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Recirculation System (recirculation + system)
Selected AbstractsPermanganate Treatment of an Emplaced DNAPL SourceGROUND WATER MONITORING & REMEDIATION, Issue 4 2007Neil R. Thomson In situ chemical oxidation (ISCO) using permanganate is one of the few promising technologies that have recently appeared with the capability of aggressively removing mass from nonaqueous phase liquid (NAPL) source zones. While NAPL mass in regions of the treatment zone where delivery is dominated by advection can be removed rather quickly, the rate of mass removal from stagnant zones is diffusion controlled. This gives rise to partial mass removal and a concomitant reduction in the NAPL mass, downgradient ground water concentrations, and the dissolution rate associated with the source zone. Therefore, monitoring the performance of a permanganate ISCO treatment system is important to maintain the desired efficiency and to establish a treatment end point. In this paper, we illustrate the use of various monitoring approaches to assess the performance of a pilot-scale investigation that involved treatment of a multicomponent NAPL residual source zone with permanganate using a ground water recirculation system for 485 d. Ongoing treatment performance was assessed using permanganate and chloride concentration data obtained from extraction wells, 98 piezometers located approximately 1 m downgradient from the source, and ground water profiling. At the completion of treatment, 23 intact soil cores were extracted from the source zone and used to determine the remaining NAPL mass and manganese deposition. Based on the data collected, more than 99% of the initial NAPL mass was removed during treatment; however, remnant NAPL was sufficient to generate a small but measurable dissolved phase trichloroethene (TCE) and perchloroethene (PCE) plume. As a result of treatment, the ambient-gradient discharge rates were reduced by 99% for TCE and 89% for PCE relative to baseline conditions. The lack of complete source zone oxidation was presumed to be the result of dissolution fingers, which channeled the permanganate solution through the source zone preventing direct contact with the NAPL and giving rise to diffusion-limited mass removal. [source] Changes in amino acid composition in the tissues of African catfish (Clarias gariepinus) as a consequence of dietary L-carnitine supplementsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2002R. O. A. Ozório A study was undertaken to examine the effect of different amounts of dietary lysine (13 and 21 g kg,1 diet), lipid (80 and 160 g kg,1 diet) and L -carnitine (0.2 and 1.0 g kg,1 diet) on growth performance, proximate composition and amino acid metabolism of the African catfish (Clarias gariepinus). Juvenile African catfish (23 ± 1.5 g/fish) were stocked into 70-L aquaria (16 aquaria, 28 fish/aquarium) connected to a recirculation system during a maximum period of 74 days. All groups were fed at a level of 24 g kg,0.8 day,1 in an experiment run at pair feeding. Animals receiving 1.0 g carnitine accumulated up to six times more carnitine in their tissues than animals receiving 0.2 g (P < 0.05). Acyl-carnitine and free L -carnitine levels increased in the whole body and in tissues. Dietary L -carnitine supplements increased protein-to-fat ratios in the body, but did not affect growth rate. Protein-to-fat ratios were only affected when the biosynthesis capacity of L -carnitine was restricted due to low lysine levels and when there was a shortage of dietary fat. When lysine was offered at 21 g kg,1 feed, dietary L -carnitine supplements did not affect the amino acid concentrations of body tissues. Dietary L -carnitine supplements raised the concentration of glutamic acid,>,aspartic acid,>,glycine > alanine > arginine > serine > threonine in skeletal muscle tissue (P < 0.05). Total amino acid concentration in muscle and liver tissues (dry-matter basis) increased from 506 to 564 and from 138 to 166 mg g,1, respectively, when diets were offered with high L -carnitine, low lysine and low fat levels. These data suggest that dietary L -carnitine supplementation may increase fatty acid oxidation and possibly decrease amino acid combustion for energy. [source] Isolation and characterization of strains of Flavobacterium columnare from BrazilJOURNAL