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1.
Early weaning of marine fish larvae with dry diets delays gut maturation and reduces growth rates. In juvenile and adult forms of several marine fish species, inclusion of dietary mannan oligosaccharides (MOS) improves gut integrity and functionality, but the effects of MOS inclusion in gilthead sea bream (Sparus aurata, L.) larval diets have not been addressed yet. Thus, this study assesses the effects of dietary MOS inclusion on survival, growth performance, gut morphology, feed acceptance and quality of gilthead sea bream larvae. For that purpose, 16 days post‐hatched gilthead sea bream larvae were fed four graded levels of MOS (Biomos®, Alltech, Nicholasville, KY, USA) in weaning diets as follows: 0 g kg?1 MOS, 0.5 g kg?1 MOS, 1.5 g kg?1 MOS and 2 g kg?1MOS. Dietary MOS did not affect feed acceptance in gilthead sea bream larvae (P > 0.05). MOS supplementation was correlated in a dose‐dependent way with higher larval survival (P = 0.026). After 15 days of feeding, dietary MOS increased whole larvae (P < 0.01) arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid. Gilthead sea bream larvae fed 2 g kg?1 MOS presented higher gut occupation with goblet cells after feeding compared with larvae fed the other dietary treatments. Overall, the results suggest that inclusion of MOS in early weaning diets for gilthead sea bream improves essential fatty acid utilization and may promote growth and final survival.  相似文献   

2.
Dietary mannanoligosaccharide (MOS) from commercial product, Bio‐Mos supplementation, has been examined for its effects on weight gain and feed conversion of domestic mammals and birds, but very few studies have evaluated the responses of aquacultural species to MOS. A feeding and digestibility trial was performed to asses the potential beneficial effect of two levels of Bio‐Mos on growth, feed utilization, survival rate and nutrients’ digestion of gilthead sea bream (Sparus aurata) with an initial average weight of 170 g. Bio‐Mos was added at 2 or 4 g kg?1 to a fish meal–based control diet, and each diet was fed to triplicate groups of 1‐year‐old gilthead sea bream. After 12 weeks, there were no differences in survival rate among fish fed experimental diets (P > 0.05). It was observed that a significant improvability existed for both growth and feed utilization in fish fed diets supplemented with Bio‐Mos (P < 0.05). Body proximate composition remained unaffected by Bio‐Mos supplementation in fish fed experimental diets (P > 0.05). Apparent digestibility values for protein, carbohydrate and energy were appreciably affected by the inclusion of two different levels of Bio‐Mos, only lipid digestibility was the exception. In conclusion, the results of this trial indicate that 2 g kg?1 dietary supplementation with BIO‐MOS seem to be most positive for gilthead sea bream production.  相似文献   

3.
This study investigates the effect of corticosteroid (cortisol) administration on the stress response of the gilthead sea bream Sparus aurata subjected to a 48 h confinement. The effect of (in-vitro and in-vivo ) cortisol administration on the in-vitro ACTH sensitivity of the interrenal tissue; the plasma levels and tissue concentration of cortisol; and the plasma levels of ACTH, -MSH, -endorphin and glucose were determined. Confinement caused a transient and concomitant increase in plasma cortisol and ACTH levels. However, in cortisol-fed fish the plasma ACTH levels were lower, indicating a suppresion of the ACTH release from the corticotropes by cortisol. In contrast to the activation of the corticotropes, the levels of plasma melanotrope derived peptides were not affected. In spite of the fact that interrenal cells of cortisol-fed gilthead sea bream released less cortisol than controls, the interrenal sensitivity to ACTH was not affected by in-vivo and in-vitro cortisol administration. This suggests that the interrenal sensitivity to ACTH in stressed (confinement) sea bream is probably not regulated by -MSH, N-ac--END, or by cortisol. Thus, in gilthead sea bream the interrenal sensitivity to ACTH could be regulated at the hypothalamus and/or pituitary and communicated via circulating ACTH levels.  相似文献   

