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L’acquacoltura ha sempre rappresentato un’importante attività di allevamento animale e mai come oggi ha assunto un’importanza crescente dovuta ad una sempre maggior domanda di consumo annuo pro capite di pesce che, tuttavia, ha comportato una contestuale diminuzione dell’apporto della pesca. La movimentazione di pesce vivo è parte integrante della attività di piscicoltura in tutta Europa. Negli ultimi decenni in Italia l’allevamento del pesce e di altre specie acquatiche è stato in costante aumento, stabilizzandosi solo negli ultimi anni. Si è registrato un sempre maggiore interesse alle pratiche di acquacoltura utilizzate e ai relativi problemi di benessere dei pesci da parte del legislatore, nel campo della ricerca e da parte dei consumatori. I dati dimostrano che l’acquacoltura è un settore in crescita: nell’anno 2016 sono stati trasportati e introdotti in Italia oltre 72 milioni di Kg. di pesce vivo (35.5% trote – 14.6% spigole e orate – 4% pesce gatto e anguille) e si prevede che a livello mondiale nel 2030 il 60% del pesce consumato sarà di allevamento. In Italia le specie più trasportate sono le orate, le spigole nelle fasi giovanili e le trote. La maggior parte delle specie di pesce che sono allevate vengono spostate almeno una volta durante il loro ciclo produttivo, mentre alcuni animali vengono movimentati più volte. In acquacoltura sono allevate e trasportate oltre 60 specie diverse di pesci (oltre 30 specie in Europa). Se ne deduce che quantità di animali trasportati e la e la lunghezza durata del viaggio possono variare considerevolmente, in funzione del ciclo produttivo e delle necessità commerciali, che talvolta possono cambiare anche nel corso dello stesso anno. Il trasporto dei pesci è forse il più difficile e delicato rispetto alle altre specie di vertebrati, per cui ne deriva che un piccolissimo errore nelle varie fasi di trasporto ne comprometterebbe il benessere degli animali nonché una perdita economica nel settore. L’azione di protezione e di mantenimento delle condizioni di benessere del pesce vivo durante le operazioni di trasporto, che dovrebbe essere un dovere morale dell’allevatore e/o autotrasportatore, è un obbligo sancito dalla legislazione vigente e comporta una responsabilità legale sia degli operatori del settore, sia delle autorità competenti preposte ai controlli, le quali devono avere una alta professionalità e competenza nel corso delle operazioni ispettive e di vigilanza. Nelle attività di trasporto del pesce, è necessario eseguire le operazioni secondo specifici protocolli operativi, allo scopo di non pregiudicare lo stato di salute e indirettamente anche il valore economico degli animali oggetto di movimentazione. E’ rilevante quindi che gli operatori e il personale addetto siano formati e preparati per garantire ai pesci un trasporto senza stress. A tal proposito è importante sottolineare l’importanza fondamentale della figura del veterinario, il quale rappresenta oggi la sola figura professionale e con competenze scientifiche a cui la legge attribuisce il compito-dovere di verifica e di controllo delle condizioni degli animali e dei loro prodotti, nello specifico anche del pesce, ivi compresi i provvedimenti a tutela della protezione del benessere dell’animale durante il trasporto e che comportano, inoltre, anche la valutazione delle condizioni di dolore, stress, o sofferenze evitabili nel corso delle operazioni. Con il presente ‘Manuale’, vengono riportate una serie di misure specifiche da applicare nella gestione del trasporto su strada del pesce vivo, al fine di definire ed individuare le condizioni ottimali di benessere nel corso delle movimentazioni.

One of the major problems in artificial eel reproduction is identification of broodstock with high performance reproductive characteristics. The aim of this study was to study population characteristics and the reproductive potential of eels (Anguilla anguilla) located in Valle Campo valley (Comacchio, Italy). A total of 200 eels/period (spring–summer and autumn–winter) were measured to obtain an external indicator of their maturation state. Morphometric parameters were used to calculate condition factor (K), eye index (EI) and pectoral fin length index (PFLI). Silver index analyses showed the lack of silver males and of fully mature females. Most represented females were yellow females at stage II. Silver females represented 27.9% of the population. Seasonal analysis shows how temperature reduction favoured the presence of silver females versus yellow females. Statistical analysis of EI, cranial (CI), PFLI and gonadosomatic (GSI) indexes showed that significant differences were found for EI, CI, PFLI and GSI between yellow and silver eels. No significant difference was found between stage III and IV silver eels, while a significant difference for EI was found between stage I and II yellow eels and for IC at stage II with respect to all other stages. The present study defined how Valle Campo could present environmental and trophic conditions which could favour precocious development of a population of silver females with a noticeable reproductive potential, to be used in open sea release or in artificial reproduction programmes. On the contrary, the valley seems to present unfavourable conditions for both development and sexual maturation of male eels.

