Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Swimming down-regulates ovarian transcriptomic response of rainbow trout Oncorhynchus mykiss

ABSTRACT: Metabolic processes and sexual maturation closely interact during the long-distance reproductive migration of many fish species to their spawning grounds. In the present study, we have for the first time used exercise experimentally to investigate the effects on sexual maturation in rainbow trout. Pubertal autumn-spawning seawater-raised female rainbow trout Oncorhynchus mykiss (n=26; 50-cm, 1.5-kg) were rested or swum at a near optimal speed of 0.75 body-lengths per second in a 6,000 L swim-flume under natural reproductive conditions (16 Â°C fresh-water, starvation, 8h-light:16h-dark photoperiod). Fish were sampled after arrival and subsequently after 10 days (resting or swimming 307 km) and 20 days (resting or swimming 636 km). Ovarian development was significantly reduced in the swimmers. Analysis of the expression of key factors in the reproductive axis included pituitary kiss1-receptor, lh and fsh and ovarian lh-receptor, fsh-receptor, aromatase and vitellogenin-receptor (vtgr). Swimmers had lower pituitary lh and ovarian vtgr expression than resters. Furthermore, the number of late vitellogenic oocytes was lower in swimmers than in resters, probably resulting from the lower vtgr expression, and vitellogenin plasma levels were higher. Therefore, swimming exercise suppresses oocyte development possibly by inhibiting vitellogenin uptake. Transcriptomic changes that occurred in the ovary of exercised fish were investigated using a salmonid cDNA microarray platform. Protein biosynthesis and energy provision were among the sixteen functional categories that were all down-regulated in the ovary. Down-regulation of the transcriptomic response in the ovary illustrates the priority of energy reallocation and will save energy to fuel exercise. A swimming-induced ovarian developmental suppression at the start of vitellogenesis during long-term reproductive migration may be a strategy to avoid precocious muscle atrophy. In order to simulate the natural reproductive conditions of anadromous salmonids, experiments were performed with sea water-raised rainbow trout, Oncorhynchus mykiss. Resters and swimmers were starved during the experiment, seawater was replaced by fresh water and photoperiod was changed. These changes were expected to affect reproductive parameters but as âbackgroundâ effect because both resters as swimmers were experiencing these conditions at the same time in the same set-up. Any additional effects in swimming fish would thus be caused by swimming only. Pubertal autumn spawning rainbow trout (n=26; ~50 cm, ~1.5 kg) were purchased from a Danish exporter (Frederiksvaerk Aleexport) where they had been raised for 2 years in freshwater followed by 4 months in sea water cages at 10 â°. They were transferred by truck within 16 h to Spakenburg (Spakenburg Paling, The Netherlands) and subsequently in the same water in a similar holding tank to the swim-flume at Leiden University (The Netherlands). The next day, 5 randomly chosen fish were sampled as âstartâ-group while others were randomly divided into a ârestâ-group (n=10) and a âswimâ-group (n=11). During the following 4 days, the brackish 10 â° water was stepwise replaced by freshwater at 16 Â°C and photoperiod was changed from 16L:8D to 8L:16D. Fish were then acclimatized for two days to their new conditions. Subsequently, swimmers were first swum at a speed of 0.33 body-lengths per second (BL/s) which was increased the next day to the final, near optimal speed of 0.75 BL/s (0.34 m/s or 29.4 km/day). Fish were sampled after 10 days (5 resters and 5 swimmers) and 20 days (5 resters and 6 swimmers). At sampling, fish were anesthetized using oil of cloves that was commercially purchased from a drugstore (diluted 1:10 in ethanol and used at a dosage of 1.5 ml/l). Fish were euthanized by decapitation and dissected for the ovary which was flash frozen in liquid nitrogen. RNA was isolated from pituitary and ovary samples according to the TRIZOL reagent protocol by Invitrogen (Baro, Spain). Isolated RNA was DNAse treated using RQ1 DNAse Promega (Madison, USA) and reverse transcribed using Superscript IIITM (Baro, Spain) according to the manufacturerâs protocol. Microarray analyses were performed on ovarian tissue for 20-days-swimmers vs. 20-days-resters. A rainbow trout cDNA microarray platform was used that was previously validated and described by Koskinen et al., 2004ab, Krasnov et al., 2005, MacKenzie et al., 2006ab, 2008 and Djordjevic et al., 2009, and deposited in GEO under accession number GPL1212, the original cDNA microarray (SFA2.0 chip), and GPL6154; the updated 1.8 K platform. This platform compromises 1818 genes representing 366 functional categories. Total RNA was extracted from flash frozen samples from experimental fish of the 20-days-swim group (n=5) and 20-days-rest group (n=5) like described before. Total RNA corresponding to pooled samples from the swim or rest groups was labeled with Cye3 and Cye5-dCTP (GE Healthcare, Barcelona, Spain) using SuperScript III reverse transcriptase (Invitrogen, Baro, Spain) and oligo(dT) primer. In our experience, reverse labeling combined with multiple replication of spots provide robust normalization and high statistical power of analyses. cDNA was purified with MicroconYM30 (Millipore). The slides were pretreated with 1% BSA(fraction V), 20 Ã SSC, 10% SDS (30 min at 50Â°C) and washed with 2 Ã SSC (3 min) and 0.2 Ã SSC (3 min) and hybridized overnight in cocktail containing 50 Ã Denhardt's, 20 Ã SSC, 10% SDS, 10Î¼g/Î¼l polyadenylate and 10 Î¼g/Î¼l yeast tRNA. All chemicals were from Sigma-Aldrich. Scanning was performed with ScanArray 5000 and images were processed with QuantArray (GSI Luminomics). The measurements in spots were filtered by criteria I/B â¥ 3 and (I-B)/(SI + SB) â¥ 0.6, where I and B are the mean signal and background intensities and SI, SB are the standard deviations. After subtraction of mean background, LOWESS normalization was performed. To assess differential expression of genes, the normalized log intensity ratios (expression ratio) were analyzed with Student's t-test (P <0.05). Validation of the microarray was performed by Q-PCR of 6 differentially expressed genes (DEGs) as described above. The used primers were either published (Alpha-globin I-1: Donate Jimeno, 2008) or designed, again by using the Genamics software.

