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Aunque las especies de enterococos son flora normal del tracto gastrointestinal humano, se encuentran entre los tres agentes patógenos microbianos que más se asocian con infecciones intrahospitalarias. Tradicionalmente, los enterococos se han considerado bacterias extracelulares. Sin embargo, es creciente la información que reporta su ingreso a través de líneas celulares epiteliales o macrófagos. A pesar de que estos microorganismos constituyen el tercer grupo de aislamientos obtenido de pacientes con bacteriemia o endocarditis, su interacción con la célula endotelial no se ha descrito completamente. En el presente trabajo evaluamos si el aislamiento intrahospitalario de Enterococcus faecalis (Ef2880) podía penetrar en células endoteliales de la vena de cordón umbilical humano (HUVEC) cultivadas in vitro. Nuestros resultados indican que los cultivos primarios HUVEC después de ser inoculados con Ef2890, incubados y tratados con antibióticos bactericidas para las bacterias extracelulares y adheridas a la cara externa de la membrana celular, exhiben bacterias intracelulares que pueden ser recuperadas vivas cuatro horas después de la inoculación. El modelo biológico desarrollado se puede constituir en una herramienta útil para el estudio de las interacciones que establecen los enterococos con el endotelio.

Actualmente existe suficiente evidencia que sustenta que la ateroesclerosis es una patología en la cual están involucrados no sólo procesos de desequilibrio y aumento de lípidos, sino también procesos inflamatorios mediados por macrófagos-células espumosas. Estos hallazgos han sido encontrados en estudios llevados a cabo con animales de experimentación. Con el propósito de racionalizar la utilización de animales y de proponer un modelo biológico alterno en el que se puedan estudiar los mecanismos de patogenicidad que involucren tipos celulares relacionados con la ateroesclerosis, en el presente trabajo se estandarizó una técnica de aislamiento y cultivo de macrófagos-células espumosas, así como, los procedimientos para caracterizar los cultivos establecidos mediante la detección de esterasas no específicas. Para el análisis de la expresión de estas enzimas, se utilizó una técnica histoquímica y electroforesis en gel de poliacrilamida en condiciones no denaturantes. En la literatura revisada, este último método no ha sido empleado para evidenciar expresión de esterasas no específicas en leucocitos. El modelo biológico aportado por este trabajo puede ser usado para estudiar respuestas de los macrófagos activados y células espumosas relacionadas con la ateroesclerosis. Evidence has accumulatd to support the hypothesis that atherosclerosis involves lipid imbalance as well as inflammatory responses mediated by macrophage and foam cells. These findings have been based on animal models. To rationalize animal use and to propose an alternative biological model, a technique was standardized for macrophage-foam cell isolation and culture. The cultures were characterized by non-denaturing polyacrylamide gel electrophoresis (PAGE) of nonspecific esterases and histochemical staining. This method has not been applied previously for the characterization of the non specific esterases from leucocytes. The biological model presented here can be used to study macrophage-foam cell responses related to atherosclerosis.

Three isoproteic (47% protein) diets were formulated to contain graded levels of crude fat (diet D16:16%, diet D24: 24% and diet D32: 32%). Each diet was fed to satiation in three and to 80% satiation in two replicate groups of gilthead sea bream (Sparus aurata), having an initial body weight of 72–74 g. The trial lasted 81 days. Groups fed to satiation showed higher final body weight (FBW; 238.8–252.3 g vs. 218.0–229.3 g) and daily growth index (DGI; 2.49–2.65%/day vs. 2.27–2.34%/day) than those fed to 80% satiation. Feed intake was significantly different both for feeding level and for diet composition. Fish fed to satiation had higher feed conversion rate (FCR) compared to the 80% satiation groups (1.33–1.44 vs. 1.13–1.17; P B 0.001). Within satiation groups, FCR was significantly lower in fish fed D16 compared to fish fed D32 (1.33 vs. 1.44, P B 0.05), whereas no statistical differences were found within the 80% satiation groups. The increase in dietary lipid level did not improve growth performance, feed efficiency and protein utilization but decreased gross lipid efficiency. Conversely, a reduction in ration from satiation to 80% satiation decreased DGI, thus improving FCR. Feed costs were influenced by dietary energy level and feeding ratio, the lowest energy diet at 80% satiation being the most profitable combination among the variables.

