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Saetan J.,Mahidol University | Senarai T.,Mahidol University | Tamtin M.,Coastal Aquatic Feed Research Institute | Weerachatyanukul W.,Mahidol University | And 6 more authors.
Cell and Tissue Research | Year: 2013

We present a detailed histological description of the central nervous system (CNS: brain, subesophageal ganglion, thoracic ganglia, abdominal ganglia) of the blue crab, Portunus pelagicus. Because the presence of gonadotropin-releasing hormone (GnRH) in crustaceans has been disputed, we examine the presence and localization of a GnRH-like peptide in the CNS of the blue crab by using antibodies against lamprey GnRH (lGnRH)-III, octopus GnRH (octGnRH) and tunicate GnRH (tGnRH)-I. These antibodies showed no cross-reactivity with red-pigment-concentrating hormone, adipokinetic hormone, or corazonin. In the brain, strong lGnRH-III immunoreactivity (-ir) was detected in small (7-17 μm diameter) neurons of clusters 8, 9 and 10, in medium-sized (21-36 μm diameter) neurons of clusters 6, 7 and 11 and in the anterior and posterior median protocerebral neuropils, olfactory neuropil, median and lateral antenna I neuropils, tegumentary neuropil and antenna II neuropil. In the subesophageal ganglion, lGnRH-III-ir was detected in medium-sized neurons and in the subesophageal neuropil. In the thoracic and abdominal ganglia, lGnRH-III-ir was detected in medium-sized and small neurons and in the neuropils. OctGnRH-ir was observed in neurons of the same clusters with moderate staining, particularly in the deutocerebrum, whereas tGnRH-I-ir was only detected in medium-sized neurons of cluster 11 in the brain. Thus, anti-lGnRH-III shows greater immunoreactivity in the crab CNS than anti-octGnRH and anti-tGnRH-I. Moreover, our functional bioassay demonstrates that only lGnRH-III has significant stimulatory effects on ovarian growth and maturation. We therefore conclude that, although the true identity of the crab GnRH eludes us, crabs possess a putative GnRH hormone similar to lGnRH-III. The identification and characterization of this molecule is part of our ongoing research. © 2013 Springer-Verlag Berlin Heidelberg. Source

Plaipetch P.,Coastal Aquatic Feed Research Institute | Kuekaew J.,Coastal Aquatic Feed Research Institute | Tamtin M.,Coastal Aquatic Feed Research Institute | Choncheunchob P.,Central Administration
Kasetsart Journal - Natural Science | Year: 2014

A 60-day trial was conducted to determine the effects of a low-fishmeal diet on Asian sea bass, Lates calcarifer. A 50% fishmeal diet was used as a control and in other experimental diets, fishmeal was replaced by soybean and canola meals to give diets containing 40, 30, 20 and 10% fishmeal. The effect of supplementing the 10% fishmeal diet with 1% betaine was also tested. Fish fed the 10-30% fishmeal diets showed significantly higher specific growth rate than did fish fed the control diet. Reducing the amount of dietary fishmeal did not affect the fish survival rate, feed intake or feed conversion ratio, but decreased the nitrogen loading. Reduced dietary fishmeal increased the amount of flesh protein and most essential amino acids contents, but decreased the flesh lipid, ash and bone protein contents. The hepato-somatic and viscero-somatic indices and the condition factor were significantly increased with reducing dietary fishmeal. Supplementing the 10% fishmeal diet with 1% betaine reduced the hepato- somatic index and condition factor, but increased the feed intake, feed conversion ratio and nitrogen loading; however, this did not improve the specific growth rate and survival rate, and adversely affected fish quality by decreasing the flesh protein and increasing the lipid content. Source

Chansela P.,Mahidol University | Chansela P.,Hamamatsu University | Goto-Inoue N.,Tokyo Metroplitan University | Zaima N.,Kinki University | And 9 more authors.
PLoS ONE | Year: 2012

Ovary maturation, oocyte differentiation, and embryonic development in shrimp are highly dependent on nutritional lipids taken up by female broodstocks. These lipids are important as energy sources as well as for cell signaling. In this study, we report on the compositions of major lipids, i.e. phosphatidylcholines (PCs), triacylglycerols (TAGs), and fatty acids (FAs), in the ovaries of the banana shrimp, Penaeus merguiensis, during ovarian maturation. Thin-layer chromatography analysis showed that the total PC and TAG signal intensities increased during ovarian maturation. Further, by using gas chromatography, we found that (1) FAs 14:0, 16:1, 18:1, 18:2, 20:1, and 22:6 proportionally increased as ovarian development progressed to more mature stages; (2) FAs 16:0, 18:0, 20:4, and 20:5 proportionally decreased; and (3) FAs 15:0, 17:0, and 20:2 remained unchanged. By using imaging mass spectrometry, we found that PC 16:0/16:1 and TAG 18:1/18:2/22:6 were detected in oocytes stages 1 and 2. PCs 16:1/20:4, 16:0/22:6, 18:3/22:6, 18:1/22:6, 20:5/22:6, and 22:6/22:6 and TAGs 16:0/16:1/18:3, 16:0/18:1/18:3, 16:0/18:1/18:1, and 16:0/18:2/22:6 were present in all stages of oocytes. In contrast, the PC- and TAG-associated FAs 20:4, 20:5, and 22:6 showed high signal intensities in stage 3 and 4 oocytes. These FAs may act as nutrition sources as well as signaling molecules for developing embryos and the hatching process. Knowledge of lipid compositions and localization could be helpful for formulating the diet for female broodstocks to promote fecundity and larval production. © 2012 Chansela et al. Source

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