RESUMO
Despite the invaluable role of anesthetics as a tool for ensuring animal welfare in stressful situations, there is currently a lack of anesthetic drugs that meet the requirements of intensive aquaculture. In response to the growing interest in anesthetic substances of natural origin, this study evaluated the physiological and health impact of an anesthetic based on an extract of the microalga Heterosigma akashiwo on juvenile salmon (Salmo salar) exposed for a period of 72 h. To simulate a condition closer to reality where fish are subjected to stimuli (e.g., transport), the animals were exposed to 50 mg L-1 of algal extract and to physical stress. Functional, physiological, and histological parameters were evaluated in blood and tissues at different sampling periods (0, 24, and 72 h). There was no mortality and the induction and recovery times observed were within the established criteria for anesthetic efficacy. The anesthetic extract did not induce any side effects, such as stress or metabolic damage, indicating that this extract is a viable option for supporting fish welfare during deleterious events. This study provides information to support that the anesthetic extract tested, derived from H. akashiwo, is a promising candidate drug for operations requiring sedation (e.g., Salmonid transport).
Assuntos
Anestésicos , Salmo salar , Anestésicos/farmacologia , Animais , Aquicultura , Extratos Vegetais , Estresse FisiológicoRESUMO
The sea louse Caligus rogercresseyi has become one of the main constraints for the sustainable development of salmon aquaculture in Chile. Although this parasite's negative impacts are well recognized by the industry, some novel potential threats remain unnoticed. The recent sequencing of the C. rogercresseyi genome revealed a large bacterial community associated with the sea louse, however, it is unknown if these microorganisms should become a new focus of sanitary concern. Herein, chromosome proximity ligation (Hi-C) coupled with long-read sequencing were used for the genomic reconstruction of the C. rogercresseyi microbiota. Through deconvolution analysis, we were able to assemble and characterize 413 bacterial genome clusters, including six bacterial genomes with more than 80% of completeness. The most represented bacterial genome belonged to the fish pathogen Tenacibacullum ovolyticum (97.87% completeness), followed by Dokdonia sp. (96.71% completeness). This completeness allowed identifying 21 virulence factors (VF) within the T. ovolyticum genome and four antibiotic resistance genes (ARG). Notably, genomic pathway reconstruction analysis suggests putative metabolic complementation mechanisms between C. rogercresseyi and its associated microbiota. Taken together, our data highlight the relevance of Hi-C techniques to discover pathogenic bacteria, VF, and ARGs and also suggest novel host-microbiota mutualism in sea lice biology.
Assuntos
Copépodes/genética , Copépodes/microbiologia , Ectoparasitoses/genética , Ectoparasitoses/parasitologia , Doenças dos Peixes/parasitologia , Genômica/métodos , Interações Hospedeiro-Parasita , Microbiota/genética , Salmão/parasitologia , Animais , Chile , Copépodes/patogenicidade , Genoma/genética , Tenacibaculum/patogenicidadeRESUMO
Caligus rogercresseyi, commonly known as sea louse, is an ectoparasite copepod that impacts the salmon aquaculture in Chile, causing losses of hundreds of million dollars per year. In this study, we report a chromosome-scale assembly of the sea louse (C. rogercresseyi) genome based on single-molecule real-time sequencing (SMRT) and proximity ligation (Hi-C) analysis. Coding RNAs and non-coding RNAs, and specifically long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) were identified through whole transcriptome sequencing from different life stages. A total of 23,686 protein-coding genes and 12,558 non-coding RNAs were annotated. In addition, 6,308 lncRNAs and 5,774 miRNAs were found to be transcriptionally active from larvae to adult stages. Taken together, this genomic resource for C. rogercresseyi represents a valuable tool to develop sustainable control strategies in the salmon aquaculture industry.