ORGANISM(S): Oncorhynchus mykiss

SUBMITTER: Josep Planas

PROVIDER: E-GEOD-20131 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Publications

Saving energy to fuel exercise: swimming suppresses oocyte development and downregulates ovarian transcriptomic response of rainbow trout Oncorhynchus mykiss.

Palstra Arjan P AP Crespo Diego D van den Thillart Guido E E J M GE Planas Josep V JV

American journal of physiology. Regulatory, integrative and comparative physiology 20100505 2

Metabolic processes and sexual maturation closely interact during the long-distance reproductive migration of many fish species to their spawning grounds. In the present study, we have used exercise experimentally to investigate the effects on sexual maturation in rainbow trout. Pubertal autumn-spawning seawater-raised female rainbow trout Oncorhynchus mykiss (n = 26; 50 cm, 1.5 kg) were rested or swum at a near optimal speed of 0.75 body lengths per second in a 6,000-liter swim flume under natu ...[more]

PMID: 20445157

Similar Datasets

Project description:Training at sustainable swimming speeds can produce changes in fish skeletal muscle that are important for aquaculture due to their growth-potentiating effects. Such changes may be even more relevant when fish are fed diets containing an increasing proportion of carbohydrates as an energy source. We evaluated the effects of moderate-intensity sustained swimming on the transcriptomic response of red and white muscle in rainbow trout fed a carbohydrate-rich diet using microarray and qPCR. Analysis of the red and white muscle transcriptome revealed significant changes in the expression of a large number of genes (395 and 597, respectively), with a total of 218 differentially expressed genes (DEGs) common for both muscles. A large number of the genes involved in glucose use and energy generation, contraction, development, synthesis and catabolism of proteins were up-regulated in red and white muscle. Additionally, DEGs in both muscles were involved in processes of defense response and apoptosis. Skeletal muscle contraction activates a transcriptional program required for the successful adaptation of both muscles to the changing demands imposed by swimming conditions. Future studies should further clarify the mechanisms involved in the adaptation of both tissues to exercise and assess possible benefits of such conditions for cultured fish. Total RNA from pooled red and white skeletal muscle samples of individual rainbow trout from each group (resting fish, n=8; swimming fish, n=8) was labeled with Cy3-dUTP and Cy5-dUTP (GE Healthcare, Barcelona, Spain). We used a dye swap experimental design and each cDNA from a pooled RNA sample was hybridized to two microarrays. For the first slide, cDNAs from resting and swimming fish were labeled with Cy5 and Cy3, respectively, and for the second array dye assignment was reversed. Therefore, samples from individual fish within each group were pooled and expression values shown represent the means of 6 M-CM-^W 2 = 12 technical replicates. A total of four slides were used in this study

Project description:Abstract. The molecular pathways in embryonic vertebrates leading to gonad formation in each sex are incompletely understood. The purpose of this study was to identify novel genes that could be associated with sex-specific gonadal differentiation in a fish, the rainbow trout (Oncorhynchus mykiss). This study was facilitated by a custom microarray based on 7,681 genes derived from embryonic rainbow trout gonad cDNA libraries and public databases. Gonad samples for total RNA isolation were obtained from pvasa-green fluorescent protein (pvasa-GFP) transgenic rainbow between 300 and 700 degree days of development post-fertilization. The transgenic fish permitted the collection of gonads from embryonic rainbow trout during the period of molecular sex differentiation in advance of any morphologically distinguishable characteristics of sex. A bioinformatic method was used with the microarray data that looked for strong associations in gene expression patterns between known sex differentiation genes (the target genes) and novel genes (the target-associated genes) previously not allied with sex differentiation in fishes. The expression patterns of representative targets genes from both sexes and their target-associated genes were independently confirmed by real-time reverse transcription-polymerase chain reaction to support the validity of the bioinformatics method employed. Numerous, novel genes were identified in the gonads of embryonic female and male rainbow trout that could be involved in sex-specific differentiation pathways in this fish. Embryonic gonads were removed by dissection from known genetic female (XX) and male (XY) rainbow trout (Oncorhynchus mykiss) from a transgenic population where expression of GFP is controlled by vasa-gene regulatory elements (Yoshizaki et al. 2000; Takeuchi et al. 2002). These fish were maintained in incubators containing flowing freshwater (10Â°C) at the Ooizumi Research Station, Yamanashi, Japan. Ten female or male transgenic rainbow trout were randomly selected every 5 days, beginning at 30 days (i.e., 300 degree days = incubation temperature in Â°C x number of days) post fertilization through until 70 days (i.e., 700 degree days) post fertilization. The gonads from each sex, at each sampling time, were pooled and immediately frozen for subsequent total RNA isolation.

