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1.
A 50‐day feeding trial was conducted to examine the effects of dietary protein and lipid levels on growth, feed utilization, body composition and swimming performance of giant croaker, Nibea japonica. Fish (initial body weight 44.6 g ind−1) were fed ten test diets which were formulated at 5 crude protein levels (360, 400, 440, 480 and 520 g kg−1) and 2 crude lipid levels (90 and 150 g kg−1). In addition, a raw fish diet (fillet of small yellow croaker) served as the reference. The weight gain (WG) increased, whereas the feed intake (FI) and feed conversion ratio (FCR) decreased, with increasing dietary protein level from 360 to 520 g kg−1. At the same dietary protein level, no significant difference was found in the WG between fish fed the diets containing 90 or 150 g kg−1 crude lipid. Fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid exhibited higher WG, nitrogen retention efficiency (NRE) and energy retention efficiency (ERE) but lower nitrogen wastes output (TNW). At the end of the feeding trial, the hepatosomatic index (HSI) and viscerosomatic index (VSI) decreased, whereas the body protein content increased, with increase in dietary protein level. The body lipid content was higher in fish fed at the 150 g kg−1 lipid level than in fish fed at the 90 g kg−1 lipid level. No significant difference was found in the maximum sustained swimming speed (MSS) between fish fed at different dietary protein and lipid levels. The WG, NRE, ERE and condition factor (CF) were higher, whereas the FI, FCR, HSI, VSI and TNW were lower, in fish fed the raw fish diet than in fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. No significant difference was detected in the MSS between fish fed the raw fish diet and diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. The results of this study suggest that the suitable dietary crude protein and crude lipid levels are 480 g kg−1 and 90 g kg−1 for giant croaker reared in net pens.  相似文献   

2.
《Aquaculture Research》2017,48(4):1759-1766
A shrimp protein hydrolysate (SPH) containing 894.2 g kg−1 crude protein (CP) and 54.3 g kg−1 total lipids was tested as a partial replacement for fish meal (FM) in diets of juvenile cobia. The effects of increasing dietary levels of SPH on the survival, weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), nitrogen retention efficiency (NRE) and daily feed intake (DFI) of cobia with initial body weight of 11.9 g were evaluated. Four isoproteic (from 431.1 to 439.7 g kg−1) and isoenergetic (20 825–21 347 MJ kg−1) diets were formulated to contain 0 (Control), 120, 240 or 360 g kg−1 of dietary CP derived from SPH. Survival, WG, SGR, FCR, NRE and DFI ranged from 90 to 100%, 40.2–56.5 g, 4.7–6.1% day−1, 1.04–1.54, 26.3–44.0% and 4.7–6.0% fish−1 day−1 respectively. Survival and DFI were not affected by the dietary treatments. On the other hand, fish fed the control diet and the one containing 120 g kg−1 SPH had higher WG, SGR and FCR. Nitrogen retention efficiency was significantly higher for fish fed diets 0 and 120. It is concluded that up to 120 g kg−1 of SPH in cobia diets can be used with no significant effects on feed utilization and fish performance.  相似文献   

3.
In this study, we examined the effects of the following eight experimental diets, which varied in fructo oligosaccharides (FOS), mannan oligosaccharides (MOS) and Bacillus clausii concentrations, on the Japanese flounder: control diet (no FOS, MOS and B. clausii), diet F (5 g kg−1 FOS), diet M (5 g kg−1 MOS), diet FM (2.5 g kg−1 FOS + 2.5 g kg−1 MOS), diet B (107 cells g−1B. clausii), diet FB (5 g kg−1 FOS + 107 cells g−1B. clausii), diet MB (5 g kg−1 MOS + 107 cells g−1B. clausii) and diet FMB (2.5 g kg−1 FOS + 2.5 g kg−1 MOS + 107 cells g−1B. clausii). Japanese flounder, initially weighing an average of 21 g, were distributed into 24 net cages at a stocking density of 20 fish per cage. Each diet was hand‐fed to three groups of fish twice daily for 56 days. The weight gain rate (WGR) in fish fed diets B, MB and FMB were significantly higher than in fish fed the control diet, where the fish fed diet FMB had the highest WGR. Fish fed any of the diets, except diets F and B, exhibited better feed conversion ratio than those fed the control diet. Diets MB and FMB significantly elevated intestinal protease activity compared with the control diet, but only the diet FMB promoted amylase activity. Feeding diets FB and FMB increased body protein deposition; additionally, feeding diets B, MB and FMB significantly reduced body lipid deposition. Lysozyme (LSZ) activity was significantly higher in fish fed diets B, FB, MB and FMB than in fish fed the control diet. All diets, except diet M, decreased triglyceride (TG) levels compared to the control diet. Low‐density lipoprotein cholesterol levels in fish fed diets F, FB and FMB were significantly lower than in fish fed the control diet. Without exception, no diets affected feeding rate, condition factor, body moisture, ash contents, phagocytic activity of leucocytes or cholesterol or high‐density lipoprotein cholesterol levels. Our results suggest that diets supplemented with FOS, MOS and B. clausii improved growth performance and health benefits of the Japanese flounder more than other diets or the control diet.  相似文献   

