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1.
The efficacy of using cottonseed oil (CSO) as a fish oil (FO) substitute in gilthead seabream (Sparus aurata) juveniles feed was evaluated. Fish (BWi 4.0 ± 2.9 g) were fed one of four isoproteic (~48% CP) and isolipidic (~18% L) diets for 9 weeks. Added oil was either FO (control diet, CTRL) or CSO, replacing 50% (CSO50 diet), 60% (CSO60 diet) and 70% (CSO70 diet) of dietary FO. Results indicated that FO replacement by CSO up to 60% level had no detrimental effects on growth or nutritive utilization and composition in fish muscles. Higher CSO intake (CSO70 diet, 56 g kg?1) led to a 16% reduction in weight gain, 14% in feed utilization (FCR) and 57% in muscle n‐3 long‐chain polyunsaturated fatty acids (lc PUFA) as compared with CTRL and to abundant accumulation of lipid within the hepatocytes. Use of CSO altered fatty acid (FA) profiles of muscle and liver. Data suggested utilization of linoleic acid (LOA) by fish and retain of docosahexaenoic acid (DHA) in muscles. Therefore, limits of CSO inclusion as the main source of supplementary dietary lipid, with no negative effects on fish performance or nutritive composition and utilization in muscles, are: 40–48 g kg?1 feed for gilthead seabream juveniles.  相似文献   

2.
To improve the unnatural fade-pigmented skin of cultivated gilthead seabream, Sparus aurata, (if shown) the present study was initiated. The effects of either red bell-pepper (Capsicum annum) meal or carrot (Daucus carota) meal as a natural dietary carotenoid source, on growth and skin coloration of gilthead seabream growers were investigated. A basal/control diet (D1/CTR) was firstly formulated to contain 48% crude protein and 14% lipids, with no added-carotenoids. With this basal diet, two other test diets were similarly prepared and supplemented each with about 40mg/Kg total carotenoids from either red-pepper meal (D2) or carrot meal (D3). In a feeding trial, fish (mean IW, 94.86±0.3g) were fed one of the three diets (D1, D2, D3), in triplicates for each treatment, for 6 weeks in light-blue background PVC tanks supplied with natural seawater flow. Total carotenoids content of skin was determined spectrophotometerically at initiation and end of the experiment. Neither growth nor feed utilization were significantly (P<0.05) affected by the red pepper-added diet (D2) as compared to CTR diet. However, the carrot fed fish recorded the lowest and significant (P<0.05) weight gain (g/fish) and specific growth rate (SGR, %/d) among dietary treatments. There were no considerable (P>0.05) differences in major nutrients composition between fish fed the experimental diets. Total carotenoids content was significantly (P<0.05) increased, in the skin-opercle area, of fish fed the red pepper diet (D2) as compared to initial fish and to either carrot fed fish or CTR fish. Results have suggested that gilthead seabream can effectively bio-absorb natural carotenoid pigments (mainly capsansin and capsorbin) in red-pepper but not in carrot (mainly β-and α-carotene).  相似文献   