The reproductive performance of Octopus vulgaris broodstocks fed two different diets (mixed fish [F group, BW 1,048.14 g] or mixed crustaceans [C group, BW 998.44 g]) was analyzed using an experimental recirculating aquaculture system consisting of a tank equipped with spawning and incubation chambers. A total of 8 females (F1–4; C1–4), and 8 males (M1–M8) were selected. DI of the C group females was significantly (p

European eel Anguilla anguilla is among the highly valued species for aquaculture. Since its peculiar biology, it is not yet possible to complete the whole life cycle in artificial conditions and its supply depends entirely on wild catches. In the last 50 years this species has suffered a population reduction of 99 % mainly due to overfishing. In a conservation perspective, it is of fundamental importance to improve the aquaculture production of European eel, to avoid the extinction of this species and preserve its residual genetic variability, allowing at the same time the fulfilling of costumers request without increasing its harvesting pressure.In this study we aimed to deepen the knowledge about the mechanisms at the basis of reproduction of the European eel in semi-natural conditions, through direct observation of spawning behaviour and through the paternity assignment using microsatellite markers. The systematic and prolonged observation of the reproductive behaviour of European eel and the contextual parentage analyses we carried out for the very first time in this species on 39 adults and 432 F1 randomly collected. We contributed to unravel the sexual behaviour of this species in the most common artificial reproduction conditions (polyandry), and define the precise courtship sequence until the release of gametes, and the male-male hierarchy in courtship. We characterized for the first time three main types of male: dominant (the first who starts the courtship, and the one with the majority of F1 assigned), subordinate (which starts the courtship only in a second time and with a minor percentage of F1 ascribed) and ineffective (which sometime appears totally disinterested to courtship and has few F1 or none).The evidences here produced represent an important attempt for developing good reproduction practices of the critically endangered European eel, providing a good starting point for its future aquaculture production. Keywords: Anguilla anguilla, Aquaculture, Artificial breeding, Kinship analysis, Parentage assignment

Anguilla anguilla (Linnaeus, 1758) is a critically endangered species, whose existence in the wild is highly threatened by human activities and is included in the IUCN Red List of threatened species as “Critically Endangered”. Restocking and captive breeding programs designed to preserve the residual genetic variability should represent the future for conservation of this species. In this perspective, the present study aims to increase the knowledge about the mechanisms at the basis of reproduction of the European eel in semi-natural conditions, through paternity assignment. Here we show the very first parental assignment results of a plenty successful reproductive event that occurred in 2016: four families of European eel founded by four female plus 11 males in different mixes and their progeny, for a total of 206 samples. Parental allocations revealed the presence of different percentage of success of males in fertilizing eggs, with two “super-males” at the top of the productivity, with the 19.9% and 18.8% of total larvae (males 128 and 129) and two “weak-males” at the end of the distribution of productivity curve (males 134 and 135). Since the artificial reproduction of European eel is a very challenging topic for world aquaculture, these first results may help in drawing future breeding plans aimed both to increase the productivity for human consumption and to develop restocking plans in order to try to reduce the speed of decreasing in worldwide stocks of European eels.

The European eel has recently been included on the Red List of the International Union for Conservation of Nature (IUCN) as a critically endangered species. The rearing of Anguilla larvae is seen as a key bottleneck to the mass production of glass eels since very little ecological information is available regarding their natural nutrition. Studies of digestive physiology and ontogenetic development in eel larvae could provide useful information for solving some of the puzzles regarding larval fish culture. The aim of this study was to characterize the ontogeny of pancreatic enzymes (trypsin, lipase and amylase) and a peptide hormone regulator of pancreatic secretion (cholecystokinin) in terms of gene expression in European eel larvae from day 0 (P0) of hatching to 5, 10, 15 and 20 days post hatching during fasting. The results in the present study showed that all the genes selected were present, with different levels of expression and increasing trends, during larval development. At P0, the increase in the gene expression of lipase and amylase was higher than that of trypsin and cholecystokinin, confirming that enzymatic activity began before mouth opening and that larvae, provided with a complete enzymatic set, might have the capacity of digesting and absorbing various nutrients.

This investigation focused on an episode of chronic mortality observed in juvenile Huso huso sturgeons. The examined subjects underwent pathological, microbiological, molecular, and chemical investigations. Grossly severe body shape deformities, epaxial muscle softening, and multifocal ulcerative dermatitis were the main observed findings. The more constant histopathologic findings were moderate to severe rarefaction and disorganization of the lymphohematopoietic lymphoid tissues, myofiber degeneration, atrophy and interstitial edema of skeletal epaxial muscles, and degeneration and atrophy of the gangliar neurons close to the myofibers. Chemical investigations showed a lower selenium concentration in affected animals, suggesting nutritional myopathy. Other manifestations were nephrocalcinosis and splenic vessel wall hyalinosis. Septicemia due to bacteria such as Aeromonas veronii, Shewanella putrefaciens, Citrobacter freundii, Chryseobacterium sp., and pigmented hyphae were found. No major sturgeon viral pathogens were detected by classical methods. Next-generation sequencing (NGS) analysis confirmed the absence of viral pathogens, with the exception of herpesvirus, at the order level, also, the presence of Aeromonas veronii and Shewanella putrefaciens was confirmed at the family level by the metagenomic classification of NGS data. In the absence of a primary yet undetected biological cause, it is supposed that environmental stressors, including nutritional imbalances, may have led to immune system impairment, facilitating the entry of opportunistic bacteria and mycotic hyphae.

