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The present research focuses on the seasonal changes in the energy content and metabolic patterns of red porgy (Pagrus pagrus) sampled in a fish farm in North Evoikos Gulf (Greece). The study was designed in an effort to evaluate the influence of seasonality in several physiological feauteres of high commercial importance that may affect feed intake and growth. We determined glycogen, lipids and proteins levels, and cellular energy allocation (CEA) as a valuable marker of exposure to stress, which integrates available energy (Ea) and energy consumption (Ec). Metabolic patterns and aerobic oxidation potential were based on the determination of g lucose transporter (GLU), carnitine transporter (CTP), L-lactate dehydrogenase (L-LDH), citrate synthase (CS), cytochrome C oxidase subunit IV isoform 1 (COX1) and 3-hydroxyacyl CoA dehydrogenase (HOAD) relative gene expression. To integrate metabolic patterns and gene expression, L-LDH, CS, COX and HOAD activities were also determined. For further estimation of biological stores oxidized during seasonal acclimatization, we determined the blood levels of glucose, lipids and lactate. The results indicated seasonal changes in energy content, different patterns in gene expression and reorganization of metabolic patterns during cool acclimatization with increased lipid oxidation. During warm acclimatization, however, energy consumption was mostly based on carbohydrates oxidation. The decrease of E c and COX1 activity in the warm exposed heart seem to be consistent with the OCLTT hypothesis, suggesting that the heart may be one of the first organs to be limited during seasonal warming. Overall, this study has profiled changes in energetics and metabolic patterns occurring at annual temperatures at which P. pagrus is currently farmed, suggesting that this species is living at the upper edge of their thermal window, at least during summer. [Display omitted] • Pagrus pagrus growth is strongly dependent on sea-water temperature. • Lower feed intake and growth rate were observed in P. pagrus during cold acclimatization. • Protein mobilization in metabolism and energy provision was also observed in winter. • Optimal temperatures for P. pagrus physiological processes are 20oC–22 °C. • White muscle energy after winter recovery is associated with carbohydrate stores. [ABSTRACT FROM AUTHOR]

[Display omitted] • Red seabream faces origin labeling issues after the Fukushima disaster. • We aimed to develop biomarkers to discriminate between Japanese and Korean seabream. • We used fatty acids, amino acids, minerals analysis to determine the origin of fish. • We analyzed 29 fatty acid families, 17 amino acids, and 4 minerals in 60 samples. • Among the top 10 distinct fatty acids, linoleic acid emerged as a precise biomarker. Red seabream (Pagrus major) has been one of the most popular fish in East Asia since early times. However, the discharge of nuclear wastewater into the sea following the Fukushima nuclear disaster in Japan has led to violations of the country of origin labeling. Therefore, the aim of the present study was to determine the origin of fish based on fatty acid, amino acid, and mineral analyses, and to develop biomarkers that can discriminate between Japanese and Korean red seabream. To identify the differences between the two groups, 29 fatty acid families, 17 amino acids, and 4 minerals were analyzed in 60 fish samples (standard sample collected in autumn), and fatty acid profiles were analyzed using heatmap with hierarchical clustering analysis and orthogonal projections to latent structures discriminant analysis. The top 10 fatty acids that were different between the two groups were selected from all seasonal fish samples by combining variable importance in projection scores and p-values. According to the receiver operating characteristic curve analysis results, we proposed percentage linoleic acid (C18:2n-6, cis) as a candidate biomarker with excellent sensitivity and specificity. This study introduces a strategy to identify the origins of red seabream using linoleic acid obtained from fatty acid analysis. [ABSTRACT FROM AUTHOR]

To assess the impact of sand mining on resource utilization by the red seabream (Pagrus major) and the trophic structure of fish assemblages two years after mining activities, we compared stable isotope ratios (δ13C and δ15N) and isotopic niches between aggregated mining and control sites in April and August 2022. Our results showed no spatial differences in the δ13C and δ15N values of red seabream between the sand mining and control sites, suggesting that the mining did not affect their dietary resources. Furthermore, the considerable overlap among fish consumers suggested that the fish food web in mining areas has trophic functions similar to those in natural habitats after mining activities. Overall, our study enhances our understanding of ecosystem conservation and the ecological-based management of coastal areas. • Impact of sand mining on resource use by red seabream was assessed. • Isotope values of red seabream did not differ between mining and control sites. • Substantial isotopic overlap of fishes was observed between mining and control sites. • These data suggest trophic recovery of marine ecosystem post-mining. [ABSTRACT FROM AUTHOR]

• Korean and Japanese red seabream metabolites were evaluated using LC-Orbitrap MS. • 12 and 19 metabolites for discriminating between regions were detected. • Anserine is a candidate biomarker for discrimination different origins. Red seabream (Pagrus major) is widely consumed in East Asia. As nuclear wastewater is discharged into Japanese waterbodies, the country of origin of marine products must be accurately labeled. Here, we aimed to discover candidate metabolite biomarkers to discriminate between Korean and Japanese red seabream using LC-Orbitrap mass spectrometry. In total, 95 and 138 putative metabolites were detected via chromatographic separation of fish sampled in the warm and cold seasons, respectively. The spectrometric and chromatographic data were analyzed using principal component analysis and orthogonal partial least squares discriminant analysis. We identified 12 and 19 influential metabolites to discriminate between each origin fish in the warm and cold seasons, respectively, using variable importance in projection scores and p values. Anserine was further selected as a candidate biomarker based on receiver operating characteristic curve analysis. This study provides a basis for using anserine to determine the geographic origin of red seabream. [ABSTRACT FROM AUTHOR]

Although aquaculture industry has made great efforts to reduce the levels of fish meal (FM) in aquaculture feeds, further efforts and investigations are still needed to increase aquaculture production, which has more than tripled in the last two decades. This study was implemented to Six replicate groups of fish (24.6 ± 0.1 g) were fed one of the experimental diets to apparent satiety twice daily for 15 weeks; half of them were subjected to a daily net chasing stress for 1 min in the morning, 1 h before feeding. At the end of the feeding trial, fish were challenged with Edwarselia tarda injection. LFM diet resulted in comparable growth and feed efficiency performance to HFM group. However, significant impairments were observed in apparent digestibility coefficients, condition factor, hematocrit and serum super oxide dismutase activity. Fish fed LFM showed much lower resistance to E. tarda challenge. Both TH and SH resulted in enhanced fish nutritional and health performance with significant improvements in growth performance, feed efficiencies, digestibility, serum non-specific immunity and gut morphometric parameters. Fish fed TH and SH also exhibited the highest survival after E. tarda challenge. Principal component analysis (PCA) showed significant differences between stress and dietary groups for dimension 1 (33.3% of the variability), which was mostly characterized by growth and health variables. SH and TH coordinates were significantly higher on dimension 1 compared to HFM and LFM ones. Daily repeated stress affected most of measured performance parameters of all dietary groups with very few interactions. The stressed fish groups fed TH or SH showed lower cortisol levels compared to those fed HFM and LFM (p < 0.01). Strong correlations were observed between feed efficiency and fish gut morphometrics as quantified by villi length, enterocyte height and goblet cell density. Dietary supplementation of aquatic protein hydrolysates such as TH and SH appeared to be essential for maintaining good fish performance when they were subjected to a daily husbandry stressor or to an infectious challenge. • FM reduction may result in an impaired fish health status despite good growth • APH mitigate stress adverse effects • APH help to reduce FM and antibiotic uses [ABSTRACT FROM AUTHOR]

Dietary intake of a large amount of soybean meal (SBM) adversely affects the physiological condition and growth of fish, while SBM is a commonly used substitute for fish meal (FM) in aquaculture feed. In the present study, we investigated the effects of feeding an SBM-based diet (SBMD) for 8 weeks on hepatopancreatic metabolic condition in red seabream Pagrus major , using comprehensive analyses of the transcriptome and metabolome. Compared with fish fed an FM-based control diet (FMD), fish fed the SBMD showed delayed growth, decreases in hepatopancreatic somatic index and serum cholesterol concentration, and hepatopancreatic tissue degeneration. Transcriptome sequencing analysis identified 454, 353, and 566 differentially expressed genes at 2, 4, and 8 weeks, respectively. Analysis of the hepatopancreas metabolome using capillary electrophoresis-time-of-flight mass spectrometry identified 301 quantifiable metabolites in the FMD and SBMD groups. Transcriptome analysis showed increases in gene expression levels in the terpenoid and steroid biosynthesis pathways, suggesting that hepatic cholesterol biosynthesis was up-regulated in the SBMD group. In addition, the results of transcriptome and metabolome analyses suggested that the SBMD affects glutathione and glycine metabolism. These findings provide valuable information that enhances our understanding of the effects of dietary SBM intake on red seabream metabolism. • Red seabream were fed a soybean meal–based diet (SBMD) for 8 weeks. • Fish fed SBMD showed delayed growth and several physiological abnormalities. • The results of omics analyses suggest SBMD affects cholesterol metabolism. • Hepatic glutathione and glycine metabolism were also affected by SBMD feeding. [ABSTRACT FROM AUTHOR]

