The dynamics of arsenic and copper in solid and aqueous phases in reactive confluences receiving acid drainage: The role of turbidity and particle size.

The fate of suspended solids in aqueous systems enriched with copper (Cu) and arsenic (As) is still poorly understood, especially in mildly acidic streams with natural turbidity. This study integrated field, laboratory, and modeling to determine how turbidity, particle size distribution, and the partition of Cu and As interact in two model river confluences in an Andean watershed (upper Elqui, North-Central Chile). The mildly acidic Toro River (40.4 mgL-1; CuTOTAL>8 mgL-1) was diluted and neutralized at two consecutive confluences, resulting in dissolved As and Cu lower than 0.04 and 0.1 mgL-1, respectively. On-site laser scattering measurements showed that the size of suspended sediments was dominated by ultrafine (d<6 µm) and fine (6200 µm) were not observed, contrasting with other reactive Andean confluences that work as natural coagulation-flocculation reactors. Laboratory mixing experiments with filtered endmembers followed closely the trends observed in the field measurements. SEM observations and thermodynamic calculations, suggested that As-rich amorphous Fe minerals dominated the fine suspended solid inflow (d<15 µm) from the Toro River, while XRD did not reveal significant amounts of crystalline forms of Fe, As, or Cu minerals. Despite fresh precipitates that further associated dissolved As and Cu, the particles from the Toro River grew only slightly after the confluences, thus limiting particle settling potential and a significant metal-(loid)s removal. Consequently, the seasonal variation in the size and chemical nature of suspended solids in acid drainage inflows control the distinct physical and chemical fates of As and Cu after neutralization, as well as hydrodynamic or hydraulic conditions likely also constrain sediment deposition. The combined monitoring of chemical parameters and particle size distributions is a simple and cost-effective method to obtain information about the behavior of metal(loid)s and sediments.

Proximal composition and fatty acid profile of Hemigrapsus crenulatus (H. Milne Edwards, 1837) as one of the main foods of "patagonian blenny"Eleginops maclovinus (Cuvier, 1830) / Composição proximal e perfil de ácidos graxos de Hemigrapsus crenulatus (H. Milne Edwards, 1837) como um dos principais alimentos da "blenny patagônica" Eleginops maclovinus (Cuvier, 1830)

Abstract The Patagonian blenny (Eleginops maclovinus) is species endemic to South America with physiological characteristics that would facilitate its incorporation into Chilean aquaculture. However, there is currently no specific artificial food that can be used to raise E. maclovinus. In light of this problem, this study describes the proximal composition and fatty acid profile of the crab Hemigrapsus crenulatus, one of the main foods of E. maclovinus. The purpose of the study is to serve as basic information for the development of a specific artificial diet for juveniles of this fish species. The proximal analysis of the complete body of H. crenulatus indicates that it is mainly composed of ash (35.9%), proteins (32.2%), glucides (19.8%) and minor lipids (3.6%). The fatty acid profile is 40.7% PUFAs, 29.7% MUFAs and 29.5% SAFAs, and the most abundant acids are Eicosapentaenoic (18.8%), Oleic (6.8%) and Palmitic (16.6%), respectively. H. crenulatus has highest level of proteins, lipids and PUFAs among the species of the Brachyura infraorder.

Resumo O "blenny da patagônia" (Eleginops maclovinus) é uma espécie endêmica da América do Sul, com características fisiológicas que facilitariam sua incorporação na aquicultura chilena. No entanto, atualmente não há alimento artificial específico que possa ser usado para criar E. maclovinus. Diante desse problema, este estudo descreve a composição proximal e o perfil de ácidos graxos do caranguejo Hemigrapsus crenulatus, um dos principais alimentos de E. maclovinus. O objetivo do estudo é servir como informação básica para o desenvolvimento de uma dieta artificial específica para espécies juvenis desse peixe. A análise proximal do corpo completo de H. crenulatus indica que ele é composto, principalmente, de cinzas (35,9%), proteínas (32,2%), glicídios (19,8%) e lipídios menores (3,6%). O perfil de ácidos graxos é 40,7% PUFA, 29,7% MUFA e 29,5% SAFA, e os ácidos mais abundantes são eicosapentaenoico (18,8%), oleico (6,8%) e palmítico (16,6%), respectivamente. H. crenulatus possui o mais alto nível de proteínas, lipídios e PUFAs entre as espécies da infraordem de Brachyura.

