Marine fish broodstock development at SEAFDEC/AQD: status and advances

The success of a fish culture operation depends, in part, on adequate supply of seed for hatchery and grow-out. The culture and husbandry of many of Southeast Asia's marine fish species are constrained by the unreliability of seed supply which are seasonally gathered from coastal areas. To augment the natural seed supply and decrease the dependence on wild catch, SEAFDEC/AQD has undertaken studies to develop a captive source of breeders for some of the economically important marine fish species in the region. This paper presents a brief update of the status and recent advances in marine fish broodstock development undertaken by SEAFDEC/AQD

Preliminary trials on the effects of weaning and larval diets on survival and growth of silver therapon (Leiopotherapon plumbeus) larvae

Abstract only.Success in larval rearing of silver therapon can be achieved through early weaning of fish larvae from live food to artificial diet. Two experiments were carried out to investigate the effects of (a) weaning age (abrupt and gradual) and (b) larval diets (artificial and live foods) on survival and growth of silver therapon (Leiopotherapon plumbeus). In the first experiment, larvae were randomly stocked in round 4-l plastic basins at 15 larvae per basin to provide triplicates of four weaning age treatments (8, 14, 20 and 26 days after hatching or DAH, respectively). Larvae were fed thrice daily for 21 days with commercial feed (CF) and with copepods (COP) which served as the control. Larvae weaned at 26 DAH had the highest survival, body weight and total length among the treatment groups, which were comparable with that of the control. In the co-feeding protocol, larvae were fed Artemia nauplii (ART) as the control group and co-fed with either zooplankton i.e. 50% COP + 50% CF or 50% ART + 50% CF for 8 (8-15 DAH), 6 (14-19 DAH) and 4 (20-23 DAH) days, and suddenly weaned to FM until 21 days. Survival ranged from 22.2 ± 16.8 to 40.0 ± 24.0% between treatments, but was still lower than the control (88.9 ± 3.8%). Body weight and total length were significantly higher in larvae with co-feeding for 4 days (70.1 ± 2.8 mg; 18.1 ± 0.8 mm), but were still lower than that of the control (142.8 ± 7.6 mg; 22.3 ± 0.3 mm). In the second experiment, 26-day old larvae were stocked in 20-l glass aquaria at 4 larvae l-1. Larval diets ((I) commercial prawn feed (38% crude protein); (II) Artemia nauplii; (III) copepods; and (IV) free-living nematode Panagrellus redivivus) were given twice daily for 28 days. Survival was highest in larvae fed Artemia nauplii and poor in copepod fed larvae. Final total length (TL) of larvae fed prawn diet was higher than those fed copepod or nematodes. However, best growth was noted in larvae fed Artemia nauplii (TL= 24.30 ± 0.81 mm; BW = 156 ± 8 mg; specific growth rate or SGR = 5.33 ± 0.19%/d)

Structural Characterization of a Cation-Selective, Self-Assembled Peptide Pore in Planar Phospholipid Bilayers.

GALA is a 30-residue amphipathic peptide that self-assembles into multimeric transmembrane pores in a pH-dependent fashion. In this study, we characterize the size, multimeric structure, and cation selectivity of GALA pores in planar phospholipid bilayers using electrical impedance spectroscopy and molecular dynamics simulations. We demonstrate that in planar bilayers GALA pores are likely formed by six peptide monomers rather than eight to 12 monomers as previously reported for lipid vesicles. We further show that in planar bilayers, GALA pores exhibit previously unreported cation selectivity. We propose that the difference between the predicted pore structures in planar bilayers and lipid vesicles exemplifies the importance of phospholipid bilayer structural properties on the aggregation of transmembrane helical structures

Inhibition of Nuclear Factor of Activated T-Cells (NFAT) Suppresses Accelerated Atherosclerosis in Diabetic Mice

OBJECTIVE OF THE STUDY: Diabetic patients have a much more widespread and aggressive form of atherosclerosis and therefore, higher risk for myocardial infarction, peripheral vascular disease and stroke, but the molecular mechanisms leading to accelerated damage are still unclear. Recently, we showed that hyperglycemia activates the transcription factor NFAT in the arterial wall, inducing the expression of the pro-atherosclerotic protein osteopontin. Here we investigate whether NFAT activation may be a link between diabetes and atherogenesis. METHODOLOGY AND PRINCIPAL FINDINGS: Streptozotocin (STZ)-induced diabetes in apolipoprotein E(-/-) mice resulted in 2.2 fold increased aortic atherosclerosis and enhanced pro-inflammatory burden, as evidenced by elevated blood monocytes, endothelial activation- and inflammatory markers in aorta, and pro-inflammatory cytokines in plasma. In vivo treatment with the NFAT blocker A-285222 for 4 weeks completely inhibited the diabetes-induced aggravation of atherosclerosis, having no effect in non-diabetic mice. STZ-treated mice exhibited hyperglycemia and higher plasma cholesterol and triglycerides, but these were unaffected by A-285222. NFAT-dependent transcriptional activity was examined in aorta, spleen, thymus, brain, heart, liver and kidney, but only augmented in the aorta of diabetic mice. A-285222 completely blocked this diabetes-driven NFAT activation, but had no impact on the other organs or on splenocyte proliferation or cytokine secretion, ruling out systemic immunosuppression as the mechanism behind reduced atherosclerosis. Instead, NFAT inhibition effectively reduced IL-6, osteopontin, monocyte chemotactic protein 1, intercellular adhesion molecule 1, CD68 and tissue factor expression in the arterial wall and lowered plasma IL-6 in diabetic mice. CONCLUSIONS: Targeting NFAT signaling may be a novel and attractive approach for the treatment of diabetic macrovascular complications