Assuntos
Copépodes/genética , MicroRNAs/genética , RNA Longo não Codificante/genética , Transcriptoma , Animais , Cromossomos , Copépodes/patogenicidade , Doenças dos Peixes/parasitologia , Estágios do Ciclo de Vida/genética , Salmão/parasitologiaRESUMO
The interaction between host immune response and the associated microbiota has recently become a fundamental aspect of vertebrate and invertebrate animal health. This interaction allows the specific association of microbial communities, which participate in a variety of processes in the host including protection against pathogens. Marine aquatic invertebrates such as scallops are also colonized by diverse microbial communities. Scallops remain healthy most of the time, and in general, only a few species are fatally affected on adult stage by viral and bacterial pathogens. Still, high mortalities at larval stages are widely reported and they are associated with pathogenic Vibrio. Thus, to give new insights into the interaction between scallop immune response and its associated microbiota, we assessed the involvement of two host antimicrobial effectors in shaping the abundances of bacterial communities present in the scallop Argopecten purpuratus hemolymph. To do this, we first characterized the microbiota composition in the hemolymph from non-stimulated scallops, finding both common and distinct bacterial communities dominated by the Proteobacteria, Spirochaetes and Bacteroidetes phyla. Next, we identified dynamic shifts of certain bacterial communities in the scallop hemolymph along immune response progression, where host antimicrobial effectors were expressed at basal level and early induced after a bacterial challenge. Finally, the transcript silencing of the antimicrobial peptide big defensin ApBD1 and the bactericidal/permeability-increasing protein ApLBP/BPI1 by RNA interference led to an imbalance of target bacterial groups from scallop hemolymph. Specifically, a significant increase in the class Gammaproteobacteria and the proliferation of Vibrio spp. was observed in scallops silenced for each antimicrobial. Overall, our results strongly suggest that scallop antimicrobial peptides and proteins are implicated in the maintenance of microbial homeostasis and are key molecules in orchestrating host-microbiota interactions. This new evidence depicts the delicate balance that exists between the immune response of A. purpuratus and the hemolymph microbiota.
Assuntos
Regulação da Expressão Gênica/imunologia , Hemócitos , Hemolinfa , Microbiota/imunologia , Pectinidae , Vibrio/imunologia , Animais , Forma Celular/imunologia , Hemócitos/citologia , Hemócitos/imunologia , Hemócitos/microbiologia , Hemolinfa/citologia , Hemolinfa/imunologia , Hemolinfa/microbiologia , Pectinidae/citologia , Pectinidae/imunologia , Pectinidae/microbiologiaRESUMO
Caligus rogercresseyi is a copepod ectoparasite with a high prevalence in salmon farms in Chile, causing severe welfare and economic concerns to the sector. Information on the parasite's underpinning mechanisms to support its life strategy is recently being investigated. Due to the critical role of microbiota, this study aimed to characterize the microbiota community associated with C. rogercresseyi from different regions with salmon aquaculture in Chile. Using third-generation sequencing with Nanopore technology (MinION) the full 16S rRNA gene from sea lice obtained from 8 areas distributed over the three main aquaculture regions were sequenced. Microbiota of the parasite is mainly comprised of members of phyla Proteobacteria and Bacteroidetes, and a core microbiota community with 147 taxonomical features was identified, and it was present in sea lice from the three regions. This community accounted for 19% of total identified taxa but more than 70% of the total taxonomical abundance, indicating a strong presence in the parasite. Several taxa with bioactive compound secretory capacity were identified, such as members of genus Pseudoalteromonas and Dokdonia, suggesting a possible role of the lice microbiota during the host infestation processes. Furthermore, the microbiota community was differentially associated with the salmon production, where several potential pathogens such as Vibrio, Tenacibaculum, and Aeromonas in Los Lagos, Aysén, and Magallanes region were identified. Notably, the Chilean salmon industry was initially established in the Los Lagos region but it's currently moving to the south, where different oceanographic conditions coexist with lice populations. The results originated by this study will serve as foundation to investigate putative role of sea lice as vectors for fish pathogens and also as reservoirs for antibiotic-resistant genes.