We compared the secretion of antimicrobial peptides (AMPs) in the epidermal mucus of three healthy fish species: two aquacultured teleost species, Dicentrarchus labrax and Sparus aurata , and one wild-caught species, Pagrus pagrus. The AMPs detected in all mucus by LC-MS/MS-QTOF are: Chrysophsin-1, -2 and -3, Piscidins −1, −2, −3 and −4, terminal Histone parts and Hepcidin-like peptides. Secretion analysis of the mucus from aquacultured fish using ProGenesis IQ software distinguished the bactericidal activities of histone peptides and probiotic flora from those of other AMPs. Chrysophsin-1 was statistically the most abundant peptide in both mucus samples (p < 0.0035). A lower detection of Piscidins was also observed. Interestingly, the presence of Oncorhyncin I was most pronounced in Sparus aurata mucus. Altogether, these results suggest that Chrysophsin-1 and Oncorhyncin I are potential biomarkers for immunodetection-based studies of changes in secretion patterns which will be further investigated during bacterial challenge. [Display omitted] • Standardization of purification and quantification protocols allows comparison of AMP secretion levels. • Wild Pagrus pagrus mucus has an effective natural antibacterial activity. • Progenesis IQ-based LC-MS-MS data analysis highlights Chrysophsins and Oncorhyncin I as potent biomarkers. • Farmed fish AMPs are key elements in differential study of secreted patterns. [ABSTRACT FROM AUTHOR]

To clarify the effects of dietary soybean meal (SBM) on the digestive physiology of red seabream Pagrus major , two isonitrogenous and isolipidic diets; a fishmeal-based diet (diet FM) and a SBM-based diet (diet SBM), were prepared and the acute and chronic effects of the diets on the digestive physiology of the fish were examined. In the acute effects trial (<48 h), the only difference observed was a lower level of trypsin activity in the intestinal content of the SBM group than the FM group, indicating that SBM administration reduces trypsin secretion on a short-term basis. In the chronic effects trial (six weeks), there were clear differences in several parameters assessed. There was a clear retardation of growth in fish fed the SBM diet, in addition to a faster gastric transit rate, stacked intestinal content, lower gallbladder weight, lower activities/gene expression levels of hepatopancreatic enzymes (trypsin, chymotrypsin, amylase and/or lipase) and reduced protease activity (trypsin and chymotrypsin) in the intestinal content compared to fish fed the FM diet. Taken together, these results indicate that feeding SBM over a long period (chronic exposure) leads to reduced storage, production and secretion of bile and pancreatic digestive enzymes. SBM protein does not appear to fully activate or stimulate the digestive system of red seabream in either the short or long term. This may be due to a lack of stimulation or to an inhibitory effect that becomes more pronounced on a long-term basis. Such inhibition of the digestive process may be one of the main reasons for the low growth performance observed in fish fed SBM-based diets. [ABSTRACT FROM AUTHOR]

We evaluated the effects of long-term feeding of a fishmeal-free (FMF) diet on the growth parameters and physiological status, especially the bile acid status, of red sea bream (Pagrus major) yearlings. Two isonitrogenous and isolipidic diets were prepared; a fishmeal-based diet as the control, and an FMF diet containing soybean meal, corn gluten meal, soy protein concentrate, and pea protein concentrate as plant-derived ingredients, and poultry by-product meal and feather meal as animal-derived ingredients. Six hundred red sea bream yearlings were accommodated in six net cages, and the two experimental diets were hand-fed for 36 weeks. Throughout the 36-week trial, mean body weight and feed intake were significantly lower in the FMF group than in the control group. The concentrations of serum total cholesterol and high-density lipoprotein cholesterol were also significantly lower in the FMF group than in the control group throughout the trial. The total bile acid amount per fish was significantly lower in the FMF group than in the control group between Week 32 and 36 when the water temperature was the lowest (14.3–17.2 °C). Gene expression levels of hepatic cyp7a1 and cyp8b1 tended to be lower in the FMF group than in the control group from Week 20 to the end of the trial. Expression levels of hepatic sqle were higher in the FMF group than in the control group through the trial period and were markedly high at Week 36. Expression of hmgcr was also higher in the FMF group than in the control group at Week 32 and 36. The hindgut asbt expression of fish fed the FMF diet was lower than those fed the control diet at Week 28 and 32. These results suggest that the long-term feeding of an FMF diet to red sea bream yearlings causes reduced growth due to a significant reduction in feed intake and bile acid production, and enterohepatic circulation are strongly disturbed when water temperatures are low from autumn to winter. • Fishmeal-free and fishmeal-based diets were fed to red sea bream yearlings for 36 weeks. • Mean body weight and feed intake were significantly reduced when fed an FMF diet. • FMF diet decreased bile synthesis genes and increased cholesterol synthesis genes • This change was via causing cholesterol shortage under the low water temperature • Adverse effects were attributed to disruption of the enterohepatic circulation of bile acid. [ABSTRACT FROM AUTHOR]

In order to study the effects of dietary β-glucan (BG), vitamin C (VC) and their combination (BG/VC) on growth, humoral and mucosal immune responses of red sea bream ( Pagrus major ) and its resistance to low water salinity stress, 240 healthy fish with initial body weight of 1.98 ± 0.01 g were randomly divided into four groups: a control group fed with basal diet and three treated groups fed with basal diets supplemented with 1000 mg kg − 1 BG, 800 mg kg − 1 VC, and the combination of 500 mg kg − 1 BG + 400 mg kg − 1 VC, respectively. The obtained results showed that, compared with the control, the final body weight, weight gain and specific growth rate, feed and protein efficiency ratio, body protein content, nitro blue tetrazolium (NBT), total serum protein and tolerance against low salinity stress increased in fish fed BG or/and VC supplementations with the highest being in fish fed both BG and VC supplements while body moisture content, plasma glucose, triglyceride and malondialdehyde (MDA) contents decreased ( P < 0.05); body lipid content, hematocrit, serum and mucus lysozyme activities, superoxide dismutase (SOD), alternative complement pathway and mucus secretion also significantly increased in fish fed BG and VC supplements ( P < 0.05). Moreover, the fish fed BG diet had better improvement ( P < 0.05) in mucus bactericidal activity than the VC group. Furthermore, fish fed BG diet exhibited higher serum peroxidase activity (PA), however, fish fed VC diet showed higher mucus PA than the control group ( P < 0.05). Thus, the basal diet supplemented with BG or/and VC could promote the growth, antioxidant capacity, humoral and mucosal immune responses of red sea bream, and enhance the resistance to low salinity stress. Statement of relevance A combination of β-glucan and vitamin C presented an additive effect on inducing the growth, immune responses and oxidative status of red sea bream. We recommend that treatment of 500 mg of β-glucan and 400 mg of vitamin C per kg diet is the appropriate concentration of inducing the red sea bream immune response. [ABSTRACT FROM AUTHOR]

Physiological stress patterns of marine organisms in their natural habitats are considerably complex in space and time. These patterns can eventually contribute in the shaping of fish' thermal limits under natural conditions. In the view of the knowledge gap regarding red porgy's thermal physiology, in combination with the characterization of the Mediterranean Sea as a climate change "hotspot", the aim of the present study was to investigate this species biochemical responses to constantly changing field conditions. To achieve this goal, Heat Shock Response (HSR), MAPKs pathway, autophagy, apoptosis, lipid peroxidation and antioxidant defense were estimated and exhibited a seasonal pattern. In general, all the examined biochemical indicators expressed high levels parallel to the increasing seawater temperature in spring, although several bio-indicators have shown increased levels when fish were cold-acclimatized. Similar to other sparids, the observed patterns of physiological responses in red porgy may support the concept of eurythermy. [Display omitted] • Physiological stress patterns in nature are far more complex in space and time. • Biochemical indicators expressed high levels with increasing sea temperature. • Several bio-indicators increased their levels in cold-acclimatized fish. • Physiological responses in red porgy may support the concept of eurythermy. [ABSTRACT FROM AUTHOR]

The viral infectious disease called viral nervous necrosis (VNN) or viral encephalopathy and retinopathy (VER) is a particularly lethal virus for larvae and juvenile fish, and seven genotypes have been reported thus far. These viruses are capable of both vertical and horizontal transmission. In this study, molecular biological and histopathological analyses were performed to determine the cause of mass mortality in juvenile Pacific cod (Gadus macrocephalus), which began to feed on red seabream (Pagrus major) eggs. Vacuolization, one of the characteristic symptoms of VNN, was confirmed in the brain and eyes of brood red seabream (P. major) and juvenile Pacific cod (G. macrocephalus). In addition, the inclusion body-like structure was confirmed in the electron microscopic analysis of the gonads and eggs of brood red seabream (P. major). In molecular biological analysis, the target bands were also found in the brain, kidney, liver, spleen, gonad (P. major brood only), and egg (P. major brood only). This vertical/horizontal interspecies transmission needs to be controlled with particular care when producing seedlings, considering that seedlings can be produced for release for the creation or recovery of aquatic resources in addition to aquaculture. • Viral nervous necrosis (VNN) is known as capable of vertical and interspecies transmission. • On the 56th day, all the juvenile Pacific cod that were fed NNV-infected eggs of red seabream brood died within two weeks. • Nervous necrosis virus (NNV) was confirmed in histopathological and molecular biological analysis of all samples. • The result reported in this study reveals that it is critical for breeders to observe broodstock consciously and carefully. [ABSTRACT FROM AUTHOR]

Histone H1 acts as an essential chromatin component and participates in the formation of higher chromatin structures together with core histones. In addition, H1 also has important functions in physiological processes such as gene expression regulation, DNA repair, and the immune response. In this study, the histone homologous protein Pm-H1.2-like was identified from the transcriptome database of Pagrus major we studied previously. Conservatism of evolution was investigated by sequence alignment and phylogenetic analysis. Transcripts of Pm-H1.2-like were detected in P. major tissues. The highest expression level was found in gill and skin tissues. Consistent with the data from the transcriptome database, we observed that the expression of Pm-H1.2-like was rapidly induced in nonspecific cytotoxic cells (NCCs) infected with inactivated Vibrio anguillarum. Gene silencing of Pm-H1.2-like by RNAi significantly suppressed the expression of NK-lysin and GZMB in NCCs at 12 h after pathogen stimulation, but had no significant effect on IFN-γ expression. Next, we obtained the fusion proteins rPm-H1.2-like and rPm-H1.2-like (36–80) through prokaryotic expression. ELISA showed that rPm-H1.2-like bound to oligonucleotide (ODN) in a concentration-dependent manner, while no binding activity of rPm-H1.2-like (36–80) with ODN was observed. This study confirmed that Pm-H1.2-like actively participates in the immune response of NCCs to bacterial infection, deepening the understanding of the immune features of histone H1 in fish. • Histone H1 homologous protein Pm-H1.2-like was identified in Pagrus major. • RNAi of Pm-H1.2-like suppressed the expression of NK-lysin and GZMB but not IFN-γ. • rPm-H1.2-like but not rPm-H1.2-like (36–80) could bind to OND. [ABSTRACT FROM AUTHOR]

Juvenile Pagrus major (mean length 15.8 ± 1.6 cm, and mean weight 90.4 ± 4.7 g) were exposed for 4 weeks with waterborne selenium concentration (0, 50, 100, 200, and 400 μg L −1 ). In oxidative stress indicators, liver and gill superoxide dismutase (SOD) activity and glutathione S-transferase (GST) activity were markedly elevated after 4 weeks exposure. Similarly, glutathione (GSH) level in liver and gill was also increased in response to the highest Se exposure after 4 weeks exposure. In neurotoxicity, AChE activity was inhibited in brain and muscle tissues by waterborne Se exposure. In the non-specific immune responses, lysozyme activity of plasma and kidney was significantly increased by waterborne Se exposure. Peroxidase activity and anti-protease activity were decreased at high Se concentration. The results suggest that waterborne Se exposure can induce significant oxidative stress, inhibition of AChE activity, and immunological alterations. [ABSTRACT FROM AUTHOR]

Snapper ( Pagrus auratus ) is harvested extensively by recreational anglers in New Zealand and Australia but knowledge of discard mortality and sub-lethal stress is essential for sustainable and effective fisheries management. While it has been established that anatomical hooking location (gut hooking) is a cause of mortality less is known about the sub-lethal and lethal impacts of angling among the majority of the recreational catch which are not gut hooked and discarded in apparently good condition. Laboratory based trials were therefore performed during winter (14 °C–16 °C) and summer (20 °C–22 °C) where sub-legal P. auratus were exposed to simulated angling as graded levels of strenuous exercise (manual chasing) and air exposure. Following simulated angling fish either had physiological stress assessed (N = 160), or were monitored for mortality over 20 days (N = 180). The post-stress condition of all fish was also assessed by reflex impairment (RI) which may be a useful predictor of discard mortality. A physiological stress response was apparent in all fish exposed to simulated angling, but was only correlated with the duration of chasing and appeared to be more severe in summer. RI was also apparent and was significantly related to both the duration of chasing and air exposure. RI also correlated with some measures of physiological stress, in particular those related to exhaustive exercise stress (muscle pH and plasma lactate). Despite increased RI and physiological stress, only two fish monitored for mortality died. The findings of this study suggest that sub-legal P. auratus are able to recover from the physiological disturbances resulting from strenuous exercise and air exposure imposed during angling. Anglers, however, should avoid extended playing times and minimise air exposure in order to reduce sub-lethal physiological stress and RI in released fish. RI was correlated with the intensity of capture stress and some indices of physiological stress, and may therefore provide a simple and non-invasive method of measuring fish vitality in field studies. [ABSTRACT FROM AUTHOR]

Oxytetracycline (OTC) is a widely used antibiotic in aquaculture. In this study, red seabream (Pagrus major), the most popular aquaculture species in Japan, were treated with OTC mimicking a real administration scenario in aquaculture. The treatment groups were as follows: no OTC, 40 mg/kg body wt/day (equivalent to the dose used in actual aquaculture), or 178 mg/kg body wt/day. The first exposure was conducted for a week (1st OTC exposure period), followed by a 4-week interval, and the second exposure was for one week (2nd OTC exposure period). We investigated the effects of OTC on the liver proteome with the isobaric tags for relative and absolute quantitation (iTRAQ) technology accompanied by liquid chromatography and mass spectrometry. The pathway and disease enrichment analyses of differentially abundant proteins in OTC-exposed groups compared to their respective controls showed that the abundance of proteins related to the immune and nervous systems was altered after the 1st and 2nd OTC exposures, respectively. Quantitative real-time PCR of the transcripts of immune-related genes corroborated with the results of proteome analysis. OTC exposure also modulated the expression of metabolism-related proteins after the 1st and 2nd OTC exposures. Furthermore, after four weeks of the 2nd exposure, weight loss and changes in the expression of proteins related to metabolism were observed, suggesting that OTC exposure disrupts the metabolic system and causes growth inhibition. Based on these results, we suggest that the use of OTC in aquaculture poses a health risk in fish species. Thus, we need to pay more attention to the contamination with OTC in aquaculture. [Display omitted] • Effects of oxytetracycline (OTC) exposure on red seabreams were investigated. • OTC exposure mimicked a real administration scenario. • Hepatic proteome was analyzed 1 day and 4 weeks after OTC exposure. • Proteins related to immune, metabolic, and neuronal systems were affected. • Alterations in the hepatic proteome by OTC may account for growth inhibition. [ABSTRACT FROM AUTHOR]

Various host characteristics (i. e., feeding habits, geographic distribution) and habitat characteristics (i.e., seasonality) influence the structure of parasite assemblages. To compare the parasite assemblages of hosts representatives of two genera of the same fish family, simultaneously occupying a geographic region, and to examine if seasonal variations influence parasite occurrence and abundance, we examined the parasite assemblages of two sympatric marine fish, Pagrus pagrus (n = 308) and Pagellus bogaraveo (n = 315) off the coast of Algeria in the western Mediterranean. Specimens were collected during summer and autumn over three consecutive years (2014–2016). Parasite assemblages were high in species richness and abundance. We compiled an inventory of 40 parasite taxa, including ectoparasitic monogeneans and crustaceans, and endoparasitic trematodes, cestodes, acanthocephalans, and nematodes. Endoparasite taxa primarily consisted of adult gastro-intestinal parasites and long lived larval helminths. Information on the parasite community structure and seasonal variations in parasite populations of these two hosts from the Mediterranean is here provided. Observed patterns of composition, diversity, dominance, and similarity indicate an overall consistency in assemblage structure. Although each host species harbored distinct parasite communities, they shared a high proportion of parasite species suggesting similar use of a common local pool of parasites. However, most shared species did not contribute to structuring the assemblages. Seasonal patterns in parasite abundance were observed for both hosts, with peak prevalence, abundance, and diversity in autumn. Results suggest that, regardless of a common pool of parasites being available to sympatric species, several ecological filters over time, led to distinct, independent variations in the parasite assemblages in each species. Shade plot illustrating the abundances of parasite 28 taxa in each single host Pagellus bogaraveo (above) and 29 taxa in P. pagrus (below), presented separately for each season. The intensity of color shading of entry rectangles indicate the species abundance. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: A study was conducted to determine the effects of dietary oxidized fish oil (OFO) and vitamin E (VE) supplementation on growth and reduction of oxidative stress in juvenile red sea bream. An 8-week feeding trial on juveniles (average weight of 1.8g) was conducted in triplicate groups with test diets containing two degrees of OFO (83.8 and 159.0meq/kg) supplement with three levels of VE (0, 100 and 200ppm), respectively. Fresh fish oil (13.5meq/kg) with supplementation of 100ppm VE was employed as control group. No significant differences were found on growth performance between fish fed with 100 or 200ppm VE supplemented groups and control group. However, fish fed without VE supplement diets indicated significantly lower growth than control group. Increased dietary VE levels led to reduce liver thiobarbituric acid reactive substances value, while the highest value was observed in fish fed high OFO without VE supplemented diets. Liver vitamin C concentrations increased with increasing dietary VE levels. In conclusion, the results demonstrated that dietary OFO increased the oxidative stress condition of fish, but supplement of more than 100mg/kg VE may prevent tissues from lipid oxidation, and improve growth and health of juvenile red sea bream. [Copyright &y& Elsevier]

