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Felix Acosta

Disease prevention is pivotal in aquaculture, and while vaccines offer protective immunity, challenges such as cost and low efficacy persist. The present study investigated the potential of plant-derived compounds, known as phytogenics,... more
Disease prevention is pivotal in aquaculture, and while vaccines offer protective immunity, challenges such as cost and low efficacy persist. The present study investigated the potential of plant-derived compounds, known as phytogenics, to bolster the effectiveness of vaccines against vibriosis in European seabass. Two phytogenic blends, namely PHYTO1 (terpenes) and PHYTO2 (terpenes and flavonoids) were supplemented to a commercial diet to obtain three experimental diets: a non-supplemented control diet, PHYTO1 (a 200-ppm blend of garlic and Lamiaceae oils with 87.5 mg kg − 1 terpenes), and PHYTO2 (a 1000 ppm blend containing citrus fruits, Asteraceae and Lamiaceae oils with 57 mg kg − 1 terpenes and 55 mg kg − 1 flavonoids). Following vaccination by bath immersion, juvenile European seabass were divided into groups and fed one of the three diets for 30 days. After this feeding period, fish were anesthetized and boosted with a single dose of vaccine through intraperitoneal injection. They continued to be fed their respective diets for another 30 days. At day 60, after the priming vaccination, fish were challenged with Vibrio anguillarum via intraperitoneal injection. Various parameters were measured at different time points post each vaccination, including total weight, circulating plasma cortisol and glucose levels, serum immunoglobulin M (IgM) titers, antioxidant power of leucocytes, and the expression of several antioxidant and immune-related genes. The results showed that fish fed with phytogenic supplements did not differ in weight compared to the control group. However, they exhibited lower plasma cortisol and glucose levels, increased IgM titers, and enhanced antioxidant protection and antioxidant power of head kidney leucocytes. In addition, phytogenics upregulated several immune-related genes in the gills and head kidney immediately after each vaccination. Notably, PHYTO2, enriched with flavonoids and terpenes, exhibited an even more pronounced positive effect on boosted fish by reducing vaccine-associated stress while improving antioxidant protection and modulating the vaccine-induced immune response. This synergistic effect of vaccination combined with phytogenics introduces new pathways for enhancing fish health in aquaculture.
Therapeutic bacteriophages, commonly called as phages, are a promising potential alternative to antibiotics in the management of bacterial infections of a wide range of organisms including cultured fish. Their natural immunogenicity often... more
Therapeutic bacteriophages, commonly called as phages, are a promising potential alternative to antibiotics in the management of bacterial infections of a wide range of organisms including cultured fish. Their natural immunogenicity often induces the modulation of a variated collection of immune responses within several types of immunocytes while promoting specific mechanisms of bacterial clearance. However, to achieve standardized treatments at the practical level and avoid possible side effects in cultivated fish, several improvements in the understanding of their biology and the associated genomes are required. Interestingly, a particular feature with therapeutic potential among all phages is the production of lytic enzymes. The use of such enzymes against human and livestock pathogens has already provided in vitro and in vivo promissory results. So far, the best-understood phages utilized to fight against either Gram-negative or Gram-positive bacterial species in fish culture ar...
Skin mucus is considered the first barrier against diseases in fish. The skin mucus protein profile of the greater amberjack (Seriola dumerili) and its changes due to experimental infection with Neobenedenia girellae were studied by... more
Skin mucus is considered the first barrier against diseases in fish. The skin mucus protein profile of the greater amberjack (Seriola dumerili) and its changes due to experimental infection with Neobenedenia girellae were studied by combining 2-DE-MS/MS and gel-free LC-MS/MS proteomic approaches. The 2-DE results led to the identification of 69 and 55 proteins in noninfected and infected fish, respectively, and revealed that keratins were specifically cleaved in parasitized fish. Therefore, the skin mucus of the infected fish showed a higher protease activity due to, at least in part, an increase of metal-dependent protease and serine-type protease activities. Additionally, through a gel-free LC-MS/MS analysis, 1377 and 1251 different proteins were identified in the skin mucus of healthy and parasitized fish, respectively. The functional analysis of these proteins demonstrated a statistical overrepresentation of ribosomal proteins (a well-known source of antimicrobial peptides) in N. girellae-infected fish. In contrast, the components of membranes and protein transport GO categories were underrepresented after infection. Immune system process-related proteins constituted 2.5% of the total skin mucosal proteins. Among these skin mucosal proteins, 14 and 15 proteins exclusive to non-parasitized and parasitized fish were found, respectively, including specific serine-type proteases and metalloproteases in the parasitized fish. Moreover, the finding of tryptic peptides exclusive to some bacterial genera, obtained by gel-free LC-MS/MS, allowed us to construct a preliminary map of the microbiota living in the mucus of S. dumerili, with Pseudomonas and Paracoccus the most represented genera in both noninfected and infected fish.
