首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
To understand the actual production of fish culture about the utilization of dietary protein and excreta impact on the environment between mandarin fish (Siniperca chuatsi) and grass carp (Ctenopharyngodon idellus), the study to investigate the effect of temperatures (19 ± 0.5°C, 24 ± 0.5°C and 29 ± 0.5°C) on ammonia‐N excretion in mandarin fish and grass carp under fed and fasted states was conducted. These two species were fed a practical diet containing 325.2 g kg?1 crude protein at 3% body weight per day. The ammonia‐N excretion rate was significantly increased when temperature increased from 19 to 29°C, and a linear relationship between ammonia‐N excretion rate and temperature. The maximum ammonia‐N excretion levels of mandarin fish and grass carp were observed at 4–8 h and 2–4 h after feeding, respectively, and the minimum values for both species were observed at 24 h after feeding. Under the feeding condition, mandarin fish had a lower ammonia‐N excretion level compared to grass carp at 24°C and 29°C. The average amount of ammonia‐N excreted by mandarin fish at 24 h is significantly higher than grass carp under fasting conditions, except 19 ± 0.5°C. These results indicated that mandarin fish might make better use of protein at higher temperature than grass carp when fed practical diets in commercial production. These results of this study suggested that mandarin fish had a lower ammonia‐N excretion level compared with grass carp, making a less contribution to environmental loading in an intensive fish culture.  相似文献   

2.
Non-faecal phosphorus (P) was determined for large yellowtail to estimate a minimum available P requirement (Experiment  1) and to justify inorganic P supplementation in a fish meal-based diet (Experiment 2). In Experiment 1, purified diets with incremental P concentrations were fed to yellowtail (mean weight 917 g) at a feeding rate of 1.5% of body weight. The peaks of non-faecal P excretion appeared 5–6 h after feeding in fish fed more than 4.5 g available P kg−1 dry diet. Broken-line analysis indicated that the minimum available P requirement was 4.4 g kg−1 dry diet. In Experiment 2, a purified diet (PR) containing 6.5 g available P kg−1 and a fish meal-based diet with (F1) and without (F0) additional phosphorus were fed to yellowtail (mean weight 1.1 kg) at 1.5% (PR) and 2% (F0 and F1) feeding rates respectively. There was no significant difference in P excretion between fish fed the F0 (5.5 g soluble P kg−1 dry diet) and the PR diet. However, significantly higher (34.5%) amounts of non-faecal P excretions (7.4 g soluble P kg−1 dry diet) were found in fish fed F1 compared with the F0 diet. This suggested that there was an excess of dietary P in the F1 diet and that supplementation is not needed in fish meal-based diets for large yellowtail.  相似文献   

3.
ABSTRACT:   The effect of dietary phosphorus (P) manipulation on environmental loading of P and nitrogen (N) from carp was investigated. Two commercial diets (A and B) were re-prepared as four experimental diets A, B, AP, and BP, the latter two being topped up to the required available P level for carp. The total P ranged between 1.52 and 1.99% and water-extractable (or available) P was 0.50, 0.36, 0.62, and 0.63% for A, B, AP, and BP, respectively. A 20% fishmeal diet was chosen as the control and it contained 1.41% total P and 0.67% water-extractable P. Duplicate groups of carp (size, 8.6 g) were fed the test diets for 12 weeks. The best growth performance was that of fish fed the control diet, followed by the test diets supplemented with P. The highest rates of P absorption and retention of P and N were obtained for the control group followed by the AP, A, BP, and B experimental groups. In the case of waste discharge, the reduction in P loading was marginal, but N loading was markedly lower for P supplemented test diets. The control diet was the least-loading diet. Thus commercial carp feed formulations could be improved by incorporating sufficient available P in order to reduce discharges of P and N into the water.  相似文献   

4.
ABSTRACT:   Through a series of experiments, it has been demonstrated successfullythat an appropriate choice of ingredients is primary for achievinga reduction in phosphorus (P) and nitrogen (N) loading from carpculture. In this final study, four multi-ingredient diets were examined.In addition to the basal ingredients (fish meal 15%, corngluten meal 8%, defatted soybean meal 10%, blood meal3–5%), three of the test diets (PF, MM, and SP)contained 6% each of either poultry feather meal, meatmeal or soy protein concentrate, respectively, and the fourth diet(PMS) had each of the three aforementioned ingredients includedat 3%. These diets had crude protein < 35%,digestible energy > 3.5 kcal/g,available P between 0.65 and 0.66% and total P rangingfrom 1.26 to 1.36%. The diets were fed to juvenile carpduring a 12-week feeding trial. The highest growth was obtained forfish fed the MM diet. The absorption and retention rates of P werehigher for the PF diet, whereas these values for N did not showtreatment-related differences. The total discharges per ton fish productionwere estimated to range between 7.8 and 9.2 kg for P andbetween 39.1 and 40.7 kg for N. These were lower than thefigures for Lake Kasumigaura, a main carp culture site, indicatingthat proper balancing of protein ingredients aids in efficientlylowering emissions from aquaculture.  相似文献   

