the fish. The size of the Z. arugamensis larvae ranged between 3-11 mm on day-9. In that stage, they were able to produce eggs. Therefore, we argue that Z. arugamensis only requires 17 to 22 days to develop into the adult stage.