Assuntos
Copépodes/microbiologia , Reservatórios de Doenças/microbiologia , Peixes/microbiologia , Peixes/parasitologia , Microbiota/genética , Sequenciamento por Nanoporos , Animais , Biodiversidade , Chile , Análise por Conglomerados , Geografia , FilogeniaRESUMO
Husbandry conditions often expose fish to several stressors, compromising organism's global homeostasis, which has consequences on aquaculture production. In order to depict intestinal homeostatic responses to deleterious conditions and the potential beneficial effects of functional diets in aquaculture fish, the effects of chronic suboptimal density condition on the neuro-immune endocrine system of rainbow trout was investigated through a transcriptomic survey. After 30â¯days under high stocking density, 67% of genes involved in homeostasis were found down-regulated whereas when fed with a diet supplemented with the probiotic Saccharomyces cerevisiae, <1% of these genes were found down-regulated. Genes involved in apoptotic mechanisms were found to be particularly responsive to both density and diets. At high density, several genes involved in the intrinsic and extrinsic apoptotic pathway (Fadd, Fas, Bcl-2 and Bax) as well as caspases (Casp8 and Casp3) were found down-regulated (Fold change <-7). However, fish fed with a diet supplemented with the probiotic yeast had an opposite response, indicating mitigation of stress effects. Overall, these results indicate the activation of homeostatic machinery and particularly genes involved in the apoptotic pathway as a result of probiotic feeding, counteracting apoptotic molecular repression derived from chronic stress.
Assuntos
Ração Animal , Apoptose , Dieta , Proteínas de Peixes/genética , Homeostase , Oncorhynchus mykiss/genética , Transcriptoma , Animais , Aquicultura , Regulação para Baixo , Mucosa Intestinal/metabolismo , Prebióticos , ProbióticosRESUMO
Fish respond to increasing stocking density as a stressor, adjusting physiological functions to increase energy supply for coping with deleterious effects and adapting. These responses are complex and systemic, and the molecular mechanisms involved remain undetermined. One of the most sensitive organs to environmental and homeostatic disruptions is the intestine, and since it plays several vital functions, understanding the molecular underpinnings of this organ under deleterious conditions is imperative for health improvement in aquaculture systems. This study aimed to understand how different stocking densities of rainbow trout (Oncorhynchus mykiss) modulates the coding and non-coding RNAs profiling, that in turn, play key roles to maintain the fish homeostasis. For this, the intestine tissue of juvenile trout stocked for 30â¯days either at low (LD: 3â¯kgâ¯m-3) or high density (HD: 40â¯kgâ¯m-3) were sampled to isolate total RNA and then construct cDNA libraries for an illumina sequencing platform. Differential gene expression analysis revealed a generalized downregulation of transcripts, including coding and long non-coding RNAs (lncRNAs). Notably, significant differences in transcripts involved in metabolic pathways, as well as immune and epithelium integrity and stability related pathways were found. A high number of downregulated transcripts enriched these pathways, and a strong correlation was observed between the most differentially expressed transcripts and the highly expressed lncRNAs. This study suggests a cross-talk between coding and non-coding RNAs in the intestine of fish exposed to suboptimal conditions, providing new insights into the regulatory role of the lncRNAs on fish response to stressors.
Assuntos
Proteínas de Peixes/genética , Mucosa Intestinal/metabolismo , Oncorhynchus mykiss/fisiologia , Transcriptoma , Animais , Aquicultura , Perfilação da Expressão Gênica , Oncorhynchus mykiss/genética , Oncorhynchus mykiss/crescimento & desenvolvimento , RNA Longo não Codificante/genéticaRESUMO
The advent of functional genomics has sparked the interest in inferring the function of non-coding regions from the transcriptome in non-model species. However, numerous biological processes remain understudied from this perspective, including intestinal immunity in farmed fish. The aim of this study was to infer long non-coding RNA (lncRNAs) expression profiles in rainbow trout (Oncorhynchus mykiss) fed for 30 days with functional diets based on pre- and probiotics. For this, whole transcriptome sequencing was conducted through Illumina technology, and lncRNAs were mined to evaluate transcriptional activity in conjunction with known protein sequences. To detect differentially expressed transcripts, 880 novels and 9067 previously described O. mykiss lncRNAs were used. Expression levels and genome co-localization correlations with coding genes were also analyzed. Significant differences in gene expression were primarily found in the probiotic diet, which had a twofold downregulation of lncRNAs compared to other treatments. Notable differences by diet were also evidenced between the coding genes of distinct metabolic processes. In contrast, genome co-localization of lncRNAs with coding genes was similar for all diets. This study contributes novel knowledge regarding lncRNAs in fish, suggesting key roles in salmons fed with in-feed additives with the capacity to modulate the intestinal homeostasis and host health.