4.
An 8‐week feeding trial was conducted in flow through system to examine the effects of dietary supplementation of microbial phytase on growth, nutrient utilization, haemato‐biochemical status and body compositions in common carp, Cyprinus carpio (L.) fingerlings (average weight 6.66 ± 0.08 g). The aim of experiment was also to determine whether dicalcium phosphates (DCP), tracemineral premix and lysine and methionine supplemental levels in carp diet could be reduced if microbial phytase was supplemented. Control diet (diet 1) supplemented with DCP, tracemineral premix and lysine and methionine without microbial phytase supplementation. Four experimental diets were formulated with reduction of either dietary DCP or trace minerals or lysine and methionine or all four supplementation levels by 100% of control diet without microbial phytase supplementation (diet 2, 3, 4 and 5 respectively). Another two experimental diets were formulated with reduction of all dietary DCP, trace minerals, lysine and methionine supplementation levels by 0 and 100% of control diet with dietary microbial phytase supplementation at 500 FTU kg−1 diet (diet 6 and 7 respectively). After acclimation of fish for 2 weeks, 20 fish were randomly stocked into triplicate tanks for each of seven treatments (T0, T1, T2, T3, T4, T5 and T6 for diet 1, 2, 3, 4, 5, 6 and 7 respectively) and fed with respective diet to apparent satiation. Results indicated that phytase was effective in releasing most of the phytate bound proteins, amino acids and minerals for optimum utilization and performance. Results also suggested that DCP, trace minerals and lysine and methionine supplementation level could be replaced by microbial phytase supplementation at 500 FTU kg−1 in soybean‐based common carp diets without altering the optimum performance of fish. Optimum replacement level of dietary DCP, trace minerals and lysine and methionine with phytase supplementation at 500 FTU kg−1 soybean‐based carp diet needs to be standardized in further investigations.  相似文献   

5.
A feeding trial was conducted to determine the dietary methionine requirement of juvenile golden pompano (initial body weight 12.40 ± 0.02 g). Six diets were formulated with six graded levels of methionine (8.6, 9.2, 10.4, 11.5, 13.2 and 14.5 g kg−1). Each diet was randomly assigned to triplicate groups of 20 juvenile fish in seawater floating net cages (1.0 m × 1.0 m × 1.5 m). Fish were fed twice daily (08:30 and 16:30) to apparent satiation for 56 days. Weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), feed efficiency (FE), nitrogen retention efficiency (NRE), proximate body composition, morphometry and haematology were significantly (P < 0.05) affected by the dietary methionine levels. WG, SGR and FE increased with increasing levels of methionine up to 13.2 g kg−1 diet (P < 0.05) and remained nearly the same thereafter. NRE also increased with increasing levels of methionine up to 13.2 g kg−1 diet (P < 0.05) and remained nearly the same thereafter. Linear regression analysis on WG and NRE indicated that the recommended optimum dietary methionine levels for optimal growth of juvenile pompano were 10.6 and 12.7 g kg−1 diet, respectively, corresponding to 24.6 and 29.5 g kg−1 dietary protein, respectively, so the level of dietary methionine should be between 10.6 and 12.7 g kg−1 diet, corresponding to 24.6–29.5 g kg−1 dietary protein. Additionally, the estimated requirements for the other essential amino acids were calculated from A/E ratios of whole‐body amino acid profile based on the methionine requirement determined from the present experiment.  相似文献   

6.
The dietary arginine requirement of fingerling hybrid Clarias (Clarias gariepinus×Clarias macrocephalus) (4.2±0.03 cm, 0.56±0.04 g) was determined by feeding six isonitrogenous (400 g kg−1 crude protein) and isocaloric (17.9 kJ g−1) amino acid test diets containing casein, gelatin and l ‐crystalline amino acids with graded levels of arginine (10.0, 12.5, 15.0, 17.5, 20.0 and 22.5 g kg−1) for 4 weeks to triplicate groups. Diets were fed twice a day at 09:00 and 16:00 hours at 8% body weight day−1. Maximum weight gain (523%), best feed conversion ratio (FCR, 1.41), protein efficiency ratio (1.78) and specific growth rate (6.53%) were recorded in fish fed the diet containing arginine at 20.0gkg−1 of the diet. Second‐degree polynomial regression analysis of live weight gain and FCR values indicated the dietary arginine requirement at 17.8 and 20.0 g kg−1 of dry diet respectively. Significantly higher carcass protein and protein deposition values were recorded at the requirement level (20.0 g kg−1). Higher fat and lower moisture values were obtained in carcass of fish fed the diet with 15.0g kg−1 arginine. The maximum carcass ash value was noticed in the fish fed at 20.0 g kg−1 dietary arginine. We recommend that the diet for hybrid Clarias (C. gariepinus×C. macrocephalus) should contain arginine in the range of 17.8–20.0 g kg−1 of the dry diet, corresponding to 44.5 and 50 g kg−1 of dietary protein respectively.  相似文献   

7.
Triplicate groups of Indian catfish, Heteropneustes fossilis (Bloch), fingerlings (average wet weight 3.55 ± 0.03 g) were fed semi-purified diets containing six levels of biotin (0, 0.086, 0.26, 0.86, 2.5 and 4.3 mg kg−1 diet) for 15 weeks. After 42 days of feeding, fish fed the control (no biotin) diet had developed severe deficiency signs characterized by convulsions, heavy mortality, listlessness, poor feed conversion and feed intake, dark skin colour, tetanus and weight loss. None of these signs was seen in fish fed biotin-supplemented diets. Among all the biotin-supplemented diets, percentage weight gain was significantly highest for fish fed the diet supplemented with 0.26 mg of biotin kg−1 and significantly lowest for fish fed the diet supplemented with 0.086 mg of biotin kg−1. Feed conversion ratio (FCR) and protein efficiency ratio (PER) patterns were similar to that of percentage weight gain. The carcass protein and lipid contents were influenced by the dietary biotin up to fish fed 0.26 mg of biotin kg−1. Significantly higher body biotin content, liver pyruvate carboxylase and acetyl CoA carboxylase activities were observed in fish fed biotin-supplemented diets than in fish fed the control diet. Broken-line analyses showed that the optimum dietary requirement for biotin for maximal weight gain, body biotin content, liver pyruvate carboxylase and acetyl CoA carboxylase activities was about 0.25 mg kg−1. Associated liver pyruvate carboxylase and acetyl CoA carboxylase activities for normal growth ranged from 105 to 120 units mg−1 protein and from 9 to 11 units mg−1 protein respectively.  相似文献   

8.
This study examined the effect of dietary protein and lipid levels on growth, feed utilization and body composition of Asian catfish Pangasius hypophthalmus reared in cages. Eight test diets were formulated at four protein (340, 380, 420 and 460 g kg−1 crude protein) and two lipid (50 and 90 g kg−1 crude lipid) levels. Fish (initial weight 4.7 g fish−1) were fed the test diets for 8 weeks. Final body weight, weight gain (WG), feed intake (FI), feed conversion ratio (FCR), contents of crude protein, lipid and energy in whole body were dependent on both dietary protein and lipid levels, while specific growth rate (SGR), hepatosomatic index and body moisture content were dependent on dietary lipid level. The WG and SGR increased with the increase in either dietary protein level (at the same lipid level) or lipid level (at the same protein level). The FI and FCR decreased with the increase in dietary protein level (at the same lipid level) or lipid level (at the same protein level). Protein sparing action occurred in case dietary lipid level increased. Fish fed the diet containing 453 g kg−1 crude protein and 86 g kg−1 lipid had the highest WG and SGR, but the lowest FI and FCR, among the diet treatments. There were no significant differences in the protein retention efficiency (PRE) and energy retention efficiency (ERE) among the diet treatments, although PRE and ERE were relatively high in fish fed the diet containing 453 g kg−1 crude protein and 86 g kg−1 lipid. At the end of the feeding trial, body protein content increased, while body lipid content decreased, with the increase in dietary protein content at the same lipid level. Our results suggest that dietary levels of 450 g kg−1 crude protein and 90 g kg−1 lipid are adequate to support fast growth of P. hypophthalmus reared in cages.  相似文献   

9.
The vitamin A (VA) concentration in salmon aquaculture feeds is varying and may lead to sublethal adverse effects. In this study, 135 g Atlantic salmon postsmolts were given eight diets in duplicates with 6, 12, 26, 55, 82, 112, 360 and 749 mg retinol (ROL) kg−1 for 116 days. Subsequently, fish given 6, 82 and 749 mg ROL kg−1 were transferred to a common net pen and given a standard commercial diet for further 28 weeks. Feed conversion rate, liver functionality and markers of VA homoeostasis were not negatively affected by dietary VA level, but chronic high VA intakes led to adverse effects on growth and bone health. In plasma, there was an antagonistic effect of dietary ROL on circulating 1,25 (OH)2 vitamin D3 (calcitriol). Moreover, a dose–response of VA on craniofacial deformities, condition factor and vertebral morphometry and mechanical strength was observed. Vertebral deformities were observed after 28 weeks on a standard diet and not immediately after the 116 days on the experimental diet. Elevated VA is a risk factor for bone deformities, and the dietary intake of VA should not exceed 37 mg ROL kg−1 body weight day−1 in Atlantic salmon postsmolts.  相似文献   

10.
Bioavailability of oxytetracycline HCl was investigated in Atlantic salmon (Salmo salar L.) in seawater at 7–8 °C. A group of 80 fish received an intravascular injection of 20 mg kg−1 body weight. Another group of about 90 fish were force-fed with medicated feed containing a dose of 50 mg kg−1 body weight. The oral bioavailability was found to be only 2%.  相似文献   

11.
To determine dietary magnesium (Mg) requirements of juvenile grass carp, Ctenopharyngodon idella, magnesium sulphate was added to the basal diet at 0, 150, 300, 600, 1200, 2400 mg Mg kg−1 diet. Each diet was fed to three replicate groups of juvenile grass carp (initial weight: 7.69 ± 0.13 g) in a closed, recirculating rearing system for 76 days. No mortality or nutritional deficiency signs were observed except the growth depression in fish fed the Mg‐deficient diet. Growth performance and activities of serum superoxide dismutase (SOD), glutathione peroxidase (GPx) and lysozyme (LSZ) were highest (P <0.05) in fish fed the diet supplemented with 600 mg Mg kg−1. The serum malondialdehyde (MDA) content was higher (P <0.05) in fish fed the diets supplemented with 0 and 150 mg Mg kg−1 than that in fish fed the diets with ≥300 mg Mg kg−1. Mg concentrations both in whole‐body and vertebrae increased with the increase in dietary Mg level up to 300 mg kg−1, whereupon the response reached a plateau. Analysis by second‐order polynomial regression of weight gain, by broken‐line regression of vertebrae Mg concentration and by linear regression of whole‐body Mg retention of fish indicated that the adequate dietary Mg concentration for juvenile grass carp was 713.5, 627.7 and 469.8 mg kg−1 diet, respectively.  相似文献   

