Embryology and early ontogeny of an anemonefish Amphiprion ocellaris

The present study describes the embryonic development and early ontogeny of Amphiprion ocellaris from fertilization to post hatching. Anemonefish spontaneously spawned at 27???28??C. The newly laid eggs were orange in colour and elliptical in shape (1.8??0.8 mm). Melanin appeared as a black mass situated at the vegetal pole in mature eggs. This is rarely seen in eggs of other fish species. We documented developmental times at 27???28??C to egg activation (0.5 h), cleavage (4 h), blastula (11.5 h), gastrula (20 h), neurula (24.5 h), somite (28.5 h), turnover (72 h), blood formation (113 h) and internal ear and jaw formation (144 h). Hatching occurred 152 h after fertilization. On day 4, the eye buds were pigmented and melanophores formed on the ventral surface of the embryo. Internal ear and gill formation were completed on day 5 and coincided with movement of the opercula and pectoral fins. The mouth formed on day 6 and the digestive tract appeared on day 7. By day 10, the yolk was fully absorbed and a substantial amount of food was observed in the gut. Dark and orange pigments were dispersed and aggregated through muscle contractions by day 14, but red pigments did not appear until the fish were three months old. This study contributes to a further understanding of the embryology and the early ontogeny of damselfish and may help improve the culture of coral reef fish

Cultivation of Isochrysis galbana in Phototrophic, Heterotrophic, and Mixotrophic Conditions

Copyright © 2013 Yousef Alkhamis and Jian G. Qin. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This study compared the growth and biomass production of Isochrysis galbana under hetero-, mixo-, and phototrophic conditions using different organic carbon sources. The growth of I. galbana was inhibited in heterotrophy but was enhanced in mixotrophy compared to that in phototrophy. Subsequently, the influences of organic carbon and environmental factors (light and salinity) on the growth of I. galbana were further investigated. Algal dry weight increased as glycerol concentrations increased from 0 to 200 mmol and the highest algal production occurred at 50 mmol glycerol. At a range of light intensities of 25–200 μmol photons m−2 s−2, the highest algal growth rate occurred at 100 photons μmol m−2 s−2. The growth of I. galbana was significantly affected by photoperiod, and the maximal dry weight was obtained at 12 h light and 12 h dark. In the salinity test, I. galbana could grow in a wide range of salinities from 10 to 65‰, but the 35‰  salinity was optimal. This study suggests that the growth and production of I. galbana can be improved using mixotrophic culture at 50 mmol glycerol in 35‰  salinity

Anthropogenic shift of planktonic food web structure in a coastal lagoon by freshwater flow regulation

This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/Anthropogenic modification of aquatic systems has diverse impacts on food web interactions and ecosystem states. To reverse the adverse effects of modified freshwater flow, adequate management of discharge is required, especially due to higher water requirements and abstractions for human use. Here, we look at the effects of anthropogenically controlled freshwater flow regimes on the planktonic food web of a Ramsar listed coastal lagoon that is under recovery from degradation. Our results show shifts in water quality and plankton community interactions associated to changes in water flow. These shifts in food web interactions represent modifications in habitat complexity and water quality. At high flow, phytoplankton-zooplankton interactions dominate the food web. Conversely, at low flow, bacteria, viruses and nano/picoplankton interactions are more dominant, with a substantial switch of the food web towards heterotrophy. This switch can be associated with excess organic matter loading, decomposition of dead organisms, and synergistic and antagonistic interactions. We suggest that a lower variability in flow amplitude could be beneficial for the long-term sustaining of water quality and food web interactions, while improving the ecosystem health of systems facing similar stresses as the Coorong

Aggregation-induced emission fluorogens as biomarkers to assess the viability of microalgae in aquatic ecosystems

Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.Microalgae can be a valuable indicator for monitoring water pollution due to their sensitivity to the changes induced by pollutants in the environment. In this study, an aggregation-induced emission fluorogen was used as a novel tool to differentiate dead and live microalgae and quantify the link between live algal concentration and fluorogen intensity. Protein in the cell protoplasm is the key component contributing to fluorescence emission in algae

Case report: Desquamating dermatitis, bilateral cerebellar lesions in a late-onset methylmalonic acidemia patient

