Larviculture newsletter < Year 2005 < Issue 221

ELECTRONICAL LARVICULTURE NEWSLETTER ISSUE 221
June 1st, 2005

VITAMIN C REQUIREMENT OF KURUMA SHRIMP POSTLARVAE, MARSUPENAEUS JAPONICUS (BATE), USING L-ASCORBYL-2-MONOPHOSPHATE-NA/CA

Yin Yin Moe, Shunsuke Koshio, Manabu Ishikawa, Shin-ichi Teshima, Arthur Panganiban Jr, Moe Thu, Fady Raafat Michael, Torgjun Ren-2005
Aquaculture Research, 36 (8): 739 -745
Abstract:
L-ascorbyl-2-monophosphate-Na/Ca (AMP-Na/Ca) was used as a vitamin C source to investigate the ascorbic acid (AsA) requirements on growth performance and stress resistance of the post-larval kuruma shrimp, Marsupenaeus japonicus. Purified carrageenan-microbound diets with six levels of AMP-Na/Ca, AsA equivalent to 0, 20, 56, 87, 759 and 1697 mg kg 1 diet were fed to triplicate groups of M. japonicus (mean initial weight 16±0.3 mg) for 30 days. The diets with AsA 0, 20 and 56 mg kg 1 showed high cumulative mortality after 10 days of feeding. After the 30-day trial, the shrimp fed these diets had significantly lower survival and weight gain (WG, %) than those fed the 87, 759 and 1697 mg AsA kg 1 diets. Specific growth rate and individual dry weight showed the same pattern as WG (%). There were no significant differences in growth performance among the groups fed the AsA levels at 87, 759 and 1697 mg kg 1 at the termination of feeding trial. Broken-line regression analysis indicated that 91.8 mg AsA kg 1 in the diet was the optimum for post-larval shrimp. On the other hand, dietary level of more than 800 mg AsA kg 1 was needed to ensure high resistance to stressful conditions such as osmotic and formalin stressors.
(Science of Marine Resources, The United Graduate School of Agricultural Science, Kagoshima University, Kagoshima, Japan; email of S. Koshio: koshio@fish.kagoshima-u.ac.jp)

EVALUATION OF PROGENY OF FOURTH GENERATION SYDNEY ROCK OYSTER SACCOSTREA GLOMERATA (GOULD, 1850) BREEDING LINES

John A Nell, Ben Perkins-2005
Aquaculture Research, 36 (8): 753 -757
Abstract:
The progeny of four 4th generation Sydney rock oyster Saccostrea glomerata (Gould, 1850) breeding lines that were selected for fast growth were compared in a 3-year farming experiment. Oysters of the most improved breeding line (line 2) reached market size (50-g whole weight) 15 months earlier than non-selected control oysters (3 years and 5 months). The average reduction in time to market size for oysters of all four breeding lines was 12.5 months.
(NSW Department of Primary Industries, Port Stephens Fisheries Centre, Taylors Beach, NSW 2316, Australia; email of J. Nell: john.nell@fisheries.nsw.gov.au

HATCHERY PERFORMANCE OF EARLY BENTHIC JUVENILE AMERICAN LOBSTERS (HOMARUS AMERICANUS) FED ENRICHED FROZEN ADULT ARTEMIA DIETS

Michael F. Tlusty, Jason S. Goldstein, Denise R. Fiore-2005
Aquaculture Nutrition, 11 (3): 191 -198
Abstract :
One of the main factors hindering aquaculture production of American lobsters (Homarus americanus) is the need for a cost-effective and nutritionally sound diet. Live Artemia results in good growth, but is expensive and is a constant source of contamination. Frozen Artemia, although lower in cost, generally results in decreased survivorship and growth relative to live Artemia. The recent advent and mass production of enriched frozen Artemia products may provide for a cost-effective and nutritionally complete food source for culturing American lobsters. Here, commercially available frozen adult Artemia enriched with either n-3 fatty acids, or Spirulina was fed to juvenile American lobsters, and their growth and survivorship for three months was compared with that of animals fed unenriched frozen adult Artemia. Both enriched Artemia products produced survivorship superior to that for animals fed unenriched Artemia. Results for growth were equivocal although animals fed the Spirulina-enriched Artemia had the greatest condition factor. Although more costly by the end of the experiment, enriched diets were more economically efficient than unenriched Artemia. This research demonstrates that enriched feedstuffs are cost-effective over longer time intervals, and benefits may continue beyond the hatchery-rearing phase. Enriched diets may also yield animals with a better condition factor, which may further influence their survivorship when released to the wild in enhancement programmes.
(New England Aquarium, Research Department, 1 Central Wharf, Boston, MA 02110, USA; email of M. Tlusty: mtlusty@neaq.org)