Sperm density and performance of wild and farmed male European eels were evaluated to investigate the effect of maintenance in captivity on ejaculate quality. Hormonal stimulation (with human chorionic gonadotropin) lasted for 17 weeks. Different origins of the male European eels partially influenced the quality of the ejaculates. Indeed, wild animals (i.e., collected at a natural site) had greater sperm longevity during the hormonal stimulation, whereas there was no significant effect of the origin on sperm density, spermatocrit, the percentage of motile sperm, and plasma testosterone concentrations. The different origins of the males also affected fatty acid sperm content, with greater unsaturated fatty acid and omega-6 concentrations in wild eels and lesser concentrations of saturated fatty acids and omega-3 fatty acids in farmed eels. Regarding sperm quality of European eels, this is the first study that takes into account the effect of different origins of stimulated males (wild-caught compared with farmed) on sperm quality, and these findings may help to improve the production of high-quality gametes in this endangered species.

The reproductive performances of silver European eel in term of gonad development and egg production, employing slow-release implants with the androgen 17-MT (1Â mg) in combination with traditional weekly injection of carp pituitary extract (CPE) was evaluated. Wild female European eels (Anguilla anguilla) underwent a standard induction protocol with CPE and were randomly divided into three groups (N-group, no implant; Y-group, with implant; and control, C-group, no treatment). The results showed that 17-MT-treated females (Y-group) reproduced spontaneously about 6 weeks earlier than the N-group females with a saving of almost 40% in CPE and time of induction. Concerning artificial induction of maturation in female silver eels, our study demonstrated that they positively respond to androgen exposure also in terms of eggs productivity. Indeed, Y-group was more productive than N-group: in Y-group, 11 eels ensured an eggs production that exceeded 50% of initial body weight (BW), whereas in N-group only three eels have exceeded this value. The results suggest that 17-MT should be considered in future protocols for the improvement of the artificial reproduction of female silver European eels.

This study aimed to compare the fertility of eggs between artificially matured female silver eels that spawned spontaneously and those that were spawned by manual stripping. The effects of the two methods of spawning on ovulation and fertilization rate were also investigated. For this purpose, 18 wild female European els captured in Bonello lagoon (North Adriatic Sea) were carp pituitary extract-injected to undergo sexual maturation and ovulation; a final injection of 17,20b-dihydroxy-4-pregnen-3-one (DHP) was administered when at least 30% of the oocytes were fully transparent. After the DHP-injection, nine eels were transferred to a new closed recirculating aquaculture system, where they were housed with spermiating males (sex ratio 4/1) to allow spontaneous spawning (SPT-group); the remaining nine eels were transferred to a 250 L tank and ovulation was checked at four-hourly intervals by manual stripping (STR-group). The number of eggs per female in the SPT-group was significantly greater than that in the STRgroup. Furthermore, fertilization rates in the SPT-group were notably higher than those observed in the STR-group. Significantly, the best performances were obtained among eels in which at least 50% of oocytes were fully transparent at the time DHP was administered. We conclude that the fertility of eggs from spontaneously spawning eels is superior to that of eggs acquired by strip-spawning and artificial fertilization.

Enrofloxacin (EF) is a veterinary drug for respiratory, gastrointestinal and urinary tract infections. Parenteral administration at doses higher than the manufacturer recommended dosage has induced cartilage lesions in juvenile mammals and poultry. In elasmobranchs EF is commonly used for the treatment of infectious diseases, however only one study has been performed previously to evaluate pharmacokinetics and the potential chondrotoxicity of a fluoroquinolone in adult skates. In present study juvenile lesser spotted dogfish (Scyliorhinus canicula, Linnaeus, 1758) were treated with low (LD, 5 mg/kg) and high dose (HD, 10 mg/kg) of EF daily via intramuscular injection for 15 consecutive days, as indicated in a recognized treatment. Hematological parameters, oxidative stress and histology of vertebral cartilage were evaluated. No cartilage damage was observed. Hematological parameters evaluation underlined a significant (p = 0.035), dose-dependent reduction in red blood cell count and in hematocrit (40% and 6%, respectively). Anyway, the biological significance of this reduction is doubtful, due to limited decrease observed. The evaluation of oxidative stress parameters underlined that glutathione levels, as well as glutathione S-transferase and catalase activities, were significantly increased in HD group animals, with respect to untreated and solvent control groups. Obtained data do not support a toxic effect of EF on dogfish cartilage, while concern arises from hematological and oxidative stress data.

