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1.
Optimization of blue mussel (Mytilus edulis) seed culture using recirculation aquaculture systems
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By introducing recirculation aquaculture systems (RAS) in the nursery phase of the blue mussel (Mytilus edulis) (17–18 mm), we aimed at a similar growth and survival and a similar water quality compared to the commonly used flow‐through systems (FTS). To calculate water flow and size of the biofilter, a series of experiments were done to determine clearance rate (9.26 mL min?1), pseudo faeces threshold (60 000 cells Pavlova lutheri mL?1), nitrogen production (0.00065 mg TAN h?1 ind?1 and 1.6 × 10?5 mg NO2–N h?1 ind?1) and oxygen consumption (0.03 ± 0.01 mg O2 h?1 ind?1). RAS showed no significant differences in water quality (0.06 mg TAN L?1; 7.7 mg O2 L?1) and growth performance of mussel seed specific growth rate (SGR = 5% day?1) after the experimental period of 4 weeks compared with FTS. The low water refreshment, 10% per day, as well as the constant chlorophyll concentrations (9.76 ± 1.06 μg L?1), suggests the potential of RAS as culture system for mussel seed. 相似文献
2.
Six hundred Labeo rohita (average weight, 6.78 g) were distributed in 24 tanks (25 fish per tank), which were allotted to eight experimental groups in triplicates. Half of the experimental groups were maintained at ambient water temperature of 26 °C, whereas the other half were exposed to 32 °C for 1 week then later maintained at 26 °C for 4 weeks. Fish reared under different temperature regimes were fed one of the four diets containing 200 g kg?1, 300 g kg?1, 400 g kg?1 or 450 g kg?1 protein. Growth, feed efficiency and protein retention were higher at 32 °C and continued for the next 2 weeks after decreasing the temperature. The dietary protein level and water temperature interactions were more effective in modulating the response of hepatic glucokinase than that of hexokinase and pyruvate kinase. In contrast, hepatic gluconeogenesis was not affected by rearing temperature. Hepatic aspartate aminotransferase and alanine aminotransferase activity was found higher (P < 0.05) at low temperature and at high protein level. It is suggested that the metabolic activities of fish are triggered by short‐term exposure to higher temperature and the increased metabolic activity extended for a duration of 3 weeks during which 400 g kg?1 dietary protein level was found to support growth of fish. 相似文献
3.
Acute toxicity of nitrite on white shrimp Litopenaeus vannamei (Boone) juveniles in low‐salinity water
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Javier Ramírez‐Rochín Martín G Frías‐Espericueta Juan F Fierro‐Sañudo Suammy G Alarcón‐Silvas Marcela G Fregoso‐López Federico Páez‐Osuna 《Aquaculture Research》2017,48(5):2337-2343
The nitrite toxicity was estimated in juveniles of L. vannamei. The 24, 48, 72 and 96 h LC50 of nitrite‐N on juveniles were 8.1, 7.9, 6.8 and 5.7 mg L?1 at 0.6 g L?1; 14.4, 9.6 8.3 and 7.0 mg L?1 at 1.0 g L?1; 19.4, 15.4, 13.4 and 12.4 mg L?1 at 2.0 g L?1 of salinity respectively. The tolerance of juveniles to nitrite decreased at 96 h of exposure by 18.6% and 54.0%, when salinity declined from 1.0 to 0.6 g L?1 and from 2.0 to 0.6 g L?1 respectively. The safe concentrations at salinities of 0.6, 1.0 and 2.0 g L?1 were 0.28, 0.35 and 0.62 mg L?1 nitrite‐N respectively. The relationship between LC50 (mg L?1), salinity (S) (g L?1) and exposure time (T) (h) was LC50 = 8.4688 + 5.6764S – 0.0762T for salinities from 0.6 to 2.0 g L?1 and for exposure times from 24 to 96 h; the relationship between survival (%) and nitrite‐N concentration (C) for salinity of 0.6–2.0 g L?1, nitrite‐N concentrations of 0–40 mg L?1 and exposure times from 0 to 96 h was as follows: survival (%) = 0.8442 + 0.1909S – 0.0038T – 0.0277C + 0.0008ST + 0.0001CT–0.0029SC, and the tentative equation for predicting the 96‐h LC50 to salinities from 0.6 to 35 g L?1 in L. vannamei juveniles (3.9–4.4 g) was 96‐h LC50 = 0.2127 S2 + 1.558S + 5.9868. For nitrite toxicity, it is shown that a small change in salinity of waters from 2.0 to 0.6 g L?1 is more critical for L. vannamei than when wider differences in salinity occur in brackish and marine waters (15–35 g L?1). 相似文献
4.