3.
The recent decreasing worldwide supplies of marine oils have forced the aquaculture industry to investigate alternative lipid sources for use in marine fish feeds. The aim of this study was to determine the impact of dietary replacement of fish oil by vegetable oils on gilthead seabream (Sparus aurata) growth performance, nutritive utilization, body composition, and fatty acid profile as well as feed cost. Two dietary vegetable oil (VO) mix blends (VO1 and VO2) in which: sunflower (SO), cottonseed (CO) and linseed (LO) for VO1 or soybean oil (SBO) for VO2, were tested as 60% fish oil (FO) substitutes versus the 100% FO control or reference diet (FO). Three iso-proteic (46% CP) and iso-lipidic (18%) experimental diets were hand fed, twice a day, 6 days a week to apparent visual satiety to triplicate groups of seabream growers (average initial weight, 130.9 ± 3.44 g), until fish reached market size (300–400 g/fish) after 20 weeks at mean ambient temperature 27.0 ± 1.8°C. All experimental diets were well accepted by seabream growers regardless of the different lipid sources used, as overall mean feed intake (FI) and daily intake (DFI) were not significantly different (P > 0.05) among dietary treatments. In terms of growth performance, fish fed VO1 diet (with LO) exhibited a relatively lower, but significant (P < 0.05), total weight gain (WG) than fish fed all FO diet (FO). However, mean value of WG of fish fed either vegetable oil-tested diet was nonsignificantly different. Feeding seabream growers vegetable oil (VO) diets (VO1 or VO2) had no significant effect on specific growth rate (SGR), daily weight index (DWI), or feed conversion ratio (FCR) among dietary treatments. Consumption of VO for 20 weeks did not significantly alter the major nutrient composition of fish, but the muscle fatty acid (FA) profile was significantly altered compared to the reference FO diet. Comparatively reduced levels of eicosapentaenoic acid (EPA) and docosahexaenoic acids (DHA), as well as elevated levels of linoleic and linolenic acids (LA and LNA) compared with fish fed the FO were noticed. In terms of economics, 17 or 20% reduction in Kg feed cost was obtained for diets VO1 or VO2, respectively. In terms of growth performance and cost, VO2 diet showed slight relative superiority over VO1 diet. However, in terms of liver structure morphology, VO1 diet (with LO) has resulted in less fat-infiltration and altered hepatic cells than VO2 (with SBO). As these traits do not affect yield or the price paid for the fish, VO2 diet has therefore been considered better than VO1 as complementary lipid sources for gilthead seabream grower diets.  相似文献   

4.
There is a need to find sustainable alternatives to fishmeal (FM) and fish oil (FO) in feed formulations to support the continued growth of aquaculture. FM is mostly produced from mass‐caught pelagic species, but the production has been relatively constant for several decades. The aim of this study was to investigate the potential of dietary krill meal (KM) inclusion as a sustainable alternative to FM. In view of that, a feeding trial with gilthead seabream juveniles was conducted to evaluate whether dietary KM at 3%, 6% and 9% inclusion improves growth performance in comparison with a control diet. At the end of the study, fish in the 9% KM group showed significantly higher body weight (32.76 g) compared with fish fed the control diet (30.30 g). Moreover, FM replacement by 9% KM indicated a reduction in the accumulation of lipid droplets in the hepatocytes and around the pancreatic islets. In summary, this study suggests that FM can be reduced in diets for seabream without negatively affecting growth performance, when KM is added. On the contrary, KM enhances gilthead seabream growth and reduces lipid accumulation and damage of hepatocytes, which will open an interesting innovation line to completely replace FM by alternative terrestrial protein sources and the partial inclusion of KM.  相似文献   

5.
Currently, the larviculture of many marine fish species with small-sized larvae depends for a short time after hatching, on the supply of high-quality live zooplankton to ensure high survival and growth rates. During the last few decades, the research community has made great efforts to develop artificial diets, which can completely substitute live prey. However, studies aimed at determining optimal levels of minerals in marine larvae compound feeds and the potential of novel delivery vectors for mineral acquisition has only very recently begun. Recently, the agro-food industry has developed several nano-delivery systems, which could be used for animal feed, too. Delivery through nano-encapsulation of minerals and feed additives would protect the bioactive molecules during feed manufacturing and fish feeding and allow an efficient acquisition of active substances into biological system. The idea is that dietary minerals in the form of nanoparticles may enter cells more easily than their larger counterparts enter and thus speed up their assimilation in fish. Accordingly, we evaluated the efficacy of early weaning diets fortified with organic, inorganic, or nanoparticle forms of trace minerals (Se, Zn, and Mn) in gilthead seabream (Sparus aurata) larvae. We tested four experimental diets: a trace mineral-deficient control diet, and three diets supplemented with different forms of trace minerals. At the end of the feeding trial, larvae growth performance and ossification, and the level of expression of six target genes (SLC11A2β, dmt1, BMP2, OC, SOD, GPX), were evaluated. Our data demonstrated that weaning diets supplemented with Mn, Se, and Zn in amino acid-chelated (organic) or nanoparticle form were more effective than diets supplemented with inorganic form of minerals to promote bone mineralization, and prevent skeletal anomalies in seabream larvae. Furthermore, nanometals markedly improved larval stress resistance in comparison to inorganic minerals and upregulated mRNA copy number of OC gene. The expression of this gene was strongly correlated with mineralization degree, thus confirming its potency as a good marker of bone mineralization in gilthead seabream larvae.  相似文献   

