Cryopreservation of Chinese mitten crab, Eriocheir sinensis H. Milne Edwards, 1853 (Decapoda, Brachyura), embryos by vitrification

Though cryopreservation of some invertebrate embryos was successful, the cryopreservation of crustacean embryos has not yet been reported. On the basis of previous study, a single vitrifying cocktail (Code A: 30% propanediol and 20% dimethyl formamide) was selected as a cryoprotectant from six kinds of vitrifying solutions to cryopreserve E. sinensis embryos. The cleavage stage, the gastrula, the pre-nauplius, and the first zoea stage embryos were serially acclimated in 25, 33, 50, 67 and 100% vitrifying solution A for 6 min. Embryos were acclimated for 1 min on the 20 cm liquid nitrogen (LN2) layer, and then plunged into liquid nitrogen. After storage for several minutes in LN2, straws containing frozen embryos were acclimated for 1 min on the 20 cm liquid nitrogen (LN2) layer, then quickly removed from LN2. For thawing, straws were immersed quickly for 1 min in a water bath at 37°C, then carefully washed with 0.25 mol/l sucrose and were then incubated with 15 ppt seawater in a Petri dish at 25°C. The survival rate in the vitrifying solution differed for embryos in different stages of development, and the survival rate of different stage embryos declined with the increase of acclimation time in code A vitrifying solution. The survival rate of pre-nauplius stage embryos did not significantly differ when the embryos were washed for 5, 10, 15, or 20 min with 0.25 mol/l sucrose after thawing. There was no survival after either cleavage stage embryos, or gastrula stage embryos were frozen. Eight pre-nauplius stage embryos survived and the survival rate was 9.3 ± 2.5%, but subsequently the embryos died at the fourth day. Seven first zoea stage embryos survived, and the survival rate was 11.3 ± 3.6%, one frozen-thawed embryo hatched at the seventh day. We conclude that cryopreservation of E. sinensis embryos by vitrification is feasible.

GROWTH IN NURSERY AND GROW-OUT PHASES OF WHITE SHRIMP AFTER IMMERSED IN RECOMBINANT GIANT GROUPER GROWTH HORMONE

The growth of white shrimp (Litopenaeus vannamei) can be improved by using recombinant fish growth hormone through immersion. This research was performed to evaluate the white shrimp growth at nursery and grow-out phases after recombinant giant grouper growth hormone (rElGH) immersion. Shrimp were immersed at different stages in one liter seawater containing 15 mg rElGH for two hours. At the nursery stage 30,000 PL4 that previously immersed at nauplius stage (treatment A1), at PL4 (treatment B1) and control without rElGH immersion (K1) were reared in fiber tanks containing 750 L seawater for 8 days. At the grow-out phase, 100 PL11 that have been immersed in rElGH solution at nauplius stage (treatment A2), at PL4 (B2), PL11 (C2) and control without rElGH immersion (K2) were separately reared in fiber tanks containing 750 L seawater for 55 days. Each treatment consisted of three replications. The results showed that at the end of the nursery phase, B1 treatment increased 19% of body length, 30.2% of the body weight and decreased the coefficient of length variation 34.9% compared to control K1 (P<0.05). At the grow-out phase, C2 treatment enhanced 38.2% of body weight and 32% of biomass compared with control K2 (P<0.05). Thus, hatchery is better to immerse PL4, and the farmer should used rElGH-immersed PL11 for growing-out.Keywords: growth promoting, nursery, grow out, Litopenaeus vannamei, rElGH

GROWTH IN NURSERY AND GROW-OUT PHASES OF WHITE SHRIMP AFTER IMMERSED IN RECOMBINANT GIANT GROUPER GROWTH HORMONE

<p><em>The growth of white shrimp (<span style="text-decoration: underline;">Litopenaeus</span> <span style="text-decoration: underline;">vannamei</span>) can be improved by using recombinant fish growth hormone through immersion. This research was performed to evaluate the white shrimp growth at nursery and grow-out phases after recombinant giant grouper growth hormone (rElGH) immersion. Shrimp were immersed at different stages in one liter seawater containing 15 mg rElGH for two hours. At the nursery stage 30,000 PL4 that previously immersed at nauplius stage (treatment A1), at PL4 (treatment B1) and control without rElGH immersion (K1) were reared in fiber tanks containing 750 L seawater for 8 days. At the grow-out phase, </em><em>1</em><em>00 PL11 that </em><em>have been </em><em>immersed in rElGH solution at nauplius stage (treatment A2), at PL4 (B2), PL11 (C2) and control without rElGH immersion (K2) were separately reared in fiber tanks containing 750 L seawater for 55 days. Each treatment consisted of three replications. The results showed that at the end of the nursery phase, B1 treatment increased 19% of body length, 30.2% of the body weight and decreased the coefficient of length variation 34.9% compared to control K1 (P&lt;0.05). At the grow-out phase, C2 treatment enhanced 38.2% of body weight and 32% of biomass compared with control K2 (P&lt;0.05). Thus, hatchery is better to immerse PL4, and </em><em>the </em><em>farmer should </em><em>used</em><em> rElGH-immersed PL11 for growing-out.</em></p><p><strong><em>Keywords</em></strong>: <em>growth promoting, nursery, grow out</em>, <em>Litopenaeus vannamei</em>, <em>rElGH</em></p>

Effect of SKT-b Vibrio probiotic bacteria addition at different developmental stages on tiger shrimp Penaeus monodon larvae survival rate