Inter‐ and intra‐individual variability in growth and food consumption in pikeperch,Sander lucioperca L., larvae revealed by individual rearing
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Fabian J Schaefer Sebastian Flues Stefan Meyer Myron A Peck 《Aquaculture Research》2017,48(3):800-808
We examined short‐term, inter‐ and intra‐individual variability in rates of growth and food consumption in fish early life stages to gain a mechanistic understanding of why larvae in the same environments often grow at vastly different rates. We made parallel measurements of growth rate in standard length (GRSL) and food consumption rate (C), and provide estimates of weight growth rate (GRDW) and gross growth efficiency (GGE = 100*GRDW/C) of individually reared larvae of pikeperch, Sander lucioperca L., fed Artemia nauplii at 20°C and a salinity of 2.0 g L?1. Within two trials, GRSL, C and GGE were obtained for 108 larvae over a maximum period of 28 days. Mean (±SD) initial size, GRSL, C and GGE were 19.49 (9.19) mm, 0.68 (0.21) mm day?1, 0.85 (0.44) mg day?1 and 36.5 (10.2)% respectively. The vast majority (91%) of the variability in growth was explained by differences in food consumption. When isolated from conspecifics for 28 days, relatively small larvae grew faster than relatively large ones, partially mitigating initial differences in size‐at‐age. 相似文献
5.
Effects of salinity on standard metabolic rate of juvenile marbled spinefoot (Siganus rivulatus)
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Marbled spinefoot, Siganus rivulatus, is a herbivorous euryhaline teleost widely distributed in the Eastern Mediterranean. It is an economically valuable species and a suitable candidate for warm water aquaculture. Accordingly, understanding the effects of environmental factors on fish metabolism is important to optimize culture conditions. Two experiments were performed to establish standard metabolic rate and study the effect of salinity on metabolism of marbled spinefoot. In the first experiment, a series of flow‐through respirometry experiments was performed at 27°C and 35 g L?1. The standard metabolic rate of marbled spinefoot juveniles was calculated as 0.57 ± 0.02 mg O2 g?1 h?1 (mean ± SE). In the second experiment, fish were maintained at salinities of 25, 30, 35 and 40 g L?1 for 2 weeks. Flow‐through respirometry was performed to measure respiration rates at the various salinities. Respiration rates were similar among fish in salinities of 30, 35 and 40 g L?1 but increased significantly at 25 g L?1. Results suggest that despite the euryhalinity of marbled spinefoot, farmers should maintain salinity within the optimal range of 30–40 g L?1 in order to improve productivity. 相似文献
6.
Female northern whitefish were treated with salmon [D‐Arg6Pro9Net]‐sGnRHa emulsified in Freund′s incomplete adjuvant as a sustained release treatment (sGnRHa‐FIA) or with [D‐Arg6Pro9Net]‐sGnRHa dissolved in physiological saline as acute release treatment (sGnRHa‐PS). Females in four experimental groups (A, B, C, D) and one control group (E) were injected intraperitoneally as follows: A and B – sGnRHa‐FIA at doses of 50 and 25 μg kg?1, respectively; C – double injection (DI) of sGnRHa‐PS at 25 μg kg?1 administered 3 days apart; D – single injection (SI) of sGnRHa‐PS at 25 μg kg?1; and E – control group receiving a 1:1 mixture of FIA and physiological saline. All treatments induced and synchronized ovulation. Mean time to ovulation was significantly reduced (P < 0.05) in GnRHa‐treated groups compared with control. Hormone treatments did not affect the relative fecundity. Slight differences were found in ovarian fluid pH between group A and D (P < 0.05). Except for group C, egg size was significantly reduced (P < 0.01) in hormonally synchronized groups compared with the control. Survival to the eyed stage of eggs from females in groups A, B and C was significantly lower (P < 0.01) than in groups D and E. Per cent hatched alevins was lower (P < 0.01) in groups A, B and C than in groups D and E. We conclude that synchronization of ovulation in northern whitefish can be induced by a single acute injection of [D‐Arg6Pro9NEt]‐sGnRHa at 25 μg kg?1 BW if given near the natural spawning time determined by water temperature below 2°C. 相似文献
7.
