Netting the Stress Responses in Fish

In the last decade, the concept of animal stress has been stressed thin to accommodate the effects of short-term changes in cell and tissue physiology, major behavioral syndromes in individuals and ecological disturbances in populations. Seyle's definition of stress as “the nonspecific (common) result of any demand upon the body” now encompasses homeostasis in a broader sense, including all the hierarchical levels in a networked biological system. The heterogeneity of stress responses thus varies within individuals, and stressors become multimodal in terms of typology, source and effects, as well as the responses that each individual elicits to cope with the disturbance. In fish, the time course of changes after stress strongly depends on several factors, including the stressful experiences in early life, the vertical transmission of stressful-prone phenotypes, the degree of individual phenotypic plasticity, the robustness and variety of the epigenetic network related to environmentally induced changes, and the intrinsic behavioral responses (individuality/personality) of each individual. The hierarchical heterogeneity of stress responses demands a code that may decrypt and simplify the analysis of both proximate and evolutionary causes of a particular stress phenotype. We propose an analytical framework, the stressotope, defined as an adaptive scenario dominated by common environmental selective pressures that elicit common multilevel acute stress-induced responses and produce a measurable allostatic load in the organism. The stressotope may constitute a blueprint of embedded interactions between stress-related variations in cell states, molecular mediators and systemic networks, a map of circuits that reflect the inherited and acquired stress responses in an ever-changing, microorganismal-loaded medium. Several features of the proposed model are discussed as a starting point to pin down the maximum common stress responses across immune-neuroendocrine relevant physiological levels and scenarios, including the characterization of behavioral responses, in fish

Fish health challenge after stress : indicators of immunocompetence

Changes in the nervous and endocrine systems of fish after stress episodes have consequences on their immune system and thereby affect the ability to maintain immunocompetence. Fish mainly depend upon innate immune responses, which include a rich and powerful array of mechanisms, that appear to be more potent than in higher vertebrates. Thus, fish provide a unique model to understand the evolution of immune defence system. When the organism is challenged by an antigen or by stressors, a number of responses of reactive nature are engaged in an attempt to counteract the threat and recover homeostasis. However, if the challenge is maintained, changes in the immune system become chronic, and suppression can be observed in several key immune mechanisms, leading to maladaptation. Therefore, the time factor is of key importance in immune assessment. Taking into account this dynamic pattern of infection and stress, specific indicators should be identified in order to detect functional changes in the immune system. Furthermore, there is a need for specific markers that reflect either activation in the initial stages or suppression in response to a chronic challenge.Els canvis en els sistemes nerviós i endocrí després d'episodis d'estrès generen conseqüències en el sistema immunitari que influeixen en la capacitat de mantenir la immunocompetència. Els peixos depenen especialment de la resposta immunitària innata, un ampli conjunt de mecanismes que sembla que actuïn amb més potència que en vertebrats superiors. Així, els peixos es troben en una posició evolutiva única per a comprendre els models de mecanismes de defensa en els vertebrats. Quan l'organisme és afectat per un antigen o per situacions que provoquen estrès, s'inicien una sèrie de respostes de naturalesa reactiva per a contrarestar-ne els efectes i recobrar l'homeòstasi. Altrament, els canvis en el sistema immunitari esdevenen crònics i es pot observar una depressió en alguns mecanismes immunitaris que acaben amb una mala adaptació. Per tant, el factor temps és clau en la determinació de la resposta immunitària. Tenint en compte aquest patró dinàmic en la infecció i l'estrès, és important determinar indicadors específics que detectin canvis funcionals del sistema immunitari dels peixos. Els marcadors més apropiats són els que indiquen tant una activació dels mecanismes immunitaris en els estadis inicials com una depressió en situacions cròniques

Unveiling the effect of dietary essential oils supplementation in Sparus aurata gills and its efficiency against the infestation by Sparicotyle chrysophrii

A microencapsulated feed additive composed by garlic, carvacrol and thymol essential oils (EOs) was evaluated regarding its protective effect in gills parasitized by Sparicotyle chrysophrii in Sparus aurata. A nutritional trial (65 days) followed by a cohabitation challenge with parasitized fish (39 days) were performed. Transcriptomic analysis by microarrays of gills of fish fed the EOs diet showed an up-regulation of genes related to biogenesis, vesicular transport and exocytosis, leukocyte-mediated immunity, oxidation–reduction and overall metabolism processes. The functional network obtained indicates a tissue-specific pro-inflammatory immune response arbitrated by degranulating acidophilic granulocytes, sustained by antioxidant and anti-inflammatory responses. The histochemical study of gills also showed an increase of carboxylate glycoproteins containing sialic acid in mucous and epithelial cells of fish fed the EOs diet, suggesting a mucosal defence mechanism through the modulation of mucin secretions. The outcomes of the in vivo challenge supported the transcriptomic results obtained from the nutritional trial, where a significant reduction of 78% in the abundance of S. chrysophrii total parasitation and a decrease in the prevalence of most parasitic developmental stages evaluated were observed in fish fed the EOs diet. These results suggest that the microencapsulation of garlic, carvacrol and thymol EOs could be considered an effective natural dietary strategy with antiparasitic properties against the ectoparasite S. chrysophrii.info:eu-repo/semantics/publishedVersio