Experimental transmission of Caligus rogercresseyi between two different fish species.

Caligus rogercresseyi is the dominant sea louse parasite affecting the salmon and trout industry in southern Chile. This parasite has a wide range of native and endemic fish hosts. The Patagonian blenny Eleginops maclovinus, which is parasitized mostly by the caligid species Lepeophtheirus spp. and C. rogercresseyi, is presumably responsible for the transmission of C. rogercresseyi to salmonids. The aim of this study was to characterize the transmission of parasites between different fish species and parasite cohort development under laboratory conditions. Parasite abundances and intensities were quantified. Transmission of parasites from Patagonian blenny to Atlantic salmon Salmo salar was lower (~9%, mainly corresponding to C. rogercresseyi) than from salmon to Patagonian blenny (14.7-26.9%, where only C. rogercresseyi were observed). This suggests that the transmission of C. rogercresseyi from salmon individuals is higher than the transmission from a native fish. Parasite cohorts developed successfully on both fish species, but apparently under different developmental rates. Water temperature, oxygen, and juvenile abundances were the variables that better explained cohort development success and variation in C. rogercresseyi adult abundances over time.

Proximal composition and fatty acid profile of Hemigrapsus crenulatus (H. Milne Edwards, 1837) as one of the main foods of "patagonian blenny"Eleginops maclovinus (Cuvier, 1830).

The Patagonian blenny (Eleginops maclovinus) is species endemic to South America with physiological characteristics that would facilitate its incorporation into Chilean aquaculture. However, there is currently no specific artificial food that can be used to raise E. maclovinus. In light of this problem, this study describes the proximal composition and fatty acid profile of the crab Hemigrapsus crenulatus, one of the main foods of E. maclovinus. The purpose of the study is to serve as basic information for the development of a specific artificial diet for juveniles of this fish species. The proximal analysis of the complete body of H. crenulatus indicates that it is mainly composed of ash (35.9%), proteins (32.2%), glucides (19.8%) and minor lipids (3.6%). The fatty acid profile is 40.7% PUFAs, 29.7% MUFAs and 29.5% SAFAs, and the most abundant acids are Eicosapentaenoic (18.8%), Oleic (6.8%) and Palmitic (16.6%), respectively. H. crenulatus has highest level of proteins, lipids and PUFAs among the species of the Brachyura infraorder.

Cellular stress responses of Eleginops maclovinus fish injected with Piscirickettsia salmonis and submitted to thermal stress.

Fluctuations in ambient temperature along with the presence of pathogenic microorganisms can induce important cellular changes that alter the homeostasis of ectothermic fish. The aim of this study was to evaluate how sudden or gradual changes in environmental temperature together with the administration of Piscirickettsia salmonis modulate the transcription of genes involved in cellular stress response in the liver of Eleginops maclovinus. Fish were subjected to the following experimental conditions in duplicate: C- 12 °C: Injection only with culture medium, C+ 12 °C: Injection with P. salmonis, AM 18 °C: Injection only with culture medium under acclimation at 18 °C, AB 18 °C: Injection with P. salmonis under acclimation at 18 °C, SM 18 °C: Injection only with culture medium and thermal shock at 18 °C and SB 18 °C: Injection with P. salmonis and thermal shock at 18 °C and sampling at 4-, 8-, 12-, 16- and 20-day post injection (dpi). The genes implied in the heat shock response (HSP70, HSC70, HSP90, and GRP78), apoptosis pathway (BAX and SMAC/Diablo), ubiquitination (E2, E3, ubiquitin, and CHIP), and 26 proteasome complex (PSMB7, PSMC1, and PSMA2) showed expression profiles dependent on time and type of injection applied. All the genes greatly increased their expression levels at day 16 and showed moderate increases at day 20, except for PSMA2 which showed a higher increase between 4- and 12-day post challenges. Our results suggest that the changes observed at the final days of the experiment are due to temperature more than P. salmonis.