4.
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.  相似文献   

5.
The purpose of this study was to determine whether gilthead sea bream and sea bass treated with combination of trimethoprim and sulfamethoxazole (TMP-SMX) differed in terms of physiological and innate immune biomarkers. Fish were exposed to TMP-SMX at 40 ppm concentration for 1 h as a prophylactic usage. Plasma cortisol, glucose, electrolytes (Ca, P, Na, K, Cl, and Mg) as well as plasma lysozyme activity, C-reactive protein (CRP), and ceruloplasmin (Cp) were measured soon after treatment and following 24 and 48 h in normal sea water for recovery. Treatment with TMP-SMX in both gilthead sea bream and sea bass led to an increase in plasma cortisol and glucose. Fluctuations in some electrolytes were found after treatment and during recovery period, however, the ratios of monovalent ions in treated sea bream were similar to control. Hematocrit values as well as plasma lysozyme activity in gilthead sea bream and sea bass were not affected by the treatment. CRP in gilthead sea bream and Cp in sea bass responded to the treatment with decreased levels. Both gilthead sea bream and sea bass displayed a rapid physiological stress response and sensitivity to TMP-SMX exposure, which requires more than 48-h period for regaining homeostasis.  相似文献   

6.
Juvenile and adult black sea bass (Centropristis striata L.) were exposed to various concentrations of four anaesthetics to determine practical dosages for handling as well as for procedures such as bleeding, ovarian biopsy or tag implantation. In experiment 1, juveniles exposed to either 2.0 mg L?1 metomidate, 15 mg L?1 clove oil, 70 mg L?1 tricaine methanesulphonate (TMS) or 200 mg L?1 2‐phenoxyethanol (2‐PE) reached stage II of anaesthesia in 3–5 min and could be handled for weighing and measuring. All fish had completed recovery to stage III within 6 min. In experiment 2, the established concentrations of each anaesthetic were tested on juveniles to determine their ability to prevent a reflex to a subcutaneous needle puncture. All of the fish exposed to clove oil (20 mg L?1) and 40% of the TMS‐treated (70 mg L?1) fish reacted while none of the fish anaesthetized in metomidate (2.0 mg L?1) or 2‐PE (200 mg L?1) responded to the needle puncture. In experiment 3, metomidate (5.0 mg L?1), clove oil (30 mg L?1) TMS (125 mg L?1) or 2‐PE (300 mg L?1) were all effective for performing an ovarian biopsy or tag implantation on adults. In experiment 4, TMS (125 mg L?1) exacerbated the cortisol response to a short handling stressor during a 30 min exposure. Fish anaesthetized in 2‐PE (300 mg L?1), metomidate (5.0 mg L?1) or clove oil (40 mg L?1) had increased cortisol levels associated with the handling stressor but there were no further increases during the remainder of the experimental period. The results demonstrate that these anaesthetics are effective for sedation and anaesthesia of black sea bass and that the best choice is dependant upon the procedures to be performed.  相似文献   

7.
The objective of this study was to evaluate the effect of harvest practices and slaughter method on stress, quality and shelf life of whole fish (gilthead sea bream, European sea bass and red sea bream) towards the development of a humane slaughter practice. The use of hook and line resulted in significantly lower plasma cortisol and glucose in European sea bass and gilthead sea bream. Water temperature at harvest affected significantly the concentrations of stress indicators (plasma cortisol and glucose), mainly in European sea bass and gilthead sea bream. No significant differences were observed between the harvesting methods, regarding fish appearance, microbial spoilage and sensory scoring and subsequently shelf life. However, significantly lower hardness was recorded in fish harvested using the electric stunner, compared to the fish killed with slurry ice of the same harvesting period. Shelf life ranged between 13–18 days for gilthead seabream, 10–16 days for European sea bass and 10–14 days for red sea bream, depending on harvesting period.  相似文献   

8.
Juvenile gilthead sea bream (initial body weight ca. 100 g) were reared in an indoor flow through marine water system for 1 year. Fish were fed two isoenergetic [19.2 kJ g−1 dry matter (DM)] and isoproteic (426 g kg−1 DM) diets either based on fish meal (diet FM) or on a mixture of plant protein sources (diet PP), replacing 75% of fish meal protein. The growth trial was conducted in duplicate, two tanks for each dietary treatment. Growth performance and feed utilization were registered. Fillet quality parameters were evaluated and sensory analyses on cooked fillet were performed. Both groups had similar weight gain and specific growth rates. Feed intake was higher in sea bream fed diet FM (0.48 versus 0.44), while feed efficiency and protein efficiency ratio were significantly higher in sea bream fed PP (0.83 versus 0.77 and 2.0 versus 1.76, respectively). Sea bream fed diet FM had a lower hepatosomatic index (0.80 versus 0.87%), and a higher fillet yield (45.9 versus 44.9%). The fillet from sea bream fed diet FM had higher moisture (696 versus 682 g kg−1), lower lipid levels (91 versus 100 g kg−1) with higher levels of n‐3 polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA), while the PP fed sea bream presented a higher level of PUFA n‐6. There were minor differences in muscle free amino acid levels between the two diet groups. As regards sensory evaluation of cooked fillet, the judges were unable to discriminate the two dietary groups of fish. Summarizing, the results demonstrate the possibility to use diets containing high levels (750 g kg−1) of plant ingredients in gilthead sea bream without affecting growth performance and with minor effects on quality traits of commercial size sea bream.  相似文献   