Abstract: Characterization of the muscle tissue proteome is key to many aspects of fish aquaculture, encompassing physiology, growth, food safety, seafood authentication and quality, traceability and shelf-life. In this study, a 2D-PAGE-MS study was performed on gilthead sea bream (Sparus aurata, L.) muscle tissue along the production cycle in four offshore floating cage plants and two repopulation lagoons located in different areas of Sardinia, Italy. The aim of this study was to accomplish systematic characterization of the gilthead sea bream muscle proteome, and to gather data about its variability in physiological conditions occurring in both farmed and wild fish. In general, a relatively stable protein expression pattern was observed in farmed sea bream muscle compared to other more dynamic tissue proteomes, such as liver. However, several statistically significant variations in abundance of some proteins and their isoforms were detected, related to growth and environmental factors. Among these, parvalbumins, troponins, and Wap65 showed variations according to fish length and water temperature. Interestingly, the ratio of structural proteins versus glycolytic enzymes was also observed to change during the production cycle, showing an increase with fish length. In order to assess whether the farming conditions were able to induce alterations in the muscle proteome, farmed and wild fish were subjected to a differential proteomics analysis. The data gathered in this study indicate that the protein expression profile of muscle tissue is comparable in wild and maricultured gilthead sea breams of commercial size, supporting the view that farming in offshore floating cages might favor proper muscle tissue development, and therefore enable the production of higher quality fish. In conclusion, this work describes the detailed characterization of the sea bream muscle proteome, and provides a number of insights on its size and environment-related variability. [ABSTRACT FROM AUTHOR]

Abstract: A feeding trial was conducted to improve the nutritional quality of low FM diets by supplementing crude ingredients. Seven isonitrogenous (50% crude protein), isolipidic (12.5% total lipid) and isocaloric (22KJ/g gross energy) test diets were formulated, where diet 1 was a FM based control diet (FM), and diets 2 to 7 were prepared by replacing 60% FM protein (24% FM contents) as follows: soybean protein concentrate (SPC) alone (SP); SPC with 2.5% crystalline amino acids (CAA) (SPAA); SPC with 10% fish soluble (FS) (SPFS); SPC with 10% krill meal (KM) (SPKM); SPC with 10% squid meal (SM) (SPSM) and SPC with a mixture (total 15%) of FS, KM and SM each at 5%, respectively (SPMX). Triplicate groups of fish (average initial weight 0.82±0.01g) were randomly stocked in 21 100-l polycarbonate tanks at a stocking density of 15 fish per tank. The fish were fed to satiation by hand twice daily, 7days per week for a period of 50days. Results showed that weight gain (%) and specific growth rate (SGR) of fish were both significantly lower in fish fed SP, but those parameters recovered when fed diets with supplementation of ingredients used in the study. The fastest growth was found in fish fed SPMX, followed by SPFS, whose values were not significantly different (P >0.05) from each other, and those groups grew significantly faster than FM. However, no difference was found among FM, KM and SM groups. The growth results were mostly reflected in feed intake (FI). Similarly, feed efficiency ratio, protein efficiency ratio and protein retention (% of intake) were also significantly decreased in fish fed SP while no difference was detected between those fed FM and the rest. Therefore, this study demonstrates that the dietary amino acids were balanced by supplementation of FS, KM and SM, and those would have acted as feeding stimulants. Whole body proximate compositions were not markedly influenced by the dietary treatments. No difference was found in the digestive tract and liver protease activity among treatments. Blood parameters showed that the physiological condition of fish fed SP was significantly depleted, but it was recovered with the supplementation of either CAA or crude ingredients. Based on the overall performances of fish, it can be concluded that supplementation of FS, KM and SM is as effective as CAA to maintain amino acid balance and can act as attractants in high SPC based diets for maintaining normal feeding behavior, growth performance, health and welfare of juvenile red sea bream. [Copyright &y& Elsevier]

Abstract: A collagenolytic serine proteinase (CSP) was purified from red sea bream (Pagrus major) skeletal muscle to homogeneity by ammonium sulfate fractionation and chromatographies including DEAE-Sephacel, Phenyl Sepharose and Hydroxyapatite. The molecular mass of CSP was approximately 85kDa as estimated by SDS–PAGE and gel filtration. Optimum temperature and pH of CSP were 40°C and 8.0, respectively. CSP was specifically inhibited by serine proteinase inhibitors, while inhibitors to other type proteinases did not show much inhibitory effects. The K m and k cat values of CSP for Boc-Leu-Lys-Arg-MCA were 3.58µM and 0.13s−1 at 37°C, respectively. Furthermore, CSP hydrolyzed gelatin and native type I collagen effectively though its degradation on myosin heavy chain (MHC) was not significant, suggesting its involvement in the texture tenderization of fish muscle during the post-mortem stage. [Copyright &y& Elsevier]

Abstract: To investigate the role of detoxification-related liver genes in amnesic shellfish poisoning toxin metabolism, red sea bream Pagrus major were exposed to domoic acid (DA, 2μgg−1 wet weight) for 24h. Hepatic mRNA expression levels of AHR, ARNT, CYP1 and GSTs were determined by semi-quantitative RT-PCR. The cytosolic factors aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor nuclear translocator (ARNT) mRNA levels of DA exposure group were substantially enhanced by 113.3% and 90.9%, respectively. Consistent with this result, the phase I xenobiotic metabolizing enzyme (XME) cytochrome P-450 1A (CYP1A) was significantly induced. In contrast, the transcriptions of three major phase II XME glutathione S-transferases as well as heat shock protein 70 were not significantly affected by DA exposure. These results suggest a possible role of CYP1A after DA exposure in the toxin metabolism of marine fish, possibly through the AHR/ARNT signaling pathway. [Copyright &y& Elsevier]

Abstract: Three species of seabreams, Acanthopagrus berda, Acanthopagrus schlegelii and Pagrus major, living at different depths, were chosen to investigate how visual spectra and opsin genes evolve in response to various photic environments. The λmax of photoreceptors and opsin genes were measured and cloned from these species. Eight to twelve nm spectral shifts in the rod and blue cone cells were observed between the deep-sea, P. major, and shallow-sea species, A. berda and A. schlegelii. Furthermore, the deep-sea P. major has lost its red light vision. Six opsin genes, Rh1, Rh2A, Rh2B, SWS1, SWS2 and LWS, were identified from all three seabream species, with the LWS genes of P. major having undergone pseudogenization. These data indicate that the photic environment of habitats select for the physiology of visual spectra and coding of opsin genes. [Copyright &y& Elsevier]

Abstract: To determine whether external factors affect the adipogenic function of fish adipocytes, the effects of 2-bromopalmitate (a PPAR agonist) on the fatty acid composition in differentiating adipocytes of red sea bream were investigated in vitro. In the presence of 2-bromopalmitate, the red sea bream adipocytes were differentiated and the effects on the fatty acid composition and the adipogenic gene expression were analyzed. With the level of 2-bromopalmitate, the content of 16:1n-7, a delta-9 desaturation product, increased in association with the increase in a stearoyl CoA desaturase (SCD) gene expression level while the triglyceride accumulation was not affected. Subsequently, the effects on the bioconversion of the n-3 and n-6 fatty acids, which are main series of dietary essential fatty acids, were examined. In the presence of 300 μM of 18:3n-3 or 18:2n-6, red sea bream stromal-vascular cells accumulated the lipid in the cytoplasm within 3 days by the fatty acid uptake with the increase of corresponding fatty acid contents. Furthermore, in both the 18:3n-3 and 18:2n-6 stored cells, the products of delta-6 desaturation (18:4n-3 and 18:3n-6, respectively) and C18–20 elongation (20:3n-3 and 20:2n-6, respectively) were detected. However, neither the delta-6 desatutration nor C18–20 elongation of 18:3n-3 and 18:2n-6 were enhanced by 2-bromopalmitate treatment. In conclusion, the results indicate that the adipocyte function in fish, e.g. adipogenic gene expression and fatty acid composition, can be modified by external factors and a main effect of 2-bromopalmitate is the increase in the content of delta-9 desaturation product by stimulating the SCD gene expression. [Copyright &y& Elsevier]