Inclusion of sustained-release androgen implants into fertility treatment regimes of female freshwater eels has been proposed to benefit artificial maturation outcomes. This study sought to test whether co-administration of the androgen 17-methyltestosterone (17-MT) in combination with ‘traditional’ hypophysation of female European silver eels would affect egg quality and subsequent larval survival. Implants, containing 1 mg 17-methyltestosterone (17α-methyl-4-androsten-17β-ol-3-one in a matrix of cholesterol:cellulose = 95:5), were administered twice, at 1 and 5 weeks after onset of experimentation (MTA- and MTB-groups); control eels (Ctrl) were given a blank implant. Female eels received weekly injections with carp pituitary homogenates (CPH) from either Week 1 (MTA- and Ctrl groups) or Week 5 onwards (MTB-group). First 4 injections were made with 10 mg CPH/kg body weight (BW) in sterile physiological saline (0.9% NaCl); the subsequent 12 injections with 30 mg/kg CPH and thereafter, 40 mg/kg CPH was injected until fish were considered ready for induction of final maturation. Bi-weekly blood samples were collected (Day 0 onwards) and analyzed for levels of testosterone (T) and estradiol-17β (E2) by radioimmunoassay. After reaching maturity, fertilized eggs were obtained upon spontaneous spawning of co-housed breeders and egg performance (fertilization, hatching, survival rates) was recorded. No differences were observed between eels from the MTA- and MTB-groups; however, egg performance was notably better in eels treated with 17-MT + CPH compared to eels receiving CPH only, with hatching rates reaching mean values as high as around 70% for both 17-MT and CPH co-treated groups, but only averaging 21.0 ± 8.4% for eggs from the Ctrl-group. Furthermore, 17-MT treated eels displayed a more distinct pre-spawning peak for levels of plasma T and E2 and for body weight, the latter being indicative of increased batch fecundity. We conclude that androgen co-treatment holds promise for future development of eel captive breeding technologies. Statement of relevance Artificial propagation of the European eel is increasingly urgent to release the strain on natural populations. This study presents a novel approach to artificial maturation of female eels: centered around the incorporation of androgens during fertility treatment. Accordingly, increased performance was observed in terms of fertilization, hatching and survival rates, which contributes to completing the life cycle of this fish in captivity. © 2017 Elsevier B.V.

This study aimed to set up a method for the long-term management of Adriatic sturgeon, through the analysis of sex steroids and the genetic profiling of individuals in order to maximize the already reduced genetic variability of this species. Ten A. naccarii adults (nine of captive origin, one captured in the Ticino river and then moved into captivity) and eight subadults located in a semi-natural land-locked pond in Abbiategrasso (Milan, Italy) were analysed. Plasma testosterone differed significantly in the eight analysed subadults allowing their differentiation into two groups: the first group with an average testosterone concentration of 5.42 ± 1.31 ng/ml (probably female) and the second group with an average of 423.14 ± 75.97 ng/ml (probably male), as subsequently confirmed by artificial stripping. The plasma testosterone level was also significantly different between adult males and females (371.37 ± 43.58 vs. 95.34 ± 51.10 ng/ml), while the E2 levels showed no significant differences. Animals were genotyped on the basis of 10 microsatellite loci and their parental relationships were defined: four adults, two females and two males, generated the eight subadults. On the basis of pedigree analyses and genetic distances, 15 unrelated couples were identified for the future breeding seasons. Finally, the adult female captured in the Ticino River showed an interesting genetic profile, widely different from all of the other 17 specimens analysed, and represents a valuable source of genetic diversity.

There is very little scientific literature about the impact of Eel virus European X (EVEX) on eels held under artificial reproduction condition, and its effective role in eel decline is uncertain and still unclear. Following a disease outbreak of European eels, farmed in an experimental hatchery in Italy, a sample of the affected animals was analyzed to determine the cause of illness. Virological isolation, PCR assay and molecular characterization revealed the presence of EVEX in the diseased animals. The complete N, P, M and G gene regions were amplified by using novel primers specific for EVEX. The EVEX strain identified in this study was phylogenetically close to the known EVEX isolates; however, this Italian isolate diverges and localizes in a separated branch of this cluster. In addition, some unique amino acid changes in three out of four analyzed viral proteins differentiated the Italian virus from reported EVEX sequences which, although few in number, do cover different geographical areas and a 30-year time span. Molecular data are needed to gain further insight into the genetic variability of EVEX, to better define its phylogenetic and evolutionary relationships and to unravel the existence of different circulating strains. Examination of samples caught in the same area failed to detect the presence of EVEX infection. These results strongly indicate that the presence and risk factors associated with EVEX infection are not well established and further study should be performed in this field, in particular on stress and temperature dependence for disease development.

The objective of the present study was to obtain spontaneous reproduction in captivity of the European eel ( Anguilla anguilla ) by using a new closed recirculating aquaculture system provided with spawning and incubation chambers. The influence of two levels of water-flow rates (Low-Flow: 0.8 ± 0.05 L/s and High-Flow: 2.4 ± 0.05 L/s) on the spawning, fecundity and egg quality was also investigated. For this purpose 12 silver eel females were induced with increasing doses of carp pituitary extract (10, 20, 30 and 40 mg CPE/kg BW). Twenty-four hours after the last CPE injection, each female ovulation was induced by injecting a DHP-solution and then transferring them to a new closed recirculating aquaculture system, where they were maintained for 16 h with spermiating males (sex ratio 4/1) in order to obtain spontaneous reproduction. The reproduction was tested with 6 females in Low-Flow rate conditions and 6 females in High-Flow rate conditions. The results showed that the designed closed-loop system made it possible to carry out a more spontaneous reproduction for more than 80% of the females that underwent standardized gonadotropic treatment and favored the automatic and complete transfer of the eggs to the hatchery. The results also point out that high or low water current conditions in the tank do not hinder the mating and the emission of gametes by the breeders, but the High-Flow rate in the two incubation chambers showed unsuitable hydrodynamic conditions for embryonic development resulting in a constant loss of viable eggs which reached a mortality of 100% among females with the highest incubation density.

