Project description:This study examined differentially expressed (DE) gene transcripts and regulated pathways of two geographically distinct channel catfish (Ictalurus punctatus) strains and one hybrid catfish (I. punctatus x [blue catfish] I. furcatus) strain to test whether one particular catfish type handled thermal stress better. Following a six-week growth experiment, where fish were subjected to daily cycling temperatures of either 27-31M-BM-0C or 32-36M-BM-0C, mimicking pond fluctuations. We sequenced 18 cDNA libraries of liver samples to obtain 61 million reads per library. There were 5,443 DE transcripts and 41,689 regulated pathways. Northern channel catfish had the highest amount of DE transcripts (48.6%), 5 times that of southern channel catfish, and the greatest amount of transcripts with fold changes M-bM-^IM-% 2. The overall amount of temperature-induced DE transcripts between southern hybrid and southern channel catfish was fairly comparable in relation to that of northern channel catfish, however, there were more transcripts up- or downregulated with M-bM-^IM-% 2 fold changes in channel catfish strains compared to the southern hybrid catfish. Results from this study strongly suggest genetic differences between geographic catfish types affect physiological responses to thermal stress. Furthermore, a number of genes were linked to thermal stress tolerance, which may be beneficial for understanding geographic differences in thermal stress tolerance in ectotherms and for strain development of catfish. Hepatic mRNA profiles of three fingerling catfish types following a six week growth experiment of daily cycling temperatures of either 27-31M-BM-0C or 32-36M-BM-0C, mimicking pond fluctuations.
Project description:This study examined differentially expressed (DE) gene transcripts and regulated pathways of two geographically distinct channel catfish (Ictalurus punctatus) strains and one hybrid catfish (I. punctatus x [blue catfish] I. furcatus) strain to test whether one particular catfish type handled thermal stress better. Following a six-week growth experiment, where fish were subjected to daily cycling temperatures of either 27-31°C or 32-36°C, mimicking pond fluctuations. We sequenced 18 cDNA libraries of liver samples to obtain 61 million reads per library. There were 5,443 DE transcripts and 41,689 regulated pathways. Northern channel catfish had the highest amount of DE transcripts (48.6%), 5 times that of southern channel catfish, and the greatest amount of transcripts with fold changes ≥ 2. The overall amount of temperature-induced DE transcripts between southern hybrid and southern channel catfish was fairly comparable in relation to that of northern channel catfish, however, there were more transcripts up- or downregulated with ≥ 2 fold changes in channel catfish strains compared to the southern hybrid catfish. Results from this study strongly suggest genetic differences between geographic catfish types affect physiological responses to thermal stress. Furthermore, a number of genes were linked to thermal stress tolerance, which may be beneficial for understanding geographic differences in thermal stress tolerance in ectotherms and for strain development of catfish.
Project description:The hybrid between female channel catfish (Ictalurus punctatus) and male blue catfish (Ictalurus furcatus) is superior in feed conversion, disease resistance, carcass yield, and harvestability compared to both parental species. However, heterosis and heterobeltiosis only occur in pond culture, and channel catfish grow much faster than the other genetic types in small culture units. This environment-dependent heterosis is intriguing, but the underlying genetic mechanisms are not well understood. In this study, phenotypic characterization and transcriptomic analyses were performed in the channel catfish, blue catfish, and their reciprocal F1s reared in tanks. The results showed that the channel catfish is superior in growth-related morphometrics, presumably due to significantly lower innate immune function, as investigated by reduced lysozyme activity and alternative complement activity. RNA-seq analysis revealed that genes involved in fatty acid metabolism/transport are significantly upregulated in channel catfish compared to blue catfish and hybrids, which also contributes to the growth phenotype. Interestingly, hybrids have a 40-80% elevation in blood glucose than the parental species, which can be explained by a phenomenon called transgressive expression (overexpression/underexpression in F1s than the parental species). A total of 1,140 transgressive genes were identified in F1 hybrids, indicating that 8.5% of the transcriptome displayed transgressive expression. Transgressive genes upregulated in F1s are enriched for glycan degradation function, directly related to the increase in blood glucose level. This study is the first to explore molecular mechanisms of environment-dependent hetero-sis/heterobeltiosis in a vertebrate species and sheds light on the regulation and evolution of heterosis vs. hybrid incompatibility.