Effectiveness of eugenol sedation to reduce the metabolic rates of cool and warm water fish at high loading densities
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Aaron R Cupp Christopher F Hartleb Kim T Fredricks Mark P Gaikowski 《Aquaculture Research》2016,47(1):234-242
Effects of eugenol (AQUI‐S®20E, 10% active eugenol) sedation on cool water, yellow perch Perca flavescens (Mitchill), and warm water, Nile tilapia Oreochromis niloticus L. fish metabolic rates were assessed. Both species were exposed to 0, 10, 20 and 30 mg L?1 eugenol using static respirometry. In 17°C water and loading densities of 60, 120 and 240 g L?1, yellow perch controls (0 mg L?1 eugenol) had metabolic rates of 329.6–400.0 mg O2 kg?1 h?1, while yellow perch exposed to 20 and 30 mg L?1 eugenol had significantly reduced metabolic rates of 258.4–325.6 and 189.1–271.0 mg O2 kg?1 h?1 respectively. Nile tilapia exposed to 30 mg L?1 eugenol had a significantly reduced metabolic rate (424.5 ± 42.3 mg O2 kg?1 h?1) relative to the 0 mg L?1 eugenol control (546.6 ± 53.5 mg O2 kg?1 h?1) at a loading density of 120 g L?1 in 22°C water. No significant differences in metabolic rates for Nile tilapia were found at 240 or 360 g L?1 loading densities when exposed to eugenol. Results suggest that eugenol sedation may benefit yellow perch welfare at high densities (e.g. live transport) due to a reduction in metabolic rates, while further research is needed to assess the benefits of eugenol sedation on Nile tilapia at high loading densities. 相似文献
8.
Effects of temperature and dietary protein on the growth performance and IGF‐I mRNA expression of juvenile mirror carp (Cyprinus carpio)
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Juvenile mirror carp were fed with five different diets containing 303, 322, 341, 361 and 379 g kg?1 protein and reared at three different water temperatures (18, 23 and 28 °C) for 60 days. We investigated the insulin‐like growth factor I (IGF‐I) mRNA expression, growth performance and the relationship between IGF‐I mRNA expression and the growth performance. The results indicated that the IGF‐I mRNA expression, final body weight, specific growth rate (SGR) and feed efficiency (FE) were enhanced significantly with increasing dietary protein levels (P < 0.05), whereas the protein efficiency ratio, hepatosomatic index (HSI) and viscerosomatic index (VSI) were decreased. Moreover, the IGF‐I mRNA expression, final body weight and SGR were increased significantly with temperature, whereas the HSI and VSI indices were decreased significantly with temperature. Correlation analysis showed that the IGF‐I mRNA expression levels in the brain and liver were positively related to the SGR and FE growth indices (P < 0.01). Finally, the optimal protein requirements for fish growth in different seasons were determined based on the values of SGR and FE, that is 343–348 g kg?1 protein at 18 °C, 354–352 g kg?1 at 23 °C and 371–362 g kg?1 at 28 °C. In this way, we can adjust the dietary protein levels according to culture temperature to reduce any negative impacts on dietary costs and environmental pollution. 相似文献
9.