9.
Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha–1 to the total yield of 1,700 kg ha–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha–1, while in marine cages, yields ranged from 4–10 kg m3. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.  相似文献   

10.
The survival of milkfish broodstock (body weight range 1–11 kg) was determined until 30 days after handling and transport in open tanks or in sealed oxygenated bags containing chilled sea water (20–25 °C). Maintenance of cool sea water was achieved by the gradual addition of ice chunks or frozen gel packs. A survival rate of 50% after transporting fish at a loading density of 45 kg m?3 for 4 h in open tanks was not significantly different from those that were handled but not transported (86%). Similarly, survival rates (67–83%) among broodstock confined for 8 h in chilled sea water at 40 and 60 kg m?3 were not significantly different from each other or from a group not subjected to confinement. Nevertheless, low dissolved oxygen (DO) and accumulation of total ammonia–nitrogen beginning 1 h after transport and confinement may be responsible for low survival rates of milkfish in open tanks. In contrast, all milkfish survived 10 h of overland transport in sealed bags with chilled and diluted (28 g L?1) sea water. Likewise, all milkfish survived after being bagged and immediately transferred to a communal rearing tank, or bagged and placed in a styrofoam box for 10 h. Except for total ammonia–nitrogen levels, which increased slightly (0.7–0.8 mg L?1) above background, seawater temperature (20–24 °C), salinity (28 g L?1) and DO (6 to > 20 mg mL?1) titres in transport bags were maintained during the 10‐h test. The effectiveness of handling and transporting milkfish broodstock in sealed bags containing chilled sea water was verified in actual field trials. Spawning of sexually mature milkfish subjected to these stressors was not impaired. These results demonstrate that mortalities of large milkfish broodstock can be minimized when fish are handled and transported in sealed oxygenated bags containing chilled sea water.  相似文献   

11.
In this study, we investigated the effect of repeated handling on the oxidative state of gilthead sea bream, Sparus aurata. We determined the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPX), glutathione transferase (GST), and DT‐diaphorase (DTD) in liver, digestive tract, brain, gills, and white muscle. We also measured the lipid‐peroxidation level (malondialdehyde – MDA – concentration) and the glucose 6‐phosphate dehydrogenase activity (G6PDH). The results show that repeated low‐intensity handling on gilthead sea bream alter the oxidative status of tissues such as liver, digestive tract, and muscle in the last term can affect its welfare. The brain in a situation of handling stress is protected from oxidative damage by the activity of antioxidant enzymes. Finally, the concentration of MDA in tissues can be a good candidate as a biomarker of stress and welfare in fish.  相似文献   

12.
Gastric evacuation rates of the gilthead sea bream, Sparus aurata, fed with commercial pelleted food and polychaetes (Nereis diversicolor) were determined under experimental conditions. The estimated gastric evacuation rate for pelleted food was 7.97% h–1, with a total time of digestion of approximately 9 h. The respective values for the natural food were 6.24% h–1, with a total digestion time of approximately 12 h. The daily consumption of fish reared in earth ponds in a semi-intensive aquaculture facility was estimated through 24 h cycles performed between April and August. The daily consumption varied from 18.58 to 31.98 mg g–1. There was a constant increase in the average daily consumption per individual of 1.8–4.6 g (dry weight). During these cycles, samples of stomachs were taken and the contents preserved for further observation. The feeding behaviour of the reared fish was compared with a fish sample caught in the Ria Formosa lagoon. No common species were found between samples. A total of 38 prey were identified, which suggests that the gilthead sea bream is a non-specific predator. Despite the high abundance of natural prey in the ponds, the dependence of sea bream on pelleted food was high.  相似文献   