<p>This experiment was conducted to study the effect of probiotic bacteria SKT-b <em>Vibrio</em> addition at different developmental stages on survival rates of tiger shrimp <em>Penaeus monodon </em>larva.<em> </em>Main activity of this experiment consisted of tiger shrimp rearing started from nauplius stage until Pl₁₀ and addition of 10⁶ CFU/ml SKT-b <em>Vibrio</em> probiotic bacteria at various developmental stages namely at early nauplius stage, early zoea zoea stage, early mysis stage, early postlarva (Pl) stage, every developmental stage changes, everyday, and control (without probiotic bacteria addition). Results showed that survival rates of shrimp larva ranged at 24,17%-35,83% with the higest value in the treatment of probiotic bacteria addition at every developmental stage changes namely 35,83%, whereas the lowest was found at control (without probiotic bacteria addition) namely 24,17%. No significantly different was found in term of shrimp growth rate among control and treatment. Growth rate in length of tiger shrimp larva ranged 18,64%-19,09% for SKT-b <em>Vibrio</em> addition and 18,47% for control.</p> <p>Key word: Probiotic bacteria, SKT-b<em> Vibrio</em>, <em>Penaeus monodon</em>, shrimp larvae stages</p> <p> </p> <p>ABSTRAK</p> <p>Penelitian ini dilakukan untuk mempelajari pengaruh pemberian bakteri probiotik <em>Vibrio</em> SKT-b pada stadia yang berbeda terhadap kelangsungan hidup larva udang windu <em>Penaeus monodon.</em> Kegiatan utama dari penelitian ini adalah pemeliharaan udang windu yang dimulai dari stadia nauplius sampai Pl₁₀ dan diberi bakteri probiotik <em>Vibrio</em> SKT-b dengan dosis 10⁶ CFU/ml pada waktu yang berbeda yaitu pada awal stadia nauplius, awal stadia zoea, awal stadia mysis, awal stadia postlarva (Pl), setiap pergantian stadia, setiap hari, dan kontrol (tanpa pemberian bakteri probiotik). Hasil penelitian yang diperoleh menunjukkan bahwa tingkat kelangsungan hidup larva udang berkisar antara 24,17%-35,83% dengan nilai tertinggi terdapat pada perlakuan pemberian bakteri probiotik pada setiap pergantian stadia yaitu sebesar 35,83%, sedangkan terendah pada perlakuan kontrol (tanpa pemberian bakteri probiotik) yaitu 24,17%. Sedangkan terhadap pertumbuhan tidak terdapat perbedaan yang signifikan antara kontrol dengan perlakuan. Nilai laju pertumbuhan panjang larva udang windu dengan penambahan bakteri probiotik <em>Vibrio</em> SKT-b berkisar antara 18,64%-19,09% dan kontrol sebesar 18,47%.</p> <p>Kata kunci: Probiotik, <em>Vibrio</em> SKT-b, <em>Penaeus monodon</em>, stadia larva udang</p>

Divergence and convergence in early embryonic stages of metazoans

The early stages of organogenesis in metazoans differ drastically between higher order taxa such as phyla and classes. The segmented germ band stage in insects, the nauplius stage of crustaceans, and the neurula/pharyngula stage in vertebrates are examples of this diversification. In striking contrast with this divergence, is the similarity of these stages within these taxa, i.e., within insects, crustaceans, and vertebrates. The early stages of organogenesis, or phylotypic stages, have, thus, remained very similar in most species since the evolutionary origin of the taxa. These phylotypic stages are considerably more similar to each other than to the earlier stages of cleavage and gastrulation. Cleavage and gastrulation stages display not only great variability, but also striking examples of apparent convergence among species in different phyla, for example in the many cases of epiblastic cleavage in yolk-rich eggs. This leads to the paradoxical situation that the overall similarity of cleavage and gastrulation stages is in general higher among metazoans than of the early stages of organogenesis, but within phyla and classes the situation is the reverse. We discuss data on cleavage, gastrulation, and early organogenesis and evaluate possible causes for conservation, homoplasy, and diversification in an attempt to throw light on this paradoxical situation. In addition, we discuss a hypothesis that has been proposed to explain the diversity of early stages of organogenesis at the level of metazoans and the similarity within many phyla and classes.

The Copepodid of Peniculisa Shiinoi Izawa, 1965 (Copepoda, Siphonostomatoida, Pennellidae), a Single Free-Swimming Larval Stage of the Species

The copepodid stage of the parasitic copepod Peniculisa shiinoi Izawa, 1965 (Siphonostomatoida, Pennellidae), parasitic on the fins of a puffer fish, Canthigaster rivulatus, is described based on specimens reared from eggs. This is the only free-swimming larval stage of P. shiinoi. The copepodid is distinctly smaller than those of the known pennellids. However, the dispensability of the free-swimming nauplius stage is independent of the egg-size. The copepodid antennae of the pennellids are certainly uniramous. The setation of the rami of the copepodid legs varies among pennellids.

Early Stages of Some Copepods (Crustacea) Parasitic on Marine Fishes of British Columbia

Detailed descriptions and illustrations are presented of the nauplii (the only, or the first nauplius stage) of Bomolochus cuneatus, Holobomolochus spinulus, Chondracanthus gracilis, Ergasilus turgidus, Eudactylina similis, Pseudocharopinus dentatus, and Haemobaphes diceraus, and the copepodid stages of H. diceraus, P. dentatus, and Nectobrachia indivisa.The naupliar morphology of Ergasilus is similar to that of free-living Cyclopidae but differs in significant details from that of supposedly related Bomolochus. The nauplii of poecilostome and siphonostome copepods are similar. The morphology of the free-living larval stages might offer valuable clues to intrafamilial relationships of Lemaeopodidae. Differences were observed between copepodids of two species of Haemobaphes.