EFFECT OF DIFFERENT FEED FORMULATIONS ON FEED EFFICIENCY, GONAD YIELD AND GONAD QUALITY IN THE PURPLE SEA URCHIN HELIOCIDARIS ERYTHROGRAMMA

M. Senaratna, L.H. Evans, L. Southam, E. Tsvetnenko-2005
Aquaculture Nutrition, 11 (3): 199 -208
Abstract :
The nutritive values of three pelleted prepared diets, based on animal (AP), vegetable (VP) and yeast protein (YP) were studied for the sea urchin Heliocidaris erythrogramma (Val.). Fresh macroalga Ulva australis was used as a natural control diet. Triplicate groups of five animals were fed one of the four diets ad libitum every second day for 85 days. Sea urchins fed pelleted feeds had significantly higher food consumption rates (dry basis) and significantly lower total and protein absorption efficiencies compared with the algal diet. The gonad yield and gonad production efficiency in sea urchins fed the natural diet were significantly higher compared with initial group (gonad yield only) and urchins fed animal and vegetable diets, but did not differ significantly from those of the animals fed the yeast diet. Percent protein and lipid in the gonads were not affected by the dietary source. The taste and smell of gonads were generally better in sea urchins collected from the wild or fed yeast and natural diets than in sea urchins fed animal and vegetable diets. The animal protein diet was the most stable in seawater while the yeast protein diet had the poorest water stability. The results of this study suggest that development of a more stable, single-cell, protein-based diet has a potential to promote gonad production of H. erythrogramma.
(Aquatic Science Research Unit, Curtin University of Technology, PO Box U1987, Perth, WA 6845, Australia; email of E. Tsvetnenko: e.tsvetnenko@curtin.edu.au)

ULTRASTRUCTURAL FEATURES OF THE EGG ENVELOPE OF SILVER CARP, HYPOPHTHALMICHTHYS MOLITRIX (OSTEICHTHYES, CYPRINIDAE)

Hamid Reza Esmaeili, Mohinder Singh Johal-2005
Abstract:
We investigated the ultrastructure of the egg membrane surface (unfertilized egg) of Hypophthalmichthys molitrix using scanning electron microscopy. The eggs of silver carp like most other teleosts are surrounded by a relatively thick egg membrane, and have a type III micropyle at the animal pole. The micropyle is almost circular in shape and the micropyle canal is located in its center. The micropyle region is not flat. Round or oval accessory pores are also observed in the canal. The surface of zona radiata is wavy and uneven with a uniform distribution of almost round pores with lips. Microvilli like structure are found in the pore opening region.
(Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran; emai of H.R. Esmaeli: hresmaeili@yahoo.com)

FOREWORD: ONTOGENY OF THE FISH IMMUNE SYSTEM

R.A. Dalmo-2005
Fish & Shellfish Immunology, 19 (5): 395-396
(Department of Marine Biotechnology, Norwegian College of Fishery Science, University of Tromsø, N-9037 Tromsø, Norway; email: royd@nfh.uit.no)

COMPARATIVE ORGAN DIFFERENTIATION DURING EARLY LIFE STAGES OF MARINE FISH

I.B. Falk-Petersen-2005
Fish & Shellfish Immunology, 19 (5): 397-412
Abstract:
The basic developmental mechanisms of teleosts are similar, but there are differences with respect to the timing of developmental events. These events are controlled by genetic and environmental factors. Direct comparisons of organogenesis are complicated due to large variations in egg sizes and incubation temperatures between species. But in general, cultivated small marine pelagic fish larvae originating from rather small eggs (like gadoids, flatfishes, sparids) hatch with a relatively large yolk sac, a larval finfold and subdermal space and under-developed organs. Developmental status at hatch differs between species and the duration of the yolk sac period varies. Main organs and organ systems become functional by first feeding and differentiate during the larval stage and metamorphosis. Species developing directly via large yolk-rich eggs and a long incubation period have a juvenile like morphology and organ functionality at first feeding, sometimes immediately after hatch (like wolffishes). Histomorphological and cell- or organ functional studies of developing embryos and larvae of cultivated species constitute basic information for understanding species-specific events, of utmost importance for improving production protocols. Information is still lacking on early functionality of endocrine and immunocompetent tissues and organs, areas that deserve future focus.
(Institute of Aquatic BioSciences, The Norwegian College of Fishery Science, University of Tromsø, N-9037 Tromsø, Norway; email: ingerf@nfh.uit.no)

