Project description:Commercial production of tilapia relies on monosex cultures of males, which so far proved difficult to maintain in large scale production facilities. Thus, a better understanding of the genetic architecture of the complex trait of sex determination in tilapia is needed.We aimed to detect genes that were differentially expressed by gender at early embryonic development. Artificial fertilization of O. niloticus females with either sex-reversed males (ΔXX) or genetically-modified YY 'supermales' resulted in all-female and all-male embryos, respectively. Pools of all-female and all-male embryos at 2, 5 and 9 days post fertilization were used for custom Agilent eArray. 56 pool samples of Nile tilapia full siblings groups (female or male) at day 2, 5 or 9 post fertilization were subjected to total RNA extraction from whole embryo tissues and hybridized to the custom Agilent array. Each sample was yielded from different cross of artificial fertilization: six dams X five sires. The resulting gender were known based on the sire, sex-reversed males (ΔXX) or genetically-modified YY 'supermales' resulted in all-female and all-male embryos, respectively.
Project description:One of the largest river systems in South Africa, the Olifants River, has experienced significant changes in water quality due to anthropogenic activities. Since 2005, there have been various "outbreaks" of the inflammatory disease pansteatitis in several vertebrate species. Large-scale pansteatitis-related mortality events have decimated the crocodile population at Lake Loskop and decreased the population at Kruger National Park. Most pansteatitis-related diagnoses within the region are conducted post-mortem by either gross pathology or histology. The application of a non-lethal approach to assess the prevalence and pervasiveness of pansteatitis in the Olifants River region would be of great importance for the development of a management plan for this disease. In this study, several plasma-based biomarkers accurately classified pansteatitis in Mozambique tilapia (Oreochromis mossambicus) collected from Lake Loskop using a commercially available benchtop blood chemistry analyzer combined with data interpretation via artificial neural network analysis. According to the model, four blood chemistry parameters (calcium, sodium, total protein and albumin), in combination with total length, diagnose pansteatitis to a predictive accuracy of 92 percent. In addition, several morphometric traits (total length, age, weight) were also associated with pansteatitis. On-going research will focus on further evaluating the use of blood chemistry to classify pansteatitis across different species, trophic levels, and within different sites along the Olifants River.
Project description:The cold stress is considered the bottleneck problem limiting the development of red tilapia industry. Fish (initial weight: 72.71±1.32 g) was divided into the cold stressed group (C) and the control normal water temperature group (N). The water temperature was reduced by 2℃ per day from 20℃ to 8℃ in cold group, and the control group kept the water temperature at 20℃ during the experiment. At the end of the experiment, the gill(G)、liver(L) and skin(S) tissues from the fish of cold(C) group and control normal water temperature (N) group were taken. The DIA proteome analysis of 18 samples was completed, and 6341 trusted proteins containing quantitative information were obtained. Our aim is to understand the protein expression profiles of cold stress in red tilapia.
Project description:Dissolved oxygen (DO) in cultured water is one of the important environment factor in fish farming. Hypoxic environment affects fish growth, metabolism and immune system. Multi-omics integrative analysis helps to uncover the underlying molecular mechanisms. In this study, the 96h median lethal hypoxia (96h-LH50) for Genetically Improved Farmed Tilapia (GIFT, Oreochromis niloticus) was first analyzed by linear interpolation. We built control (5mg/l) and hypoxic stress (96h-LH50) groups, and extracted the liver tissues for high-throughput transcriptome and metabolome sequencing. The identification and quantification results of metabolites showed that a total of 19656 metabolites had been obtained, of which 10390 were annotated. There were 3028 differentially expressed (DE) metabolites, of which 1596 metabolites were up-regulated and 1432 metabolites were down-regulated. We obtained 2375 DE genes, of which 1201 genes were up-regulated and 1174 genes were down-regulated. We verified 8 DE genes by quantitative real-time PCR. Our finding reveals the changes in metabolites and genes expression of GIFT and facilitate the understanding of regulatory pathways under hypoxic stress, which will help reduce the damage caused by hypoxic stress during culture.
Project description:Commercial production of tilapia relies on monosex cultures of males, which so far proved difficult to maintain in large scale production facilities. Thus, a better understanding of the genetic architecture of the complex trait of sex determination in tilapia is needed.We aimed to detect genes that were differentially expressed by gender at early embryonic development. Artificial fertilization of O. niloticus females with either sex-reversed males (ΔXX) or genetically-modified YY 'supermales' resulted in all-female and all-male embryos, respectively. Pools of all-female and all-male embryos at 2, 5 and 9 days post fertilization were used for custom Agilent eArray.
Project description:Cichlids fishes exhibit extensive phenotypic diversification and speciation. In this study we integrate transcriptomic and proteomic signatures from two cichlids species, identify novel open reading frames (nORFs) and perform evolutionary analysis on these nORF regions. We embark comparative transrcriptomics and proteogenomic analysis of two metabolically active tissues, the testes and liver, of two cichlid species Oreochromis niloticus (Nile tilapia, ON) and Pundamilia nyererei (Makobe Island, PN). Our results suggest that the time scale of speciation of the two species can be better explained by the evolutionary divergence of these nORF genomic regions.
Project description:The imbalance of intestinal flora can affect the immune function and structural integrity of the intestinal barrier, leading to the colonization and reproduction of opportunistic pathogenic bacteria in the intestine to become the dominant flora, eventually inducing enteritis. This study aimed to investigate whether fecal microbiota transplantation (FMT) could improve the gut barrier in Nile tilapia (Oreochromis niloticus). The experiment involved administering normal saline (NS group) and fecal microbiota (FMT group) (from the negative control group (C group)) to tilapia that had been treated with oxytetracycline hydrochloride (OTC) (M group) by gavage. A total of 300 male tilapia (mean body weight 596.65 ± 47.18 g) were used, with 180 of them being fed OTC (120 mg/kg body weight/day) for 7 days to induce intestinal oxidative stress, while the rest served as the control group. After confirmation of mild chronic enteritis, the tilapia were treated in different ways.
Project description:The increasing use of manufactured nanoparticles (NP) in different applications has triggered the need to understand their putative ecotoxicological effects in the environment. Copper oxide nanoparticles (CuO NP) are toxic, and induce oxidative stress and other pathophysiological conditions. The unique properties of NP can change depending on the characteristics of the media they are suspended in, altering the impact on their toxicity to aquatic organisms in different environments. Here, Mozambique tilapia (O. mossambicus) were exposed to flame synthesized CuO NP (0.5 and 5 mg · L(-1)) in two environmental contexts: (a) constant freshwater (FW) and (b) stepwise increase in environmental salinity (SW). Sublethal effects of CuO NP were monitored and used to dermine exposure endpoints. Fish exposed to 5 mg · L(-1) CuO in SW showed an opercular ventilation rate increase, whereas fish exposed to 5 mg · L(-1) in FW showed a milder response. Different effects of CuO NP on antioxidant enzyme activities, accumulation of transcripts for metal-responsive genes, GSH ? GSSG ratio, and Cu content in fish gill and liver also demonstrate that additive osmotic stress modulates CuO NP toxicity. We conclude that the toxicity of CuO NP depends on the particular environmental context and that salinity is an important factor for modulating NP toxicity in fish.