IntroductionCobalamin C (cblC) deficiency is a rare hereditary disorder affecting intracellular cobalamin metabolism, primarily caused by mutations in MMACHC. This condition is characterized by combined methylmalonic acidemia and hyperhomocysteinemia, displaying a wide range of clinical manifestations involving multiple organs. Owing to its uncommon occurrence and diverse clinical phenotypes, diagnosing cblC deficiency is challenging and often leads to delayed or missed diagnoses.Case descriptionIn this report, we present a case of late-onset cblC deficiency with brown desquamating dermatitis on the buttocks. Magnetic resonance imaging (MRI) of the brain revealed bilateral cerebellar abnormalities. The suspicion of an inherited metabolic disorder was raised by abnormal serum amino acid and acylcarnitine levels, along with increased urine methylmalonic acid and serum homocysteine levels. Whole-exome sequencing helped identify a homozygous variant (c.482G>A) in MMACHC, confirming the diagnosis of cblC deficiency. However, despite receiving treatment with hydroxocobalamin and betaine, the patient did not experience clinical improvement, which may be attributed to the delayed diagnosis as indicated by the declining homocysteine and methylmalonic acid levels.ConclusionCollectively, we emphasize the significance of recognizing the skin lesions and observing serial MRI changes in patients with cblC deficiency. Our case underscores the importance of early diagnosis and timely therapeutic intervention for this severe yet frequently manageable condition

Length–weight relationship and condition factor of giant tiger shrimp, Penaeus monodon (Fabricius, 1798) from four breeding families

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Background: Length–weight relationships and condition factors of giant tiger shrimp Penaeus monodon (Fabricius, 1798) from four breeding families (family S: South China seas family, family A: African family, family SA: ♂ South China seas family × ♀ Africa family, family AS: ♂ Africa family × ♀ South China seas family) were evaluated in this study. Findings and conclusion: Length–weight relationships can be expressed as W = 0.0239BL2.789 (R2 = 0.8977) in family S, W = 0.0206BL2.9107 (R2 = 0.9107) in family A, W = 0.0211BL2.831 (R2 = 0.8869) in family SA, and W = 0.0249BL2.781 (R2 = 0.9159) in family AS. The growth of P. monodon from four breeding families follows a negative allometric trend. Fulton’s body condition factor (K) was not significantly different in males, while in females, the highest K (3.07) was observed in family AS, and the lowest K was found in family A (1.88). Results from the present study indicate that the cross group family AS (♂ Africa family × ♀ South China seas family) has obvious heterosis in females. This may suggest that the direction of further breeding of P. monodon, should be conducted by using Africa family as male parent, and South China seas family as female parent. Results from the present study will provide valuable information on selective breeding in P. monodon. Methodology used in the present study can also be applied in other similar species

Dietary supplementation of selenium yeast enhances the antioxidant capacity and immune response of juvenile Eriocheir Sinensis under nitrite stress

© 2019 Elsevier Ltd. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 12 month embargo from date of publication (December 2018) in accordance with the publisher’s archiving policyThis study elucidates the response to nitrite stress and the effect of dietary selenium supplements on the growth, antioxidant activity, immunity and transcriptome of juvenile Chinese mitten crab Eriocheir sinensis. In the control group, the crabs were fed the diet without selenium supplementation and there was no nitrite addition to the water. In the test group, the crabs were fed diets with three levels of selenium 0 (N1), 0.5 (N2) and 1.0 (N3) mg/kg in the water containing 2 mg/L NO2N as a stress factor for eight weeks. Feed conversion ratio (FCR) was improved by adding dietary selenium. There was no significant difference in specific growth rate and weight gain between N1 and the control groups, or among different selenium levels in the test group. The superoxide dismutase (SOD) activity was significantly lower, but malondialdehyde (MDA) was higher in the N1 group than those in the serum and hepatopancreas of the control group. The activities of SOD, glutathione peroxidase (GPx) and acid phosphatase increased at the medium level of selenium but decreased as the level of dietary selenium increased to 1.0 mg/kg. The serum lysozyme (LZM) activity increased but the MDA content in both serum and hepatopancreas decreased with the increase of selenium levels. The total clean reads of the crabs in the control group, N1 and N3 groups reached 390.7M and were assembled into 106 471 transcripts. Compared with the control group, 1196 gene were significantly expressed (588-up and 608-down) in the N1 group under nitrite stress. Between the N1 and N3 groups, the expression of 1537 genes (751-up and 786-down) were significantly different. KEGG pathway analysis reveals that 11 and 19 pathways were significantly different between N1 and control and between N3 and N1 groups, respectively. Transcriptome results demonstrate that nutrient metabolism is much more active in crabs fed additional selenium under nitrite stress. This study indicates that dietary selenium can improve both antioxidant capacity and immune response and alter the protein and carbohydrate metabolism of E. sinensis under nitrite stress