DEVELOPMENT AND FUNCTION OF THE THYMUS IN TELEOSTS

T.J. Bowden, P. Cook, J.H.W.M. Rombout-2005
Fish & Shellfish Immunolog,y 19 (5): 413-427
Abstract:
The thymus plays a pivotal role in the development of the adaptive immune system, an important factor that separates higher vertebrates from the rest of the animal phyla. The development of functional T-cells from thymocytes is a crucial step in the development of a functional vertebrate immune system and whilst recent advances in molecular and developmental biology have advanced our understanding of T-cell development, they have also provided potential model species across the vertebrate phyla including the zebrafish (Danio rerio). However, this species is one of more than 20,000 species of fish that could assist in elucidating the development of the vertebrate thymus and, consequently, the evolution of the vertebrate immune response. In this paper we review the knowledge of the teleost thymus through the organogenesis and development studies in teleosts together with advances in molecular and functional approaches. Where necessary we will combine this knowledge with that obtained in higher vertebrates.
(Department of Zoology, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ Scotland, UK; email of T. Bowden: t.bowden@abdn.ac.uk)

ONTOGENY OF HUMORAL IMMUNE PARAMETERS IN FISH

B. Magnadottir, S. Lange, S. Gudmundsdottir, J. Bøgwald, R.A. Dalmo-2005
Fish & Shellfish Immunology, 19 (5): 429-439
Abstract:
The first appearance of IgM in lymphocytes varies considerably among fish species. Generally, the first appearance of B-lymphocytes and immunoglobulins is late in marine species compared to fresh water species, and larvae have reached about 20–30 mm in length when IgM is first expressed. Rainbow trout and channel catfish show the first appearances of surface IgM at about 1 week after hatching. Marine species like the sea bass, spotted wolffish and cod show IgM positive lymphocytes 1–10 weeks after hatching. Transfer of maternal antibody to eggs and embryos has been demonstrated in several species. Examples are plaice, tilapia, carp, sea bass and salmon, but not cod. The ontogeny of complement component C3 has been studied in Atlantic halibut (Hippoglossus hippoglossus L.), Atlantic cod (Gadus morhua L.) and the spotted wolffish (Anarhichas minor O.). By Western blotting experiments C3 was found in unfertilised eggs in the spotted wolffish indicating a maternal transfer. RT-PCR analysis revealed C3 mRNA transcripts from 290 d° in spotted wolffish eggs. Using immunohistochemistry and in situ hybridisation, C3 was found in liver, brain, kidney and muscle of cod larvae 2 days post-hatching and in intestines, pancreas, heart and gills at different stages of larval development. Also, C3 was detectable in halibut larvae in yolk sac, muscle, liver, brain, chondrocytes, spinal chord, eye, heart, intestines and kidney. These studies suggest that complement may play a role in generation of different organs, not only in the defence against invading pathogens. Lysozyme is a bactericidal enzyme present in mucus, lymphoid tissue and serum of most fish species, but not in cod and wolffish. The enzyme has been detected in oocytes, fertilised eggs and larval stages of fish species like coho salmon, sea bass and tilapia. The activity of other enzymes like the cathepsins has been described in eggs and larvae of sea bass, cod and salmonids. Cathepsins may have a bactericidal role in the skin of fish. Lectins are carbohydrate-binding proteins that interact with pathogenic surface structures that result in opsonization, phagocytosis or activation of complement. Lectins have been isolated from the eggs of various fish species.
(Institute for Experimental Pathology, University of Iceland, Keldur, IS-112 Reykjavik, Iceland; email of B. Magnadottir: bergmagn@hi.is)