Adipose tissue is not only an energy depot but also an important endocrine and immunological tissues in mammals. However, the study of functions of fish adipose tissue, other than lipid storage, is considerably limited. In the present study, we investigated resident leukocyte populations in the visceral adipose tissue (VAT) of the red sea bream, Pagrus major, an important species of Japanese aquaculture with a well-developed VAT. We found that the tissue contains a significant number of leukocytes; it is mainly composed of eosinophilic granulocytes, macrophages, unclassified large cells, and a smaller number of lymphocytes. The VAT cellular composition is similar to that of peritoneal cells, but not of the peripheral blood leukocytes. Gene expression analysis also confirmed that all examined genes, including CD4, CD8α, membrane and secretory IgM heavy chains, macrophage-colony stimulating factor receptors (type 1 and 2), macrophage mannose receptor, MHC class II, and Toll-like receptors 2, 3, 5, and 9, were expressed in the VAT. Intraperitoneal injection of formalin-killed Vibrio anguillarum markedly upregulated the mRNA expression of IL-1β, IL-8, and IL-6 in the VAT within six hours. In addition, in vitro bacterial stimulation upregulated these cytokines. These results indicate that the VAT of P. major is an immune-competent organ that evokes an inflammatory response against intraperitoneally introduced bacteria. • Visceral adipose tissue (VAT) of sea bream (Pagrus major) harbored numerous leukocytes. • Eosinophilic granulocytes accounted for approximately 70% of the VAT leukocytes. • Various leukocyte markers and Toll-like receptors were expressed in the VAT. • Intraperitoneal injection of bacteria upregulated interleukin (IL)-1β, IL-6, and IL-8 in the VAT. • These cytokines were also upregulated in vitro in VAT by bacterial stimulation. [ABSTRACT FROM AUTHOR]

A rearing study was undertaken to investigate whether trypsin inhibitor (TI) activity reduction in soy protein concentrate (SPC) derived from soymilk can afford more replacement of fish meal (FM) protein in the diet of juvenile red sea bream, Pagrus major. A diet containing 67% FM as the sole protein source was used as the control (C). SPC products with TI activities of 36, 21 and 13 TIU/mg sample were prepared. Approximately 80% of FM protein in diet C was replaced by a combination of SPC products and corn gluten meal (4:1) and referred to as T36, T21 and T13, respectively. Aqueous krill extract (KE) was added at 1% in diets T36, T21 and T13 and termed T36K, T21K and T13K, respectively. Phytase was supplemented at 1000 FTU/kg diet in all SPC-based diets. Each of seven diets was fed to a group of 20 fish (mean weight 19 g) in triplicate twice per day to apparent satiation for 10 weeks. The final mean weight (P = 0.001), specific growth rate (SGR) (P = 0.001) and feed efficiency (FE) (P = 0.002) were significantly lower in fish fed the T36 and T36K diets than in those fed the other diets. However, there were no significant differences in final mean weight (P = 0.088), SGR (P = 0.314) and FE (P = 0.829) in fish fed diets T21, T13, T21K and T13K compared to the control diet. Although there were no significant differences in the digestibility of protein (P = 0.076) and energy (P = 0.066) among the treatments, the productive values of protein (P = 0.002) and energy (P = 0.001) were significantly reduced in fish fed the T36 and T36K diets. In contrast, a significantly lower phosphorus (P) retention efficiency (P = 0.026) in fish fed the control diet resulted in significantly higher P discharge (P = 0.001) to the environment compared with diets T21, T13, T21K and T13K. There were no major variations in hematocrit level or plasma constituents among the treatments, except glutamic oxaloacetic transaminase (GOT) and triglyceride. The results suggest that the reduction in TI activity at ≤21 TIU/mg sample (≤9.66 TIU/mg diet) in SPC from soymilk made it possible to replace 80% of FM protein without affecting growth performance and health status. Moreover, a significant reduction in P discharge suggests that ecological benefits can be achieved through improving diet utility by reducing TI activity in SPCs derived from soymilk. • TI reduction in SPC from soymilk can help to increase FM protein replacement levels. • SPC replaced FM protein by up to 80% without affecting growth or feed efficiency in red sea bream. • Digestibility of nutrients was not affected by SPC at 80% FM protein replacement. • TI reduction can help to establish eco-friendly diet by reducing P discharge to environment. • SPC from soymilk will help to achieve sustainability of aquaculture industry. [ABSTRACT FROM AUTHOR]

Abstract: For improving the economic and environmental sustainability of fish farming, it is necessary to optimize feeding regimes. From this viewpoint, we monitored the growth and mortality of red sea bream (Pagrus major), C and N fluxes and sediment chemistry at 2 commercial fish cages; cage 1 (conventional satiation feeding) and cage 2 (restricted feeding: same feeding frequency but 18% reduction in the feed amount) for 276 days. The similar specific growth rates (0.43% in cage 1 and 0.39% in cage 2) but different feed conversion efficiencies (0.54 in cage 1 and 0.62 in cage 2) and mortality (>2-times higher in cage 1) between the 2 cages, indicate overfeeding in cage 1 culture. Elemental and stable isotopic analyses of sediment trap materials enabled the quantification of waste feed- and fecal matter-derived organic matter (OM) separately. The results shows that (1) aquaculture-derived OM comprised most of the fish-farm settling OM, excluding the period from January to April, when natural OM often accounted for a half of the bulk OM, (2) there was a difference in the seasonal trend between the fluxes of waste feed and fecal matter, and (3) there were no differences in the percentage compositions and fluxes of waste feed and fecal matter between the 2 cages. The isotopic analysis showed that the waste feed-derived OM in the sediment below cage 2 was 24% less than that below cage 1, suggesting effect of restricted feeding. Determining the relative amount of waste feed and fecal matter in settling and sedimentary OM is an effective method to evaluate the optimum feeding regime. [Copyright &y& Elsevier]

Temperature is a pivotal key in fish physiology but is limited in determining blood bone biomarker as a stressor. In this study, fourteen blood biochemical markers were evaluated by employing clinical blood test methods to identify the causation between temperature and the levels of sensitivity for the given temperature in a red sea bream, Pagrus major. The survival rate of 2-year-old P. major decreased below 10 °C. The physiological biomarkers could be categorized into four clusters based on their level-changing patterns. Cluster 1 included the factors that did not change by temperature. Cluster 2 significantly changed at cold temperature including direct bilirubin (≤ 6 °C), cortisol (≤ 8 °C), albumin (≤ 8 °C), and total cholesterol (≤ 8 °C), and free T 3 and aspartate aminotransferase (≤10 °C). Total bilirubin, which is classified as cluster 3, significantly changed at both cold (≤ 8 °C) and high temperature (28–30 °C). Cluster 4 comprised total protein, glucose, lactate, and IL-8, which significantly responded to both low temperature (≤ 15 °C) and high temperature (28–30 °C). These results suggest that some physiological diagnostic biomarkers have temperature specific blood levels, so classifying them by their sensitivity and tracing them with clusters are useful to evaluate stress or stressors in P. major. In addition, the markers belonging to clusters 2, 3, and 4 were more sensitive to acclimated temperature, therefore, clustering and comparing them might be very useful for the case of P. major health and environmental monitoring programs. • The suggested biomarkers can be clustered into four. • They can be used as biomarker to evaluate the stress originated from temperature. • They can be used as biomarkers of acclimated physiological characters. • A suggesting assessment model is useful for determine the environmental stressor. • It will be useful to environmental monitoring program. [ABSTRACT FROM AUTHOR]