OF FISH DISEASES, Issue 4 2005H C P Figueiredo Abstract Flavobacterium columnare is an important pathogen of freshwater fish, implicated in skin and gill disease, often causing high mortality. An outbreak of skin disease in fingerling and adult Nile tilapia, Oreochromis niloticus (L.), cultivated in a recirculation system, was investigated. Four strains were isolated and characterized by biochemical reactions, enzyme production, fatty acid profile and analysis of the 16S-23S rDNA intergenic spacer region. All strains were identified as F. columnare. Experimental infection assays with one of these strains (BZ-5-02) were conducted and pathogenicity (by intramuscular route) was demonstrated in Nile tilapia and channel catfish, Ictalurus punctatus (Rafinesque). This is the first report of characterization of Brazilian strains of F. columnare. [source] Evaluation of Alternative Protein Sources to Replace Fish Meal in Practical Diets for Juvenile Tilapia, Oreochromis sppJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2009Tri N. Nguyen Two feeding experiments were conducted to evaluate if methionine is limiting in practical grow-out diets for tilapia, Oreochromis spp. Four diets containing 32% protein and 5% lipid were designed to compare the use of diets high in dehulled solvent-extracted soybean meal (DSESM) and expeller pressed soybean meal (EPSM) compared with a diet containing 6% fish meal (FM). Tilapia (4.78 ± 0.07 g, mean ± SD) were randomly stocked into twelve 600-L flow-through tanks at 20 fish per tank. After 6 wk, there were no notable trends or statistically significant differences (P > 0.05) in final mean weight, survival rate, and feed conversion ratio (FCR) among the treatments. Because results of this study indicated that DSESM could totally replace FM in practical diets for juvenile tilapia, a second batch of diets were formulated using other protein sources. Typical levels of cottonseed meal (CSM), DSESM, and meat and bone meal (MBM) were used to evaluate whether methionine could be limiting. Two basal diet formulations were tested either without or with methionine supplement (0.06/100 g diet). The first diet contained 15% CSM, 27% DSESM, and 10% MBM and the second diet contained 15% CSM and 37% DSESM. These diets contained 28% protein and 5% lipid. Tilapia (3.90 ± 0.05 g) were randomly stocked into twelve 60-L glass aquaria of a recirculation system at 18 fish per aquarium for 5 wk and then moved to the 600-L flow-through tanks for five more weeks. After 10 wk, there were no statistically significant differences (P > 0.05) in final mean weight, survival rate, and FCR among the four treatments. Results of the present study indicated that DSESM and EPSM could totally replace FM's inclusion rate in commercial diets for juvenile tilapia. Furthermore, methionine did not appear to be limiting in practical diets using typical levels of CSM, DSESM, and MBM as primary protein sources. [source] Effect of Feeding Frequency, Water Temperature, and Stocking Density on the Growth of Tiger Puffer, Takifugu rubripesJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2006Kotaro Kikuchi Effects of daily feeding frequency, water temperature, and stocking density on the growth of tiger puffer, Takifugu rubripes, fry were examined to develop effective techniques to produce tiger puffer in a closed recirculation system. Fish of 4, 14, and 180 g in initial body weight were fed commercial pellet diets once to five times a day to apparent satiation each by hand for 8 or 12 wk at 20 C. Daily feeding frequency did not affect the growth of 14- and 180-g-size fish. However, the daily feed consumption and weight gain of the 4-g-size fish fed three and five times daily were significantly higher than those of fish fed once daily (P < 0.05). Fish of 4 and 50 g in initial body weight were reared with the pellet diet at 15,30 C for 8 wk. The weight gain of fish increased with increasing water temperature up to 25 C and decreased drastically at 30 C for both sizes. Similar trends were observed for feed efficiency, although 4-g fish had highest efficiency at 20 C. Effects of stocking density on growth were examined with fish of 8, 13, and 100 g in initial body weight. Fish were reared with the pellet diet for 8 or 16 wk at 20 C. Fish were placed in floating net cages in the culture tank, and the stocking