The effects of dietary lipid and fibre levels on digestibility of diet and on the growth performance of sharpsnout seabream (Diplodus puntazzo)

In the present study, sharpsnout seabream (Diplodus puntazzo) were fed three experimental isonitrogenous diets composed of 45 g 100g-1 protein and varying lipid and fibre contents as follows: diet A: 45/10/1.5, B: 45/15/1.5 and C: 45/15/5. The effects of the diet composition were investigated by measuring digestibility, growth, carcass composition and haematological parameters. The apparent digestibility coefficients (ADCs) for proteins, fats and carbohydrates, measured at high (26˚C) and low (16˚C) water temperatures in laboratory conditions, were not affected by the diet or temperature treatments. Growth was evaluated in a seven-month trial using animals held in sea cages. The specific growth rate (SGR) showed no significant differences among the treatments while the feed conversion ratio (FCR) was significantly improved in the fish that were fed a low-fat diet. A significant increase in body fat was detected in the fish that were fed high-fat diets. The blood serum total lipid levels were elevated for the fish that were fed diet C. In conclusion, a diet containing a protein/fat/fibre ratio of 45/10/1.5 g 100g-1 can result in satisfactory growth and an improved FCR value when compared with diets with higher fat and/or fibre levels, demonstrating that the required fat level for sharpsnout seabream is lower than 15 g 100g-1

Feed and nutrition in organic aquaculture

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Post-prandial amino acid changes in gilthead sea bream

Following a meal, a series of physiological changes occurs in fish as they digest, absorb and assimilate ingested nutrients. This study aims to assess post-prandial free amino acid (FAA) activity in gilthead sea bream consuming a partial marine protein (fishmeal) replacement. Sea bream were fed diets where 16 and 27% of the fishmeal protein was replaced by plant protein. The essential amino acid (EAA) composition of the white muscle, liver and gut of sea bream was strongly correlated with the EAA composition of the 16% protein replacement diet compared to the 27% protein replacement diet. The mean FAA concentration in the white muscle and liver changed at 4 to 8 h after a meal and was not different to pre-feeding (0 h) and at 24 h after feeding. It was confirmed in this study that 16% replacement of marine protein with plant protein meets the amino acid needs of sea bream. Overall, the present study contributes towards understanding post-prandial amino acid profiles during uptake, tissue assimilation and immediate metabolic processing of amino acids in sea bream consuming a partial marine protein replacement. This study suggests the need to further investigate the magnitude of the post-prandial tissue-specific amino acid activity in relation to species-specific abilities to regulate metabolism due to dietary nutrient utilization

Effects of novel ingredients on growth performance in european sea bass, dicentrarchus labrax

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Pharmacokinetics of chloramphenicol (CAP) in gilthead sea bream (Sparus aurata) and its in vitro activities against important bacterial fish pathogens

Στη μελέτη αυτή διερευνήθηκαν οι φαρμακοκινητικές ιδιότητες της χλωραμφενικόλης (CAP) στην τσίπουρα {Sparus aurata) και η in vitro αποτελεσματικότητα της κατά των διαφόρων βακτηριακών ασθενειών. Μετά από ενδοφλέβια χορήγηση της CAP στη δόση των 10 mg/kg/ψάρι, ο χρόνος ημίσειας ζωής της κατανομής (t1/2α ) και ο χρόνος ημίσειας ζωής της απομάκρυνσης (t1/2β) βρέθηκαν ότι είναι 1.6 και 69h, αντίστοιχα. Η διάχυση της CAP στους ιστούς της τσιπούρας ήταν μέτρια εφόσον αμφότεροι, τόσο ο φαινομενικός όγκος κατανομής (Vd(ss)) όσο καιο φαινομενικός όγκος του κεντρικού διαμερίσματος (Vc), υπολογίσθηκαν σε 1,13 και 0,90 L/kg. Η ολική σωματική απομάκρυνση (CLT) της CAP ήταν βραδεία (0,022 L/kg/h). Οι τιμή MIC της CAP σε απεσταγμένο νερό με προσθήκη 2% NaCl κατά των Vibrioanguillarum ορότυπος lb, Photobacterium damsela subsp.piscicida, V. alginolyticus και Vßuvialis υπολογίσθηκε σε 4,78μg/mL, ενώ ήταν 0,60 μg/mL για το V damsela. Η προσθήκη στο υπόστρωμα 10 mM Ca2+ και 55 mM Mg2+ έδωσε τιμές MIC 19,13μg/mL για το V alginolyticus και το V tluvialis, ενώ δεν παρατηρήθηκε κάποιο αποτέλεσμα με το V. anguillarum P. damsela subsp.Piscicida και το V. damsela. Τα αποτελέσματα αυτά έδειξαν ότι η CAP παρουσιάζει μια ικανοποιητική εικόνα κινητικής και ότι απομακρύνεται γρήγορα από τη σάρκα της τσιπούρας, ενώ οι υψηλές τιμές MIC δείχνουν μια πιθανή αναποτελεσματικότητα ενάντια σημαντικών παθογόνων βακτηρίων στα ψάρια της Μεσογείου.The pharmacokinetics of chloramphenicol (CAP) in gilthead sea bream (Sparus aurata), a warm water farmed fish species and its in vitro efficacy against important bacterial diseases of Mediterranean mariculture were investigated in this study. After an intravascular injection (10 mg/kg/fish), the distribution half-life (tl/2a) and the elimination half-life (tl/2ß) of CAP were calculated to be 1.6 and 69 h, respectively. Tissue penetration of CAP was found to be moderate since both the apparent volume of distribution of the drug at steady-state (V<i(ss)) and the apparent volume of the central compartment (Vc) were calculated to be 1.13 and 0.90 L/kg. The total clearance (CLp) of the drug was slow (0.022 L/kg/h). The minimum inhibitory concentration (MIC) values of CAP in distilled water supplemented with 2% NaCl against Vibrio anguillarum serotype lb, Photobacterium damsela subsp. piscicida, V alginolyticus and V ßuvialis were determined to be 4.78 pg/mL, while it was 0.60 pg/mL for V. damsela. The addition of 10 mM Ca2+ and 55 mM Mg2+ in the medium revealed MIC values of 19.13 pg/mL for V alginolyticus and V ßuvialis, whereas showed no effect for V anguillarum P. damsela subsp. Piscicida and V damsela. The results indicate that CAP displayed a satisfactory kinetic profile and it is eliminated fast from gilthead sea bream muscle; however, its high MIC values stress show a possible inefficacy against important bacterial pathogens of Mediterranean mariculture