12.
An 8‐week experiment was designed to determine the optimum dietary iron requirement of juvenile cobia Rachycentron canadum (mean initial weight, 15.89 ± 0.84 g) with iron sulphate (FeSO4•7H2O) and iron methionine (FeMet) as iron sources, using a semi‐purified diet based on casein and white fish meal as the protein sources. The basal diet was supplemented with 0, 30, 60, 120, 240 and 480 mg iron kg−1 dry diet from either FeSO4 or FeMet, respectively. Survival was not significantly affected by the all dietary treatment. Weight gain (WG), feed efficiency (FE), serum catalase activity (SCAT), and haemoglobin were significantly affected by any of the dietary treatments from both of two iron sources. Based on broken‐line regression analysis of WG, FE and SCAT, a minimum requirement for dietary iron was recommended to be 80.5–94.7 mg kg−1 from FeSO4 and 71.3–75.1 mg kg−1 from FeMet. Iron supplement to the basal diet had no significant effect on haematocrit, erythrocyte count, iron concentration in whole body and fillet. Our experiment also showed that the bioavailability of FeMet and FeSO4 to juvenile cobia was similar for WG and FE, and the relative bioavailability of FeMet and FeSO4 to juvenile cobia was 275% for maximum SCAT.  相似文献   

13.
Due to lack of information on the use of non‐protein energy sources in diets for pacu (Piaractus mesopotamicus), a 2 × 2 × 3 factorial experiment was conducted to evaluate the performance and digestibility of 12 diets containing approximately two crude protein (CP; 220 and 250 g kg−1), two lipid (40 and 80 g kg−1) and three carbohydrate levels (410, 460 and 500 g kg−1). The pacu juveniles‐fed diets containing 220 g kg−1 CP did not respond (P > 0.05) to increased dietary lipid and carbohydrate levels, but the fish‐fed diets containing 250 g kg−1 CP showed a better feed conversion ratio. There were interactions in weight gain (WG), specific growth rate (SGR), crude protein intake (CPI) and feed conversion rate (FCR) dependent on dietary carbohydrate and lipid levels, showing positive effects of increasing carbohydrate levels only for fish‐fed diets containing 80 g kg−1 lipid level. However, when the diets contained 40 g kg−1 lipid, the best energy productive value (EPV) results were obtained at 460 g kg−1 carbohydrate. A higher usage of lipids (80 g kg−1) reduced CPI and was detrimental to protein [apparent digestibility coefficient (ADC)CP] and energy (ADCGE), but did not affect growth. The ADCGE improved proportionally as dietary carbohydrate levels increased (P < 0.05), increasing the concentration of digestible energy. In addition, the WG, CPI, ADCGE results showed best use of the energy from carbohydrates when dietary protein level was 250 g kg−1 CP. The utilization of 250 g kg−1 CP in feeds for juvenile pacu for optimal growth is suggested. Therefore, the optimum dietary lipid and carbohydrate levels depend on their combinations. It can be stated that pacu uses carbohydrates as effectively as lipids in the maximization of protein usage, as long as it is not lower than 250 g kg−1 CP or approximately 230 g kg−1 digestible protein.  相似文献   

14.
《Journal of fish diseases》2017,40(3):411-424
The pharmacokinetics of florfenicol (FF) in turbot (Scophthalmus maximus) was studied after single intravenous (10 mg kg−1) and oral (100 mg kg−1) administration. The plasma concentration–time data of florfenicol were described by an open one‐compartment model. The elimination half‐life (t1/2) was estimated to be 21.0 h, and the total body clearance, Cl, was determined as 0.028 L kg h−1. The apparent volume distribution (Vd) was calculated to be 0.86 L kg−1 and the mean residence time (MRTiv) was 30.2 h. Following oral administration, the maximum plasma concentration (Cmax) of 55.4 μg mL−1 was reached at 12 h (Tmax). The absorption constant (ka) was 0.158 h−1. The bioavailability was estimated to be 57.1%. The low bioavailability observed at higher doses was explained by the saturation of the mechanisms of absorption. The drug absorption process was limited by its inherent low solubility, which limited the amount of available FF absorbed in the gastrointestinal tract. Based on the pharmacokinetic data, an optimal dosing schedule for FF administration is hereby provided. Based on the minimum inhibitory concentration found for susceptible strains of Aeromonas salmonicida, oral FF administration of first, an initial dose of 30 mg FF kg−1, followed by 6 maintenance doses at 18 mg kg−1/daily could be effective against furunculosis in turbot.  相似文献   