5.
ABSTRACT: To clarify the total phosphorus (P) and nitrogen (N) loading from carp culture, five commercial diets were selected from a major location in Japan, Lake Kasumigaura, for a 12-week feeding trial. These diets were prepared as per the 'Kasumigaura Feed Standard' (crude protein < 35% and digestible energy > 3.5kcal/g), and total P ranged from 1.4% to 2.0%. However, for most of the diets the P available was lower than the requirement level. A control diet was formulated with 25% fishmeal to comply with that standard and contain adequate available P. Duplicate groups of juvenile carp were fed the aforementioned diets to satiation, three times a day, six days a week throughout the trial. Growth performance was significantly higher for the control group and values of P absorption (20.4–47.0%) and retention (14.0–36.3%) varied widely among the groups. Consequently, the total P loading (kg/t production) values based on retention fluctuated from 14.8 to 26.4 among the commercial diet groups compared with the low level of 8.5 for the control group. Similarly, the total N loading (kg/t production) values varied from 30.9 to 86.0 and was lowest for the control group. A higher whole body lipid and lower bone P and Ca confirmed the deficiency of the dietary available P in commercial diets. Better growth and comparatively less P and N loading rates were observed in the diet that had sufficient available P, not to mention that the control diet ranked best. It was concluded that an inadequacy of available P among the commercial diets affects the growth of carp and produces high P and N loading into the water. Therefore, if the commercial diets do not supply adequate levels of available P to carp, growth is negatively affected and may result in greater waste loading.  相似文献   

6.
ABSTRACT:   In order to verify methods for minimizing waste output of phosphorus (P) into the water and preserve an adequate growth rate in rainbow trout, a succession of two feeding trials were performed employing three test diets that were formulated with a low proportion of fish meal (FM), low-P ingredients (defatted soybean meal, corn gluten meal, feather meal, and blood meal), and varying levels of monocalcium phosphate (MCP) as a P supplement (0, 0.5 and 1% of diet which represent 0, 1 and 2 mg/g of available P, respectively). Total P concentrations achieved were 6.2, 8.7 and 9.6 mg/g, respectively. A control diet was formulated with FM as the main protein source and without MCP (total P content was 17.0 mg/g). Diets were fed until apparent satiation to duplicate groups of 50 (1.5 g) and 15 fish (147.8 g) during 24 and 14 weeks, respectively. In both cases, the lowest growth was observed in fish fed the basal diet without MCP. The test diet supplemented with 0.5% MCP provided growth and feed performance comparable to that obtained in fish fed the control diet. These results suggest that diets formulated with low-P ingredients should be supplemented with an adequate amount of P in order to meet the fish requirements and reduced diet-related P loading.  相似文献   

7.
ABSTRACT:   Ten lots of common carp and six lots of crucian carp (each lot of 100 fish) were treated under anoxia for five days at water temperatures of 25–31°C. The average per group mortality of common carp was 17%, but none of the 600 crucian carp died. The digestive tract tissues of the common carp that died had significantly lower zinc concentrations than those that survived (59 ± 41 vs 142 ± 60 μg/[g fresh tissue], P  < 0.001). The digestive tract tissues of the crucian carp had mean zinc concentrations of 652 ± 458 μg/(g fresh tissue). One lot of common carp that had low tolerance for anoxia was fed a high zinc diet (2000 mg zinc/kg diet) for 1, 2 or 6 months and then subjected to 5 days anoxia. The survival rates of those fed the high zinc diet 1 and 2 months increased from 0 to 50%, respectively; all of fish that had fed a high zinc diet for 6 months survived. Thus, anoxia survival in common carp and crucian carp is closely related to the high concentrations of zinc in their tissues.  相似文献   