Project description:Sustainable aquaculture, which entails proportional replacement of fish-based feed sources by plant-based ingredients, is impeded by the poor growth response frequently seen in fish fed high levels of plant ingredients. To evaluate the potential to improve, by means of early nutritional exposure, the growth of fish fed plant-based feed, rainbow trout swim-up fry were fed for 3 weeks either a plant-based diet (diet V, V-fish) or a diet containing fishmeal and fish oil as protein and fat source (diet M, M-fish). After this 3-week nutritional history period, all V- or M-fish received diet M for a 7-month intermediate growth phase. Both groups were then challenged by feeding diet V for 25 days during which voluntary feed intake, growth, and nutrient utilization were monitored (V-challenge). The results of the V-challenge showed a higher growth rate and higher feed intake in fish of nutritional history V compared to M (see PMID:24386155). To identify the molecular mechanisms that govern the enhancement of feed acceptance following early-feed exposure of diet V, we performed microarray expression analysis using swim-up fry collected at the end of early-feeding exposure (diet M and diet V), as well as brain and liver of juveniles sampled at the end of the V-challenge (M-his and V-his), and employing a rainbow trout microarray platform with 8 X 60K probes per slide. Persistently differentially expressed genes were identified by isolating probes that were differentially expressed (fold change ≥ 1.5 and p {nutritional history} ≤ 0.05), both at the end of the early exposure, and in either brain or liver of juvenile trout at the end of the V-challenge. Overall, 1787 (3-week + Brain) and 924 (3-week + Liver) mRNA probes were found to be persistently affected by nutritional history of early-feeding exposure. This positive response is encouraging as a potential strategy to improve the use of plant-based feed in fish, of interest in the field of fish farming and animal nutrition in general. Furthermore, the genes associated with mediating this positive early feeding effect, could serve as potential biomarkers to evaluate increasing acceptability of plant-based diets in fish farming.

Project description:We have constructed a rainbow trout high-density oligonucleotide microarray by using all the available tentative consensus (TC) sequences from the Rainbow Trout Gene Index database (The Computational Biology and Functional Genomics Lab., Dana Farber Cancer Institute and Harvard School of Public Health). The Rainbow Trout Gene Index integrates research data from all available international rainbow trout genomic research projects. The newly designed microarray incorporates 37,394 unique transcript-specific oligonucleotide probes, 60-mer long each. The microarray was printed according to our design by Agilent Technologies using the 4 X 44-design format and contains 1417 Agilent control spots. The performance of the new microarray platform was evaluated by analyzing gene expression associated with the rainbow trout vitellogenesis-induced muscle atrophy. These chips can be ordered from Agilent using design number 016320. This microarray is anticipated to open new avenues of research that will aid in the development of novel strategies to enhance growth efficiency and quality in salmonid species. Keywords: Development of an oligo-array for rainbow trout The performance of the new microarray platform was evaluated by analyzing transcriptome response associated with the rainbow trout vitellogenesis-induced muscle atrophy. Severe muscle deterioration accompanies the physiological responses of the energetic demands of the rainbow trout spawning/vitellogenesis. Atrophying muscle of fertile fish had 11% less extractable muscle (g/bw) and 11% less protein content compared to non-atrophying muscle of sterile fish (p<0.01). The rainbow trout was used to profile changes in gene expression of atrophying muscles. Gene expression levels were determined by comparing the amount of mRNA transcript present in the experimental sample (fertile fish) to the control (sterile fish). RNAs isolated from each experimental fish were run on separate microarrays in independent experiments, with no pooling. A total of 8 fish were used in the microarray experiments (4 replicates x 2 groups). Fluorophors (Cy3 and Cy5) were randomly assigned to RNA from each of the atrophying and nonatrophying muscles to limit the dye effect.

Dataset Information

Swimming down-regulates ovarian transcriptomic response of rainbow trout Oncorhynchus mykiss

Publications

Saving energy to fuel exercise: swimming suppresses oocyte development and downregulates ovarian transcriptomic response of rainbow trout Oncorhynchus mykiss.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure