Tiram mutiara merupakan salah satu komoditas andalan dalam budidaya laut. Masalah utama yang dihadapi adalah pasok benih baik kuantitas maupun kualitas. Upaya perbaikan dilakukan dengan perkawinan silang antar varietas tiram dengan tujuan untuk memperbaiki kualitas benih Tiram Mutiara (Pinctada maxima) baik secara fenotip maupun genotip. Induk yang disilangkan secara resiprokal mempunyai karakter nacre putih (P) dan kuning (K) baik populasi Bali maupun Maluku. Hasil penelitian menunjukkan bahwa persilangan dua populasi tersebut menghasilkan tiga varietas yaitu: varietas I (K x P), varietas II (K x K) dan varietas III (P x K). Nilai SR pada fase pediveliger dari ketiga varietas menghasilkan sintasan berturut-turut 65%, 59%, dan 45%. Pertumbuhan varietas III menunjukkan pertumbuhan yang cukup baik dengan kisaran panjang cangkang 3,0-4,5 cm pada umur dua bulan pemeliharaan. Analisis genetik dengan RAPD-DNA menunjukkan bahwa induk-induk yang berhasil memijah mempunyai variasi genetik 0,3755; 0,3938; dan 0,1600. Sedangkan turunan F1 mempunyai variasi genetik lebih rendah yaitu: 0,2738; 0,2667; dan 0,0924.
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.
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.
ABSTRAKPemeliharaan benih lobster P. homarus masih menghadapi beberapa permasalahan, di antaranya infeksi penyakit bakteri (red body disease) dan mortalitas yang tinggi. Tujuan penelitian ini adalah untuk mengkaji respons imunitas benih lobster P. homarus yang diberi pakan pelet basah (moist diets) dengan penambahan probiotik. Pemeliharaan benih lobster dilakukan secara individu (1 ekor/keranjang). Lama pemeliharaan selama tiga bulan. Bobot awal puerulus P. homarus adalah 0,37 ± 0,05 g. Perlakuan meliputi pemberian pakan moist yang ditambahkan (A) ragi Saccharomyces cerevisiae, (B) kombinasi probiotik, Alteromonas sp. BY-9 dan Bacillus cereus BC, dan (C) tanpa probiotik. Respons imunitas dianalisis dengan RT-qPCR melalui tujuh gen target terkait ekspresi imunitas, setelah diuji tantang dengan Vibrio harveyi (penyebab red body disease). Hasil penelitian menunjukkan bahwa sintasan benih lobster sebesar (A) 32,22%; (B) 29,63%; dan (C) 33,33%. Pertumbuhan panjang dan bobot benih lobster tidak berbeda nyata (P>0,05). Respons imunitas benih lobster P. homarus pada perlakuan A dan B menunjukkan nilai ekspresi imun yang lebih tinggi dibandingkan dengan perlakuan C (tanpa probiotik). Ekspresi gen penyandi anti lipopolisakarida (ALFHa-1) meningkat pada (A) rata-rata sebesar 3,44 kali dan (B) 3,25 kali dibandingkan dengan perlakuan C (2,43 kali). Kelipatan ekspresi profenoloksidase (proPO) benih lobster meningkat pada perlakuan A (penambahan ragi) rata-rata sebesar 5,27 kali, sedangkan pada perlakuan B (kombinasi probiotik) sebesar 12,92 kali. Ekspresi Clotting sistem (transglutaminase, clotting protein) dan antioxidant defense mechanism (glutathione peroxidase/GPO) dan SAA juga mengalami peningkatan pada perlakuan A dan B.
The bacterial populations in the farming of spiny lobster could have either beneficial or harmful effects depending on the prevailing conditions. We designed this study to identify and to perform a pathogenicity test of some bacteria isolated from wild and farmed spiny lobsters Panulirus homarus. The adult farmed lobsters were obtained from Pangandaran and Lombok coastal areas, while the wild lobsters were collected from Lombok, with five lobsters for each location. The bacteria were isolated from the midgut, gill, hepatopancreas, and muscle tissues of the lobsters. The identification of the bacteria was carried out by molecular methods. Pathogenicity test was performed by intramuscular injection of 0.1 ml bacterial suspensions at the density of 7×106cfu/ml into each three adult apparently healthy lobsters for every eight bacterial isolates. Our study identified six bacterial isolates that exhibited high homology of a nucleotide sequence with Shewanella algae, Bacillus firmus, Vibrio alginolyticus, Tenacibaculum lutimaris, Pseudomonas sp. and Vibrio sp., while two isolates were reminded unidentified due to low nucleotide similarities (< 97%). The pathogenicity test showed that there was no mortality of lobsters injected with those bacterial isolates. This may because the dose of injection was too low to induce bacterial infection particularly for Vibrio, or the bacteria were not pathogenic for lobster or even have the potency as probiotic bacteria.
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