Prophylaxis can be defined as all the actions taken to prevent disease and therefore can be considered as a synonym of disease prevention. Biosecurity is also related to disease prevention but mainly consists of actions that minimize the... more
Prophylaxis can be defined as all the actions taken to prevent disease and therefore can be considered as a synonym of disease prevention. Biosecurity is also related to disease prevention but mainly consists of actions that minimize the risk of introduction and spreading of an infectious disease in a particular place and also spreading to other places. In aquaculture, therefore, biosecurity should be mainly related to those practices aiming at reducing the risk of specific infectious and parasitic diseases, whereas disease prevention and prophylaxis should be viewed with a wider scope, including measures and actions to reduce the susceptibility to infectious diseases and also non-infectious diseases and factors such as stress or environmental conditions, that are closely related to the emergence and expression of the diseases. Prophylaxis, disease prevention and biosecurity should also be clearly differentiated from disease treatments and disease remediation, although in cases, cer...
As many other farming activities, aquatic animals and particularly finfish can be affected by several infectious and non-infectious diseases. The specific diseases and pathogens or other causes triggering the development of these... more
As many other farming activities, aquatic animals and particularly finfish can be affected by several infectious and non-infectious diseases. The specific diseases and pathogens or other causes triggering the development of these diseases, since there are usually multifactorial, can be related to a number of different factors: characteristics of the infectious agents, affected fish species or genetic susceptibility, environment and environmental conditions, geographical parameters, and farming systems amongst others.
The supplementation of fish diets with OH-SeMet reduces oxidative stress and modulates immune response against bacterial infection. However, despite the importance of essential polyunsaturated fatty acids in fish nutrition and their high... more
The supplementation of fish diets with OH-SeMet reduces oxidative stress and modulates immune response against bacterial infection. However, despite the importance of essential polyunsaturated fatty acids in fish nutrition and their high risk of oxidation, the potential protective effect of OH-SeMet on these essential fatty acids has not been studied in detail. Moreover, while viral infection is very relevant in seabream production, no studies have focused the Se effects against viral infection. The aim of the present study was to assess the impact of dietary supplementation with OH-SeMet on gilthead seabream fatty acid profiles, growth performance and response against viral infection. Gilthead seabream juveniles (21.73 ± 0.27 g) were fed for 91 days with three experimental diets, a control diet without supplementation of Se (0.29 mg Se kg diet−1) and two diets supplemented with OH-SeMet (0.52 and 0.79 mg Se kg diet−1). A crowding stress test was performed at week 7 and an anti-vira...
Acinetobacter baumannii is a common cause of health care associated infections worldwide. A. pittii is an opportunistic pathogen also frequently isolated from Acinetobacter infections other than those from A. baumannii. Knowledge of... more
Acinetobacter baumannii is a common cause of health care associated infections worldwide. A. pittii is an opportunistic pathogen also frequently isolated from Acinetobacter infections other than those from A. baumannii. Knowledge of Acinetobacter virulence factors and their role in pathogenesis is scarce. Also, there are no detailed published reports on the interactions between A. pittii and human phagocytic cells. Using confocal laser and scanning electron microscopy, immunofluorescence, and live-cell imaging, our study shows that immediately after bacteria-cell contact, neutrophils rapidly and continuously engulf and kill bacteria during at least 4 hours of infection in vitro. After 3 h of infection, neutrophils start to release neutrophil extracellular traps (NETs) against Acinetobacter. DNA in NETs colocalizes well with human histone H3 and with the specific neutrophil elastase. We have observed that human neutrophils use large filopodia as cellular tentacles to sense local envi...