Influence of feeding regime and temperature on development and settlement of oyster Ostrea edulis (Linnaeus, 1758) larvae
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Under controlled conditions of food density and temperature, larval performances (ingestion, growth, survival and settlement success) of the flat oyster, Ostrea edulis, were investigated using a flow‐through rearing system. In the first experiment, oyster larvae were reared at five different phytoplankton densities (70, 500, 1500, 2500 and 3500 μm3 μL?1: ≈1, 8, 25, 42 and 58 cells μL?1 equivalent TCg), and in the second, larvae were grown at four different temperatures (15, 20, 25 and 30°C). Overall, larvae survived a wide range of food density and temperature, with high survival recorded at the end of the experiments. Microalgae concentration and temperature both impacted significantly larval development and settlement success. A mixed diet of Chaetoceros neogracile and Tisochrysis lutea (1:1 cell volume) maintained throughout the whole larval life at a concentration of 1500 μm3 μL?1 allowed the best larval development of O. edulis at 25°C with high survival (98%), good growth (16 μm day?1) and high settlement success (68%). In addition, optimum larval development (survival ≥97%; growth ≥17 μm day?1) and settlement (≥78%) were achieved at 25 and 30°C, at microalgae concentrations of 1500 μm3 μL?1. In contrast, temperature of 20°C led to lower development (≤10 μm day?1) and weaker settlement (≤27%), whereas at 15°C, no settlement occurred. The design experiments allowed the estimation of the maximum surface‐area‐specific ingestion rate = 120 ± 4 μm3 day?1 μm?2, the half saturation coefficient {XK} = 537 ± 142 μm3 μL?1 and the Arrhenius temperature TA = 8355 K. This contribution put a tangible basis for a future O. edulis Dynamic Energy Budget (DEB) larval growth model. 相似文献
10.
Depletion of florfenicol amine in tilapia (Oreochromis sp.) maintained in a recirculating aquaculture system following Aquaflor®‐medicated feed therapy
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Mark P Gaikowski Melissa K Whitsel Shawn Charles Susan M Schleis Louis S Crouch Richard G Endris 《Aquaculture Research》2015,46(8):1842-1857
Aquaflor® [50% w w?1 florfenicol (FFC)], is approved for use in freshwater‐reared warmwater finfish which include tilapia Oreochromis spp. in the United States to control mortality from Streptococcus iniae. The depletion of florfenicol amine (FFA), the marker residue of FFC, was evaluated after feeding FFC‐medicated feed to deliver a nominal 20 mg FFC kg?1 BW d?1 dose (1.33× the label use of 15 mg FFC kg?1 BW d?1) to Nile tilapia O. niloticus and hybrid tilapia O. niloticus × O. aureus held in a recirculating aquaculture system (RAS) at production‐scale holding densities. Florfenicol amine concentrations were determined in fillets taken from 10 fish before dosing and from 20 fish at nine time points after dosing (from 1 to 240 h post‐dosing). Water samples were assayed for FFC before, during and after the dosing period. Parameters monitored included daily feed consumption and biofilter function (levels of ammonia, nitrite and nitrate). Mean fillet FFA concentration decreased from 13.77 μg g?1 at 1‐h post dosing to 0.39 μg g?1 at 240‐h post dosing. Water FFC concentration decreased from a maximum of 1400 ng mL?1 at 1 day post‐dosing to 847 ng mL?1 at 240 h post‐dosing. There were no adverse effects noted on fish, feed consumption or biofilter function associated with FFC‐medicated feed administration to tilapia. 相似文献
11.
Sperm cryopreservation of silver barb (Barbodes gonionotus): cryoprotectants,cooling rate and storage time on sperm quality
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Verapong Vuthiphandchai Kanokporn Wilairattanadilok Sumate Chomphuthawach Treerat Sooksawat Subuntith Nimrat 《Aquaculture Research》2015,46(10):2443-2451
Effectiveness and efficiency of frozen sperm on fertilization and hatching success of eggs from silver barb was examined in relation to cryoprotectants, freezing rate and storage period. Sperm was diluted in calcium‐free Hank's balanced salt solution, equilibrated with dimethylsulphoxide (DMSO), propylene glycol, sucrose or methanol at 5%, 10%, 15% or 20% final concentrations, and frozen in 250‐μL straws using a one‐step freezing procedure (1, 5 and 8°C min?1 from 25 to ?40°C). Highest post‐thaw sperm motility was found from a treatment using 10% DMSO and 5°C min?1 (82.2 ± 2.1%), similar to that of 10% DMSO and 8°C min?1 (87.8 ± 3.2%). Post‐thaw motility of sperm frozen at 5 or 8°C min?1 was significantly higher than 1°C min?1. Relative sperm motility declined significantly after 10 months of cryostorage while viability did not change during a 12‐month cryostorage. Average fertilization rates of sperm after 1 and 4 months of storage were 64.5 ± 4.6% and 61.3 ± 3.4%, respectively, similar to those of fresh sperm (69.6–72.3%). Hatching rates of cryopreserved sperm (45.4–51.2%) were similar to those of fresh sperm (51.8–57.8%). This study developed suitable methods for cryopreservation of silver barb sperm that can be used to facilitate hatchery operation. 相似文献
12.