13.
Infectious Lepeophtheirus salmonis (Krøyer) cause localized inflammation at the site of attachment on the host fish, while the greatest physiological impact occurs with the development of the subadult and adult stages. We exposed Oncorhynchus mykiss (Walbaum) to infectious copepods at 30, 25 and 14 days prior to a net confinement procedure, while a second group were sham infected. Fish were sampled at time zero, 2, 4, and 6 h of continuous net confinement, and at 24 h after 2 h confinement. Plasma Na+, Cl–, gill Na+/K+‐ATPase activity and skin mucous cell numbers were measured, and skin and gill condition assessed microscopically. Exposure to copepods resulted in lower numbers of acidophilic mucous cells and poor condition of the skin and gill epithelia. Total numbers of mucous cells were decreased in net confined infected fish only. Plasma Na+ was elevated in all samples from non‐infected netted fish, without altered gill Na+/K+‐ATPase activity, while infected fish had higher plasma Na+ only at 2 h and increased gill ATPase activity at 4 h. The epithelia of infected fish were more severely affected by the confinement procedure. Exposure to juvenile lice can induce effects that become apparent only when a stressor is applied.  相似文献   

14.
Methods were developed to assess whole‐body immunoreactive corticosteroid concentrations (IRC) and plasma levels of cortisol in Atlantic cod subjected to several common, acute stressors. A measurable corticosteroid stress response was observed at the first sampling in whole bodies of 8‐day post‐hatch (dph) larvae. Two groups of juveniles (～5 and 30 g) were subjected to a 30 s net stressor and whole‐body IRC and plasma cortisol levels were determined. Post‐stressor IRC in smaller fish rose approximately 14‐fold, peaked at 1 h, were sustained for 3–6 h and returned to pre‐stressor levels within 24 h. Post‐stressor plasma cortisol levels in larger fish rose approximately 18‐fold, peaked at 0.5–1 h, were sustained for 1–3 h and then returned to near pre‐stressor levels after 24 h. Immunoreactive corticosteroid concentrations appeared to remain elevated longer than plasma cortisol levels suggesting that steroids other than cortisol were contributing to total immunoreactivity in homogenates. Juveniles exposed to either a grading procedure or high density transport had maximal IRC and plasma cortisol levels within 90 min which returned to pre‐stressor levels within 24–72 h. A reduction in water salinity (20 g L?1) did not moderate the corticosteroid response in juveniles. The results show that Atlantic cod respond to common, acute stressors in a manner similar to other teleosts. Whole‐body homogenates can be used to identify changes in IRC in response to acute stress in cod with the caveat that recovery IRC may differ from plasma cortisol concentrations.  相似文献   

15.
Gilthead sea bream Sparus aurata Linnaeus, 1758 were subjected to repeated stresses, namely confinement and handling once a month for 5 consecutive months. Plasma cortisol concentration was determined as a primary stress response, and plasma glucose and osmolality, serum agglutination and growth rate were analysed as indicators of the secondary and tertiary effects of stress. The results of the mean values after the five trials showed that most indicators followed a consistent pattern with time. Cortisol and growth rate were positively correlated, and cortisol and osmolality were negatively correlated after stress. Analysis of the individual responses throughout all 5 months showed that 6–20% of the fish displayed a consistently high or low response depending on the parameter analysed.  相似文献   

16.
European sea bass (Dicentrarchus labrax), one of the most economically important fish in Mediterranean mariculture, shows high basal cortisol concentrations compared with other teleosts. The present study aims (a) to identify cortisol diel variation in fish held under a 12L:12D cycle and minimum handling stress, and (b) to establish the effect of fish size and stressor duration on the cortisol response. The results indicate high intrapopulation variability in plasma cortisol and a significant diel fluctuation with a peak value at dusk (18 h). Stressors of different intensity and/or duration affected the cortisol stress response in a differential manner according to fish size (and/or age). Maximum cortisol values in small-size fish were found at 1 and 2 h post-stress, depending on the duration of the stressor, while at 0.5 h post-stress in large fish regardless stress duration.  相似文献   