Phylogenetic inferences of Atelinae (Platyrrhini) based on multi-directional chromosome painting in Brachyteles arachnoides, Ateles paniscus paniscus and Ateles b. marginatus

We performed multi-directional chromosome painting in a comparative cytogenetic study of the three Atelinae species Brachyteles arachnoides, Ateles paniscus paniscus and Ateles belzebuth marginatus, in order to reconstruct phylogenetic relationships within this Platyrrhini subfamily. Comparative chromosome maps between these species were established by multi-color fluorescence in situ hybridization ( FISH) employing human, Saguinus oedipus and Lagothrix lagothricha chromosome-specific probes. The three species included in this study and four previously analyzed species from all four Atelinae genera were subjected to a phylogenetic analysis on the basis of a data matrix comprised of 82 discrete chromosome characters. The results confirmed that Atelinae represent a monophyletic clade with a putative ancestral karyotype of 2n = 62 chromosomes. Phylogenetic analysis revealed an evolutionary branching sequence \{Alouatta \{Brachyteles \{Lagothrix and Ateles\}\}\} in Atelinae and \{Ateles belzebuth marginatus \{Ateles paniscus paniscus \{Ateles belzebuth hybridus and Ateles geoffroyi\}\}\} in genus Ateles. The chromosomal data support a re-evaluation of the taxonomic status of Ateles b. hybridus. Copyright (C) 2005 S. Karger AG, Basel

A guide to the establishment and maintenance of milkfish broodstock

The manual describes methods used at the SEAFDEC Aquaculture Department in order to establish milkfish broodstock. It is presented under the following major section headings: Establishing broodstock farms; Farms for rearing bangus juveniles; Maturation cages for rearing broodstock to maturity; Gathering data; Spawning and egg collection; and Larval rearing.This study as well as the publication of this guide was partly supported by the International Development Research Centre of Canada under Project No. 3-P78-0033 (Phase II) and No. 3-P81-0171 (Phase III)

Larval rearing of silver therapon (Leiopotherapon plumbeus) in outdoor tanks

Abstract only.Silver therapon (Leiopotherapon plumbeus, Kner 1864), locally known as ayungin, is an important freshwater food fish species found in Laguna de Bay, the largest lake in the Philippines. Its market price is twice that of other most sought after freshwater fishes such as tilapia and milkfish. However, intense fishing pressure on the species has significantly reduced the wild stock in Laguna de Bay. Studies to develop hatchery techniques for this indigenous freshwater fish species are therefore needed to produce seedstock for possible culture and wild stock rehabilitation. This study highlights the successful larval rearing of silver therapon in outdoor concrete tanks. Larvae reared in outdoor tanks with natural food (grown two weeks beforehand) reached the juvenile stage (40 days after hatching (DAH)), suggesting the presence of some suitable live food organisms in pre-conditioned rearing water. However, larval survival rates were low (11.58 ± 6.56% at stocking density of 0.9 larvae l-1), which is probably linked to the density of food items, particularly during the onset of exogenous feeding or due to high stocking density of larvae. To improve the availability of natural food for the larvae, fertilization of the rearing water in the outdoor tanks stocked with larvae at two densities (0.4 and 0.6 larvae l-1) was performed. Larval growth and survival were improved at stocking density of 0.4 larvae l-1 than at 0.6 larvae l-1. Diet composition of first-feeding silver therapon larvae in outdoor tanks inoculated with cultured microalgae (Chorella sorokiniana) and zooplankton was also determined. Larvae were able to consume rotifers and some phytoplankton beginning at 2 DAH and larger preys such as cladocerans and insect larvae starting at 12 DAH. The efficacy of raising silver therapon larvae in outdoor tanks using ambient lake water was also evaluated. Larvae reared in ambient lake water grew well but survival (48.44 ± 7.85%) was significantly improved in treatments where tropical almond or talisay Terminalia catappa leaves were added during the first two weeks of larval rearing