Assuntos
Oncorhynchus mykiss/genética , Prebióticos/administração & dosagem , Probióticos/administração & dosagem , RNA Longo não Codificante/genética , Ração Animal/análise , Animais , Aquicultura , Dieta/veterinária , Genoma , Mucosa Intestinal/metabolismo , Oncorhynchus mykiss/metabolismo , RNA Longo não Codificante/metabolismo , TranscriptomaRESUMO
The acute phase response to pathogens alters the production of proinflammatory cytokines that, in turn, activate the synthesis of acute phase proteins. These proteins neutralize, prevent, and indicate tissue damage, thereby influencing the specific immune response and allowing the organism to regain homeostasis. Functional diets based in pre- and probiotics are used in aquaculture to improve fish health and resistance to diseases, but there is an information gap on the mechanisms involved in these effects and if these diets are efficient when fish are raised under high stocking densities. This study aimed an evaluation of the acute phase response in Oncorhynchus mykiss fed functional diets supplemented with pre- and probiotics (i.e. mannan-oligosaccharides and Saccharomyces cerevisiae, respectively) and challenged by either Vibrio anguillarum or chronic stress via maintenance under high stocking densities. For this, the relative expression of acute phase response related genes in liver, and of inflammatory response related genes in head kidney was evaluated by RT-qPCR. The supplemented diets differentially modulated the acute phase protein response to the assessed challenge conditions, specifically evidencing an overexpression of the genes HAPT, SAA, LECT2, and IL-1ß under chronic stress and of HAPT, IL-1ß, IL8, and LECT2 at 24 h post-challenge with V. anguillarum. The observed early-stage regulation of acute phase proteins and of the immune response by the probiotic S. cerevisiae and by prebiotic mannan-oligosaccharides suggests that both supplements have high immunostimulatory potentials for fish farmed under high stocking densities.
Assuntos
Proteínas de Fase Aguda/genética , Dieta/veterinária , Doenças dos Peixes/imunologia , Imunidade Inata , Oncorhynchus mykiss , Estresse Fisiológico/fisiologia , Vibrioses/veterinária , Proteínas de Fase Aguda/metabolismo , Ração Animal/análise , Animais , Feminino , Doenças dos Peixes/genética , Doenças dos Peixes/microbiologia , Mananas/administração & dosagem , Oligossacarídeos/administração & dosagem , Oncorhynchus mykiss/genética , Oncorhynchus mykiss/imunologia , Prebióticos/administração & dosagem , Probióticos/administração & dosagem , Saccharomyces cerevisiae/química , Vibrio/fisiologia , Vibrioses/genética , Vibrioses/imunologiaRESUMO
The transcriptomic response of the sea louse Caligus rogercresseyi during the infestation on Atlantic salmon (Salmo salar) and coho salmon (Oncorhynchus kisutch) was evaluated using 27 genes related to immune response, antioxidant system and secretome. Results showed early responses of TLR/IMD signaling pathway in sea lice infesting Atlantic salmon. Overall, genes associated with oxidative stress responses were upregulated in both host species. This pattern suggests that reactive oxygen species emitted by the host as a response to the infestation, could modulate the sea louse antioxidant system. Secretome-related transcripts evidenced upregulation of trypsins and serpins, mainly associated to Atlantic salmon than coho salmon. Interestingly, cathepsins and trypsin2 were downregulated at 7 days post-infection (dpi) in coho salmon. The principal component analysis revealed an inverse time-dependent pattern based on the different responses of C. rogercresseyi infecting both salmon species. Here, Atlantic salmon strongly modulates the transcriptome responses at earlier infection stages; meanwhile coho salmon reveals a less marked modulation, increasing the transcription activity during the infection process. This study evidences transcriptome differences between two salmon host species and provides pivotal knowledge towards elaborating future control strategies.