Effect of Flavobacterium psychrophilum on the neuroendocrine response of rainbow trout (Oncorhynchus mykiss) in a time course experiment.

The aim of this study was to examine the effects of Flavobacterium psychrophilum, a pathogen that is economically important in the aquaculture sector, on the neuroendocrine response of Oncorhynchus mykiss during a time course experiment with sampling at 0.5, 1, 2, 6, 10, and 30 days post injection (dpi). In the brain, serotonin (5HT) content increased in the infected group at all the measured time points, a similar pattern was observed for 5-hydroxyindole-3-acetic acid (5HIAA). Infected fish presented an increase in brain dopamine levels on day 0.5 and 1 dpi. A non-significant variation in noradrenaline levels was observed on all treatment days. Foregut 5-HT and 5-HIAA content in the infected group presented the highest 5-HT concentrations with 248.6 and 983.5 ng/g tissue at 0.5 dpi respectively. Midgut 5-HT and 5-HIAA levels presented the highest 5-HT concentrations, 486.9 ng/g tissue and 1006.4 ng/g tissue respectively, at the beginning of the experiment (0.5 dpi). 5-HT levels in the hindgut presented the highest concentrations with 233.9 ng/g tissue at 0.5 dpi, while 5-HIAA presented the highest concentrations, 690.5 ng/g tissue, at the same time point. After injection with F. psychrophilum the neuroendocrine response in rainbow trout was tissue dependent. Brain levels of 5HT and 5HIIA indicate that the neuroendocrine response increased together with dopamine following intramuscular infection. These increases are in line with reports from other authors, indicating an early response of catecholamines as neurotransmitters to stressful stimulus. In addition the intestinal response was also increased, implying that there could be a possible relationship between the serotonergic system at the intestinal level and the immune system.

High doses of Francisella noatunensis induces an immune response in Eleginops maclovinus.

Francisella noatunensis subsp. noatunensis, the etiological agent of Francisellosis, affects a large number of farmed species such as Salmo salar. This species coexists with several native species in the same ecosystem, including Eleginops maclovinus. Our objective was to evaluate the susceptibility, presence of clinical symptoms, and the ability of Eleginops maclovinus to respond to Francisella infection. For this, healthy individuals were inoculated with 1.5 × 101, 1.5 × 105, and 1.5 × 1010 bact/µL of Francisella by intraperitoneal injection, subsequently the fish were sampled on days 1, 3, 7, 14, 21, and 28 post injection (dpi). At the end of the experiment, no mortality, nor internal and external clinical signs were observed, although in the high dose anaemia was detected. Additionally, bacteria were detected in all three doses, however there was replication at day 28 only in the liver in the high dose. Analysis of gene expression by qPCR showed that the spleen generated an immune response against infection from day 1 dpi, however at day 7 dpi most of the genes suffered repressed expression; observing over expression of the genes C3, NLRC3, NLRC5, MHCI, IgM. In contrast, expression in the anterior kidney did not vary significantly during the challenge. IgM quantification showed the production of antibodies in the medium and high doses. This study provides new knowledge about Francisella infection and the long-lasting and specific immune response generated by Eleginops maclovinus. It also demonstrates its susceptibility to Francisellosis where there is a difference in the immune response according to the tissue.

Effect of ration level on growth performance, body composition, intermediary metabolism and serum parameters in juvenile Patagonian blennie Eleginops maclovinus.