Retracted: Effectiveness of carp pituitary extract and luteinizing hormone releasing hormone analogue administration (by either injection or cholesterol pellet implantation) on spawning performance in female sturgeon,Huso huso
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Mohammad Sadegh Aramli Rajab Mohammad Nazari Parham Farsi Nooshin Mehdinejad Salim Aramli Ebrahim Sotoudeh 《Aquaculture Research》2017,48(4):1915-1922
The effectiveness of common carp pituitary extract (CPE), luteinizing hormone releasing hormone analogue (LHRH‐A2) injections and LHRH‐A2 implants for spawning induction in female sturgeon, Huso huso was examined. In the first trial, fish were injected with 7% physiological saline (control), 50 mg kg?1 CPE or LHRH‐A2 at 3.5, 7, 8 or 10 μg kg?1. In the second trial, fish were treated with LHRH‐A2 cholesterol pellet implants containing 0, 3.5, 7, 8 and 10 μg kg?1 LHRH‐A2. Ovulated eggs were removed using a minimally invasive surgical technique and were artificially fertilized. Injection of CPE and LHRH‐A2 at doses of 3.5, 7, 8 and 10 μg kg?1 resulted in the number of ovulated fish more than LHRH‐A2 implants (similar doses) or controls, although there was no significant difference at doses of 8 and 10 μg kg?1 (P ≥ 0.05). The latency period of fish receiving CPE and LHRH‐A2 injections was approximately 20 h, which was significantly lower than in fish receiving LHRH‐A2 implants (P ≤ 0.05). Furthermore, there were no significant differences in rates of fertilization or hatching among the progeny produced in any of the treatment groups (P ≥ 0.05). In conclusion, the data from this study could be useful for artificial propagation of not‐fully‐matured females of H. huso at sturgeon hatcheries. 相似文献
13.
Effects of temperature and dietary protein on gene expression of Hsp70 and Wap65 and immunity of juvenile mirror carp (Cyprinus carpio)
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Juvenile mirror carp were fed diets containing 303.4, 321.7, 341.2, 361.0 and 379.1 g kg?1 proteins, respectively, and reared at different water temperatures (18, 23 and 28°C) for 60 days. Gene expression of heat shock protein gene (Hsp70) and the warm temperature acclimation‐related 65 kDa protein gene (Wap65), immunity and antioxidant status in the carp were investigated. Results indicated that the contents of serum complement 3 (C3), complement 4 (C4) and immunoglobulin M (IgM), as well as activities of liver superoxide dismutase (SOD) and lysozyme (LSZ) were significantly enhanced with increasing dietary protein (P < 0.05), while content of malondiadehyde (MDA) decreased. Gene expression level of Wap65 in the liver significantly increased with dietary protein, while gene expression of Hsp70 decreased. The contents of C3, C4 and IgM, the activities of SOD and LSZ and gene expression level of Wap65 in the liver significantly increased with temperature. These results suggest that: Serum immune parameter, antioxidant enzymes and Hsp70 and Wap65 expression interact in fish to improve ability to adapt to the environment; and the optimal conditions for the immunity of carp are 348.1?354.5 g kg?1 protein at 18°C, 352.3?364.9 g kg?1 at 23°C and 360.2?364.3 g kg?1 at 28°C, and the optimum temperature for carp is 23°C. 相似文献
14.
Effects of temperature on feed intake,growth and oxygen consumption in adult male king crab Paralithodes camtschaticus held in captivity and fed manufactured diets
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The current study investigates whether it is possible to increase the meat content of captive male king crab (Paralithodes camtschaticus) (average = 2.2 kg) by feeding manufactured diets at different temperatures (4°C, 8°C and 12°C). A 110 days trial was undertaken with groups of male king crabs held in 12 land‐based holding tanks. All crabs survival in the lowest temperature treatment, one animal died in the medium‐temperature group (8°C) and four animals in the highest temperature treatment (12°C). The results showed that feed intake increased with increasing temperature from an average of 1.0 g kg?1 day?1 at 4°C to 2.8 g kg?1 day?1 crab at 12°C. The percentage meat content was significantly higher at the final census (60.0%) compared with the initial census (37.5%) in all temperature groups, but there were no significant differences in the percentage meat content of the king crabs held in the different temperature treatments at the conclusion of the experiment. Oxygen consumption was also significantly affected by temperature and increased with increasing temperature. The results of the experiment show that the optimal temperature to maintain, and enhance, the meat content of king crab is close to 4°C. 相似文献
15.