The main objective of this study was to determine the effect of two forms of mannan oligosaccharides (MOS: Bio-Mos and cMOS: Actigen, Alltech Inc, USA) and their combination on greater amberjack (Seriola dumerili) growth performance and... more
The main objective of this study was to determine the effect of two forms of mannan oligosaccharides (MOS: Bio-Mos and cMOS: Actigen, Alltech Inc, USA) and their combination on greater amberjack (Seriola dumerili) growth performance and feed efficiency, immune parameters and resistance against ectoparasite (Neobenedenia girellae) infection. Fish were fed for 90 days with 5 g kg MOS, 2 g kg cMOS or a combination of both prebiotics, in a Seriola commercial base diet (Skretting, Norway). At the end of the feeding period, no differences were found in growth performance or feed efficiency. Inclusion of MOS also had no effect on lysozyme activity in skin mucus and serum, but the supplementation of diets with cMOS induced a significant increase of serum bactericidal activity. Dietary cMOS also reduced significantly greater amberjack skin parasite levels, parasite total length and the number of parasites detected per unit of fish surface following a cohabitation challenge with N. girellae, ...
The surface-associated proteins play a key role in bacterial physiology and pathogenesis, and are the major targets in the development of new vaccines. These proteins contribute to the adaptation of bacteria to different hosts and... more
The surface-associated proteins play a key role in bacterial physiology and pathogenesis, and are the major targets in the development of new vaccines. These proteins contribute to the adaptation of bacteria to different hosts and environments. To study differences at the genomic level, we first sequenced the whole genome of Streptococcus iniae from fish (IUSA-1 strain) and compared it to Streptococcus iniae from human (9117 strain), revealing a high similitude between both strains. To gain further insights into host- and environment-specific differences, we then studied proteins in silico and by High Performance Liquid Chromatography. This approach successfully identified 54 secreted and surface proteins, including several proteins involved in cell wall synthesis and transport of solutes, as well as proteins with yet unknown function. These proteins highlight as interesting targets for further investigation in the interaction between Streptococcus iniae and its environment. Results...
A clinical isolate ofHafnia alvei(strain HUMV-5920) was obtained from a urine sample from an adult patient. We report here its complete genome assembly using PacBio single-molecule real-time (SMRT) sequencing, which resulted in a... more
A clinical isolate ofHafnia alvei(strain HUMV-5920) was obtained from a urine sample from an adult patient. We report here its complete genome assembly using PacBio single-molecule real-time (SMRT) sequencing, which resulted in a chromosome with 4.5 Mb and a circular contig of 87 kb. About 4,146 protein-coding genes are predicted from this assembly.
Hafnia alvei is a gram-negative facultatively anaerobic bacillus that belongs to the family Enterobacteriaceae. This organism is a causative agent of intestinal disorders and is found in different environments. H. alvei has received... more
Hafnia alvei is a gram-negative facultatively anaerobic bacillus that belongs to the family Enterobacteriaceae. This organism is a causative agent of intestinal disorders and is found in different environments. H. alvei has received increased clinical attention as a cause of different infections in humans. This study was performed to compare the MicroScan WalkAway automated identification system in conjunction with the new MicroScan Combo Negative type 1S panels with conventional biochemical methods for identification of 21 H. alvei strains. The MicroScan WalkAway system was found capable of correctly identifying 20 of the 21 strains tested.
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抄録 Hafnia alvei is a Gram-negative bacillus that belongs to the family Enterobacteriaceae and has been isolated from different fish species. H. alvei causes a wide variety of diseases, including hemorrhagic septicemia, ikidney ilesions... more
抄録 Hafnia alvei is a Gram-negative bacillus that belongs to the family Enterobacteriaceae and has been isolated from different fish species. H. alvei causes a wide variety of diseases, including hemorrhagic septicemia, ikidney ilesions and mortality in different fish species, ...

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