Eleginops maclovinus is an endemic species of the southern cone with beneficial physiological characteristics for aquaculture. However, this species has a low growth rate under captive conditions, and the optimal feed ration together with the metabolic process is unknown. This study aimed to determine the optimum feed ration during 90 days based on growth performance, body composition, intermediary metabolism, and serum parameters. For this, fish were randomly assigned to rations of 0.5, 1, 2 and 4% of body weight. No fish mortality was registered, but all fish, developed fatty liver. The results of weight, length, growth performance (WGR, SGR), and body parameters (HSI, VSI and K) followed a similar pattern, with the lowest values observed in the 0.5% and no significant differences between rations of 1, 2 and 4%. The feed intake and feces increased with the feed ration. However, the percentage of food consumed by the fish decreased with the ration size and the feed conversion ratio was lowest in the 1% ration. Total serum proteins and calcium were lowest in the 0.5% ration and presented no differences in the rations 1, 2 and 4%, while triglyceride content was significantly different only between the rations of 0.5 and 4%. Blood cortisol levels were significantly higher in the rations of 0.5 and 1%, and decreased in rations of 2 and 4%. The lipids, fiber, and energy of the total body mass increased with the feed ration, while dry matter, proteins, and ash of the body decreased to higher feed ration. In liver, triglyceride and protein levels decreased with a larger feed ration, amino acids increased in the rations of 0.5 and 4%, while glucose levels increased in rations of 2 and 4%. Liver enzymes Glucose-6-phosphate dehydrogenase and Glutamate dehydrogenase increased their activity at a higher feed ration, while Glycogen Phosphorylase, Aspartate aminotransferase and 3-Hydroxyacyl-CoA dehydrogenase presented their highest enzymatic activity only in the 4% ration. Fructose-1,6-bisphosphate showed low enzymatic activity in rations of 2 and 4% and Glycerol-3-phosphate dehydrogenase was significantly different only between the ration of 0.5 and 1%. Finally, our results suggests that optimal feed rations for E. maclovinus corresponds to 1% since this ration size produces the highest growth and metabolism with a minimum loss of food and feces present in the environment. Additionally, we recommend to reduce the percentage of fat in the diet to avoid the development of fatty liver.

The expression pattern of calcium signaling-related genes during smoltification of Salmo salar in productive conditions.

Variations in the mRNA expression of hepatic and muscle genes that are related to calcium signaling were analyzed by real-time qPCR in farmed Atlantic salmon (Salmo salar L. 1758) to determine changes in expression between parr and smolt stages. These organs were selected due to their close relationship with calcium signaling and metabolism (e.g., glycolysis, oxidative phosphorylation, muscle contraction). Differential expression between smolt and parr specimens and between organs was observed. Compared to parr specimens, smolts exhibited upregulated expression of the calcitonin receptor precursor, calcitonin receptor, calcitonin isoform, parathyroid hormone, and calmodulin in the liver. This pattern was inverse in muscle, with the exception of calmodulin, which was significantly upregulated in smolts compared to parr. Additionally, plasma calcium was decreased in the smolt condition. This study is the first to characterize the expression pattern of calcium signaling-related genes in the liver and muscle of parr and smolt S. salar. However, further functional studies are required to obtain a wider understanding about the physiological changes that accompany the productive conditions during smoltification.

The effects of intraperitoneal administration of Francisella noatunensis subsp. noatunensis on hepatic intermediary metabolism and indicators of stress in Patagonian blennie Eleginops maclovinus.

Francisellosis is a disease produced by Francisella spp. which affects farmed fish. Eleginops maclovinus specimens can be caught close to salmon farming centers, feeding on un-consumed pellet, making the transmission of pathogens such as Francisella noatunensis possible. The aim of this study was to evaluate the effect of F. noatunensis on liver intermediary metabolism in E. maclovinus. 144 fish were injected intraperitoneally with F. noatunensis at a low dose LD (1 × 101 cells/µL), medium dose MD (1 × 105 cells/µL), high dose HD (1 × 1010 cells/µL), or with culture medium C (control), and sampled at 1, 3, 7, 14, 21 and 28 days post injection (dpi). No mortality was recorded during the experimental period, but there was a marked metabolic response in fish injected with high doses. Metabolites in plasma were lowest in the high bacterial dose. Cortisol levels were highest at day 7 in the high dose and then decreased from day 14 until the end of the study. Liver enzymes showed a similar pattern to plasma metabolites, with decreased enzymatic activity, mostly with the high bacteria dose. PK was the exception, with increased enzymatic activity in a dose-dependent manner over time. Liver metabolites were highly variable, except in the high bacterial dose where variability and total levels decreased significantly. Our results show that fish infection with F. noatunensis induces a clear stress response, especially with at the highest dose, shifting intermediary metabolism towards mobilization of energy and suggesting that E. maclovinus detects experimental infection of F. noatunensis as a stressor, which it is dependent on the bacterial dose.