Comparative study on dietary protein requirements for juvenile and pre‐adult gibel carp (Carassius auratus gibelio var. CAS III)
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Two 8‐week growth trials were conducted in indoor recirculation system to evaluate the protein requirements for juvenile (3.70 ± 0.20 g) and pre‐adult (85.2 ± 0.70 g) gibel carp, Carassius auratus gibelio var. CAS III. Six isoenergetic diets were formulated for each trial using fish meal and casein as protein sources, and protein level was 250–450 g kg?1 in Trial 1 and 200–450 g kg?1 in Trial 2. With the increasing dietary protein, feeding rate (FR) and feed conversion ratio (FCR) significantly decreased (P < 0.05). Weight gain (WG) increased first and then reached a plateau in 330–450 g kg?1 in Trial 1 (P > 0.05), while decreased after the maximum value in 350 g kg?1 in Trial 2 (P < 0.05). Productive protein values (PPVs) were lower in 370–450 g kg?1 in Trial 1 and 400–450 g kg?1 in Trial 2 (P < 0.05). Increasing dietary protein level increased protein content and decreased lipid content in whole fish body and white muscle (P < 0.05). Apparent digestibility coefficient of dry matters (ADCd) decreased, while apparent digestibility coefficient of protein (ADCp) increased in 370–450 g kg?1 in Trial 1 and 250–450 g kg?1 in Trial 2 (P < 0.05). Trypsin activity significantly increased in 370–450 g kg?1 in Trial 1 (P < 0.05) and was not affected in Trial 2 (P > 0.05). Hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in both trials increased when dietary protein was above 400 g kg?1 (P < 0.05). Based on quadratic regression of WG, it was estimated that dietary protein requirement for maximum growth was 414 g kg?1 (digestible protein of 376 g kg?1) and 365 g kg?1 (digestible protein of 324 g kg?1) for juvenile (3.70 g) and pre‐adult gibel carp (85.2 g). 相似文献
16.
17.
Constructed wetlands for treatment of harvest effluents from grow‐out ponds of the Amazon river prawn
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Alexandre Augusto Oliveira Santos Antonio Fernando Monteiro Camargo 《Aquaculture Research》2015,46(11):2676-2684
Effluent discharges from aquaculture can reduce water quality in receiving water bodies and that strategies or practices to reduce this are necessary. One possibility is to reduce, or eliminate, water renewal in grow‐out ponds. In this study, we eliminated water renewal in grow‐out ponds associated with the culture of 40 individuals m?2 of Amazon river prawn (Macrobrachium amazonicum). At the end of the culture period it was, however, necessary to drain the pond to harvest the prawns. An experiment was performed in triplicate, in which the water supply characteristics and harvest water characteristics of ponds were evaluated. To reduce these concentrations of total N and P, an aquatic macrophyte (Eichhornia crassipes, water hyacinth) treatment system (CWs) was adopted. The water characteristics in the CWs were evaluated after 1, 3, 7, 14 and 21 days. The water supply of ponds presented the average concentrations of 0.67 ± 0.32 mg L?1 and 17.4 ± 14.7 μg L?1 of total‐N and total‐P respectively. The harvest effluent of ponds had elevated concentrations of different forms of nitrogen (4.44 mg L?1 of total‐N) and phosphorous (100.9 μg L?1 of total‐P). After 1 day of the experiment we found the following reductions in key nutrients in treatment system containing E. crassipes: 90%, 78% and 45% reductions in the concentrations of particulate matter, orthophosphates and nitrates respectively. We noted that after 3 days the nitrates had been reduced by 53%. We concluded that 3 days of this treatment was sufficient for the removal of the additional nutrients that had accumulated in the Amazon river prawn ponds. 相似文献
18.