Unveiling the effect of dietary essential oils supplementation in Sparus aurata gills and its efficiency against the infestation by Sparicotyle chrysophrii

A microencapsulated feed additive composed by garlic, carvacrol and thymol essential oils (EOs) was evaluated regarding its protective effect in gills parasitized by Sparicotyle chrysophrii in Sparus aurata. A nutritional trial (65 days) followed by a cohabitation challenge with parasitized fish (39 days) were performed. Transcriptomic analysis by microarrays of gills of fish fed the EOs diet showed an up-regulation of genes related to biogenesis, vesicular transport and exocytosis, leukocyte-mediated immunity, oxidation–reduction and overall metabolism processes. The functional network obtained indicates a tissue-specific pro-inflammatory immune response arbitrated by degranulating acidophilic granulocytes, sustained by antioxidant and anti-inflammatory responses. The histochemical study of gills also showed an increase of carboxylate glycoproteins containing sialic acid in mucous and epithelial cells of fish fed the EOs diet, suggesting a mucosal defence mechanism through the modulation of mucin secretions. The outcomes of the in vivo challenge supported the transcriptomic results obtained from the nutritional trial, where a significant reduction of 78% in the abundance of S. chrysophrii total parasitation and a decrease in the prevalence of most parasitic developmental stages evaluated were observed in fish fed the EOs diet. These results suggest that the microencapsulation of garlic, carvacrol and thymol EOs could be considered an effective natural dietary strategy with antiparasitic properties against the ectoparasite S. chrysophrii.info:eu-repo/semantics/publishedVersio

Les nanopartícules d'or poden alterar el sistema immunitari dels peixos

Les nanopartícules d'or (AuNP) s'utilitzen habitualment en aplicacions d'alta tecnologia, però encara en sabem poc dels seus efectes en el medi ambient, i, especialment, en els organismes aquàtics. Investigadors de la UAB i la Universitat d'Aveiro (Portugal) han estudiat com afecten a l'orada (Sparus aurata), una de les especies comercial més importants en Europa. Els resultats indiquen que quan les AuNP dissoltes a l'aigua entren a l'organisme, els peixos poden patir variacions en els nivells d'hormones que, com el cortisol, regulen la resposta a l'estrès, i també alteracions en l'expressió de gens vinculats al sistema immunitari. Aquests resultats porten als investigadors a alertar sobre l'impacte potencial de les nanopartícules en els peixos marins.Las nanopartículas de oro (AuNP) se utilizan habitualmente en aplicaciones de alta tecnología, pero la información sobre sus efectos en el medio ambiente y en particular en los organismos acuáticos es escasa. Investigadores de la UAB y la Universidad de Aveiro (Portugal) han estudiado cómo afectan a la dorada (Sparus aurata), una de las especies comerciales más importantes en Europa. Los resultados indican que cuando las AuNP disueltas en el agua entran en el organismo, los peces pueden sufrir variaciones en los niveles de hormonas que, como el cortisol, regulan la respuesta al estrés, y también alteraciones en la expresión de genes vinculados al sistema inmunitario. Estos resultados llevan a los investigadores a alertar sobre el potencial impacto de las nanopartículas en los peces marinos.Gold nanoparticles (AuNP) are among the most used nanoparticles in high technology applications. However, there is still little information about their effect on the environment and, particularly, on aquatic organisms. Researchers from the UAB and the University of Aveiro, Portugal, have studied how these nanoparticles affect Sparus aurata (gilthead sea bream), a very important commercial fish species in Europe. The results indicate that when AuNP float freely in the water and enter these fishes, they can cause changes in the levels of hormones that regulate stress response, such as cortisol. AuNP also induced changes in the expression of genes associated with immune responses. For this reason, researchers warn about the potential impact of these nanoparticles on marine fishes

Unveiling the effect of dietary essential oils supplementation in Sparus aurata gills and its efficiency against the infestation by Sparicotyle chrysophrii