Temperature modulates the immunological response of the sub-antarctic notothenioid fish Eleginops maclovinus injected with Piscirickettsia salmonis.

Eleginops maclovinus is a eurythermic fish that under natural conditions lives in environments with temperatures ranging from 4 to 18 °C and can be usually captured near salmon farming areas. The aim of this study was to evaluate the effect of temperature over the innate and adaptive immune response of E. maclovinus challenged with Piscirickettsia salmonis following different treatments: C (control injection with culture medium at 12 °C), C+ (bacterial injection at 12 °C), 18 °C c/A + B (injection with culture medium in acclimation at 18 °C), 18 °C c/A + B (bacterial injection in acclimation at 18 °C), 18 °C s/A + M (injection with culture medium without acclimation at 18 °C) and 18 °C s/A + B (bacterial injection without acclimation at 18 °C). Each injection had 100 µL of culture medium or with 100 µL at a concentration 1 × 108 of live bacteria, sampling six fish per group at 4, 8, 12, 16 and 20 days post-injection (dpi). Expression of the mRNA related with the innate immune response gene (TLR1, TLR5, TLR8, NLRC3, NLRC5, MyD88 and IL-1ß) as well as the adaptive immune response gene (MHCI, MHCII, IgMs and IgD) were measured in spleen and head kidney. Gene expression profiles were treatment-type and time dependent. Levels of Immunoglobulin M (IgM) increased in challenged groups with P. salmonis from day 8-20 post challenge, which suggest activation of B cells IgM + through P. salmonis epitope detection. Additionally, a rise in temperature from 12 °C (C+) to 18 °C (with/without acclimation) also resulted in antibody increment detected in serum with significant differences between "18 °C c/A + B" and "18 °C s/A + B" groups. This is the first study that evaluates the effect of temperature changes and mRNA expression related with immune system gene over time on E. maclovinus, a native wild life fish that cohabits in the salmon farming environment.

Immunological response of the Sub-Antarctic Notothenioid fish Eleginops maclovinus injected with two strains of Piscirickettsia salmonis.

Eleginops maclovinus is an endemic fish to Chile that lives in proximity to salmonid culture centers, feeding off of uneaten pellet and salmonid feces. Occurring in the natural environment, this interaction between native and farmed fish could result in the horizontal transmission of pathogens affecting the aquaculture industry. The aim of this study was to evaluate the innate and adaptive immune responses of E. maclovinus challenged with P. salmonis. Treatment injections (in duplicate) were as follows: control (100 µL of culture medium), wild type LF-89 strain (100 µL, 1 × 108 live bacteria), and antibiotic resistant strain Austral-005 (100 µL, 1 × 108 live bacteria). The fish were sampled at various time-points during the 35-day experimental period. The gene expression of TLRs (1, 5, and 8), NLRCs (3 and 5), C3, IL-1ß, MHCII, and IgMs were significantly modulated during the experimental period in both the spleen and gut (excepting TLR1 and TLR8 spleen expressions), with tissue-specific expression profiles and punctual differences between the injected strains. Anti-P. salmonis antibodies increased in E. maclovinus serum from day 14-28 for the LF-89 strain and from day 14-35 for the Austral-005 strain. These results suggest temporal activation of the innate and adaptive immune responses in E. maclovinus tissues when injected by distinct P. salmonis strains. The Austral-005 strain did not always cause the greatest increases/decreases in the number of transcripts, so the magnitude of the observed immune response (mRNA) may not be related to antibiotic resistance. This is the first immunological study to relate a pathogen widely studied in salmonids with a native fish.

Ectoparasite Caligus rogercresseyi modifies the lactate response in Atlantic salmon (Salmo salar) and Coho salmon (Oncorhynchus kisutch).