Doctor fish (Garra rufa) have recently been used for aesthetic purposes and as a medical treatment in patients with psoriasis (ichthyotherapy). For this particular kind of human therapy it is essential to guarantee adequate hygienic conditions for both people and fish. The aim of this study was to test two concentrations of water disinfectants, chloramine T and peracetic acid, on Garra rufa to ascertain possible exposure damage to the epidermis and gills. Fish were exposed to 2 mg/l and 10 mg/l of chloramine T and to 15 μl/l and 45 μl/l of peracetic acid in a 40-minute static bath up to six times a day for one week. The epidermis and gills were checked for histological changes and the number of epidermal mucous cells, club cells and taste buds were quantified; mucous cells were also characterized histochemically to detect alterations in mucin production. No mortality or severe histological changes were found in treated or control fish. Cell count showed a significant increase (p

A trial was conducted to evaluate the growth performance and survival of common catfish, Ameiurus melas. A total of 54,420 catfish juveniles (5.1 ± 1.2 g; 6 ± 1 cm) were reared in two groups: PN group, represented by 3-1,000 m2 ponds; RC group composed by 3-2 m3 indoor tanks working in closed recirculated system. In these two groups, catfish were reared at two different densities (PN=15 fish m3 ; RC=1,570 fish m3 ) for 181 days. The main water physico-chemical parameters were monitored and the main blood metabolites and growth performances were evaluated. Catfish exhibited a final mean body weight similar in the two groups (PN=142.7 ± 30 g; RC=151.5 ± 34 g). The survival rate was high for both PN (86.6%) and RC (99%). A very high stocking density was reached in the RC system (235.5 kgm3 ). The presence of multi-trays in the RC tanks may be helped the specimens to reduce aggressiviness and territorial competition as demonstrated by blood metabolites which did not affect by rearing conditions. This trial showed that common catfish can be successfully cultured in indoor systems without negatively affecting productive performances (growth and survival) and the natural resources.

Florfenicol (FF) is employed in fish farms to contest or prevent bacterial infections. However, this pharmaceutical may produce reactive oxygen species that may cause biochemical changes in antibiotic-treated fish. The aim of this study was to evaluate the effect of FF on Rainbow Trout Oncorhynchus mykiss treated for 10 d with 7.5 and 15 mg/kg FF followed by a withdrawal period of 5 d. Superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, glyoxalase I and glyoxalase II, total glutathione, lactic dehydrogenase, and alkaline phosphatase were investigated in the livers of treated and untreated fish. A general impairment of antioxidant enzymes and metabolic indicators was measured in FF-treated Rainbow Trout. Onset of oxidative damage may have occurred during the antibiotic treatment as a consequence of the effect of FF toxicity at mainly the highest dose. Nevertheless, the rise in levels of total glutathione and glutathione S-transferase even after the withdrawal period may shield the antibiotic-mediated oxidative processes. Received December 22, 2015; accepted May 26, 2016.

This study evaluated the growth performance and survival rate of Anguilla anguilla glass eels reared in 4750 m2 earthen ponds and dependent on trophic resources provided by natural macrobenthic populations. Two ponds (M ponds) had mostly muddy-soil bottom whereas the other two (S ponds) had mostly sandy-soil bottom. A total of 4795 pigmented glass eels (0.73 ± 0.26 g) were stocked, at a density of 1.6 fish/m2 . After 360 days of growth, in S ponds eels exhibited a final mean body weight (15.57 ± 5.36 g) significantly higher than those seeded in M ponds (9.85 ± 4.11 g). Mean final length of S eels (21.55 ± 3.33 cm) was statistically higher than that of M eels (17.85 ± 2.42 cm). In M ponds, relatively higher abundances of Crustacea appeared to promote higher survival of glass eels in the post-seeding phase. Consequently, the relatively higher densities of eels in M ponds could have resulted in slower growth compared to eels in S ponds; however, eels grown in M ponds exhibited a significantly higher conditioning factor at the end of the growth period. We conclude that M ponds host highly viable macrobenthic prey populations that better sustain the early growth phases of A. anguilla . Furthermore, this study demonstrated that artificial feed supplements are not necessary for the rearing of A. anguilla juveniles in earthen ponds.