density was determined based on the total weight of fish and volume of the net cage. Fish of 8 g in body weight grew up to 35,36 g during the 8-wk rearing period independent of the stocking density of 8, 15, and 31 kg/m3 at the end of rearing. Final biomass per cage reached 32, 60, and 115 kg/m3 for 13-g-size fish, and 10, 18, and 35 kg/m3 for 100-g-size fish, and the growth of the fish tended to decrease with increasing stocking density for both sizes. [source] MARS dialysis in decompensated alcoholic liver disease: A single-center experienceLIVER TRANSPLANTATION, Issue 8 2007Birger Wolff Acute decompensation of chronically stable alcoholic liver disease (ALD) is the most common cause of terminal liver failure in developed countries. Molecular adsorbent recirculation system (MARS) is increasingly used as artificial liver support to facilitate spontaneous organ recovery. However, the experience to date and the evidence to justify this therapeutic strategy in acutely decompensated ALD are still insufficient. We report our clinical experience with MARS in 14 patients with acutely decompensated ALD (6 male subjects; median age [interquartile range], 51 [47-56] years; Child-Pugh score, 12 [10-13]; Acute Physiology and Chronic Health Evaluation (APACHE) II score, 20 [18-24]) and severely impaired liver function whose disease was unresponsive to conventional supportive care. At least 3 sessions were applied in any patient (48 sessions in total). Under MARS treatment, the following levels decreased: bilirubin (544 [489-604] to 242 [178-348] ,mol/L; P < 0.001), creatinine (212 [112-385] to 91 [66-210] ,mol/L; P = 0.002), cholestatic parameter gamma-glutamyl transpeptidase (5.9 [1.8-13.1] to 4.6 [1.8-8.3] ,mol/L) (P < 0.001), blood urea nitrogen (56 [32-91] to 34 [21-68] mmol/L; P = 0.044), and platelet count (176 [85-241] to 84 [31-145] Gpt/L; P = 0.004). In contrast, MARS failed to improve daily urine output (P = 0.846), ammonia levels (P = 0.340), or thromboplastin time (P = 0.775). Only 3 patients survived the hospital stay (mortality 78.6%). Although MARS improved laboratory parameters of hepatic detoxification and renal function in patients with acutely decompensated ALD, the patients' mortality remained unsatisfactorily high. Our experience does not support the indiscriminative use of MARS in acutely decompensated ALD without further controlled studies. Liver Transpl 13:1189,1192, 2007. © 2007 AASLD. [source] Feasibility of a new method to collect exhaled breath condensate in pre-school childrenPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 1-Part-II 2010Philippe P. R. Rosias Rosias PPR, Robroeks CM, van de Kant KD, Rijkers GT, Zimmermann LJ, van Schayck CP, Heynens JW, Jöbsis Q, Dompeling E. Feasibility of a new method to collect exhaled breath condensate in pre-school children. Pediatr Allergy Immunol 2010: 21: e235,e244. © 2009 John Wiley & Sons A/S Exhaled breath condensate (EBC) is a promising non-invasive method to assess respiratory inflammation in adults and children with lung disease. Especially in pre-school children, condensate collection is hampered by long sampling times because of open-ended collection systems. We aimed to assess the feasibility of condensate collection in pre-school children using a closed glass condenser with breath recirculation system, which also collects the residual non-condensed exhaled breath, and subsequently recirculates it back into the condenser. Condensate was collected before and after breath recirculation in 70 non-sedated pre-school children with and without recurrent wheeze. Cytokines (IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, TNF-,) were measured in 50 ,l samples using ultrasensitive multiplexed liquid bead array. The success rate of condensate collection increased from 64% (without recirculation) to 83% (after breath recirculation), and mean condensate volume from 214 to 465 ,l respectively. Detection of cytokines was successful in 95,100% of samples. Cytokine concentrations before and after breath recirculation were not different (p > 0.232). In asthmatic children, only TNF-, concentrations were significantly decreased, compared to non-asthmatics. In pre-school children, the collection of EBC is feasible using a new closed glass condenser with breath recirculation system. This new method may help to assess , non-invasively , cytokine profiles in asthmatic and non-asthmatic pre-school children. [source] Effect of dietary carbohydrate-to-lipid ratios on growth performance, body composition, nutrient utilization and hepatic enzymes activities of herbivorous grass carp (Ctenopharyngodon idella)AQUACULTURE NUTRITION, Issue 3 2010W. GAO Abstract Six isonitrogenous (390 g kg,1) and isoenergetic (16.2 kJ g,1) diets with varying carbohydrate : lipid (CHO : L) ratios (202.5,1.74), were fed to triplicate groups of 25 fish in indoor recirculation system. Over 8-week-growth trial, best weight gain (WG), specific growth rate, feed conversion ratio, protein efficiency ratio and protein production value (P < 0.05) were observed in fish-fed diets with CHO : L ratio of 7.5. Fish fed either the lowest (1.7) or highest (202.5) CHO : L ratio tended to produce lower (P < 0.05) growth and feed conversion efficiencies. The values of viscerosomatic index, hepatosomatic index and intraperitoneal fat ratio increased as dietary CHO : L ratios decreased. There were no significant differences in whole body and liver crude protein among dietary treatments. Whole body and liver lipid increased as CHO : L ratios decreased. Plasma cholesterol and triacylglyceride levels increased linearly as dietary CHO : L ratios decreased. Activities of glucokinase and pyruvate kinase were stimulated by elevated levels of dietary carbohydrate; however, activities of lipase (LPS) and alkaline phosphatase were stimulated by elevated levels of dietary lipid. Based on a second-order polynomial regression analysis of WG against dietary carbohydrate and lipid levels, 275 g kg,1 of carbohydrate and 59 g kg,1 of lipid, corresponding to a CHO : L ratio of 4.7, in a diet holding 390 g kg,1 of crude protein and 16.3 kJ g,1 of gross energy, proved to be optimal for grass carp. These results indicated that utilization of dietary lipid and carbohydrate was moderate in grass carp, but the fish were a little more capable of utilizing lipid compared with carbohydrate. [source] Re-evaluation of total sulphur amino acid requirement and determination of replacement value of cystine for methionine in semi-purified diets of juvenile Nile tilapia, Oreochromis niloticusAQUACULTURE NUTRITION, Issue 3 2009T.N. NGUYEN Abstract Two feeding experiments were conducted to re-evaluate the total sulphur amino acid (TSAA; methionine and cystine) requirement and determine the replacement value of cystine for methionine of juvenile Nile tilapia (Oreochromis niloticus). Semi-purified diets used in both experiments contained 3510 kcal gross energy and 280 g of protein per kilogram diet from casein, gelatin and crystalline amino acids. The basal diet of the first experiment contained 3.1 g methionine and 0.4 g cystine per kilogram. l -methionine was added to the seven remaining diets at 1.0 g kg,1 increment to produce methionine levels ranging from 3.1 to 10.1 g kg,1 diet. Each diet was fed to four replicate groups of juvenile Nile tilapia (1.28 g mean weight) in a recirculation system for 8 weeks. Broken-line regression analysis of weight gain data indicated that the TSAA requirement of juvenile Nile tilapia was 8.5 g kg,1 of the diet or 30.4 g kg,1 of dietary protein. In the second experiment, TSAA level was set at 95% of the requirement value determined in the first experiment. Seven diets were made with different ratios of l -methionine and l -cystine (20 : 80, 30 : 70, 40 : 60, 50 : 50, 60 : 40, 70 : 30 and 80 : 20, based on an equimolar sulphur basis). Each diet was also fed to four replicate groups of juvenile Nile tilapia (4.14 g mean weight) in a recirculation system for 8 weeks. Regression analysis of weight gain data using broken-line model indicated that cystine (on a molar sulphur basis) could replace up to 49% of methionine requirement in semi-purified diets for juvenile Nile tilapia. [source] Effects of varying dietary fatty acid profile on growth performance, fatty acid, body and tissue composition of juvenile pike perch (Sander lucioperca)AQUACULTURE NUTRITION, Issue 6 2005C. SCHULZ Abstract Pike perch (Sander lucioperca) has been identified as specie destined to diverse European inland aquaculture, but knowledge on the nutritional requirements is weak. Therefore, we investigated the effect of varying dietary fatty acid (FA) profile by partial replacement of fish oil (FO) with