Abstract: Feeding trials were carried out to determine the effects of zinc (Zn) and manganese (Mn) supplementation in Artemia on growth, survival, body composition and skeletal deformity of red sea bream larvae. Triplicate groups of red sea bream larvae from 15–30 day post-hatching (dph) were fed four types of Artemia enriched with Zn (Z), Mn (M), both Zn and Mn (ZM) and without Zn or Mn (control). At 30 dph, significantly higher (P <0.05) growth performance of the fish was recorded in M group (TL=15.60±0.45 mm) compared to that of the control (TL=14.90±0.41 mm). Fish fed Artemia supplemented with only Zn and with both Zn and Mn showed similar growth performance compared to that of the control. Survival of the fish was not affected either by Zn or Mn supplementation. Increased Mn or both Zn and Mn in Artemia nauplii significantly elevated (P <0.05) crude lipid content in 30dph juvenile compared to that in the Z group. At 30 dph, Mn content in juvenile of M and ZM groups was significantly higher (P <0.05) compared to that in the other groups. Similarly, Zn content in the Z group was significantly higher (P <0.05) compared to that in the M and control groups. Skeletal deformities in the experimental fish at 30 dph were highest (P <0.05) in the control group and were significantly improved by supplementation with Zn and Mn. The major skeletal deformities were observed in the vertebral column, neural and hemal spines. In the vertebral column, occurrence of deformities in the neck, hemal and preural were higher than in other regions. The results of the present study demonstrated that maintenance of Mn level in Artemia nauplii from 12 to 42.8 µg g−1 (dry-matter basis) improved growth performance of red sea bream larvae. Zn and Mn supplementation in Artemia promoted normal skeletal development of red sea bream larvae. [Copyright &y& Elsevier]

Abstract: Importin α proteins are critical modulators of the classical nuclear protein import pathway. Although the physiological roles of importin α have been extensively studied in invertebrates and mammals, very little is known about their counterparts in lower vertebrates. In this study, to elucidate the roles of importin α in a teleost species, we isolated and characterized red seabream (Pagrus major) importin α cDNA derived from ovary and found changes in the mRNA levels of importin α in male and female red seabream during sexual maturation. The 1846-bp cDNA encodes a 520 amino acid protein that includes the importin β-binding domain, a short acidic domain, and an armadillo (arm) repeat domain. Northern blot analysis and reverse transcription-polymerase chain reaction (RT-PCR) showed transcription of red seabream importin α in testis and ovary but not in the other tissues. The importin α mRNA levels in males increase in association with testicular development, whereas those in females remain high throughout sexual maturation. These findings suggest that red seabream ovary-derived importin α may be controlled in a tissue-specific manner and may perform unique functions in the gonad in addition to its involvement in nuclear transport. [Copyright &y& Elsevier]

Abstract: To investigate the molecular mechanism of fish adipocyte differentiation, the three subtypes of PPAR genes (α, β and γ) were characterized in a marine teleost red sea bream (Pagrus major). The primary structures of red sea bream PPARs exhibited high degrees of similarities to their mammalian counterparts, and their gene expression was detected in various tissues including adipose tissue, heart and hepatopancreas. During the differentiation of primary cultured red sea bream adipocytes, three PPARs showed distinct expression patterns: The α subtype showed a transient increase and the β gene expression tended to increase during adipocyte differentiation whereas the gene expression level of PPARγ did not change. These results suggest that they play distinct roles in adipocyte differentiation in red sea bream. In the differentiating red sea bream adipocytes, mammalian PPAR agonists, 15-deoxy-Δ12,14-prostaglandin J2, ciglitazone and fenofibrate did not show clear effects on the adipogenic gene expression. However, 2-bromopalmitate increased the PPARγ and related adipogenic gene expression levels, suggesting the γ subtype plays a central role in red sea bream adipocyte differentiation and in addition, fatty acid metabolites can be used as modulators of adipocyte function. Thus our study highlighted the roles of PPARs in fish adipocyte differentiation and provided information on the molecular mechanisms of fish adipocyte development. [Copyright &y& Elsevier]

Abstract: The objectives were to investigate the effect of cryoprotectants on the hatching rate of red seabream embryos. Heart-beat embryos were immersed in: five permeable cryoprotectants, dimethyl sulfoxide (DMSO), glycerol (Gly), methanol (MeOH), 1,2-propylene glycol (PG), and ethylene glycol (EG), in concentrations of 5–30% for 10, 30, or 60min; and two non-permeable cryoprotectants: polyvinylpyrrolidone (PVP), and sucrose (in concentrations of 5–20% for 10 or 30min). The embryos were then washed and incubated in filtered seawater until hatching occurred. The hatching rate of the embryos treated with permeable cryoprotectants decreased (P <0.05) with increased concentration and duration of exposure. In addition, PG was the least toxic permeable cryoprotectant, followed by DMSO and EG, whereas Gly and MeOH were the most toxic. At a concentration of 15% and 30min exposure, the hatching rate of the embryos immersed in PG was 93.3±7.0% (mean±S.D.), however, in DMSO, EG, Gly, and MeOH, it was 82.7±10.4, 22.0±5.7, 0.0±0.0, and 0.0±0.0%, respectively. Hatching rate of embryos treated with PVP decreased (P <0.05) with the increase of concentration and exposure time, whereas for embryos treated with sucrose, there was no significant decrease in comparison with the control at the concentrations used. [Copyright &y& Elsevier]

Abstract: Allozyme electrophoresis was used to investigate the genetic stock structure of snapper, Pagrus auratus (Bloch and Schneider) on the east coast of Australia. Spatial variation in allele frequency was examined at nine polymorphic loci. The results support a single, relatively weak genetic disjunction among the P. auratus populations north of Sydney (latitude 33°52′) but south of Forster (latitude 31°58′) on the central coast of New South Wales. There was also evidence for genetic isolation by distance on the east coast. The influence of the East Australian Current (EAC) in transporting larvae to the south, coupled with the general northward migration pattern of adult snapper is believed to be responsible for maintaining a panmictic snapper population on much of the east coast of Australia. [Copyright &y& Elsevier]

Abstract: Insulin-like growth factors (IGFs) I and II (IGF-I and IGF-II) play important roles in fish growth and development. The present study was aimed at isolating cDNAs encoding both IGF-I and IGF-II in the redbanded seabream (Pagrus auriga), and at measuring relative gene expression levels in different organs and during larval development. A fragment of 1321 nucleotides coding for IGF-I was cloned from liver using 3′ and 5′ RACE techniques. It included an open reading frame of 558 nucleotides, encoding a 185-amino acid preproIGF-I. With respect to IGF-II, a fragment of 1544 nucleotides was cloned as well. The open reading frame spanned 648 nucleotides, rendering a 215-amino acid preproIGF-II. The deduced mature 67-amino acid IGF-I and 70-amino acid IGF-II exhibited high sequence identities with their corresponding fish counterparts, ranging between 88.6-100% and 79.1–98.5%, respectively. Real-time PCR showed the highest IGF-I transcripts in liver (∼200-fold higher than head-kidney). In contrast, the highest IGF-II mRNAs were detected in gills and heart (∼16-fold higher than head-kidney). In addition, both IGFs exhibited different gene expression patterns during larval development suggesting that their expression is developmentally regulated. IGF-I reached the highest expression levels at 18 days after hatching (11.6-fold higher than 1 day after hatching), whereas IGF-II expression did not change significantly. Both hepatic IGF-I and IGF-II mRNA levels increased sharply (3.1- and 19-fold higher than control, respectively) 3 h after injection of porcine growth hormone, but remained unchanged from 6 to 24 h after treatment. Our results are discussed in relation to those previously reported for other bony fish. [Copyright &y& Elsevier]

We have developed a “microscopic bubble generating system for the fish farm” and evaluated its ability to improve the quality of seawater and costs of it in marine cages of red sea bream (Pagrus major) in Kusuura Bay, Japan. Our results revealed that DO concentration of bubbling net pens increased and became significantly higher than the level outside the net pen (between 0.52 and 0.87mg/L), and the whole water column was nearly saturated. Temperatures of the bubbling net pens decreased slightly between 0.08 and 0.12°C in all the layers. Furthermore, micro-bubbles seemed to reach the deeper water due to the downward flow and diffusion. This study demonstrated that the microscopic bubble generating system developed in our research project could increase efficiently the dissolved oxygen concentration throughout all water layers of the fish farm. A capital and operation costs of the system is recoverable within a year. [Copyright &y& Elsevier]

Abstract: Variables affecting the short-term survival of snapper (Pagrus auratus) captured using commercial fish traps and subsequently released were investigated by holding the fish in cages. A logistic regression model showed that capture depth had the greatest affect on short-term survival of snapper, with no mortalities observed from depths of less than 21m and ∼2% from depths of less than 30m. Mortality of snapper increased rapidly after 30m and was ∼39% between capture depths of 30 and 44m and ∼55% between capture depths of 45 and 59m. Survival was also effected by fish length, with smaller fish being more likely to die. The rate of ascent of captured snapper and the density of fish in cages were kept reasonably constant and did not appear to affect survival. The number of snapper swimming upside-down prior to being returned to the sea floor in cages was not a good predictor of mortality. Future studies that use cages to assess discard mortality rates would benefit from underwater video observations of fish behaviour. The results demonstrate that the discard mortality of snapper should be considered when managing the fishery in New South Wales, Australia. [Copyright &y& Elsevier]