This study aimed to describe the response variability of females silver eels in terms of gonad development and eggs production to standardized gonadotropic treatment (Carp pituitary extracts -CPE), and to relate this variability to population characteristics. For this purpose, sexual maturation, ovulation and fertilization were induced in two eel populations coming from different locations in Adriatic Sea (Comacchio -CM and Marano-Grado -MG lagoons), and after that, their reproductive capacity was valuated. External (Silver index -SI, Eye index –EI, Pectoral fin length index –PFLI, Condition factor -K) and hormonal (17β-estradiol -E2, testosterone -T) parameters were measured and some subject/group were sacrificed for histological and lipid analysis and age determination. Morphometric parameters showed the CM-Group to have highest values of Body weight (BW), Body length (BL) and K, while MG-Group presented highest PFLI and Gonadosomatic index (GSI) values. Regarding hormonal analysis, the CM-Group showed significantly higher T and E2 levels than the MG-Group, both groups showed considerably rapid increase at T5 (5th injection). A positive trend in gonadal development was found through histological evaluation; a more regular maturation was observed in the MG-Group whereas the CM-Group presented an exponential oocytes development starting from T10 (10th week), which led to an anticipated spawning. Lipid content showed significant differences in T0 (start study), post-ovulation and Control (30th week) between CM and MG eels. As to zootechnical performances, while MG eels released spontaneously into the water the CM’s were stripped in order to check ovulation. The MG eels were statistically the most productive with 40.1±6.33% BW of eggs released. Furthermore CM females ovulated mainly between the 19th and 22nd week (77.8% spawned eels) instead in the MG’s ovulation goes from the 24th to the 28th week (100% spawned eels). As fertilization is of concern, in both groups fertilized eggs were obtained with no difference in larvae production. These results seem to indicate that bigger dimensions, higher K and larger lipid content (Comacchio eels) could fasten gonadic maturation without positively influence reproductive performance of animals, both in term of quantity and quality of produced eggs. Smaller females with a highest SI (Marano-Grado eels) presented a more regular gonadic development, leading the animals to spontaneous spawning

Nonylphenol, an estrogenic-like compound, can induce vitellogenin synthesis in males and immature Teleostean species, but little is known about its effects on thyroid hormones balance. The present study evaluated the potential effects of a single acute exposure to nonylphenol (i.p. injected) on the thyroid and reproductive axis of 250 shubunkins (Carassius auratus). Plasma levels of thyroid hormones were quantified immunoenzymatically by ELISA assay. Nonylphenol induced a significant decrease of thyroxin levels, whereas no effect on triiodothyronine concentrations was detected. No histopathological changes were detected in thyroid or testes. The toxicological data confirmed that nonylphenol exerts an estrogenic effect on male fish. In addition, nonylphenol was suspected to inhibit the thyroid hormones balance, suggesting the thyroid should be included among the other endocrine glands susceptible to endocrine disruption.

Summary Seabass (SBS) and seabream (SBM) juveniles were reared with the goal of obtaining three different final densities (SINT = 40 kg m−3; INT = 20 kg m−3; SEM = 0.2 kg m−3) to ascertain the effects thereof on the welfare of the fish. Significant blood metabolites and hepatic glycogen were determined every 3 months and at harvest. Trials lasted 18 months in seabass and 17 months in seabream. At the end of experiment the main biometric productive parameters and quality of body composition were also recorded. Regarding intensively reared seabass (SINT-SBS, INT-SBS), the plasma triglycerids, total cholesterol and transaminases (AST, ALT) were always significantly higher than in semi-intensively maintained fish (SEM-SBS). At the final sampling in the SINT-SBS batch, the total protein and glucose were also markedly increased. Conversely, at harvest the liver glycogen content decreased in SINT-SBS (34 ± 8 mg g−1 liver) with respect to INT-SBS (57 ± 12 mg g−1 liver) and SEM-SBS (63 ± 11 mg g−1 liver). No differences among groups were observed for creatine kinase (CK) and lactate dehydrogenase (LDH). With regard to seabream, SINT-SBM and INT-SBM constantly showed plasma triglycerids and total cholesterol as being significantly higher when compared to SEM-SBM. In the final two blood samplings, SINT-SBM exhibited the most elevated values for LDH. At harvest, AST, ALT, total protein and glucose markedly increased in SINT-SBM, whereas liver glycogen content was reduced (22.5 ± 9 mg g−1 liver), more than in INT-SBM (70 ± 16 mg g−1 liver) and SEM-SBM (75 ± 20 mg g−1 liver). In both seabass and seabream, body composition was very similar in the different stocking densities, except for total cholesterol. Total n-3 polyunsaturated fatty acid (PUFA) in seabream was significantly different from fish of the semi-intensive groups; however, nutritional values and fatty acid profiles were equally good. The intermediate final density of seabass and seabream at 20 kg m−3 seemed to give the best results in terms of their well being when compared to fish reared at 40 kg m−3. The absence of differences in blood metabolites and hepatic glycogen levels between the intensive batch and the semi-intensive groups until harvest was a reference to the positive status of the fish. A density of 20 kg m−3 can be considered acceptable for farm strategy planning for raising healthy on-growing seabass and seabream juveniles.

Growth performances of sunshine bass (initial m.b.w.=200±50 g) were examined in 3 different rearing conditions: concrete square basins (HSB-1); raceways (HSB-2); natural ponds (HSB-3). Fish received the same extruded feed (prot. 48.8%; lip. 17.8%). The trial lasted 16 months in HSB-1 and HSB-2 and only 12 months in HSB-3 due to unfavourable welfare status and low growth performances. At harvest (after 16 months), sunshine bass reached a satisfactory mean weight with- out significant differences between groups. HSB-2 fish were longer with a smaller circumference, prob- ably due to different hydrodynamics of the raceway. Glucose, cholesterol, triglycerides, protein, lactic dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), glycogen of plasma or tissue were not affected by rearing conditions as well as the proximate composition and the fatty acid profile of the fillet.