PHYLOGENY AND ONTOGENY OF FISH LEUCOCYTES

J.H.W.M. Rombout, H.B.T. Huttenhuis, S. Picchietti, G. Scapigliati-2005
Fish & Shellfish Immunology, 19 (5): 441-455
Abstract:
In contrast to higher vertebrates, most fish species hatch at the embryonic stage of life. Consequently, they have to defend against a variety of micro-organisms living in their aquatic environment. This paper is focussed on the development of leucocytes functioning within this early innate system and later on in the acquired immune system (B and T cells). Most of the data are derived from cyprinid fish (zebrafish, carp), which are excellent models to study early ontogeny. Attention is also paid to the phylogeny of leucocytes, with special attention to early chordates. It is clear that young fish use innate mechanisms during the first weeks/months of their development. In zebrafish, a variety of hematopoietic genes have been sequenced which allow a detailed picture of the development of the distinct leucocytes and their precursors. In cyprinids and sea bass, the thymus is the first lymphoid organ and T cells appear to be selected there much earlier than the first detection of T cell-dependent antibody responses. The first B cells are most probably generated in head kidney. Although T cells are selected earlier than B cells, T cell independent responses occur earlier than the T cell-dependent responses. The very early (pre-thymic) appearance of T-like cells in gut of sea bass and carp suggests an extra-thymic origin of these cells. However, B cells populate the GALT much later than spleen or kidney, indicating a rather late appearance of mucosal immunity. The first plasma cells are found long after the intake of food in cyprinids, but in many marine fish they appear around the first food intake. In general, acquired immunity is not correlated to food intake.
(Cell Biology and Immunology Group, Department of Animal Sciences, Wageningen University, AH Wageningen 6709, The Netherlands; email of J. Rombout: jan.rombout@wur.nl)

THE USE OF IMMUNOSTIMULANTS IN FISH LARVAL AQUACULTURE

Ian Bricknell, Roy A. Dalmo-2005
Fish & Shellfish Immunology, 19 (5): 457-472
Abstract:
The production of fish larvae is often hampered by high mortality rates, and it is believed that most of this economic loss due to infectious diseases is ca. 10% in Western European aquaculture sector. The development of strategies to control the pathogen load and immuno-prophylactic measures must be addressed further to realise the economic “potential” production of marine fish larvae and thus improve the overall production of adult fish.
The innate defence includes both humoral and cellular defence mechanisms such as the complement system and the processes played by granulocytes and macrophages. A set of different substances such as ß-glucans, bacterial products, and plant constituents may directly initiate activation of the innate defence mechanisms acting on receptors and triggering intracellular gene activation that may result in production of anti-microbial molecules. These immunostimulants are often obtained from bacterial sources, brown or red algae and terrestrial fungi are also exploited as source of novel potentiating substances.
The use of immunostimulants, as dietary supplements, can improve the innate defence of animals providing resistance to pathogens during periods of high stress, such as grading, reproduction, sea transfer and vaccination. The immunomodulation of larval fish has been proposed as a potential method for improving larval survival by increasing the innate responses of the developing animals until its adaptive immune response is sufficiently developed to mount an effective response to the pathogen. To this end it has been proposed that the delivery of immunostimulants as a dietary supplement to larval fish could be of considerable benefit in boosting the animals innate defences with little detriment to the developing animal. Conversely, there is a school of thought that raises the concern of immunomodulating a neotanous animal before its immune system is fully formed as this may adversely affect the development of a normal immune response.
FRS Marine Laboratory, PO Box 101, 375 Victoria Road, Torry, Aberdeen AB11 9DB, UK; email of I. Bricknell: i.r.bricknell@marlab.ac.uk)

EXTERNAL EGG MEMBRANE CHARACTERISTICS OF LANDLOCKED FALL CHINOOK SALMON EYED EGGS TREATED WITH HYDROGEN PEROXIDE OR FORMALIN

Hans Stephenson, Mark Gabel, Michael E. Barnes
North American Journal of Aquaculture 67 (3): 171–176
Abstract.:
This study examines the microscopic characteristics of external egg membranes from eyed eggs of landlocked fall Chinook salmon Oncorhynchus tshawytscha treated with formalin (1,667 mg/L) or hydrogen peroxide (700 mg/L) for 15 min daily until hatching. Just before the start of hatching, the internus layer became significantly less differentiated in the membranes of eggs treated with hydrogen peroxide compared with those in the formalin treatments or untreated controls. There were no significant differences among the treatments in total membrane thickness, pore canal height, basal layer height, pore canal width, and the number of pore canals per 50-µm lengthwise segment along the membrane. Overall membrane thickness (externus and internus layers combined) averaged 51.5 µm during the test period. Thickness of externus averaged 0.69 µm, nearly two times that reported previously for nonlandlocked Chinook salmon.
(Department of Biology, Black Hills State University, 1200 University, Spearfish, South Dakota 57799, USA)

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