vegetable oils on growth, FA and body composition of juvenile pike perch. An extruded basal diet containing 59 g kg,1 crude lipids (FO) was added with 60 g kg,1 FO, 60 g kg,1 linseed oil (LO) or 60 g kg,1 soybean oil (SO). The resulting dietary FA composition differed mainly in the triglyceride fraction and was characterized by highest amounts of linolenic acid (18:3 n-3) in the LO diet and linoleic acid in the SO diet. Diet enriched with FO contained highest contents of highly unsaturated FA 20:5 n-3 (eicosapentaenic acid) and 22:6 n-3 (docosahexaenic acid). Pike perch were held in a recirculation system and each feeding group (in triplicate) was fed with experimental diets at a daily rate of 35 g kg,1 of biomass for 57 days by automatic feeders. Weight gain and specific growth rate of experimental feeding groups ranged between 18.47 and 19.58 g and 1.37,1.45% day,1 and was not affected by the dietary composition indicating that FO can be replaced by vegetable oils without negative impact on growth performance. In contrast to the whole body and muscle composition, liver tissue was affected by the varying diets. Liver tissues of fish fed diets enriched with vegetable oils showed significantly increased lipid contents of 162 (LO) and 147 (SO) g kg,1 and indicate decreased lipid utilization compared with fish fed FO diet (liver lipid content 112 g kg,1). Nevertheless, hepatosomatic index of pike perch was not influenced by dietary lipid composition. The FA profile of pike perch was generally determined by the dietary FAs. [source] Influence of different sources and levels of dietary protein and lipid on the growth, feed efficiency, muscle composition and fatty acid profile of Snakehead Channa striatus (Bloch, 1793) fingerlingAQUACULTURE RESEARCH, Issue 9 2010Mohammed Aliyu-Paiko Abstract Nine isoenergetic (18.5 kJ g,1) diets were formulated, in a 3 × 3 factorial design, by varying three levels of dietary protein (350, 400 and 450 g kg,1) at each of three levels of dietary lipid (65, 90 and 115 g kg,1) accordingly. Each diet was hand fed two times daily for 8 weeks to triplicate homogenous groups of eight fish (average weight 3.34 ± 0.02 g) per tank connected to a recirculation system. Results showed that the feed efficiency and growth performance significantly (P<0.05) increased with increasing protein level at the two lower lipid levels (65 and 90 g kg,1), respectively, as indicated by indices such as %weight gain, specific growth rate, protein efficiency ratio, feed conversion ratio and feed intake, but did not at the highest lipid level (115 g kg,1). The muscle polyunsaturated fatty acids (PUFA) content declined with increasing dietary protein level at the lipid levels producing the highest growth, suggesting that the utilization of PUFA influences growth. Whereas the muscle monounsaturated fatty acids level was generally lower than the dietary levels in all the treatments tested, indicating preferential catabolism for energy, the muscle saturated fatty acids level was comparatively higher than in the diets, indicating selective deposition. Docosa hexaenoic acid (22:6n3, DHA), which was very low in the diet and in the initial fish, was higher in the muscle of some of the treatments, indicating the ability of Channa striatus to desaturate and elongate short-chain PUFA to long-chain HUFA, due to the availability of dietary 18:3n3 and 20:5n3 (the precursors for DHA biosynthesis). It could be concluded, based on the results of this trial, that a diet formulated to contain 65 g kg,1 lipid and 450 g kg,1 protein, with a gross energy of 18.5 kJ g,1 and a dietary n3/n6 PUFA ratio of about 0.1, is sufficient to promote good feed efficiency and growth performance in C. striatus fingerling. [source] Protein lipid ratio for the growth and survival of juvenile crayfish Procambarus acanthophorus (Hobbs 1972) reared under controlled conditionsAQUACULTURE RESEARCH, Issue 9 2010Enrique Cervantes-Santiago Abstract The influence of dietary protein/lipid levels on growth and survival in juvenile crayfish (Procambarus acanthophorus) was evaluated during a 12-week nutritional trial. Twenty experimental diets were formulated containing different protein (200, 250, 300, 350 and 400 g kg,1) and lipid (60, 80, 100 and 120 g kg,1) levels. A bifactorial model (5 × 4) was used with three replicates and 15 crayfish (0.014±0.006 g) per replicate, in a recirculation system with 60,15 L rectangular tanks and a biological filter, the culture conditions were a photoperiod of 12:12 h L:D and temperature 24.7±1.0 °C. Total survival ranged from 66.6% to 86.6%, with no differences attributed to treatments. Dietary protein levels had a significant effect on growth gain and nutritional efficiency; in contrast, lipid levels had no effect on juvenile performance. The 250/120 (protein/lipid) treatment promoted the most efficient growth (final weight: 3.09 g, weight gain: 21 995%, specific growth rate: 3.35% day,1); the less efficient growth was observed in juveniles fed with 400 g kg,1 protein diets. The quadratic regression model indicated 279 g kg,1 as the optimal protein level for crayfish growth, while levels between 211 and 232 g kg,1 could minimize the feeding costs without affecting growth. [source] Survival and growth of selected marine fish larvae first fed with eggs and endotrophic larvae of the sea urchin Paracentrotus lividusAQUACULTURE RESEARCH, Issue 9 2010Joăo Gago Abstract Two sets of experiments were carried out to evaluate the potential of eggs and endotrophic larvae of captive Paracentrotus lividus as alternative live prey for marine fish larvae first feeding. The first consisted in rearing sparids, Diplodus sargus and Sparus aurata, larvae until 15 days after hatching in a recirculation system. Compared with the commonly used live prey , rotifer Brachionus spp. , general lower values of survival and growth were obtained when fish larvae were fed with the alternative live prey. Among these, eggs showed to be the preferred feeding. Broodstock feed showed to play a fundamental role on prey quality and consequent fish larvae survival. In the second set of experiments, the 24-h ingestions of the first feeding larvae in static water were determined for five currently cultured fish larvae species. Except for larger and more predatory Dicentrarchus labrax larvae, there was a trend for higher P. lividus egg ingestion, followed by pre-plutei and prisms. Prey size, colour and movement affected food selection by fish larvae. It is concluded that, in spite of the alternative live prey being readily consumed by all tested fish larvae, they cannot however presently compete with rotifers in marine fish larvae first feeding. [source] Effect of stocking density and protein/fat ratio of the diet on the growth of Dover sole (Solea solea)AQUACULTURE RESEARCH, Issue 16 2008Giovanni Piccolo Abstract Two hundred and fifty soles (30 g initial weight) were randomly stocked in 12 tanks (recirculation system) at two different stocking densities (2.3 and 1.3 kg m,2) and fed on two different diets (50% and 54% of crude protein and 21% and 18% of total lipid, respectively, for diets A and B) with triplicate tanks for treatment. The trial lasted for 300 days. Fish stocked at low density showed a significantly higher weight gain than the fish reared at 2.3 kg m,2 density (94.1±7.4 vs. 78.9±8.2 g, P<0.01) with a specific growth rate (SGR) of 0.46±0.11 and 0.43±0.16 (P<0.01) respectively. Feed conversion ratio (FCR) was more favourable for lower density groups (2.50 vs. 2.64, P<0.01). Diet B led to a higher final weight (124.1 vs. 110.2 g, P<0.01) and a better feed utilization (FCR: 2.49 vs. 2.65, P<0.01). Except for the lipid content, which was higher in the low-density group (2.6% vs. 2.3%, P<0.05), proximate composition of sole's muscle was not influenced by treatments. Dover sole reared at low stocking density showed higher monounsaturated fatty acid (35.27% vs. 34.40%, P<0.01) and lower saturated fatty acid (24.36 vs. 26.13%, P<0.01) contents, and lower atherogenic (0.67 vs. 0.75, P<0.01) and thrombogenic (0.28 vs. 0.32, P<0.01) indexes. [source] Effect of salinity on carrying capacity of adult Nile tilapia Oreochromis niloticus L. in recirculating systemsAQUACULTURE RESEARCH, Issue 16 2006M A Kabir Chowdhury Abstract Effect of salinity on carrying capacity of a recirculation system for Nile tilapia, Oreochromis niloticus L.; production was assessed. Survival, growth and feed conversion ratio of adult Nile tilapia fed 30% crude protein diet for 88 days were measured at three different salinity levels (8, 15 and 25 g L,1) and two stocking densities (20 and 40 m,3) in three independent recirculating systems. Highest survival (98%) and a linear growth in net biomass (P<0.01) was observed in both densities at 8 g L,1 and in 20 m,3 treatment at 15 g L,1. Highest net biomass growth was observed in the 40 m,3 stocking density treatment at 8 g L,1 salinity level (P<0.05). Overall biomass growth was significantly affected by salinity indicating a decrease in Nile tilapia carrying capacity with increased salinity. About 11 000 kg ha,1 crop,1 of Nile tilapia can be obtained in recirculating systems at 8 g L,1 salinity, significantly higher than the net production at 15 g L,1 (5200 kg ha,1 crop,1) and 22 g L,1 (4425 kg ha,1 crop,1). [source] Nutritional evaluation of dhaincha (Sesbania aculeata) seeds as dietary protein source for tilapia Oreochromis niloticusAQUACULTURE RESEARCH, Issue 9 2002M A Hossain An 8-week feeding trial was conducted in a warmwater recirculation system at 27 ± 0.2 °C to evaluate the nutritive value of dhaincha (Sesbania aculeata) seed meal as a possible fish meal substitute in the diet of tilapia. Five isonitrogenous and isoenergetic diets were formulated to contain 32% crude protein and 18.4 kJ g,1 gross energy. Sesbania seed meal was included in diets at various levels [0%, 9.7%, 19.4%, 29.1% and 38.8% for diets 1 (control), 2, 3, 4 and 5, respectively, which correspond to 0%, 10%, 20%, 30% and 40% of dietary crude protein]. Each treatment had two replicates, eight fish per replicate, with mean initial weight of 7.06 ± 0.03 g. Fish were fed 20 g kg,1 metabolic body weight daily. On the basis of the observed growth rate, feed conversion ratio, protein efficiency ratio, apparent net protein utilization and energy retention, diets 1 (control) and 2 (containing 9.7% Sesbania meal) were similar and significantly (P < 0.05) better than the other dietary groups. Fish fed diets 3, 4 and 5 containing higher levels of Sesbania meal showed significantly reduced growth performance compared with those fed diets 1 and 2. Fish fed diets 3, 4 and 5 had significantly lower faecal dry matter (DM) content, apparent crude protein, lipid and energy digestibility and reduced levels of cholesterol compared with the control and diet 2. Fish fed diets containing higher levels (>9.7%) of Sesbania meal had significantly higher whole-body moisture, lower lipid and gross energy content. The lower growth performance of fish fed diets containing higher levels of Sesbania meal is thought to result from the presence of tannins, saponin and the non-starch polysaccharide content of the seed. The results of this study showed that inclusion of up to 9.7% untreated Sesbania seed meal (10% of the dietary protein) in the diet did not affect the growth performance and nutrient utilization in tilapia. [source] Growth performance, survival and maturation of Litopenaeus vannamei (Boone) in an inland CRS with no water repositionAQUACULTURE RESEARCH, Issue 12 2009Abundio González-González Abstract Closed recirculation systems (CRS) present an alternative for providing organisms to the aquaculture. A CRS with zero water exchange was used in the present study; the CRS consisted of a culture and maturation facility, biofilter system and reservoirs tanks. During two consecutive trials, the CRS efficiency was evaluated by assessing the growth, survival and maturation of juveniles into adults Litopenaeus vannamei (Boone). Throughout the study, water quality parameters (temperature, pH, salinity, NH3, NO2 and NO3) and ion concentration were monitored. Most parameters showed fluctuations without significant differences. However, a decrease in pH was observed during the maturation phase, and an increase in phosphorus was detected, in both the trials, compared with that in initial seawater. Growth and survival for juvenile and pre-adult shrimps presented similar variations without significant differences. Female gonadal maturation and spawning rate were not significantly different between trials. Unfortunately, shrimp eggs underwent lysis 6 h after spawning. These results show that the growth, survival and maturation obtained under CRS conditions are reproducible, and suggest the possibility of using these systems for biosecure shrimp culture, protected against eventual diseases outbreaks. The results of this study also suggest the importance of future studies addressing ion concentration changes in a CRS with zero water exchange. [source] | |||||||||||||