Summary Survival rate, sex ratio and zootechnical performances were evaluated on 168 kg of Anguilla anguilla elvers (0.45 gj weaned into three groups (Al, A2, A3) at initial densities of 800, 1600 and 3200g m-j, respectively. In order not to modify the sex ratio, animals weaned at the different densities were maintained separately during the trials, and no size grading was performed at the fattening phase. Final mean weight achieved by females belonging to the different groups showed no statistically significant differences; weight of males was higher (P < 0.05) in A1 than in A3 where a higher percentage of males was observed. Sex ratio of eels was different among the groups, with a higher percentage of males in A3 (96%) than in A2 (78%) or in Al (69%). This finding testifies to a sex differentiation strongly affected by pre-fattening stocking density of elvers. Final load showed an increase in males corresponding to a significantly reduced biomass between A1 and A2 (10.97 and 10.24kg m-3) and A3 (8.44kg m-3). Final survival rate ranged from 87% (Alj to 90% (A3). As to food conversion, a better rate was found in A1 (1.9:l) compared to A2 (2.1:l) and A3 (2.3:lj eels.

Two experiments were performed in an hatchery; in the first 520 sole larvae, average live weight (a.l.w.) 37 mg, 52 dah, were distributed among 8 net cages and fed two microdiets, for 55 days (d). Protein, fat, EPA contents were: 64.1 and 62.6; 21.9 and 18.5% on d.m.; 8.9 and 9.0% of fat respectively for diet A and B. Artemia enriched naupli (AEN) were distributed for 28 d, at 5 (1st week), 3 (2nd w.) and 2 units/ml (3rd and 4th ws.). In the secon trial 1040 sole larvae, a.l.w. 69 mg, 87 dah, were distributed among 16 net cages (4 replicates, diet A and B,8

European eels live most of their lives in freshwater until spawning migration to the Sargasso Sea. During seawater adaptation, eels modify their physiology, and their digestive system adapts to the new environment, drinking salt water to compensate for the continuous water loss. In that period, eels stop feeding until spawning. Thus, the eel represents a unique model to understand the adaptive changes of the enteric nervous system (ENS) to modified salinity and starvation. To this purpose, we assessed and compared the enteric neuronal density in the cranial portion of the intestine of freshwater eels (control), lagoon eels captured in brackish water before their migration to the Sargasso Sea (T0), and starved seawater eels hormonally induced to sexual maturity (T18; 18 weeks of starvation and treatment with standardized carp pituitary extract). Furthermore, we analyzed the modification of intestinal neuronal density of hormonally untreated eels during prolonged starvation (10 weeks) in seawater and freshwater. The density of myenteric (MP) and submucosal plexus (SMP) HuC/D-immunoreactive (Hu-IR) neurons was assessed in wholemount preparations and cryosections. The number of MP and SMP HuC/D-IR neurons progressively increased from the freshwater to the salty water habitat (control > T0 > T18; P < 0.05). Compared with freshwater eels, the number of MP and SMP HuC/ D-IR neurons significantly increased (P < 0.05) in the intestine of starved untreated salt water eels. In conclusion, high salinity evokes enteric neuroplasticity as indicated by the increasing number of HuC/D-IR MP and SMP neurons, a mechanism likely contributing to maintaining the body homeostasis of this fish in extreme conditions.

The Mediterranean toothcarp (Aphanius fasciatus) can be used to biologically control mosquito larvae. The reproductive performance of 234 Mediterranean toothcarp (180 females and 54 males) was investigated. Reproductive factors were determined in fish kept in fresh or saline water (males and females together), and in fish kept separately by sex in saline water and hormonallytreated with carp pituitary extract (CPE). In the hormonally-treated group, the combined effect of temperature, photoperiod, and hormonal treatment induced the best ovary maturation and larvae production rates. The rate of reproduction was very high (average eggs/female: 5.9-10.5) compared to natural reproduction in the wild (average eggs/female: 2-4). Additionally, the hatching rate was 97-100%. The results of this study show that reproduction of Mediterranean toothcarp can be controlled in an artificial environment: the lack of mortality in adults during acclimation and conditioning in fresh and marine waters indicates good domestication and plasticity in reproductive parameters. The IJA appears exclusively as a peer-reviewed on-line open-access journal at http://www.siamb.org.il. Only registered persons are able to access full papers. To register free of charge, complete and return our registration form.

The productive performances and morphological traits of 60 000 Dicentrarchus labrax L. weighing 2.4 ± 0.6 g and obtained from intensive rearing were compared with 60 000 sea bass of the same age (110-day-old) weighing 2.1 ± 0.7 g obtained from a fish farm using the mesocosm technique during the larval phase. The trial lasted throughout the fattening period until harvest. Fish from the mesocosm system (SB-II) had a better final survival rate (69%) in comparison to those obtained from the intensive larval system (64.2%) (SB-I). No significant differences emerged between the two groups concerning the specific growth rate (SGR) or the feed conversion ratio (FCR). Although the weights were the same as the SB-I group, the final total length result was higher in the SB-II group (P