Metabolic response of Nile tilapia (Oreochromis niloticus) to acute and chronic hypoxia stress

© 2018 Elsevier BV. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 24 month embargo from date of publication (May 2018) in accordance with the publisher’s archiving policy.Hypoxia is a critical issue in aquaculture especially in intensive aquaculture systems. Acute hypoxia stress with dissolved oxygen (DO) 0.7±0.1 mg/L for 6 h and chronic hypoxia stress with DO 1.1±0.1 mg/L for 4 weeks were used to investigate the response of nutritional metabolic pathways in Nile tilapia Oreochromis niloticus. Fish in the acute and chronic experiments had different adaptive mechanisms. Upon acute hypoxia stress, the contents of liver glycogen and muscle glycogen were significantly lower, but there was no significant difference in triglycerides (TG). The lactate dehydrogenase (LDH) activities increased after exposure to acute hypoxia stress. The mRNA expression of genes involved in glycolysis and glycogenolysis was significantly up-regulated by acute hypoxia stress. However, the response of fish to long-term hypoxia stress was different from acute hypoxia. Compared with the normoxia treatment, the crude fat in fish decreased in the hypoxia group and TG in the liver and muscle were significantly lower. Beta oxidation of the liver was enhanced in the hypoxia group, while the hepatic glycogen content increased in the hypoxia group. Transcriptomic analysis showed that the expression of genes related to carbohydrate synthesis and lipolysis increased in the hypoxia group, while genes related to carbohydrate catabolism and fat synthesis showed the opposite. This study indicates that fish could utilize carbohydrate as a main energy source during acute hypoxia stress, and metabolize more lipid during long-term hypoxia stress. A high carbohydrate content in the diet may help reduce negative effects from acute hypoxia stress, and an appropriate increase of fat content in the diet may benefit fish growth in a hypoxia environment, e.g., in high-density aquaculture ponds

α-lipoic acid regulate growth, antioxidant status and lipid metabolism of Chinese mitten crab Eriocheir sinensis: Optimum supplement level and metabonomics response

© 2019 Elsevier B.V. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 24 month embargo from date of publication (March 2019) in accordance with the publisher’s archiving policyThe α-lipoic acid (α-LA) is a novel feed additive to improve growth, antioxidant capacity and lipid metabolism in animal husbandry. In this study, isonitrogenous and isoenergetic diets were formulated at seven levels of α-LA (0, 300, 600, 1200, 2400, 4800, or 9600 mg/kg) and fed to the Chinese mitten crab Eriocheir sinensis juveniles for eight weeks. According to weight gain and specific grwoth rate, the optimal level of α-LA supplement in the diet is estimated at 1339–1574 mg/kg for E. sinensis. The α-LA supplement significantly increased the activities of SOD, GSH-Px and T-AOC, and the content of GSH in the hepatopancreas except for SOD in the crabs fed 9600 mg/kg α-LA. Excess dietary α-LA supplement increased the content of MDA in the hepatopancreas. The E. sinensis fed 2400 mg/kg α-LA in the diet showed the highest mRNA expressions of es_TGL1, es_TGL2, es_IL and es_DGL and had higher lipid catabolism when taking 300 mg/kg α-LA than other diets, which coincides with higher mRNA expressions of es_IL, es_DGL and CPT-1 in the hepatopancreas. The crab fed 2400 mg/kg α-LA significantly modified 45 metabolites in serum compared with the control. The supplmentation of α-LA significantly influenced fatty acid metabolism, amino acid metabolism, carnitine metabolism and accumulation of plant antioxidants. This study indicates that α-LA is a promising feed additive to regulate growth, antioxidant status and lipid metabolism in E. sinensis, but its inclusion in the diet should be <2400 mg/kg α-LA to maximize the benefitial effect and minimize side effects