6.
The dietary lysine requirement of juvenile gilthead seabream was determined by the growth response of duplicate groups of fish (3.5 g initial weight) fed on six isonitrogenous (427 g kg?1) and isolipidic (135 g kg?1) diets containing graded levels of crystalline l ‐lysine HCl, with dietary lysine content ranging from 36.3 to 79.7 g kg?1 of protein. The final indispensable amino acid profile of the diets except for lysine was formulated so as to resemble that of wild seabream whole body. Except for the reduced growth performance of fish groups fed the lysine‐deficient diets no other deficiency signs were apparent. Survival observed throughout the feeding period of 6 weeks was excellent. Weight gain (in %), specific growth rate, feed efficiency and daily protein deposition (DPD) were significantly improved in response to the increasing levels of dietary lysine up to 52.7 g kg?1 of protein and remained nearly constant thereafter. Whole‐body protein content followed a similar pattern as growth parameters in relation to dietary lysine level. Non‐linear regression analysis of DPD against dietary lysine level using the four‐parameter saturation kinetic model indicated a lysine requirement of 50.4 g kg?1 of protein for this species to support growth.  相似文献   

7.
The application of probiotics on aquatic animals is increasing for a better fish welfare status as well as an environment-friendly activity which are actual demands of modern aquaculture industry. A bacterium from skin mucus of healthy gilthead seabream (Sparus aurata L.) has been isolated and identified as Shewanella putrefaciens Pdp11. Different studies have been done to know its application as probiotic in the Senegalese sole and gilthead seabream farming. This article reviews the studies carried out with this probiotic microorganism focusing on the current knowledge of its in vitro and in vivo mechanisms of action. The results suggested that the probiotic S. putrefaciens Pdp11, due to its beneficial effects, could be used in the aquaculture activity of both species.  相似文献   

8.
Partial substitutions of fish meal by 5, 15, or 25 % of Gracilaria cornea or Ulva rigida in experimental diets were evaluated to study their effects on biodiversity of intestinal microbiota composition in gilthead seabream (Sparus aurata) juveniles. The diets were offered to duplicate groups of 15 juvenile fish (14.0 ± 0.5 g) for 70 days, and at the end of the experiment the intestinal microbiota from four specimens of each treatment was analysed by denaturing gel gradient electrophoresis. Results showed that the substitution of fish meal by algae meal induced important modifications in the intestinal microbiota community, as a big reduction of the biodiversity when the highest percentage (25 %) of U. rigida was included. On the contrary, an increase on the number of species was detected when a 15 % of algae was included. Various Lactobacillus delbrueckii subspecies were selectively stimulated when G. cornea was included in the feed, and other bacterial species, such as those included in the Vibrio genus, were reduced.  相似文献   