Comparative studies on dietary protein requirements of juvenile and on‐growing gibel carp (Carassius auratus gibelio) based on fishmeal‐free diets
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Two trials were conducted to investigate protein requirements of juvenile (3.18 g in Trial 1) and on‐growing (87.1 g in Trial 2) gibel carp, Carassius auratus gibelio var. CAS III. Six isoenergetic diets containing 250–500 g kg?1 dietary protein were formulated using soy protein concentrate (SPC) and casein as protein sources. The results showed that weight gain (WG) increased when dietary protein increased from 250 to 400 g kg?1 and decreased at 400 to 500 g kg?1 CP in Trial 1, while WG increased when dietary protein increased from 250 to 350 g kg?1 and kept constant at 350 to 500 g kg?1 CP in Trial 2. With increasing dietary protein, feed conversion ratio (FCR) decreased, while protein retention efficiency (PRE) decreased in Trial 1 and was not affected in Trial 2. Apparent digestibility coefficient of protein (ADCp) increased with increasing dietary protein in two trails. Trypsin activity increased with dietary protein in the juveniles and was not affected in on‐growing fish. Hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities increased with dietary protein. Broken‐line and quadratic regression of WG estimated that dietary protein requirements for maximum growth were about 402–427 g kg?1 for the juvenile and 337–418 g kg?1 for on‐growing gibel carp. 相似文献
19.
Towards sustainable exhibits – application of an inorganic fertilization method in coral reef fish larviculture in an aquarium
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Kwee Siong Tew Yun‐Chen Chang Pei‐Jie Meng Ming‐Yih Leu David C Glover 《Aquaculture Research》2016,47(9):2748-2756
Coral reef fish are collected from the wild and exhibited in aquaria worldwide. Some of the fish spawn in captivity; however, the eggs are usually neglected. In this study, we collected the eggs spawned naturally in the exhibit tanks, hatched and cultured them indoor in 2000‐L fibreglass tanks (initial density = 18 000 egg tank?1). We applied an inorganic fertilization method commonly used in freshwater fish culture in raising these coral reef fish larvae. We maintained inorganic phosphorus concentration at 100 μg P L?1 and inorganic nitrogen at 700 μg N L?1 daily in the fertilized group (n = 4), while the control tanks (n = 4) were fed with rotifers (10 ind mL?1). Chlorophyll a at particle sizes of both 0.45–20 μm and >20 μm, as well as NH3‐N, NO3‐N, and PO4‐P concentrations were significantly higher in the fertilized group than the control. Zooplankton in the size groups of 10–50 μm (mainly flagellates) and 50–100 μm (mainly ciliates) were abundant (about 10~60 ind mL?1) during 3–7 days in fertilized tanks. The average larval fish survival rate at 21 day after hatch in fertilized group was consistently higher than the control in two trials. The experiments demonstrated that the inorganic fertilization approach can be successfully adapted for coral reef fish culture in an aquarium to achieve sustainable exhibits. 相似文献
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M.H.G. Berntssen S. Valdersnes B.T. Lunestad B. Hatlen M. Alm R. Waagbø L. Buttle 《Aquaculture Nutrition》2014,20(6):712-721
Residue levels of the antibacterials enrofloxacin and ciprofloxacin were analysed in 15 commercially relevant animal by‐products (ABPs). Enrofloxacin was detected in all ABPs, and ciprofloxacin was detected in 11 of 15 ABP samples. Feed to muscle and skin carry –over of low background enro‐ and ciprofloxacin levels were assessed by applying a simple toxicokinetic model. The muscle and skin uptake and elimination rates were established in Atlantic salmon (Salmo salar L.) fed enrofloxacin enriched diets (100 μg kg?1 ‘low’ and 4000 μg kg?1 ‘high’) in triplicate for 41 days followed by a 90 days depuration period. The terminal half‐lives were 17 ± 0.4 and 18 ± 0.7 days, and uptake rates were 9.3 ± 3.3 and 11 ± 3.1 (day?1) for the ‘low’ and ‘high’ groups, respectively. Only fish fed high background levels had quantifiable levels of the metabolite ciprofloxacin with a formation of 0.25 ± 0.01% day?1. The toxicokinetic carry‐over model predicted muscle and skin steady state levels of 1.8 μg kg?1 when fed theoretically high enrofloxacin levels (158 μg kg?1), which is below the EU limit of 100 μg kg?1 for enrofloxacin in finfish food products. The antibacterial residue levels could however be detected in EU food surveillance programmes. 相似文献