Metabolic rate characteristics and sediment cleaning potential of the tropical sea cucumber Holothuria scabra
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The oxygen consumption rate (OCR) and ammonium excretion rate (AER) of a tropical sea cucumber, Holothuria scabra, were determined in laboratory experiments. OCR and AER exhibited a significant negative correlation to body weight (BW), expressed as a power function of BW: OCR = 0.09 × BW−0.58 (mgO2/g/h, r2=0.89, n=15) and AER = 0.38 × BW−0.19 (μmolN/g/h, r2=0.54, n=15). These values were comparable to those in previous studies on other sea cucumber species. The OCR of shrimp tank sediment was reduced to less than half (4.5 ± 0.3 to 1.0 ± 0.1 mgO2/gdry/h) by the ingestion and excretion process of H. scabra. Acid volatile sulfide (AVS-S) concentration was also decreased to less than half (0.67 to 0.31 mgS/mgdry); despite the low reduction rates of organic carbon and nitrogen contents (0.19 to 0.14 mgC/mgdry and 0.022 to 0.019 mgN/mgdry, respectively). These results suggest that components in the sediment with high oxygen consumption potential were removed by H. scabra. These findings also provide fundamental information with which to evaluate the quantitative role of H. scabra in polyculture with shrimp.
CitationKodama, M., Sumbing, J. G., Lebata-Ramos, M. J. H., & Watanabe, S. (2015). Metabolic rate characteristics and sediment cleaning potential of the tropical sea cucumber Holothuria scabra.
PublisherMinistry of Tropical Agricultural Research Centre
This study was funded by the Japan International Research Center for Agricultural Sciences (JIRCAS).
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Shrimp metabolism: The roles of lactate dehydrogenase (c31), glycogen phosphorylase (c34) and protein kinase (PK) as revealed by RNA interference MVR Tare, H Kondo, I Hirono & MBB Maningas - In MRR Romana-Eguia, FD Parado-Estepa, ND Salayo & MJH Lebata-Ramos (Eds.), Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia: Challenges in Responsible Production … International Workshop on Resource Enhancement and Sustainable Aquaculture Practices in Southeast Asia 2014 (RESA), 2015 - Aquaculture Department, Southeast Asian Fisheries Development CenterEnergy metabolism is well-studied in vertebrate systems, providing insights on the genes and mechanisms involved in different pathways necessary for the survival of an organism. Yet, such studies are still lacking in invertebrate systems much more in shrimp. An earlier study has showed several contigs from the black tiger shrimp to be homologous to white spot syndrome virus (WSSV), a devastating pathogen in shrimp, including contig 31-WSSVORF82 (c31) and contig 34-WSSVORF21 (c34). This study aims to unveil the roles of three genes: c31, c34 and protein kinase (PK) in the shrimp system and its possible role in WSSV-infection. Rapid amplification of cDNA ends-polymerase chain reaction or RACE-PCR was used to obtain the full-length sequence of c31 and c34, followed by in vivo gene silencing using RNAi technology, and intramuscularly injecting dsRNA to WSSVchallenged Macrobrachium rosenbergii and Penaeus (Marsupenaeus) japonicus. Gene expression followed for healthy shrimps and dsRNA-treated shrimps. Mrc31 was revealed to be the enzyme lactase dehydrogenase (LDH), commonly released during tissue damage and is a marker for disease. The most parsimonious tree pictured Mrc31 to be sister clades to LDH of other shrimp species, Penaeus monodon and P. vannamei, supported with 100% and 72% bootstrap values, respectively. Mrc34 was highly homologous to the glycogen phosphorylase (GP) enzymes of other organisms including that of another shrimp, M. japonicus, bearing a bootstrap value of 99%. For PK, phylogenetic analysis revealed that the three open reading frames (ORFs) from P. monodon, M. rosenbergii and P. japonicus have 30% homology to WSSV-PK supported by a 98% bootstrap value. Mortality data from dsRNA-treated and WSSV-infected shrimps showed that treatment with dsRNA-LDH, GP and PK had significantly higher survival rates compared to that of the controls, Phosphate Buffered Saline (PBS) and Green Fluorescent Protein (GFP). Silencing the three genes in the shrimp has rendered some protective effect against the virus. Gene expression showed that all three genes are present in immune-related organs such as the gills, hepatopancreas and hemocyte. This study is the first to report the possible identities and functions of contigs 31, 34 and PK providing valuable data on the shrimp's genome.