Gilthead sea bream, Sparus aurata, reared in the Mediterranean Sea are submitted to high temperature during warm seasons and, being poikilotherms, their metabolism is greatly influenced. The aim of this work was to assess the most suitable dietary lipid level to cope sea bream energy request when reared at high temperature. Sixty fish (75 g initial body weight) per tank were randomly distributed in triplicate groups, in a recirculating system. Water temperature and oxygen level were kept constant at 27 1and 100% of saturation, respectively. Five experimental isoproteic diets with increasing lipid level (16%, 18%, 20%, 22% and 24% lipid level, corresponding to D16, D18, D20, D22 and D24, respectively) were administered to satiation twice a day, over 89 days. Data were analyzed using one-way ANOVA and Tukeys post test (P 0.05). The specific growth rate (SGR) didnt show any significant difference between treatments even though feed intake (FI) of fish fed D16 was significantly higher as compared to other treatments. At the same time, the feed conversion ratio (FCR) was higher in fish fed the diet with the lowest lipid level. Whole-body composition, viscerosomatic, hepatosomatic and visceral fat index were not influenced by dietary treatments. Protein efficiency ratio (PER) was significantly lower in D16 (1.44) than in the other treatments (1.55, 1.58, 1.57, 1.56). Gross protein efficiency (GPE) was significantly lower in D16 (24.9) as compared to fish fed D20, D22 and D24 (27.3, 27.3, 26.7). The two lowest dietary lipid levels gave a higher gross lipid efficiency (GLE) (69.9, 69.7) in comparison to the other groups (56.6, 56.0, 49.8). The energy levels studied seem not to influence growth at high temperatures despite the wide range of fat inclusion used. However, low energy diets show higher FCR and lower PER. These findings should be further evaluated.

Histological and morphometric techniques were employed in juvenile Senegalese sole (Solea senegalensis) livers to evaluate diet-related adaptive changes and to establish how an inte- grated morphofunctional approach could improve the under- standing of rearing strategies. Four isoenergetic diets with variable protein ⁄ lipid content (44 ⁄ 22, 49 ⁄ 20, 54 ⁄ 18 and 59 ⁄ 16) were formulated. Data compared statistically showed that an increase in protein and decrease of lipid in the diet was associated with a significantly higher specific growth rate (SGR) and reduced feed conversion rate (FCR). Histologic evaluation (visual scoring of lipid storage) and morphometry (area and perimeter) of hepatocytes showed that a high lipid diet resulted in increased lipid storage. The data confirmed that a concomitant decrease of protein with an increase in lipids in the diet led to a massive storage of unused lipid within hepatocytes associated with a reduced growth performance.

This study was undertaken to determine the influence of dietary protein levels on growth, feed utilization and liver histology in common sole. Four isoenergetic diets were formulated to contain four different crude protein levels: 39 (P39), 45 (P45), 51 (P51) and 57 (P57) % dry weight. Fifty animals per tank (initial weight 10.2 ± 0.4 g) were randomly distributed into twelve 500 litre square tanks (bottom surface: 5600 cm2) connected to a closed recirculation system. The diets were tested in triplicate for 84 days. At the end of the experiment, the final weight ranged from 19.6 (P39) to 25.4 g (P57). The specific growth rate showed statistical differences between groups, with the best results in the group fed diet P57 (1.07% day−1). Significant differences between groups were also recorded for the feed conversion ratio, with values of 1.31, 1.28, 1.12 and 0.94 in P39, P45, P51 and P57 respectively. Gross lipid efficiency was also significantly affected by the dietary treatment, with the highest value (42.07%) found in P57. Ammonia excretion, expressed as g 100 g−1 protein intake, was significantly lower for group P39 (2.46) than groups P51 (4.70) and P57 (4.75). Increased incidence of lipid droplets in hepatocytes was observed when the dietary protein levels increased and/or dietary lipid decreased.