Although Caligus rogercresseyi negatively impacts Chilean salmon farming, the metabolic effects of infection by this sea louse have never been completely characterized. Therefore, this study analyzed lactate responses in the plasma, as well as the liver/muscle lactate dehydrogenase (LDH) activity and gene expression, in Salmo salar and Oncorhynchus kisutch infested by C. rogercresseyi. The lactate responses of Atlantic and Coho salmon were modified by the ectoparasite. Both salmon species showed increasing in plasma levels, whereas enzymatic activity increased in the muscle but decreased in the liver. Gene expression was overexpressed in both Coho salmon tissues but only in the liver for Atlantic salmon. These results suggest that salmonids need more energy to adapt to infection, resulting in increased gene expression, plasma levels, and enzyme activity in the muscles. The responses differed between both salmon species and over the course of infection, suggesting potential species-specific responses to sea-lice infection.

Identification, characterization and modulation of ferritin-H in the sub-Antarctic Notothenioid Eleginops maclovinus challenged with Piscirickettsia salmonis.

Ferritin is a major iron storage protein essential not only in the infectious process, but also in any circumstance generating oxidative stress. In this study, the cDNA coding sequence of ferritin-H was obtained from the sub-Antarctic Notothenioid fish Eleginops maclovinus through transcriptomic analysis of the head kidney. This sequence contained a 534 bp open reading frame that coded for a 177 amino acid protein with a molecular weight of 20,786.2 Da and a theoretical pI of 5.56. The protein displayed a region of iron putative response elements in the 5'UTR, two putative ferritin iron-binding region signatures, and seven characteristic amino acids with ferroxidase functions. Phylogenetic analysis related this sequence to ferritin-H sequences of other Antarctic Notothenioid fish, sharing 96.61% similarity. Constitutive gene expression analysis in different organs revealed increased ferritin-H gene expression in the gills, spleen, muscle, and liver. After infection with two bacterial strains of Piscirickettsia salmonis (LF-89 and Austral-005), ferritin-H was differentially expressed depending on bacterial strain and tissue. This study provides relevant information towards understanding the iron metabolism of a sub-Antarctic Notothenioid fish.

Síndrome hepatopulmonar: poco común, pero mortal / Hepatopulmonary syndrome: uncommon, but deadly

Patients with cirrhosis may present with portal hypertension (PHT), which can lead to various complications. The most common areas cites, variceal bleeding, and hepatic encephalopathy. However, there is another entity o flow prevalence but high morbidity and mortality: the hepato pulmonary syndrome (HPS). We report the case of a 25 year-old woman with cirrhosis secondary to autoimmunehepatitis. She was admitted with respiratory symptoms suggestive of viral etiology, but evolved unfavorably. Various diagnoses of cardiovascular and respiratory conditions were successively ruled out, persisting with severe hypoxemia. Concomitantly, she developed progressive pain in the left hypochondrium area, and imaging studies show edsplenic and perisplenic form of manifestation of PHT. In context fHTP and hypoxemia, the diagnosis of HPS vs portopulmonary syndrome was considered, with the bubble test echocardiogramas a key study for such dilemma.

Los pacientes con daño hepático crónico (DHC) pueden cursar con hipertensión portal (HTP), que puede generar diversas complicaciones. Las más frecuentes son la ascitis, hemorragia variceal y encefalopatía hepática. Sin embargo, existe otra entidad de baja prevalencia, pero elevada morbimortalidad: el síndrome hepatopulmonar (SHP). Reportamos el caso de una mujer de 25 años con DHC secundario a hepatitis autoinmune. Ella ingresó con un cuadro sugerente de infección respiratoria alta de etiología viral, pero evolucionó tórpidamente. Se descartaron sucesivamente diversos diagnósticos de la esfera cardiovascular y respiratoria, persistiendo con hipoxemia grave. En forma concomitante desarrolló dolor en hipocondrio izquierdo de carácter progresivo, y las imágenes evidenciaron manifestaciones de HTP de predominio esplénico y periesplénico. En contexto de HTP e hipoxemia se consideró el diagnóstico de síndrome hepatopulmonar vs síndrome porto pulmonar, siendo el ecocardiograma con test de burbujas un estudio clave para el diagnóstico definitivo.