9.
We have studied the effects of time‐restricted food access and ration restriction on gilthead sea bream demand‐feeding behaviour and nutritional use of the diet (Sparus aurata), and also compared the nutritional efficiency of three different feeding systems: manual, automatic and modulated‐automatic. In the first trial, fish were allowed to feed from self‐feeders under three different conditions: ad libitum, ration restriction, and time‐restricted food access, and their demand‐feeding pattern, diet utilization and body composition were analysed. In the second trial, animals were fed by hand or using an automatic system, either fixed or modulated, and diet utilization and body composition were analysed as before. Restricting the amount of food modifies gilthead seabream self‐feeding behaviour, with fish increasing the number of demands provided these are rewarded with food. However, demand‐feeding activity does not increase if rewards are restricted to a certain time. Feeding gilthead sea bream by hand versus automatically, and distributing the daily food ration in two or three equal or unequal‐size daily meals, have no effect on the animals’ growth, nutritional use of the diet or body composition.  相似文献   

10.
Soy and rapeseed protein concentrates (SPC and RPC) were evaluated as fish meal substitutes in gilthead seabream Sparus aurata L. diets. The protein concentrates were used to replace 30%, 60% and 100% fish meal, and effects on feed intake, weight gain and feed gain ratio were determined in a 56‐day growth trial. Some groups were then grown beyond 56 days, until all reached an average weight of 50 g. A comparison of body composition at 50 g showed no significant differences in protein and ash content among all fish, while lipid and energy contents were different. The 100% RPC and 60% and 100% SPC replacement diets had lower body lipid and energy contents compared with those of the control diet. Feed intake and weight gains were inversely related to inclusion levels of plant proteins. Feed intake dropped to 52–72% of that of the control treatment and weight gain to 46–61%. Energy retention followed this same trend, decreasing from ERV values of 53 to 44 with an increase in dietary plant protein content. With the exception of 100% SPC substitution (PPV = 35), protein retention among treatments was similar (PPV = 37–39). These results suggest that both SPC and RPC may be promising protein sources for inclusion in seabream diets. The relative palatability of these plant proteins could be a limiting factor in their use.  相似文献   

11.
The recent increase of the local population of gilthead seabream, Sparus aurata, in three areas along the southeastern Adriatic Sea: Malostonski Bay (Croatia and Bosnia and Herzegovina), Neretva Estuary (Croatia) and Boka Kotorska Bay (Montenegro) and its adverse effects on shellfish culture by preying on Mediterranean mussels, Mytilus galloprovincialis, and the European flat oyster, Ostrea edulis, are studied. The results from the analysis of the existing information show that the main reason for the recent increase is the escapes from local fish farm which enrich the local population constantly with new gilthead sea bream. The existence of practically endless food in the area of the shellfish farms allows the concentration of the population in the region instead of its dispersion along the Adriatic coast. Moreover, ecological analysis indicates that the gilthead seabream is facing a very low competition from other local species which enhances its capacity to further populate the region. While the impact on the ecosystem is not yet known, the socio-economic impact of the increase of the gilthead seabream population is evident today. Many shellfish farms are closing today in the region since the damages may reach over 90 % of the production.  相似文献   

12.
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13.
This is an overview of our recent studies of energy metabolism in fish brain and other organs regulated by exogenous (feeding, salinity) and endogenous (hormones) factors. To highlight our approach, we present latest results concerned osmoregulation in the gills of gilthead seabream, Sparus auratus. Our model, the seabream, is a euryhaline teleost capable of adaptation to extreme changes in environmental salinity. Treatment with cortisol allowed us to achieve circulating cortisol levels similar to those observed during osmotic adaptation and to assess how elevated hormonal levels affected simultaneously metabolic and osmoregulatory capacities of the gill tissue. Cortisol-implanted fish showed higher gill Na+,K+-ATPase activity than control fish but no changes were observed in plasma osmolality and ion levels. Plasma levels of glucose and lactate increased in cortisol-implanted fish while protein levels decreased. Cortisol treatment elicited metabolic changes in liver and brain reflecting an activation of the glycogenic and gluconeogenic potential in liver, and the glycogenic potential in brain, which are confirmatory of data obtained in previous experiments. In gills, we demonstrated that cortisol treatment elicited changes in their energy metabolism that can be summarized as a decreased capacity in the use of exogenous glucose (decreased HK activity), a decrease in the capacity of the pentose phosphate pathway (decreased G6PDH activity), and an increased glycolytic potential (increased PK activity). Observed metabolic changes in gills can be associated with those occurring in nature during osmotic adaptation in the same fish species.  相似文献   

