Aluminum is a powerful adjuvant in teleost fish despite failing to induce interleukin-1β release.

Although aluminum salts (Alum) have been extensively used in human vaccination for decades, its mechanism of action is controversial. In fish, the use of Alum as a vaccine adjuvant is scarce and there are no studies aimed at identifying its mechanism of action. In the present study we report that Alum is a powerful adjuvant in the gilthead seabream (Sparus aurata L.

Aluminum adjuvant potentiates gilthead seabream immune responses but induces toxicity in splenic melanomacrophage centers.

A key goal of a successful vaccine formulation is the strong induction of persistent protective immune responses without producing side-effects. Adjuvants have been proved to be successful in several species at inducing increased immune responses against poorly immunogenic antigens. Fish are not the exception and promising results of adjuvanted vaccine formulations in many species are needed.

Histamine and mast cell activator compound 48/80 are safe but inefficient systemic adjuvants for gilthead seabream vaccination.

Histamine has a key role in the regulation of inflammatory and innate immune responses in vertebrates. Gilthead seabream (Sparus aurata L.), a marine hermaphrodite teleost of great commercial value, was the first fish species shown to possess histamine-containing mast cells (MCs) at mucosal tissues.

Cimetidine disrupts the renewal of testicular cells and the steroidogenesis in a hermaphrodite fish.

The importance of histamine in the physiology of the testis in mammals and reptiles has been recently shown. Histamine receptors (Hrs) are well conserved in fish and are functional in several fish species. We report here for the first time that histamine and the mRNA of Hrh1, Hrh2 and Hrh3 are all present in the gonad of the hermaphrodite teleost fish gilthead seabream.

Selective estrogen receptor modulators differentially alter the immune response of gilthead seabream juveniles.

17α-ethynylestradiol (EE2), a synthetic estrogen used in oral contraceptives and hormone replacement therapy, tamoxifen (Tmx), a selective estrogen-receptor modulator used in hormone replacement therapy, and G1, a G protein-coupled estrogen receptor (GPER) selective agonist, differentially increased the hepatic vitellogenin (vtg) gene expression and altered the immune response in adult gilthead seabream (Sparus aurata L.) males. However, no information exists on the effects of these compounds on the immune response of juveniles.

Tamoxifen disrupts the reproductive process in gilthead seabream males and modulates the effects promoted by 17α-ethynylestradiol.

17α-Ethynylestradiol (EE2), which is used in oral contraceptives and hormone replacement therapy, is a well documented estrogenic endocrine disruptor and an aquatic contaminant. In the present study, adult male specimens of the marine hermaphrodite teleost gilthead (Sparus aurata L.) were fed a diet containing tamoxifen (Tmx), an estrogen receptor ligand used in cancer therapy, alone or combined with EE2, for 25 days and then fed a commercial diet for a further 25 days (recovery period).

Characterization of the annual regulation of reproductive and immune parameters on the testis of European sea bass.

The European sea bass, Dicentrarchus labrax L., is a seasonal gonochoristic species, the males of which are generally mature during their second year of life. It has been demonstrated that cytokines and immune cells play a key role in the testicular development.

Antimicrobial response is increased in the testis of European sea bass, but not in gilthead seabream, upon nodavirus infection.

Antimicrobial peptides (AMPs) have a crucial role in the fish innate immune response, being considered a fundamental component of the first line of defence against pathogens. Moreover, AMPs have not been studied in the fish gonad since this is used by some pathogens as a vehicle or a reservoir to be transmitted to the progeny, as occurs with nodavirus (VNNV), which shows vertical transmission through the gonad and/or gonadal fluids, but no study has looked into the gonad of infected fish. In this framework, we have characterized the antimicrobial response triggered by VNNV in the testis of European sea bass, a very susceptible species of the virus, and in the gilthead seabream, which acts as a reservoir, both in vivo and in vitro, and compared with that present in the serum and brain (target tissue of VNNV).

Isolation of mast cells from the peritoneal exudate of the teleost fish gilthead sea bream (Sparus aurata L.).