Abstract: The objective was to identify an appropriate cryoprotectant and protocol for vitrification of red sea bream (Pagrus major) embryos. The toxicity of five single-agent cryoprotectants, dimethyl sulfoxide (DMSO), propylene glycol (PG), ethylene glycol (EG), glycerol (GLY), and methyl alcohol (MeOH), as well as nine cryoprotectant mixtures, were investigated by comparing post-thaw hatching rates. Two vitrifying protocols, a straw method and a solid surface vitrification method (copper floating over liquid nitrogen), were evaluated on the basis of post-thaw embryo morphology. Exposure to single-agent cryoprotectants (10% concentration for 15min) was not toxic to embryos, whereas for higher concentrations (20 and 30%) and a longer duration of exposure (30min), DMSO and PG were better tolerated than the other cryoprotectants. Among nine cryoprotectant mixtures, the combination of 20% DMSO+10% PG+10% MeOH had the lowest toxicity after exposure for 10min or 15min. High percentages of morphologically intact embryos, 50.6±16.7% (mean±S.D.) and 77.8±15.5%, were achieved by the straw vitrifying method (20.5% DMSO+15.5% acetamide+10% PG, thawing at 43°C and washing in 0.5M sucrose solution for 5min) and by the solid surface vitrification method (40% GLY, thawing at 22°C and washing in 0.5M sucrose solution for 5min). After thawing, morphological changes in the degenerated embryos included shrunken yolks and ruptured chorions. Furthermore, thawed embryos that were morphologically intact did not consistently survive incubation. [Copyright &y& Elsevier]

Abstract: Red sea bream iridovirus (RSIV) is a causative agent of red sea bream iridoviral disease (RSIVD) in marine fish species in Japan. Fibroblast cells were developed from a tail fin of red sea bream, Pagrus major, and then underwent single cell cloning. The successful cloned cells were named CRF-1 cells. Most CRF-1 cells had a normal diploid karyotype with 2n =48 by chromosomal analysis. RSIV-infected CRF-1 cells showed typical morphological changes that were associated with apoptosis by EGFP-annexin V staining. The serial viral passages were successful in CRF-1 cells but failed in BF-2 cells as judged by MTT assay. The expression of three genes obviously decreased in BF-2 cells compared with CRF-1 cells and finally was below detectable level. Because the expression of 591R gene showed the fastest decrease among three transcripts, the suppression of IE transcript may be responsible for the restricted replication in BF-2 cells. MCP and ATPase phylogenetic trees showed that RSIV strain U-1 belongs to a distinct group from RSIV strain ehime-1. Therefore, possibly recent epizootics of RSIVD in Japan do not originate directly from RSIV strain ehime-1. Taken together, this study confirmed that RSIV strain U-1 is more closely related to Korean RSIV isolates. [Copyright &y& Elsevier]

Abstract: In the present study, the quality of post-thaw sperm of red seabream Pagrus major frozen with 6–24% DMSO was investigated. The motility, average path velocity and fertilizing capacity of fresh and their corresponding post-thaw sperm were examined for evaluation of the post-thaw sperm motion characteristics and its association with fertilizing capacity. An analysis of sperm motility before and after cryopreservation has been performed using computer-assisted sperm analysis (CASA). For post-thaw sperm frozen with 12–21% DMSO, the percentages of motile sperm were not significantly (P >0.05) changed 10 s after activation. Moreover, the main motility pattern and swimming velocity of the motile post-thaw sperm were not significantly (P >0.05) changed and the progressive linear motion was still the dominant pattern. However, the total motility of post-thaw sperm (72.3±6.3%) 30 s after activation was (P <0.05) lower than the corresponding fresh sperm (82.7±7.2%). Additionally, the fertilizing capacity of post-thaw sperm was investigated with a standardized sperm to egg ratio 500:1. There is a linear regression relationship between the percentage of motile post-thaw sperm and fertilizing capability. These data demonstrate that 12–21% DMSO can provide good protection to the sperm during the freezing–thawing process. [Copyright &y& Elsevier]

Abstract: Pagrus auriga is a significant component of the Canarian archipelago coastal marine ecosystem. Although it is an important target species of the artisanal fishery and the aquaculture, little is known on the life history or population dynamics of this predatory sparid fish. In this study, age and growth of P. auriga were investigated by annual growth increment counts (annuli). Overall, age and growth were estimated from 615 specimens from 128 to 781mm total length. Growth analysis revealed that this species is a slow growing and a long-lived species, with ages of up to 24 years. Annulus was validated by marginal increment analysis. Each hyaline zone in the otoliths represented an annulus with a year''s growth represented by an opaque and its adjacent hyaline zone. Length at age was described by the specialized von Bertalanffy growth model (L ∞ =793mm; k =0.081year−1; and t 0 = −1.497year), the Schnute growth model (y 1 =137mm; y 2 =781mm; a =−0.059; and b =0.984), and the seasonalised von Bertalanffy growth model (L ∞ =798mm; k =0.080year−1; t 0 =−1.502year; C =0.601; and t s =0.741). A power relationship (a =23.47; and ν =1.206) was estimated between the total length and the otolith radius. Back-calculated lengths were similar to those predicted by the growth models. Growth parameters estimated from the back-calculated sizes at age were (L ∞ =803mm; k =0.082year−1; and t 0 =−1.33year). [Copyright &y& Elsevier]

Abstract: To investigate the nutritional regulation of lipid metabolism in fish, molecular characterization of lipases was conducted in red sea bream Pagrus major, and the effects of fasting and refeeding on their gene expression was examined. Together with data from a previous study, a total of four lipase genes were identified and characterized as lipoprotein lipase (LPL), hepatic lipase (HL) and pancreatic lipase (PL). These four lipase genes, termed LPL1, LPL2, HL and PL, share a high degree of similarity. LPL1 and LPL2 genes were expressed in various tissues including adipose tissue, gill, heart and hepatopancreas. HL gene was exclusively expressed in hepatopancreas. PL gene expression was detected in hepatopancreas and adipose tissue. Red sea bream LPL1 and LPL2 gene expression levels in hepatopancreas were increased during 48 h of fasting and decreased after refeeding, whereas no significant change in the expression levels of LPL1 and LPL2 was observed in adipose tissue, indicating that LPL1 and LPL2 gene expression is regulated in a tissue-specific manner in response to the nutritional state of fish. HL and PL gene expression was not affected by fasting and refeeding. The results of this study suggested that LPL, HL and PL gene expression is under different regulatory mechanisms in red sea bream with respect to the tissue-specificities and their nutritional regulation. [Copyright &y& Elsevier]

Abstract: Skin coloration patterns in fish are of great physiological, behavioural and ecological importance, can be considered as an index of animal welfare in aquaculture and as an important quality factor for the retail value, especially of red skinned fish. In the present study we developed an appropriate method for comparisons of the skin chromaticity parameters in wild (Pagrus pagrus, Pagrus caeruleostictus, and Dentex gibbosus) and farmed red skin Sparidae and investigated the effect of storage time on skin colour of farmed Pagrus pagrus. The three-dimensional characteristics of colour appearance (lightness — L ⁎, hue — H° ab and chroma —C ab ⁎) were calculated. A new index, named Entire Colour Index (ECI), was developed to express hue and chroma which as combined variables, cannot be considered separately. In all species there was a remarkable dorsoventral gradient in mean L ⁎ and H° ab , with the ventral area being statistically significant brighter than the dorsal one. ECI value was species specific but did not show any statistically significant dorsoventral gradient, with the exception of P. pagrus. Skin melanin and carotenoids content presented differences between the Pagrus and the Dentex species that may explain the differences in the observed chromaticity pattern. Storage time affected lightness and hue only in the dorsal skin area. However, the effect of storage on ice was better reflected in mean ECI value which showed a marked decrease from Day 3 to Day 7 in both the dorsal (Day 0: 8.96±0.40; Day 7: 2.86±0.29) and ventral (Day 0: 8.97±0.18; Day 7: 4.10±0.29) skin area. Our results provide data for a non-subjective determination of skin colour pattern and show that ECI offers a good index of the actual colour in a meaningful and objective way. [Copyright &y& Elsevier]

Abstract: Two bath treatment trials for the control of the monogenean Microcotyle sp. in the gills of cultured red porgy, Pagrus pagrus using formalin (200 ppm for 1 h) and mebendazole (400 ppm for 1 h) were conducted. Formalin was very effective removing all the parasites from the gills of the infected fish while mebendazole produced no significant result. Based on the results of the trial, formalin was selected for the treatment of a large population of heavily infected red porgies held in sea cages. The results of the treatment are discussed. [Copyright &y& Elsevier]

