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The use of fish meal/oil in carnivorous fish feeds remains a concern for the environmental sustainability of aquaculture. In this study, we investigated the impact of an innovative diet designed to be cost‐effective and environmentally sustainable (i.e., 60% replacement of fish meal by a blend of plant, yeast [Saccharomyces cerevisiae], and krill meal feed ingredients) on the growth, health, and welfare of gilthead seabream (Sparus aurata). Over a 135‐day experiment, fish were fed either the innovative or a commercial diet (control), and various parameters were evaluated, namely growth performance, levels of physiological blood parameters related to stress, immunity, health, and welfare, as well as swimming activity, serving as a proxy for energy expenditure. Results revealed that the innovative diet enhanced growth compared to fish fed the control diet. Hematological and biochemical indicators did not highlight any impaired welfare condition in fish fed innovative diet while higher levels of Immunoglobulin M were measured in plasma of fish fed innovative diet, potentially suggesting enhancement of humoral immunity. However, accelerometer tags data revealed that fish fed the innovative diet exhibited higher overall swimming activity, suggesting higher energy expenditure, which was consistent with greater prealbumin levels measured in the plasma. In conclusion, the higher energy metabolism in fish fed the innovative diet might be compensated by the diet's content, which may boost humoral immunity and hence help the fish develop a better adaptation to rearing environment, including its viral and bacterial load, ensuring overall better growth. Longer term investigations, including measurements of additional parameters, are required to validate these promising preliminary outcomes. [ABSTRACT FROM AUTHOR]

The present study was carried out to compare the tissue composition of wild and farmed common dentex (Dentex dentex) and the major nutrients in order to further explore the dietary requirements of this species. Wild (41±14 g) and farmed (10±2 g) fish were analyzed for proximate composition, fatty acid profile and vitamin C and E muscle and liver content. The fat content of the farmed population was almost six times higher than that measured in wild fish at the expense of water content. There were no significant differences in the protein and ash content between the two populations. The vitamin C content was insignificantly lower in wild fish liver while differences were significant in muscle compared to their farmed conspecifics. Vitamin E concentration was found to be significantly higher in both examined tissues of the farmed fish. The fatty acid profiles were different between the wild and farmed individuals. Wild fish livers were significantly richer in ω-6 fatty acids, poorer in total monounsaturates (MUFA), but no differences were observed for total polyunsaturates (PUFA) and saturated fatty acids (SFA). As regards muscle tissues, farmed fish were found to contain higher 22:6ω3 levels but significantly lower 16:1ω7 and 18:1ω9 levels than the wild ones. The information given by the present study should be evaluated for the further improvement of common dentex diets. [ABSTRACT FROM AUTHOR]

The pharmacokinetics of oxolinic acid (OA) were investigated after a single intra-vascular injection (20 mg kg−1 fish) in sharpsnout sea bream (90 g), a promising new euryhaline species for Mediterranean fish farming. The distribution half-life (t1/2α) and the elimination half-life (t1/2β) of OA were calculated to be 0.4 and 10 h respectively. The apparent volume of distribution at steady-state (Vd(ss)) and total clearance rate (CLT) of the drug were found to be 2.1 L kg and 0.2 L kg−1 h−1 respectively. The bioavailability (F%) of OA following oral administration (40 mg kg−1 fish) was estimated to be 15%. The results indicate a rapid distribution and elimination of the drug, moderate tissue penetration, but low absorption in sharpsnout sea bream.The kinetic profile of OA found in this species is comparable with that observed in another well-known sparid, gilthead sea bream. [ABSTRACT FROM AUTHOR]

This study aims to measure liver collagen fibril diameter in cultured and wild sea breams (Sparus aurata). Cultured sea breams were fed three isonitrogenous diets. The organically produced feed contained sustainable certified fish meal (45%), fish oil (14%), and organic certified wheat; the laboratory feed contained fish meal (45%), fish oil (14%), wheat meal, and soya meal; and the commercial feed included fish meal (46%), fish oil (17%), soya meal, wheat meal, and corn gluten meal. The organic diet had higher amounts of vitamins A, C, and E; specific amino acids; and minerals that enhanced the biosynthesis of collagen. This study shows that fish fed the organic feed had significantly bigger collagen fibril diameters than the fish fed the conventional feed. Furthermore, the organically fed fish had similarly sized collagen fibril diameters as wild fish. More research is needed to understand the long-term effects and the mechanism and function of fish collagen peptide intake on lipid absorption and metabolism; and to identify dietary regimes that are able to improve whole body lipid profiles and suppress the transient increase of plasma triglycerides.

The present study investigated the kinetic profile of flumequine (FLU) in gilthead sea bream Sparus aurata (170 g) held at 19 degrees C and evaluated its in vitro efficacy against important bacterial diseases in Mediterranean mariculture. Following a single intravascular injection (10 mg kg(-1) fish), the distribution half-life (t1/2alpha) and the half-life of the terminal phase of elimination (t1/2gamma) of the drug were 0.2 and 30 h respectively. Tissue penetration of FLU was low, since both the apparent distribution volume of the drug at steady-state (Vd(SS)) and the apparent volume of the central compartment (Vc) were small (0.57 and 0.15 l kg(-1)). The mean residence time (MRT) was short (11 h) and the total clearance (CL(T)) of the drug was slow (0.05 l kg(-1) h(-1)). Following oral administration (20 mg kg(-1)), the bioavailability (F %) of FLU was 29% and the maximum plasma concentration was 1.7 microg ml(-1). The minimum inhibitory concentration (MIC) of the drug in distilled water supplemented with 2% NaCl against Vibrio anguillarum Serotype 1b, Photobacterium damsela ssp. piscicida, V. alginolyticus, V. damsela and V. fluvialis was 0.15, 0.3, 1.2, 0.019 and 0.15 microg ml(-1) respectively. The addition however of 10 mM Ca2+ and 55 mM Mg2+ to the medium resulted in an 8- to >120-fold reduction in FLU activity. The results indicate that FLU has an adequate kinetic profile in gilthead sea bream and that marine cations induce a significant impact on the activity of FLU, rendering its use against bacterial pathogens questionable.