The effects of amino acids and fatty acids on the disease resistance of Epinephelus fuscoguttatus in response to Vibrio vulnificus infection.
ABSTRACT: Mass mortality resulting from bacterial infection poses a major problem in the grouper aquaculture industry. The purpose of this study was to profile the metabolites released in challenged fish and to reconstruct the metabolic pathways of brown marble grouper (Epinephelus fuscoguttatus) in response to Vibrio vulnificus infection. Metabolite profiles from control and challenged treatment groups after feeding were determined using gas chromatography-mass spectrometry (GC-MS). Forty metabolites were identified from the GC-MS analysis. These metabolites comprised of amino acids, fatty acids, organic acids and carbohydrates. The profiles showed the highest percent area (33.1%) for leucine from the amino acid class in infected fish compared to the control treatment group (12.3%). Regarding the fatty acid class, a higher percent area of the metabolite 8,11-eicosadienoic acid (27.04%) was observed in fish infected with V. vulnificus than in the control treatment group (22.5%). Meanwhile, in the carbohydrate class, glucose (47.0%) was the metabolite in the carbohydrate class present at highest percentage in the control treatment group compared to infected fish (30.0%). Our findings highlight the importance of a metabolic analysis for understanding the changes of metabolites in E. fuscoguttatus in response to bacterial infections.
Project description:Vibriosis disease by Vibrio spp. greatly reduced productivity of aquaculture, such as brown-marbled grouper (Epinephelus fuscoguttatus), which is an economically important fish species in Malaysia. Preventive measures and immediate treatment are critical to reduce the mortality of E. fuscoguttatus from vibriosis. To investigate the molecular mechanisms associated with immune response and host-bacteria interaction, a transcriptomic analysis was performed to compare between healthy and Vibrio-infected groupers. This permits the discovery of immune-related genes, specifically the resistance genes upon infection. Herein, we provide the raw transcriptome data from Illumina HiSeq. 4000 that have been deposited into NCBI SRA database with the BioProject accession number PRJNA396437. A total of 493,403,076 raw sequences of 74.5 Gb were obtained. Trimming of the raw data produced 437,186,232 clean reads of ~58 Gb. These datasets will be useful to elucidate the defence mechanisms of E. fuscoguttatus against Vibrio vulnificus infection for future development of effective prevention and treatment of vibriosis.
Project description:The intensification of aquaculture to help kerb global food security issues has led to the quest for more economical new protein-rich ingredients for the feed-based aquaculture since fishmeal (FM, the ingredient with the finest protein and lipid profile) is losing its acceptability due to high cost and demand. Although very high in protein, castor meal (CM), a by-product after oil-extraction, is disposed-off due to the high presence of toxins. Concurrently, the agro-industrial wastes' consistent production and disposal are of utmost concern; however, having better nutritional profiles of these wastes can lead to their adoption. This study was conducted to identify potential biomarkers of CM-induced enteritis in juvenile hybrid-grouper (<i>Epinephelus fuscoguttatus</i>♀ × <i>Epinephelus lanceolatus</i>♂) using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) alongside their growth and distal intestinal (DI) health evaluation. A total of 360 fish (initial weight = 9.13 ± 0.01g) were randomly assigned into three groups, namely, fish-meal (FM) (control), 4% CM (CM4), and 20% CM (CM20). After the 56-days feeding-trial, the DI tissues of FM, CM4, and CM20 groups were collected for metabolomics analysis. Principal components analysis and partial least-squares discriminant-analysis (PLS-DA, used to differentiate the CM20 and CM4, from the FM group with satisfactory explanation and predictive ability) were used to analyze the UPLC-MS data. The results revealed a significant improvement in the growth, DI immune responses and digestive enzyme activities, and DI histological examinations in the CM4 group than the others. Nonetheless, CM20 replacement caused DI physiological damage and enteritis in grouper as shown by AB-PAS staining and scanning electron microscopy examinations, respectively. The most influential metabolites in DI contents identified as the potential biomarkers in the positive and negative modes using the metabolomics UPLC-MS profiles were 28 which included five organoheterocyclic compounds, seven lipids, and lipid-like molecules, seven organic oxygen compounds, two benzenoids, five organic acids and derivatives, one phenylpropanoids and polyketides, and one from nucleosides, nucleotides, and analogues superclass. The present study identified a broad array of DI tissue metabolites that differed between FM and CM diets, which provides a valuable reference for further managing fish intestinal health issues. A replacement level of 4% is recommended based on the growth and immunity of fish.
Project description:Grouper (Epinephelus spp.) is a group of fish species with great economic importance in Asian countries. A novel hybrid grouper, generated by us and called the Hulong grouper (Hyb), has better growth performance than its parents, E. fuscoguttatus (Efu, ?) and E. lanceolatus (Ela, ?). We previously reported that the GH/IGF (growth hormone/insulin-like growth factor) system in the brain and liver contributed to the superior growth of the Hyb. In this study, using transcriptome sequencing (RNA-seq) and quantitative real-time PCR (qRT-PCR), we analyzed RNA expression levels of comprehensive genes in the muscle of the hybrid and its parents. Our data showed that genes involved in glycolysis and calcium signaling in addition to troponins are up-regulated in the Hyb. The results suggested that the activity of the upstream GH/IGF system in the brain and liver, along with the up-regulated glycolytic genes as well as ryanodine receptors (RyRs) and troponins related to the calcium signaling pathway in muscle, led to enhanced growth in the hybrid grouper. Muscle contraction inducing growth could be the major contributor to the growth superiority in our novel hybrid grouper, which may be a common mechanism for hybrid superiority in fishes.