Il Florfenicolo (FF), analogo fluorinato sintetico di Tiamfenicolo e Cloramfenicolo (CA), è un antibiotico ad ampio spettro molto utilizzato in acquacoltura. Nonostante la sua efficacia sia pari a quella del CA, rispetto a quest’ultimo, esercita una più bassa tossicità nei confronti dell’organismo sottoposto a terapia antibiotica, per l’assenza del nitrogruppo. Notoriamente gli antibiotici possono provocare fotosensibilizzazione: un eventuale effetto fototossico di questi composti è mediato, a livello cellulare, anche da una maggiore produzione di radicali liberi e radicali dell’ossigeno. L’aumento della concentrazione di radicali liberi può causare una condizione di stress ossidativo nell’organismo. Obiettivo è la valutazione di biomarkers di stress ossidativo, glutatione S-transferasi, glutatione reduttasi e concentrazione di glutatione totale, livelli residuali nel fegato e livelli dell’ormone tiroideo triiodotironina nel sangue di trota iridea alimentati per dieci giorni con due diete medicate con FF (7,5 e 15 mg/kg). La dose raccomandata per il florfenicolo in acquacoltura è 10 mg/kg per pesce per 10 giorni. Le due diete sperimentali sono state preparate a partire da un mangime commerciale per pesci di allevamento (controllo), a cui è stata aggiunta una premiscela commerciale di florfenicolo (Nuflor, 40 mg/g). Dopo l’acclimatazione, gli esemplari di trota iridea sono stati divisi in due gruppi sperimentali, di cui il primo esposto all’irradiazione di lampade solari per 12 ore al giorno, mentre l’altro è stato mantenuto in una condizione di costante ombreggiatura. Tra gli esemplari sottoposti a condizioni di irradiazione solare e quelli all’ombra, sono state evidenziate differenze di risposta sia per quanto riguarda i livelli residuali che per gli indici biochimici indagati. I livelli residuali erano più alti nelle trote mantenute in condizioni di irradiazione solare rispetto a quelle in condizioni di ombreggiatura. Livelli più bassi dell’ormone tiroideo T3 sono stati evidenziati nel gruppo trattato con un alto dosaggio di farmaco in condizioni di ombreggiamento ed in tutti e due i gruppi trattati con FF e mantenuti in condizioni di luce artificiale. La valutazione dei biomarkers di stress ossidativo ha indicato una più marcata condizione di stress ossidativo negli esemplari di trota iridea trattati con l’antibiotico e sottoposti ad irradiazione solare, come conseguenza di un potenziamento dell’effetto tossico dovuto all’azione combinata di ambedue i fattori. Infatti, sebbene l’effetto proossidante del FF, alle due dosi testate, sia stato evidente in ambedue i gruppi sperimentali, esso era più rilevante in condizioni di irradiazione solare, rispetto a quelle di costante ombreggiatura

Recentemente l’allevamento del mollusco gasteropode Haliotis tuberculata, abalone europeo, è stato intrapreso in Irlanda ed in Francia. In generale, le acque fredde proteggono questo mollusco dall’insorgenza di malattie batteriche e parassitarie, ma la colonizzazione della conchiglia da parte di policheti perforanti rappresenta un importante problema in grado di causare una riduzione del valore commerciale e degli indici di crescita. Nel corso di questo studio, condotto in Bretagna su animali allevati con differenti tecniche, si è dimostrato che l’età ed il sistema d’allevamento sono importanti fattori che influenzano l’intensità della infestazione. I policheti raccolti dagli abaloni appartenevano a due diverse famiglie: Spionidae, come già descritto in precedenti studi (Clavier, 1992) e Sabellidae, qui riportata per la prima volta nell’abalone europeo. Gli studi morfologici hanno indicato che i policheti Spionidae appartenevano a diverse specie dei generi Polydora/Boccardia. Sebbene non sia stato possibile condurre mediante osservazione morfologica l’identificazione tassonomica dei Sabellidae a livello di genere e specie, almeno due distinte specie erano presenti. La prevalenza e l’intensità dei Sabellidi era molto bassa, ma un solo esemplare era in grado di causare lesioni della conchiglia molto gravi. I risultati di questo studio hanno mostrato come la prevalenza sia positivamente correlata all’età dell’ospite e come il sistema d’allevamento possa influenzare fortemente l’intensità d’infestazione dei policheti perforanti: molto bassa negli allevamenti a terra, dove l’acqua viene filtrata e le procedure igieniche vengono applicate routinariamente alle vasche e più elevata in maricoltura, in particolare se condotta in policoltura ed in aree a basso ricambio idrico, con crescita rallentata e performance produttive ridotte.

Artificial reproduction in eels is very challenging due to their peculiar life cycle. No information is yet available on the influence of photoperiod on the sexual development of wild silver eels in captivity. Previous studies have demonstrated the photoperiod to influence sexual maturation of eels showing that dark conditions lead to a better reproductive performance in terms of a greater gonadal maturation and a higher egg production and spawning record. This study aimed to investigate the physiological mechanisms leading to different outcomes in light or dark conditions on the gonadal steroidogenesis in wild female European silver eels during pituitary extract treatment. The variation of the body weight index and gonadosomatic index suggested a positive effect in dark conditions. Sexual steroids (androgens and estrogens) showed a significant difference in plasmatic concentration in the animals kept in the dark suggesting a better wellness reproductive situation in this particular housing condition.