Effects on the metabolism, growth, digestive capacity and osmoregulation of juvenile of Sub-Antarctic Notothenioid fish Eleginops maclovinus acclimated at different salinities.

In this study we assessed the influence of three different environmental salinities (5, 15 and 31 psu during 90 days) on growth, osmoregulation, energy metabolism and digestive capacity in juveniles of the Notothenioid fish Eleginops maclovinus. At the end of experimental time samples of plasma, liver, gill, intestine, kidney, skeletal muscle, stomach and pyloric caeca were obtained. Growth, weight gain, hepatosomatic index and specific growth rate increased at 15 and 31 psu and were lower at 5 psu salinity. Gill Na(+), K(+)-ATPase (NKA) activity presented a "U-shaped" relationship respect to salinity, with its minimum rates at 15 psu, while this activity correlated negatively with salinity at both anterior and posterior intestinal portions. No significant changes in NKA activity were observed in kidney or mid intestine. Large changes in plasma, metabolite levels and enzymatic activities related to energy metabolism in liver, gill, intestine, kidney and muscle were generally found in the groups exposed to 5 and 31 psu compared to the 15 psu group. Only the pepsin activity (digestive enzymes) assessed enhanced with environmental salinity, while pyloric caeca trypsin/chymotrypsin ratio decreased. This study suggests that juvenile of E. maclovinus presents greater growth near its iso-osmotic point (15 psu) and hyperosmotic environment (31 psu). Acclimation to low salinity increased the osmoregulatory expenditure as seen by the gill and anterior intestine results, while at high salinity, branchial osmoregulatory activity was also enhanced. This requires the mobilization of lipid stores and amino acids, thereby holding the growth of fish back. The subsequent reallocation of energy sources was not sufficient to maintain the growth rate of fish exposed to 5 psu. Thus, E. maclovinus juveniles present better growth efficiencies in salinities above the iso-osmotic point and hyperosmotic environment of this species, showing their best performance at 15 psu as seen by the main osmoregulatory and energy metabolism enzymatic activities.

Combined effects of high stocking density and Piscirickettsia salmonis treatment on the immune system, metabolism and osmoregulatory responses of the Sub-Antarctic Notothenioid fish Eleginops maclovinus.

The aim of this study was to evaluate immunological, metabolic and osmoregulatory secondary stress responses in Eleginops maclovinus specimens submitted to three different stocking densities: i) low (3.1 kg m(-3)), medium (15 kg m(-3)) and high (60 kg m(-3)) during 10 days, alone or in combination with a previous treatment of a protein extract of the pathogen Piscirickettsia salmonis (0.5 µg g weight body(-1)). Plasma, liver, gill and kidney samples were obtained at the end of both experiments. Plasma cortisol and amino acid levels increased, while plasma glucose, triglyceride and lactate levels decreased at higher stocking densities. However, no effects were observed on serum Immunoglobulin type M (IgM anti P. salmonis level) values. Gill Na(+), K(+)-ATPase activity enhanced under these experimental conditions, suggesting an osmotic imbalance. Energy metabolism changes, assessed by metabolite concentrations and enzyme activities, indicated a reallocation of energetic substrates at higher stocking densities. Specimens inoculated with a protein extract of P. salmonis and maintained at different stocking densities showed primary stress response, as all groups enhanced plasma cortisol concentrations. Serum IgM levels increased after treatment with P. salmonis extract but a negative influence of high stocking density on IgM production was observed when immune system was activated. Furthermore, treatment with P. salmonis protein extract evoked deep changes in the metabolite stores in all tissues tested, indicating a mobilization of energy substrates in response to infection. The results show that stocking density induced immunological, metabolic and osmoregulatory secondary stress responses in E. maclovinus specimens and that previous treatment with P. salmonis compromise these changes.

Stocking density and Piscirickettsia salmonis infection effect on Patagonian blennie (Eleginops maclovinus, Cuvier 1830) skeletal muscle intermediate metabolism.