Inflammation is the first response of animals to infection or tissue damage. Sparus aurata (Perciformes) was the first fish species shown to possess histamine-containing mast cells at mucosal tissues. We report a separation protocol for obtaining highly enriched (over 95% purity) preparations of fish mast cells in high numbers (5-20 million mast cells per fish).

Flagellin from Marinobacter algicola and Vibrio vulnificus activates the innate immune response of gilthead seabream.

Adjuvants have emerged as the best tools to enhance the efficacy of vaccination. However, the traditional adjuvants used in aquaculture may cause adverse alterations in fish making necessary the development of new adjuvants able to stimulate the immune system and offer strong protection against infectious pathogens with minimal undesirable effects. In this respect, flagellin seems an attractive candidate due to its ability to strongly stimulate the immune response of fish.

Seasonal variations of the humoral immune parameters of European sea bass (Dicentrarchus labrax L.).

Seasonal cycles, mainly due to great variations in the light duration and temperature, are important and modulate several aspects of the animal behavior. In the case of poikilotherms animals such as fish this is very relevant. Thus, temperature changes fish immunity and affects disease resistance.

Fish granulocytes express a constitutively active androgen receptor variant.

In humans, alternative splicing of androgen receptor (AR) is usually involved in some diseases. However, our knowledge about the presence of AR variants in other species and its importance for immunity is scant. Here, we report the identification of a constitutively active AR variant lacking the ligand-binding domain (LBD), ARΔLBD, in the fish gilthead seabream.

The effect of 17α-ethynylestradiol on steroidogenesis and gonadal cytokine gene expression is related to the reproductive stage in marine hermaphrodite fish.

Pollutants have been reported to disrupt the endocrine system of marine animals, which may be exposed through contaminated seawater or through the food chain. Although 17α-ethynylestradiol (EE₂), a drug used in hormone therapies, is widely present in the aquatic environment, current knowledge on the sensitivity of marine fish to estrogenic pollutants is limited. We report the effect of the dietary intake of 5 µg EE₂/g food on different processes of testicular physiology, ranging from steroidogenesis to pathogen recognition, at both pre-spermatogenesis (pre-SG) and spermatogenesis (SG) reproductive stages, of gilthead seabream (Sparus aurata L.

Recombinant TNFα as oral vaccine adjuvant protects European sea bass against vibriosis: insights into the role of the CCL25/CCR9 axis.

Vibrio anguillarum is the main causative agent of vibriosis in cultured sea bass. Unfortunately, available vaccines against this disease do not achieve the desired protection. In this study, to accomplish uptake, processing, and presentation of luminal antigens, a commercial sea bass oral vaccine against V.

Testosterone implants modify the steroid hormone balance and the gonadal physiology of gilthead seabream (Sparus aurata L.) males.

Androgens can induce complete spermatogenesis in immature or prepubertal teleost fish; however, many aspects of the role of androgens in adult teleost spermatogenesis remain elusive. We used the in situ forming microparticle (ISM) system containing 1mg of testosterone (T)/kg body weight (T-ISM) in a homogenous population of gilthead seabream at testicular involution stage to study in vivo the effects of T on the sex steroid hormone balance and on the physiology of the gilthead seabream gonad. The levels of T, 11-ketotestosterone (11KT) and 17β-estradiol (E2) in plasma, gonad and liver were determined in T-ISM implanted specimens after 7, 14, 21 and 28 days.

In situ forming microparticle implants for delivery of sex steroids in fish: Modulation of the immune response of gilthead seabream by testosterone.

Current knowledge on the sensitivity of marine fish to androgenic environmental chemicals is limited, despite the growing interest in the effects of endocrine disrupting chemicals. To study in vivo the effects of testosterone (T) on the fish immune response, we used a microencapsulation implant technique, the in situ forming microparticle system, containing 1 mg T/kg body weight (T-ISM), in adult specimens of gilthead seabream (Sparus aurata L.), a species of great economic interest.

Muscle development and body growth in larvae and early post-larvae of shi drum, Umbrina cirrosa L., reared under different larval photoperiod: muscle structural and ultrastructural study.