14.
The first attempt to rear the gilthead seabream, Sparus aurata, in brackish water ponds in Egypt was conducted from April 1976 to February 1977. Experimental ponds were stocked with Sparus aurata fry of about 32 mm and 1.5 g average length and weight respectively at a rate of 3000 fry per one feddan of pond water (i.e. 0.42 ha). The growth rate was recorded monthly. An average length and weight of 190 mm and 78 g respectively was attained after 8 months without supplementary feeding or fertilization of pond water. mathematical equations expressing length-weight relationship and condition factor were derived for both wild and reared fish. The higher values of condition factor obtained for the reared fish in comparison to the wild fish signify their improved condition and hence their suitability for farming in Egypt.  相似文献   

15.
Results are presented of a zero‐discharge marine recirculating system used for the culture of gilthead seabream Sparus aurata. Operation of the system without any discharge of water and sludge was enabled by recirculation of effluent water through two separate treatment loops, an aerobic trickling filter and a predominantly anoxic sedimentation basin, followed by a fluidized bed reactor. The fish basin was stocked for the first 6 mo with red tilapia Oreochromis niloticus × O. aureus at an initial density of 16 kg/m3. During this period salinity was raised from 0 to 20 parts per thousand. Then, gilthead seabream, stocked at an initial density of 21 kg/m3, replaced tilapia at day 167 and were cultured for an additional 225 d. Non steady‐state inorganic nitrogen transformations occurred as a result of these salinity changes. After day 210, the system operated at all times with those water quality parameters considered critical for successful operation of mariculture systems, within acceptable limits. Thus ammonia, nitrite, and nitrate concentrations did not exceed 1.0‐mg total ammonia‐N/ L, 0.5‐mg NO2:‐N/L and 50‐mg NO3‐N/L, respectively. Sulfide levels in the fish basin were below detection limits and oxygen > 6 mg/L after the oxygen generator was added at day 315. Ammonia, produced in the fish basin and to a lesser extent in the sedimentation basin, was converted to nitrate in the aerobic trickling filter. Nitrate removal took place in the sedimentation basin and to a lesser extent in the fluidized bed reactor. Sludge, remaining in the sedimentation basin at the end of the experimental period, accounted for 9.2% of the total feed dry matter addition to the system. The system was disease‐free for the entire year and fish at harvest were of good quality. Water consumption for production of 1 kg of tilapia was 93 L and 214 L for production of 1 kg of gilthead seabream. Additional growth performance data of gilthead seabream cultured in a similar but larger system are presented. During 164 d of operation of the latter system, maximum stocking densities reached 50 kgl M3 and fish biomass production was 27.7 kg/m3. Relatively poor fish survival and growth resulted from occasional technical failures of this pilot system.  相似文献   

16.
Four isolates obtained from gilthead seabream have been tested for their adhesion to the skin, gill and intestinal mucus of gilthead seabream, and for their ability to interfere with Listonella anguillarum, an important pathogen of farmed gilthead seabream. The ability to adhere to mucus was higher than 7% for all isolates. Three isolates showed an antagonistic effect against some of the pathogenic strains tested. They were assayed to interfere with the attachment of L. anguillarum to the mucus of gilthead seabream. Only two isolates significantly reduced the adhesion of L. anguillarum to all of the mucus assayed under exclusion, competition and displacement conditions. According to the criteria applied, the isolate Pdp11 was selected and its in vivo probiotic potential was assessed by oral administration followed by challenge with the pathogen L. anguillarum. For the feeding trial, a group of 50 gilthead seabreams received a commercial diet supplemented with lyophilized 108 CFU g?1 of this isolate for 15 days. An other group of similar characteristics received the non‐supplemented commercial diet. After the challenge, the mortality of the fish receiving the diet supplemented with the potential probiotic was significantly lower than that observed in the groups of fish receiving the non‐supplemented commercial diet.  相似文献   