Altres ajuts: Industrial PhD program of Generalitat de Catalunya (Doctorats Industrials) and TECNOVIT-FARMFAES S.L. (No. 2017 DI 017)A microencapsulated feed additive composed by garlic, carvacrol and thymol essential oils (EOs) was evaluated regarding its protective effect in gills parasitized by Sparicotyle chrysophrii in Sparus aurata. A nutritional trial (65 days) followed by a cohabitation challenge with parasitized fish (39 days) were performed. Transcriptomic analysis by microarrays of gills of fish fed the EOs diet showed an up-regulation of genes related to biogenesis, vesicular transport and exocytosis, leukocyte-mediated immunity, oxidation-reduction and overall metabolism processes. The functional network obtained indicates a tissue-specific pro-inflammatory immune response arbitrated by degranulating acidophilic granulocytes, sustained by antioxidant and anti-inflammatory responses. The histochemical study of gills also showed an increase of carboxylate glycoproteins containing sialic acid in mucous and epithelial cells of fish fed the EOs diet, suggesting a mucosal defence mechanism through the modulation of mucin secretions. The outcomes of the in vivo challenge supported the transcriptomic results obtained from the nutritional trial, where a significant reduction of 78% in the abundance of S. chrysophrii total parasitation and a decrease in the prevalence of most parasitic developmental stages evaluated were observed in fish fed the EOs diet. These results suggest that the microencapsulation of garlic, carvacrol and thymol EOs could be considered an effective natural dietary strategy with antiparasitic properties against the ectoparasite S. chrysophrii

Skin multi-omics-based interactome analysis: integrating the tissue and mucus exuded layer for a comprehensive understanding of the teleost mucosa functionality as model of study

From a general structural perspective, a mucosal tissue is constituted by two main matrices: the tissue and the secreted mucus. Jointly, they fulfill a wide range of functions including the protection of the epithelial layer. In this study, we simultaneously analyzed the epithelial tissue and the secreted mucus response using a holistic interactome-based multi-omics approach. The effect of the gilthead sea bream (Sparus aurata) skin mucosa to a dietary inclusion of spray-dried porcine plasma (SDPP) was evaluated. The epithelial skin microarrays-based transcriptome data showed 194 differentially expressed genes, meanwhile the exuded mucus proteome analysis 35 differentially synthesized proteins. Separately, the skin transcripteractome revealed an expression profile that favored biological mechanisms associated to gene expression, biogenesis, vesicle function, protein transport and localization to the membrane. Mucus proteome showed an enhanced protective role with putatively higher antioxidant and antimicrobial properties. The integrated skin mucosa multi-interactome analysis evidenced the interrelationship and synergy between the metabolism and the exuded mucus functions improving specifically the tissue development, innate defenses, and environment recognition. Histologically, the skin increased in thickness and in number of mucous cells. A positive impact on animal performance, growth and feed efficiency was also registered. Collectively, the results suggest an intimate crosstalk between skin tissue and its exuded mucus in response to the nutritional stimulus (SDPP supplementation) that favors the stimulation of cell protein turnover and the activation of the exudation machinery in the skin mucosa. Thus, the multi-omics-based interactome analysis provides a comprehensive understanding of the biological context of response that takes place in a mucosal tissue. In perspective, this strategy is applicable for evaluating the effect of any experimental variable on any mucosal tissue functionality, including the benefits this assessment may provide on the study of the mammalian mucosa

RNA-Seq Reveals an Integrated Immune Response in Nucleated Erythrocytes

Background: Throughout the primary literature and within textbooks, the erythrocyte has been tacitly accepted to have maintained a unique physiological role; namely gas transport and exchange. In non-mammalian vertebrates, nucleated erythrocytes are present in circulation throughout the life cycle and a fragmented series of observations in mammals support a potential role in non-respiratory biological processes. We hypothesised that nucleated erythrocytes could actively participate via ligand-induced transcriptional re-programming in the immune response. Methodology/Principal Findings: Nucleated erythrocytes from both fish and birds express and regulate specific pattern recognition receptor (PRR) mRNAs and, thus, are capable of specific pathogen associated molecular pattern (PAMP) detection that is central to the innate immune response. In vitro challenge with diverse PAMPs led to de novo specific mRNA synthesis of both receptors and response factors including interferon-alpha (IFNα) that exhibit a stimulus-specific polysomal shift supporting active translation. RNA-Seq analysis of the PAMP (Poly (I:C), polyinosinic:polycytidylic acid)-erythrocyte response uncovered diverse cohorts of differentially expressed mRNA transcripts related to multiple physiological systems including the endocrine, reproductive and immune. Moreover, erythrocyte-derived conditioned mediums induced a type-1 interferon response in macrophages thus supporting an integrative role for the erythrocytes in the immune response. Conclusions/Significance: We demonstrate that nucleated erythrocytes in non-mammalian vertebrates spanning significant phylogenetic distance participate in the immune response. RNA-Seq studies highlight a mRNA repertoire that suggests a previously unrecognized integrative role for the erythrocytes in other physiological systems