A trial on turbot ( Psetta maxima ) juveniles was undertaken to evaluate the effect of replacing dietary fishmeal (FM) with a complementary mixture of plant proteins (PP) consisting of soybean meal (SBM), wheat gluten meal (WGM) and corn gluten meal (CGM). Four practical diets were formulated to progressively replace 25% (PP25), 39% (PP39), 52% (PP52) and 66% (PP66) of FM protein. Forty animals per tank (initial weight 24.2 ± 4.4 g) were randomly distributed into twelve 450-liter square tanks connected to a closed recirculation system (temperature 18 ± 1 °C). The diets were tested in triplicate for 77 days. Final weight ranged from 126.6 g (PP25) to 99.5 g (PP66). Voluntary feed intake of group PP66 (55.5 g fish − 1 ) was significantly lower than in PP25. Specific growth rate in fish fed diet PP25 (2.14% day − 1 ) was significantly higher than those found both in PP52 (2.01% day − 1 ) and PP66 (1.82% day − 1 ) groups. Feed conversion ratio (FCR) in groups PP25 and PP39 (0.66–0.67) was lower in comparison with those of the other groups (FCR 0.70–0.74). None of the diets affected whole-body composition and hepatosomatic index. Condition factor significantly decreased with increasing dietary PP (2.06, 2.02, 1.97 and 1.91) whereas a significant increase in viscerosomatic index was observed in fish fed PP52 and PP66 (6.70–6.95) in comparison with the other two groups (6.31–6.21). Reduced protein retention was found in groups fed diet PP52 and PP66, with protein efficiency ratio (PER) ranging from 2.71 to 2.63 and gross protein efficiency (GPE) from 40.3 to 40.0, in comparison with the other two groups (PER 2.83 and GPE 45.5–45.8), even though apparent digestibility coefficients were not reduced. Ammonia excretion, (g total ammonia nitrogen 100 g protein intake − 1 ), was significantly higher for group PP25 (3.41) than group PP52 (2.61). Gut histology examined in four different sites of intestine (pyloric caeca, proximal, intermediate and distal intestine) revealed no noticeable differences among fish of the various diet groups. In conclusion, substitution of a mixture of SBM, WGM and CGM for up to 52% of FM protein did not reduce feed intake, and at 39% substitution, turbot maintained optimal growth rate and nutrient utilization. Worsened FCR of fish fed diets containing higher plant protein levels was not associated with a reduced digestibility of ingredients or alterations of gut histology.

This study aimed to assess the health and welfare of turbot juveniles fed with experimental diets containing graded levels of a mixture of plant protein, by means of blood chemistry analyses including stress and metabolic indicators. Four extruded isonitrogenous (51%) and isolipidic diets (16%) were manufactured by Skretting ARC, Stavanger, Norway: a reference diet (diet D) contained 50% fish meal and three other diets in which fish meal was progressively reduced to 35% (diet C), 20% (diet B) and 5% (diet A) by proportionally increasing the level of wheat gluten meal, soybean meal and soy protein concentrate. Turbot juveniles (Initial weight 9.68 g ± 0.98 g) were reared in 500 l square recirculating tanks at 18°C (n= 55 fish per tank). The trial was performed in triplicate and lasted 9 weeks. Blood was withdrawn from the caudal vein, serum was collected after centrifugation and stored at -80°C for analyses of cortisol (COR), glucose (GLU), osmolality (OSM), non-esterefied fatty acids (NEFA), triglycerides (TAG), cholesterol (CHO), total protein (TP), urea (BUN), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phophatase (ALP). Biometric measurements and autoptical analysis were also performed. One-way ANOVA and discriminant analysis were applied to data set to test the effects of dietary treatment. Experimental diets significantly affected growth and metabolic status of turbot juveniles (ANOVA p

Gilthead sea bream (Sparus aurata) of 70-72 g initial body weight were fed seven extruded iso-energetic diets (22,1 MJ Kg-1) with different protein levels: 35 (diet 35), 38 (diet 38), 41 (diet 41), 44 (diet 44), 47 (diet 47), 50 (diet 50), 53 % (diet 53). Fish were fed to satiation twice a day for six days and once on Sunday during the week. The trial lasted 77 days. Protein dietary level had no effect on feed consumption. SGR was similar in fish fed diets 47, 50 and 53, where the highest values were scored. The lowest value of FCR was registered in fish fed diet 47, even though there was no statistical differences in fish fed diets containing protein from 38 to 53%. From practical considerations, the most profitable combination between SGR and FCR was found in fish fed diet 47