Project description:Channel catfish (Ictalurus punctatus) and tra catfish (Pangasianodon hypophthalmus) both belong to the order Siluriformes. Channel catfish does not possess an air-breathing organ (ABO), and thus cannot breathe in the air, while tra catfish is a facultative air-breather and use the swim bladder as its air-breathing organ, which provides for aerial breathing in low oxygen conditions. Tra and channel catfish serve as a great comparative model for studying the transition of life from water to terrestrial living, as well as for understanding genes that are crucial for development of the swim bladder and the function of air-breathing in tra catfish. We selected seven developmental stages in tra catfish for RNA-Seq analysis based on their transition to a stage that could live at 0 ppm oxygen. More than 587 million sequencing clean reads were generated in tra catfish, and a total of 21, 448 unique genes were detected. A comparative genomic analysis was conducted between channel catfish and tra catfish. Gene expression analysis was performed for these tra catfish specific genes. Hypoxia challenge and microtomy experiments collectively suggested that there are critical timepoints for the development of the air-breathing function and swim bladder development stages in tra catfish. Key genes were identified to be the best candidates of genes related to the air-breathing ability in tra catfish. This study provides a large data resource for functional genomic studies in air-breathing function in tra catfish, and sheds light on the adaption of aquatic organisms to the terrestrial environment.
Project description:Seven early developmental stages in channel catfish, Ictalurus punctatus, were selected for transcriptome sequencing and analysis, Differential expression analysis and WGCNA approach was applied. The genes that play vital roles in embryogenesis and regulation of early development in channel catfish were detected. Our work reveals new insights for exploring the underlying mechanisms of channel catfish early development.
2020-08-26 | GSE152002 | GEO
Project description:Catfish intestinal and pond microbiomes
Project description:Hypoxia is an important environmental stressor in aquatic ecosystems, with increasingly impacts on global biodiversity. Yellow catfish is an economically important farmed fish in China, which has increased dramatically. We investigated the response of hybrid yellow catfish to hypoxia under experimental conditions and focused on the analysis of the differential expression patterns of specific genes associated with hypoxia response by RNA-seq and qPCR analysis. A total of 1556 genes were captured significantly differentially expressed, and were categorized into immune response and energy metabolism. Functional enrichment analysis revealed the NLR signaling pathway play pivotal roles in hypoxia tolerance and resistance. Our study provides important insights into the physiological acclimation, immune response and defense activity of hybrid yellow catfish under hypoxia challenge.
Project description:Catfish farming remains number one among U.S. aquaculture production. Flavobacterium columnare, the causative agent of columnaris disease, produces substantial mortality during the production of freshwater farmed finfish species. F. columnare is ubiquitous in the aquatic environment, and outbreaks of disease are often triggered during the spring and summer months of the catfish production cycle. As food fish production continues to increase, the frequency of columnaris disease will only continue to rise within the aquaculture industry and thus new preventative measures will be required. Vaccination against different fish pathogens has proven to be an effective disease management practice within the aquaculture industry. To evaluate the immunological effect of bath immunization on catfish with a recombinant F. columnare DNAk protein vaccine, we performed RNA sequencing on skin samples from control and rDNAK immunized catfish at different time intervals. We evaluated the different gene expression patterns between the groups with a focus on identifying differences in innate and adaptive immune function.
Project description:Channel catfish and blue catfish represent two economically important freshwater aquaculture species in the United States. Our study aims to investigate the gene expression differences between these two catfish species by high-throughput RNA sequencing to understand their associated phenotypic differences in growth and disease resistant. Our transcriptomic analyses provide some insights into gene function differences between the two species and the molecular basis of channel catfish growth advantage in the tank culture environment.