15.
The present study was performed to assess to what degree supplemented dietary iodine (I) was retained in selected tissues, including the fillet of adult Atlantic salmon (Salmo salar) reared in sea water. Atlantic salmon weighing approximately 1.5 kg were randomly assigned to three net pens per treatment and fed moist pellets (based on minced saithe and herring) supplemented with 0, 40 or 80 mg iodine (as KI) kg?1 on dry weight basis for 150 days. The iodine concentrations in the experimental feeds were analysed to be 10, 54 and 86 mg kg?1 dry weight, respectively. Growth, mortality and blood haemoglobin concentration (Hb) were recorded. Iodine concentrations were measured in muscle, liver and kidney after 90 and 150 days of feeding by inductively coupled plasma‐mass spectrometry. In addition, plasma thyroxine (T4) and triiodo‐thyronine (T3) were determined. The weight gain during the period was approximately 1 kg for all treatments. There were no mortalities, and blood Hb levels were within normal ranges. The iodine concentration in muscle, liver and kidney were all affected by the dietary iodine level, despite wide intratreatment variation. After 150 days, fillets of fish fed 10, 54 and 86 mg I kg?1 showed mean concentrations of 0.4, 0.5 and 0.9 mg I kg?1 wet weight, respectively, whereas the iodine concentration in the liver and the kidney increased approximately three times in the dietary groups. Similarly, plasma T4 and T3 showed great variation within the treatments. No significant correlations were found between individual tissue iodine concentration and thyroid hormone concentration in any of the groups at any sampling time. This preliminary feeding experiment showed that fillet iodine in adult Atlantic salmon can be increased up to 1.4 mg I kg?1 wet weight by dietary iodine 80 times the minimum requirement for salmonids, without impacting health, performance or plasma thyroid hormone status.  相似文献   

16.
Basal diet containing 0.5, 1.0, 1.5 and 2.0 g kg?1 mixture of inosine monophosphate (IMP), adenosine monophosphate (AMP), guanosine monophosphate (GMP), uridine monophosphate (UMP) and cytidine monophosphate (CMP) (1 : 1 : 1 : 1 : 1) (mixed‐NT; Experiment 1) and 1.5 g kg?1 from each nucleotides and mixed‐nucleotides (NT; Experiment 2) were fed to triplicate groups of grouper for 8 weeks. Basal diet without NT was used as control in both Experiments. In Experiment 1, fish fed the diet with 1.5 g mixed‐NT kg?1 had higher (P < 0.05) weight gain (WG) than the control group. The superoxide anion (O2?) production ratio was higher in fish fed diets with 1.0–1.5 g mixed‐NT kg?1 than the fish fed diets with ≤0.5 g mixed‐NT kg?1. In Experiment 2, fish fed diets with nucleotides had higher WG than the control group. The O2? production ratio was higher in fish fed the diet with 1.5 g AMP kg?1, followed by fish fed diets with 1.5 g UMP and mixed‐NT kg?1, and lowest in the control group. These results suggest that growth and immune responses were enhanced in grouper fed diet with 1.5 g mixed‐NT kg?1 diet. Diet with 1.5 g kg?1 of AMP seems to be more beneficial on the immune responses in fish than other nucleotides.  相似文献   

17.
This work evaluated the performance of Litopenaeus vannamei to low fish meal diets supplemented with 2‐hydroxy‐4‐(methylthio)butanoic acid (HMTBa). A basal diet with 150.0 g kg?1 of anchovy fish meal was designed. Two positive control diets were formulated to reduce fish meal at 50% and 100% with 1.0 and 2.0 g kg?1 of MERA? MetCa (calcium salt with 84% HMTBa activity), respectively. Two nearly equivalent diets acted as negative controls, without HMTBa supplementation. A total of 50 clear‐water tanks of 500 L were stocked with 2.22 ± 0.19 g shrimp under 70 animals m?2. Shrimp survival (92.3 ± 5.1% and 81.4 ± 8.0%), yield (808 ± 12 and 946 ± 17 g m?2) and FCR (2.17 ± 0.19 and 3.12 ± 0.37) showed no differences among diets after 72 or 96 days, respectively. A significantly higher shrimp body weight and weekly growth were observed for those fed with the basal diet or diets supplemented with HMTBa compared with non‐supplemented ones. This study has shown that L. vannamei growth, body weight, survival, yield and FCR were supported by HMTBa supplementation when 150.0 g kg?1 of fish meal was replaced by soybean meal and other ingredients, at 50% and 100%.  相似文献   