17.
Maslinic acid (MA) is a natural triterpene that can be used as an additive in the diet of trout. We investigated the effects of feeding with MA and a fixed ration (10 g kg?1 body weight) with respect to growth, protein‐turnover rates and nucleic‐acid concentration in the liver of gilthead sea bream grown under fish‐farm conditions. Five groups of 12 g of a mean body mass were fed for 210 days with diets containing 0 (control), 0.05 and 0.1 g of MA per kg of diet. Two groups were fed ad libitum (control AL and MA100AL), and three with a fixed ration (control R, MA50R and MA100R). At the end of the experiment, higher body weights, liver weight, feed‐efficiency and PER were found in MA100AL and MA100R fish. Fractional and absolute protein‐synthesis rates in liver of MA100R fish were higher than in the control, resulting in a higher absolute protein‐accumulation rate and tissue growth. Total DNA content in MA100AL and MA100R was higher than in control. Studies of light and electron microscopy corroborated these results. These findings indicate that MA added to the diet can stimulate growth, hepatic protein‐turnover rates and tissue hyperplasia in gilthead sea bream.  相似文献   

18.
An experiment was conducted to determine the effects of different levels of dietary vitamin C (VC) and E (VE) supplementation on fillet quality of red sea bream fed oxidized fish oil (OFO). Fish with an average body weight of 205.0 g were fed four test diets for 9 weeks. Control diet contained fresh fish oil (FFO) with 100 mg kg?1 of VE and 500 mg kg?1 of VC (FFO100E/500C). The other three diets contained OFO with varying levels of VE (mg kg?1) and VC (mg kg?1) (OFO100E/500C, OFO200E/500C and OFO200E/1000C). After feeding trial, two fillets from each fish by hand filleting were stored in a refrigerator at 4°C for 96 h during analyses. Results showed that fish fed OFO increased fillet thiobarbituric acid reactive substances (TBARS) and K‐value, and decreased fillet VC and VE concentrations during storage time. Supplementation of VC did not have any detectable effect on fillet quality. Increasing dietary VE supplementation increased fillet VE concentrations, reduced fillet TBARS and K‐value values of red sea bream. Therefore, we suggest that dietary supplementation of 200 mg kg?1 of vitamin E could improve fillet oxidative stability of red sea bream fed OFO.  相似文献   

19.
A feeding trial evaluated the influences of different cycles of starvation and refeeding protocols for 7 weeks on growth and feed intake in 14‐g gilthead sea bream, Sparus aurata. Following 7 weeks of alternated cycles, all the groups were fed to apparent satiation for a further 3 weeks. Three groups of fish were fasted for 2, 4 or 7 days (S2, S4 and S7, respectively) and then refed until their relative feed intake differed by less than 20% of fed controls until the end of the week 7, while a fourth group (S7/Rf14) experienced three cycles, each consisting of 1 week of food deprivation followed by 2 weeks of satiation feeding. Control (C) fish were fed to satiation throughout the trial. The fish were fed a sea bream diet (450 g kg?1 crude protein) according to the protocols, twice a day for 7 weeks. Growth performance and feed intake in continuously fed control group were significantly higher than those of the deprived groups (S2, S4, S7 and S7/Rf14) (P < 0.05). Weight gain highly correlated with total feed intake (R2 = 94), and feed efficiency was the highest in the control group than other deprived groups (P < 0.05). The juveniles of gilthead sea bream demonstrated only a partial compensation during the cycling period and even after being fed to satiation for another 3 weeks. The convergence of growth trajectories and subsequent hyperphagic responses of the groups fed according to protocols are discussed in terms of possible costs of compensatory growth.  相似文献   

20.
The effects of two different environmental salinities [brackish water (BW), 12‰; sea water (SW), 39‰] and initial stock densities [low (LD), 1.0 g L?1; high (HD), 2.0 g L?1] on growth, osmoregulation, stress and energy metabolism of the fry Pagrus pagrus were investigated over a period of 45 days. Pagrus pagrus (n=80, 5.51 ± 0.25 g mean initial body weight) were randomly divided in eight groups. Growth, weight gain and specific growth rate increased in BW‐acclimated fish compared with SW‐acclimated fish. No differences were observed between the two stock densities tested at either environmental salinity. Plasma osmolality was lowest in BW‐acclimated specimens, but the stock density had no effect on this parameter. Branchial Na+,K+‐ATPase activity was positively correlated with environmental salinity, but unaltered at the renal level. Plasmatic parameters were enhanced by salinity and stocking conditions. At the hepatic level, triglyceride values were enhanced in BW‐acclimated fish maintained at LD. Muscle metabolites (glycogen, glucose and lactate) increased in BW‐ compared with SW‐acclimated fish; stock density had no influence. Our data suggest that changes in metabolic parameters could be correlated with the higher growth rates observed in P. pagrus acclimated to BW, while no significant effects due to the stocking density used were observed.  相似文献   

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