A preliminary study on the effect of hypoxia on carotenoid metabolism in black tiger shrimp Penaeus monodon Fabricius FI Heralde, M Leaño, A Reyes & R Coloso - 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center (SEAFDEC/AQD)The pigmentation of black tiger shrimp Penaeus monodon is due to astaxanthin, astaxanthin monoester, and astaxanthin diester. These carotenoids are biosynthesized from beta-carotene or zeaxanthin. Biosynthesis is postulated to be mediated by the enzymes C3 and C4 monooxygenase and caroten-4-ol dehydrogenase. Blue-shrimp syndrome, characterized by low total astaxanthin levels in shrimp epidermis, is associated with nutritional deficiency for carotenoids but other factors such as high organic matter, hypoxia, high density, and high pH may also be involved. In this study, the effect of hypoxia on carotenoid metabolism in P. monodon was investigated with respect to retention and transformation of carotenoids and the activity of the enzymes C3 and C4 monooxygenase and caroten-4-ol dehydrogenase.Two tanks were prepared each containing 25 pieces of shrimp fed a control diet (not containing any carotenoid) for two weeks. Shrimps in one tank (Treatment 1) were given beta-carotene supplemented diet (3.8 ppm) in the next two weeks while those in the other (treatment 2) were fed the control diet. Two days after introduction of the test diets, both treatments were subjected to hypoxia challenge (dissolved oxygen, 2.5-2.7 mg/L) and the carotenoid content and profile of feces monitored for succeeding days. Assay of enzyme activity was performed five days after hypoxia challenge. Results showed a ten-fold increase in fecal total carotenoid content of shrimps in treatment 2 (122.2 ppm) compared with that in treatment 1 (12.4 ppm) on hypoxia challenge and restores to basal level (3.9-4.1 ppm) after three days. The carotenoids found in the feces of shrimps in treatment 2 were astaxanthin, astaxanthin monoester, astaxanthin diesters, and an unidentified carotenoid which was also found in the muscle of stressed shrimp. Using beta-carotene as substrate, conversion to astaxanthin was not observed in the hepatopancreas homogenates of shrimps in both treatments. Instead, a slow conversion of astaxanthin to betacarotene (i.e., a reverse reaction) was noted in treatment 2 exhibiting twice the activity in treatment 1. Radiolabelling studies using 14C-labelled astaxanthin as substrate confirmed the existence of this enzyme-mediated reductive pathway from astaxanthin which occurs at a very slow rate. This study demonstrated the carotenoid-depleting effect of hypoxia on shrimp, both through enhanced fecal release and moderately elevated reductive pathway from astaxanthin. This effect suggests a possible mechanism by which blue-shrimp syndrome may develop.
The effect of dietary protein-energy levels on growth and metabolism of milkfish (Chanos chanos Forsskal) RM Coloso, LV Benitez & LB Tiro -
Comparative Biochemistry and Physiology - Part A: Physiology, 1988 - Elsevier
- Groups of milkfish juveniles (mean weight, 2.8 g) were fed diets containing white fishmeal and gelatin with varying protein-energy to total metabolizable energy (PE:TME) ratios.
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- Among the amino acid supplemented diets, best growth was observed at PE:TME ratio of 44.4%. However, the control diet gave better growth rate than any of the amino acid supplemented diets
- Specific activities of pyruvate kinase (PK) and glutamate dehydrogenase (GDH) increased significantly with increase in dietary protein-energy level.