18.
A feeding experiment was conducted to determine the dietary calcium (Ca) requirement for juvenile hybrid tilapia, Oreochromis niloticus × O. aureus reared in nature water. Purified diet supplemented with 0, 1, 2, 3, 4, 5, 7 and 10 g Ca kg−1 diet providing of 0.6, 1.6, 2.6, 3.7, 4.7, 5.5, 7.5 and 10.7 g Ca kg−1 diet, respectively, were fed to tilapia (mean initial weight: 0.52 ± 0.01 g, n = 3) for 8 weeks. Each diet was fed to three replicate groups of fish in a closed, recirculating fresh water rearing system. The rearing water contained 27.1–33.3 mg L−1 Ca. The tilapia fed the diets supplemented with ≥3.7 g Ca kg−1 had significantly (P < 0.05) higher weight gain, when compared with fish fed the diet with ≤1.6 g Ca kg−1. Fish fed the unsupplemented control showed significantly lower weight gain when compared with the other groups (P < 0.05). Bone Ca concentration was highest in fish fed the diets with ≥4.7 g Ca kg−1, intermediate in fish fed the diet with 2.6 g Ca kg−1 and lowest in fish fed the control diet. Scale Ca concentration was higher in fish fed the diets with ≥3.7 g Ca kg−1 than in fish fed the diets with ≤2.6 g Ca kg−1. Serum alkaline phosphatase activity was 36% increased in fish fed the diets with ≥2.6 g Ca kg−1 than fish fed the diets with <1.6 g Ca kg−1. Analysis by broken‐line regression of weight gain, bone and scale Ca concentrations indicated that the adequate dietary Ca concentration for tilapia in water containing 27.1–33.3 mg Ca L−1 was 3.5, 4.3 and 4.2 g Ca kg−1 diet, respectively, supplied as Ca‐lactate.  相似文献   

19.
Production trials of threatened snakehead fish (Channa striatus) were carried out under different stocking densities in earthen ponds of Bangladesh. The average weight and length of the fingerlings during stocking was 17.63 ± 1.23 g and 13.21 ± 0.52 cm. Fingerlings were stocked at 5000 ha?1 in treatment‐1 (T1), 6250 ha?1 in treatment‐2 (T2) and 7500 ha?1 in treatment‐3 (T3) respectively. Fish in all the experimental ponds were fed with supplementary feed comprising of fish meal (30%) and mustard oilcake (70%) at the rate of 3–6% of estimated body weight two times per day. In addition, trash fish were supplied at the rate of 2–3% of the estimated biomass on each alternate day. In situ water quality parameters of the pond were within the suitable range for fish culture. The growth and survival of fingerlings were significantly higher in T1 than in T2 and T3. The food conversion ratio was significantly lower (P<0.05) in T1 than in T2 and T3. The estimated gross and net production of fish was higher in T1, followed by T2 and T3. Overall, the highest growth, survival and production were obtained from T1. Therefore, it could be concluded that of 5000 fingerlings ha?1 is the most suitable stocking density for culturing C. striatus under a monoculture system in the earthen ponds for better production.  相似文献   

20.
A 6‐week growth trial was conducted to investigate the effect of dietary supplementation with maggot meal (MGM) and soybean meal (SBM) on the growth performance and antioxidant responses of gibel carp (GC) and darkbarbel catfish (DC). The basal diet was formulated to contain 114 g kg−1 fish meal (FM) and 200 g kg−1 SBM. The basal diet was supplemented with either 280 g kg−1 FM (Control), 390 g kg−1 MGM or 450 g kg−1 SBM to obtain three isonitrogenous (crude protein: 380 g kg−1) and isocaloric (gross energy: 16 kJ g−1) diets. For GC, a significant decrease in specific growth rate (SGR) was only observed in fish fed the SBM diet compared with the control (P < 0.05). Principal components analysis (PCA) of GC showed a higher similarity in antioxidant response to dietary supplementation with MGM and SBM proteins between liver and intestine, but the DC did not. The present results suggest that supplementing 390 g kg−1 MGM protein to basal diet cause an enhancement of the antioxidant capacity in GC, but supplementing 390 g kg−1 MGM and 450 g kg−1 SBM proteins to basal diets resulted in a significant attenuation of the antioxidant capacity in DC.  相似文献   

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