17.
Tissue distribution and depletion of sarafloxacin was studied in gilthead seabream, under experimental field conditions at 25 and 18 °C, after in-feed administration of sarafloxacin hydrochloride for 5 days (10 mg/kg body weight/day). Ten fish per sampling point were examined during and after treatment. Muscle plus skin (n=10), liver, kidney and vertebra (pooled) were collected and analyzed by HPLC. Sarafloxacin concentrations in these tissues increased during the medication period, and then decreased rapidly. The highest sarafloxacin concentrations were recorded in liver (335.2 and 49.8 μg/g at 25 and 18 °C, respectively). In muscle plus skin, sarafloxacin concentrations were 193.0 and 42.0 μg/kg at 25 and 18 °C, respectively. Sarafloxacin residues were eliminated rapidly; at 36 h post treatment, the levels in muscle plus skin were 10.2 and 8.5 μg/kg at 25 and 18 °C, respectively. Elimination half-lives (t1/2) were 17.8 and 32.5 h at 25 and 18 °C, respectively. Withdrawal period for the Maximum Residue Limit (MRL) of 30 μg/kg sarafloxacin in muscle plus skin (95% tolerance limit) at 25 °C was 42.2 h. The slow elimination from vertebra, relative to other tissues, suggests that vertebra behaves as a reservoir in gilthead seabream.  相似文献   

18.
《水生生物资源》1998,11(4):265-268
A model to estimate the waste production from sea cage culture was established. Using known feed inputs of nitrogen, phosphorus and organic matter, the model quantifies waste discharge from seabream culture. Daily feed intake and growth in Sparus aurata fed a commercial diet with known composition were measured and found to be dependent on fish weight and water temperature. Digestibility of the commercial feed was measured using chromic oxide as a marker and collection of feces by stripping. The proximate composition of Sparus aurata at different sizes was determined and nitrogen and phosphorus content were on average 28.5 and 7.2 g·kg−1 body mass, respectively. Excretion of ammonia-nitrogen and inorganic phosphorus after metabolic processes was calculated as the difference.  相似文献   

19.
A feeding experiment was conducted over 9 weeks with seven groups of 30 (fish per group) unpigmented gilthead seabream, Sparus aurata (L. 1875) (initial mean weight = 145.2 ± 12.3 g). Three experimental diets were prepared by adding to a basal diet free of carotenoid (final pigment content of around 40 mg per kg feed): (i) a biomass of the carotenogenic Chlorella vulgaris (Chlorophyta, Volvocales); (ii) a synthetic astaxanthin; and (iii) a mixture (1:1) of microalgal biomass and synthetic astaxanthin. At 3‐week intervals, five fish were sampled from each tank for total carotenoids analysis in skin and muscle. The carotenoid pigments (total amount = 0.4%) identified in the carotenogenic alga were lutein (0.3%), β‐carotene (1.2%), canthaxanthin (36.2%), astaxanthin, free and esterified forms (55.0%), and other pigments (7.3%). Carotenoid pigments were significantly deposited in the four skin zones studied during the feeding trial: the forefront between the eyes, the opercule, along the dorsal fin and in the abdominal area. In the muscle, regardless of the astaxanthin source, the amount of carotenoids measured was very low (less than 1 mg kg?1) and differences not significant. Moreover, no muscle pigmentation was evident, and there was no variation in the amount of carotenoid analysed in skin tissue, through the trial, for each treatment. It was concluded that supplementing the feed with C. vulgaris would be an acceptable practice in aquaculture to improve the market appeal of the gilthead seabream.  相似文献   

20.
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   

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