The need to expand aquaculture production has led to other fish to be considered as potential species for culture, such as the sub-Antarctic notothenioid Eleginops maclovinus (Valenciennes, 1830). The aim of this study was to determine the cumulative effect of density and pathogen infection by protein extract of Piscirickettsia salmonis on skeletal muscle metabolism. In a first experiment, specimens were submitted to three different stocking densities: (1) 3.1 kg m(-3), (2) 15 kg m(-3) and (3) 60 kg m(-3), for a period of 10 days. In a second experiment, metabolic changes caused by an infection of P. salmonis protein extract (a single injection of 0.5 µL P. salmonis protein extract g body weight(-1) was inoculated in the fish) and its combined effect with stocking density was assessed during a period of 10 days. This study concludes that stress caused by high stocking density led to the reorganization of some metabolic routes to fulfill skeletal muscle energy needs. Furthermore, infection response by pathogen P. salmonis differed when stocking density increased, suggesting an increase of energy needs with density in skeletal muscle of infected fish.

Hepatitis alcohólica severa no respondedor a a glucocorticoides: reporte de un caso / Alcoholic hepatitis not responding to corticosteroids: a case report

INTRODUCCIÓN: La hepatitis alcohólica corresponde a un daño inflamatorio agudo sobre un hígado progresivamente dañado por la ingesta excesiva y prolongada de alcohol. Puede presentar ictericia, manifestaciones de alcoholismo crónico e insuficiencia hepática progresiva. PRESENTACIÓN DEL CASO: Varón de 60años con antecedentes de daño hepático crónico secundario a alcoholismo activo, que presentó cuadro de dos semanas de ictericia progresiva, prurito y bradipsiquia, asociado a leucocitosis, hiperbilirrubinemia, y elevación discreta de transaminasas, con predominio de GOT sobre GPT. Hemocultivos, urocultivo y serologías para virus hepatotropos fueron negativos. La ecografía abdominal mostró signos de hepatopatía crónica, sin dilatación de vía biliar. Con una función discriminante de Maddrey de 106 puntos se inició pentoxifilina, evolucionando tórpidamente. Se agregó prednisona durante siete días; se obtiene una puntuación de Lille de 0,99 (no respondedor), suspendiendo los corticoides. Progresó la insuficiencia hepática, con posterior insuficiencia renal aguda, acidosis metabólica, trastornos hidroelectrolíticos y fallecimiento al mes de evolución. DISCUSIÓN: La hepatitis alcohólica posee alta mortalidad. Existen múltiples escalas pronósticas. Los corticoides están indicados en casos severos, sin embargo hasta un 40 por ciento se catalogan como no respondedores. Se requieren nuevos tratamientos para mejorar la supervivencia de estos pacientes.

INTRODUCTION: Alcoholic hepatitis constitutes an acute inflammatory episode due to prolonged alcohol abuse on a previously damaged liver. Clinical features include jaundice, signs of chronic alcoholism and progressive liver failure. CASE REPORT: A 60-yearold male with a history of cirrhosis due to ongoing excessive intake of alcohol presented a two week history of progressive jaundice, pruritus, and bradypsychia. Laboratory tests showed leukocytosis, hyperbilirubinemia and a mild elevation of liver enzymes (GOT over GPT). Blood and urine cultures as well as serological markers for viral hepatitis were negative. Abdominal ultrasound showed signs of chronic liver disease, with no bile duct dilatation. A modified Maddrey’s discriminant function of 106 was determinant on starting therapy with pentoxifyline. However, patient’s status deteriorated. Prednisone was added to the treatment but seven days later, the patient was categorized as a non-responder (Lille score of 0.99), so the glucocorticoids were suspended. The patient’s liver failure progressed, after which renal failure, metabolic acidosis and electrolytic abnormalities developed; that led to his death after one month from admission. DISCUSSION: Alcoholic hepatitis requires prompt diagnosis and treatment, due to its high death rate. There are various prognostic scales available, one of which is the modified Maddrey’s discriminant function. The fundamental therapeutic measure is the use of intravenous glucocorticoids; yet up to 40 percent of patients qualify as non-responders.