Abstract: Two consecutive trials were conducted to investigate the effects of photoperiod manipulation on growth rate, food intake and feed conversion efficiency (Trial 1), and the digestibility of nutrients and energy (Trial 2) in red sea bream, Pagrus major (body weight 19–120 g). Fish were exposed to four photoperiods (6L:6D, 12L:12D, 16L:8D and 24L:0D) with light intensity 1500 lx on the water surface. The fish were fed with a commercial diet to apparent satiation. In Trial 2, 0.5% chromic oxide (Cr2O3) was used as an inert marker. Significantly higher weight gain and specific growth rates were observed in fish exposed to a 24L:0D photoperiod followed by 16L:8D, 6L:6D and 12L:12D photoperiods (P <0.05). Food intake and feed conversion efficiency (FCE) were also significantly higher in fish exposed to 24L:0D followed by 16L:8D, 6L:6D and 12L:12D photoperiods (P <0.05). Fish exposed to 24L:0D and 16L:8D photoperiods showed significantly higher lipid and energy digestibility than those exposed to a 12L:12D photoperiod (P <0.05). The results demonstrated that the enhancement of growth performances under 16L:8D and 24L:0D photoperiods were attributed to improved appetite, greater food intake and higher feed conversion efficiency as well as higher digestibility. [Copyright &y& Elsevier]

Abstract: Two distinct cDNAs corresponding to GSTA1 and GSTA2 genes encoding glutathione S-transferases (GSTs) from the hepatopancreas of red sea bream, Pagrus major were cloned and sequenced. A comparison of the nucleotide sequences of GSTA1 and GSTA2 revealed 98% identity and their derived amino acid sequences had 96% similarity. Both genes could be classified as α-class GSTs on the basis of their amino acid sequence identity with other species. Genomic DNA cloning showed that both GSTA1 and GSTA2 genes consisted of six exons and five introns. In a comparison of genomic DNAs, the structures of GSTA1 and GSTA2 differed. In addition, Southern-blot analysis indicated that at least two kinds of α-class GSTs existed in the P. major genome. In order to biochemically characterize the recombinant enzymes (pmGSTA1-1 and pmGSTA2-2), both clones were highly expressed in Escherichia coli. The purified pmGSTA1-1 and pmGSTA2-2 exhibited glutathione conjugating activity toward 1-chloro-2,4-dinitrobenzene and glutathione peroxidase activity toward cumene hydroperoxide, while neither pmGSTs show detectable activity toward 1,2-dichloro-4-nitrobenzene, ethacrynic acid, 4-hydroxynonenal, or p-nitrobenzyl chloride. Despite their high level of amino acid sequence identity, the pmGSTs had quite different enzyme-kinetic parameters. [Copyright &y& Elsevier]

Red porgy, Pagrus pagrus, is a potential candidate for aquaculture. However, darkening of the body occurs after capture of wild fish and during farming of cultured animals. In fish, skin pigmentation is hormonally controlled and the main hormone involved in skin darkening, α-melanocyte-stimulating hormone (αMSH), is not only involved in pigmentation but also in the regulation of the response to stressors. In this study, several environmental conditions were evaluated for their potency to influence the skin colour and to evoke a stress response. Background colour was the main factor in controlling skin pigmentation. A light background colour restored the lightness value of the skin up to levels found in wild red porgy (L*=∼70). The background effect was enhanced by applying blue illumination. Light intensity had no clear effect on the body colour, but a high density of fish had a negative effect on the lightness. Plasma parameters (cortisol, αMSH, glucose, lactate and osmolality) were not influenced by background colour. A stocking density of 25 kg/m3 did not evoke a stress response in contrast to earlier studies on red porgy, nor influenced the body colour. We propose that this difference can be attributed to the number of fish per volume of water, which was lower than in other studies. This indicates that the number of fish per volume of water rather than the density in kilograms of fish per volume of water is the relevant factor. Furthermore, we suggest that the culture of adult red porgy can be optimised by maintenance of fish on a light background, thereby restoring the body colour to a more natural hue, without affecting the stress response. [Copyright &y& Elsevier]

Egg production from two broodstocks of captive-reared red porgy (Pagrus pagrus) was monitored for two consecutive seasons (2001 and 2002). Spawning lasted from January to April–May under water temperature between 15.8 and 19.2 °C. Spawning was mostly daily, though over the course of the two spawning seasons, the mean interval was 1.5–1.2 days spawn−1. There was a large variation in daily fecundity without a consistent trend, except for a slight peak in the middle of the spawning season. Mean (S.E.M.) annual relative fecundity ranged between 408,300 (95,800) and 442,500 (180,800) eggs kg−1 year−1. Mean fertilization success increased significantly from 36.9 (2.0)% in 2001 to 68.9 (2.5)% in 2002, resulting in mean annual viable egg production of 174,800 (87,600) and 301,500 (99,800) eggs kg−1, respectively. There were no significant differences between the 2 years in other egg quality parameters, which ranged between 74.5 and 79.3% 1-day embryo survival, 81.6–85.5% hatching success and 76.7–78.8% 5-day larval survival. Of the relations examined, fertilization % had a significantly positive correlation with 1-day embryo survival, which in turn was significantly correlated with hatching %. Larval survival was further correlated with hatching %. These data suggest that decisions on whether to proceed with the incubation of a batch of eggs and rearing of the larvae can be made within 1 day from egg collection, before much effort is invested by the hatchery. The present study presents further information on the spawning kinetics, and egg production and quality characteristics of the Mediterranean red porgy in culture, and demonstrates the suitability of this species for reproduction in captivity. [Copyright &y& Elsevier]

Four overlapping cDNA fragments encoding a partial sequence for uncoupling protein 2 (UCP2) were amplified by PCR using degenerate primers from the liver of a marine teleost fish, red sea bream (Pagrus major). The partial sequence was 674 bp long, encoding 224 amino acids. The deduced amino acid sequence from the cDNA partial sequence contained the signature motifs for mitochondrial transporter protein and revealed positional identity higher than 72.8% with UCP2 from mammals. The fish UCP2 gene was highly expressed in the liver but almost undetectable in the visceral mesenteric adipose tissue. Using beta-actin as control, the UCP2 mRNA level was determined to be at least 20-fold higher in the liver than in the visceral mesenteric adipose tissues. Neither 48 h starvation nor high lipid diet had any significant effect on liver UCP2 gene expression, indicating that the abundant UCP2 gene expression was stable and might have some basic function in a fish liver that always contains high lipid content. The striking contrast of UCP2 gene expression in the two fish fat-depot organs is consistent with their large differences in oxidative capacity. We suggest that the fish liver may adapt to a constantly high fat deposit by maintaining high UCP2 expression to constrain reactive oxygen species (ROS) production and protect hepatocytes from apoptosis. [Copyright &y& Elsevier]

Type I collagens were extracted from fish scales of Pagrus major and Oreochromis niloticas as a possible underutilized resource for medical materials. The fish scales were demineralized with EDTA and digested by pepsin. The resultant type I collagens contained more than 33.6% of glycine as the most abundant amino acid. The denaturation temperatures of the collagens from P. major and O. niloticas were 303 and 308 K, respectively, both of which were relatively lower than that of porcine dermis collagen (314 K). CD spectra indicated that the denaturation temperatures were dependent on the amount of hydroxyproline, rather than proline residues. Raman spectra also indicated that the relative intensities of Raman lines at 879 and 855 cm−1 assigned to Hyp and Pro rings were changed due to the contents of the imino acids. Significantly, the content of sulphur-containing methionine was higher in the fish scales than in porcine dermis. The enthalpy and entropy estimated from thermal analyses could be correlated to amino acid sequences (Gly-Pro-Hyp) of type I collagens and the number of methionine amino acid residues. [Copyright &y& Elsevier]

Red porgy Pagrus pagrus were placed and maintained in white, grey and black background fibreglass tanks for 2 weeks. Additionally, fish kept in white and black background tanks were then subjected to crowding stress. After 2, 9, 16 and 23 days, blood samples were taken and plasma cortisol, alpha melanocyte stimulating hormone (α-MSH) and glucose values were analysed and compared with values from uncrowded fish from white or black tanks. Measurements of plasma cortisol and α-MSH in unstressed red porgy from white, grey and black tanks revealed no significant differences among the three groups. However, the results show that background colour markedly affects the in vitro interrenal sensitivity to both α-MSH and ACTH, as interrenal cells from black adapted fish had become virtually unresponsive to both secretagogues. Crowded fish on a black background showed a prominent increase in plasma cortisol after 2 days, which was followed by a recovery. In fish crowded on a white background however, the increase of cortisol was lower but was maintained through the entire experiment. Plasma α-MSH levels increased at 23 days as a consequence of crowding; this increase was also dependent on the background, being more prominent in fish placed in white background tanks. Thus, in the red porgy, a white background appears to modify the stress response, particularly in the long term. [Copyright &y& Elsevier]