Assuntos
Copépodes/genética , Doenças dos Peixes/parasitologia , Regulação da Expressão Gênica , Oncorhynchus kisutch/parasitologia , Doenças Parasitárias em Animais/parasitologia , Salmo salar/parasitologia , Transcriptoma , Animais , Interações Hospedeiro-ParasitaRESUMO
One of the most significant threats to the Chilean salmon aquaculture industry is the ectoparasitic sea louse Caligus rogercresseyi. To cope with sea lice infestations, functional diets have become an important component in strengthening the host immune response. The aim of this study was to evaluate molecular mechanisms activated through immunostimulation by in-feed plant-derived additives in Atlantic salmon infected with sea lice. Herein, a transcriptome-wide sequencing analysis was performed from skin and head kidney tissues, evidencing that the immune response genes were the most variable after the challenge, especially in the head kidney, while other genes involved in metabolism were highly expressed individuals fed with the immunostimulants. Interestingly, defensive enzymes such as Cytochrome p450 and serpins were down-regulated in infested individuals, especially in skin tissue. Additionally, MHC-I and MHC-II genes were differentially expressed after the incorporation of the in-feed additives, giving some cues about the protection mechanisms of plant-derived compound as immunostimulants for infested salmons. This is the first published study that evaluates the transcriptomic response of sea lice-infested Atlantic salmon fed with in-feed additives.
Assuntos
Adjuvantes Imunológicos/farmacologia , Copépodes/fisiologia , Ectoparasitoses/veterinária , Doenças dos Peixes/imunologia , Imunomodulação , Salmo salar , Adjuvantes Imunológicos/administração & dosagem , Ração Animal/análise , Animais , Chile , Dieta/veterinária , Suplementos Nutricionais/análise , Ectoparasitoses/genética , Ectoparasitoses/imunologia , Ectoparasitoses/parasitologia , Doenças dos Peixes/genética , Doenças dos Peixes/parasitologia , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Perfilação da Expressão Gênica/veterinária , Regulação da Expressão Gênica , Rim Cefálico/parasitologia , Imunidade Inata , Extratos Vegetais/administração & dosagem , Extratos Vegetais/farmacologia , Pele/parasitologiaRESUMO
Cathepsins are proteases involved in the ability of parasites to overcome and/or modulate host defenses so as to complete their own lifecycle. However, the mechanisms underlying this ability of cathepsins are still poorly understood. One excellent model for identifying and exploring the molecular functions of cathepsins is the marine ectoparasitic copepod Caligus rogercresseyi that currently affects the Chilean salmon industry. Using high-throughput transcriptome sequencing, 56 cathepsin-like sequences were found distributed in five cysteine protease groups (B, F, L, Z, and S) as well as in an aspartic protease group (D). Ontogenic transcriptome analysis evidenced that L cathepsins were the most abundant during the lifecycle, while cathepsins B and K were mostly expressed in the larval stages and adult females, thus suggesting participation in the molting processes and embryonic development, respectively. Interestingly, a variety of cathepsins from groups Z, L, D, B, K, and S were upregulated in the infective stage of copepodid, corroborating the complexity of the processes involved in the parasitic success of this copepod. Putative functional roles of cathepsins were conjectured based on the differential expressions found and on roles previously described in other phylogenetically related species. Moreover, 140 single nucleotide polymorphisms (SNP) were identified in transcripts annotated for cysteine and aspartic proteases located into untranslated regions, or the coding region. This study reports for the first time the presence of cathepsin-like genes and differential expressions throughout a copepod lifecycle. The identification of cathepsins together with functional validations represents a valuable strategy for pinpointing target molecules that could be used in the development of new delousing drugs or vaccines against C. rogercresseyi.