Shi drum specimens were maintained under four different photoperiod regimes: a natural photoperiod regime (16L:8D), constant light (24L), equal durations of light and dark (12L:12D) and a reduced number of daylight hours (6L:18D) from hatching until the end of larval metamorphosis. Specimens were then kept under natural photoperiod conditions until 111 days post-hatching. Muscle and body parameters were studied.

Specific and non-overlapping functions of testosterone and 11-ketotestosterone in the regulation of professional phagocyte responses in the teleost fish gilthead seabream.

Sex hormones, both estrogens and androgens, have a strong impact on immunity in mammals. In fish, the role of androgens in immunity has received little attention and contradictory conclusions have been obtained. However, it is well known that sex steroids are involved in fish growth, osmoregulation and gonad remodelation.

Sodium alginate as feed additive in cultured sea bream (Sparus aurata): does it modify the quality of the flesh?

The objective of this study was to evaluate the effect of sodium alginate obtained from brown seaweed as a prebiotic supplement to the feed of reared sea bream (Sparus aurata). Addition of the alginate to a control diet was investigated at both concentrations 2% and 5%. Proximate composition in the flesh were not modified significantly by sodium alginate inclusion in the diet of the sea bream; however the fat and ash content in the specimens supplemented with 5% alginate were found to be significantly higher than those found in individuals who were fed the control diet.

Characterization of European sea bass transcripts by RNA SEQ after oral vaccine against V. anguillarum.

The European sea bass (Dicentrarchus labrax) is, along with the gilthead sea bream (Sparus aurata), one of the most extensively cultured species in European aquaculture productions. Massive mortalities may be caused by bacterial or viral infections in intensive aquaculture production. Evaluation of the efficacy of an oral vaccine against Vibrio anguillarum (Aquavac Vibrio Oral) in sea bass revealed specific immune gene expression profiles in the gut as well as protection of fish.

Metabolic adjustments of Dentex dentex to prolonged starvation and refeeding.

The particular metabolic strategies of the common dentex (Dentex dentex) to face a period of prolonged starvation and subsequent refeeding were assessed. Plasma metabolites, endogenous reserves, and the activity of key enzymes of intermediary metabolism in liver, white muscle, and heart were evaluated. Plasma glucose, total lipid, triglycerides, total-, HDL- and LDL-cholesterol, and protein levels, liver, and white muscle glycogen, and perivisceral, and muscle fat were significantly reduced by starvation, whereas liver lipid content was surprisingly increased.

Aquaporin-4 immunoreactivity in Müller and amacrine cells of marine teleost fish retina.

Aquaporins (AQPs) are membrane proteins that facilitate water transport across biological membranes and are essential for the proper function of neural tissue. Although AQPs have been extensively studied in mammalian retina, their presence in lower vertebrate retina is less frequently characterized. AQP4 expressed in mammalian and chick Müller cells plays a major part in maintaining retinal homeostasis.

17α-Ethynylestradiol alters the immune response of the teleost gilthead seabream (Sparus aurata L.) both in vivo and in vitro.

There is increasing public attention concerning the effect of endocrine disruptor chemicals (EDCs) on the immune system. One important group belonging to EDCs are the environmental estrogens. Commonly found in the effluents in wastewater treatment plants, 17α-ethynylestradiol (EE(2)) which is used in contraceptive pills, is an endocrine disruptor with strong estrogenic effects.

TLR agonists extend the functional lifespan of professional phagocytic granulocytes in the bony fish gilthead seabream and direct precursor differentiation towards the production of granulocytes.

Neutrophils are major cells participants in innate host responses. They are short-lived leukocytes, although microbial products activate intracellular signaling cascades that prolong their survival by inhibiting constitutive apoptosis. To gain insight into the phylogeny of this important cell type, we examined the ability of toll-like receptor agonists to extend the lifespan of gilthead seabream (Sparus aurata L.

Digestive enzymatic profile of Dentex dentex and response to different dietary formulations.

Digestive physiology of on-growing common dentex (Dentex dentex), including protease, amylase and lipase activity in stomach, pyloric caeca, anterior and posterior intestine, was evaluated. The influence of dietary macronutrient balance on these digestive processes was also assessed. Four experimental diets with different protein:lipid:carbohydrate ratios (43/16/28; 43/24/4; 38/19/28 and 38/24/13) were formulated.