8.
This study determined the digestibility of nitrogen and phosphorus, and the excretion rate of different‐sized groups of milkfish fed a commercial diet, a SEAFDEC formulated diet or lab‐lab (natural food‐based diet). Fish (31.2–263.0 g) were stocked in 12 units of 300‐L fibreglass tanks filled with aerated seawater. The postprandial total ammonia‐nitrogen (TAN) and phosphate (PO4‐P) excretion of fish were estimated from changes in TAN and PO4‐P concentrations in water for 24 h. Digestibility was determined from the nitrogen, phosphorus and Cr2O3 content of the diets, and pooled faeces after the fish had been fed diets marked with chromic oxide. TAN excretion rate (mg TAN kg?1 fish day?1) was significantly lowest (P < 0.05) in medium to very big fish fed the lab‐lab diet (60.8–124.4) and highest in small and medium fish fed the SEAFDEC diet (333.3–331.6) and small fish fed the commercial diet (280.1). Regardless of size, fish fed lab‐lab excreted (mg PO4‐P kg?1 fish day?1) significantly lower PO4‐P (36.2) but did not differ with fish fed the commercial diet (64.8). Excretion rates decreased exponentially as fish weight increased but positively increased with feed ration. Excretion pattern of milkfish revealed two peaks: the first peak occurred 6 h after feeding and the second peak at 18 h for TAN and 21 h for PO4‐P, coinciding with the start of the daylight hours. TAN and PO4‐P excretion accounted for 20.5–34.6% of total N consumed and 18.7–42.6% of P consumed respectively. Approximately 27.9–42.5% of N consumed and 47.2–58.5% of P consumed were lost as faeces. Total nutrient losses were lower using the lab‐lab diet (0.31 g N and 0.14 g P kg?1 fish) compared with the formulated diets (0.47–0.48 g N and 0.17–0.19 g P kg?1 fish); the losses decreased per kg of fish as fish size increased. Results suggest that the diet and size of fish influence wastage of N and P to the environment with greater losses in small fish and when artificial diets are used. Such measurements will provide valuable information for the preparation of N and P budgets for milkfish in grow‐out systems.  相似文献   

9.
ABSTRACT:   The present study, one in a series to clarify the phosphorus (P) and nitrogen (N) loading from carp culture, evaluated four commercial diets. The total and available P in these diets varied from 1.57 to 1.86% and from 0.38 to 0.87%, respectively. The control diet, selected based on an earlier experiment, contained 1.40% total P and 0.68% available P. The 7-week feeding trial was performed with juvenile carp. Superior feed gain ratio was obtained for the control diet (1.00) and it varied from 1.19 to 1.56 among the commercial diet groups. Similarly, the control diet showed higher rates of P absorption (43.8%) and retention (33.1%) than the rest (absorption: 18.1–40.9%; retention: 10.7–18.7%). Total P loading (kg/t production) was 10.0 for the control group but ranged from 19.1 to 25.0 among the commercial diet groups. Nitrogen absorption was not markedly different; however, fluctuations in retention resulted in N loading (kg/t production) that ranged between 47.1 and 66.3 among the commercial diets, higher than the 34.8 obtained for the control diet. The available P in the commercial diets rarely matched the requirement level, thereby negatively affecting the waste loading. The superior performance of the control diet underscores the fact that effective formulations help in keeping emission levels low.  相似文献   

10.
Abstract. Four feeding trials with Israeli carp, Cyprinus carpio L., were performed in cages or in ponds in order to investigate responses to lysine supplementation of low protein carp feeds under different practical conditions. In each of the trials one of the basic conditions was different: fish size—small (80–125g) or large (560g); temperature—22°C or 26°C; density—cages or ponds. In each trial 2–3 ration sizes × 2–3 lysine levels were tested. A basal diet of 25% protein and 1·35% lysine served for all the trials.
At low feeding levels, no responses to lysine supplements were found either at 22 ± 2°C or at 26 ± 2°C (0600 h) for all fish sizes. At higher feeding levels, at both temperatures, 0·5% lysine-HCl supplements to 1·7% total lysine yielded significant growth increases. Further supplements to 2·1% lysine (=8·4% of the protein) brought an additional response only from small fish of 90g in cages at the highest ration and temperature. In ponds at 26°C, the effects on small fish of 80g were smaller, probably due to available natural food. The reduction in lysine retention suggested that 1·7% lysine might have been adequate even at optimal conditions in ponds.  相似文献   

11.
The effect of dietary digestible protein/digestible energy (DP/DE) ratios and feeding level on growth, feed efficiency, nutrient and energy usage by Atlantic salmon ( Salmo salar ; initial body weight, 7.0 g/fish) at 15°C was investigated in a 16-week feeding trial. Three diets, differing in their DP and DE contents, namely 37/18 (regular diet, RD), 37/21 (high fat diet, HF) and 44/ 22 (high nutrient-dense diet, HND) g/MJ of dry feed were formulated. DP/DE ratios were 20, 18 and 20 g/MJ for the RD, HF and HND diets, respectively. Salmon were hand-fed three times a day at either 100% or 85% of the feed requirement estimated by a bioenergetics model. At each feeding level, DE intake (kJ/fish) was similar for all three diets. Diet composition did not affect growth rate. However, increasing the digestible energy density from 18 to 22 MJ/kg of dry feed resulted in a significant increase ( P  < 0.05) in feed efficiency. Restricting feed intake significantly decreased live body weight gains for all diets. However, feed efficiency was not affected by feeding level. Diet composition and feeding level did not affect carcass composition and nutrient and energy usage, with the exception of a higher ( P  < 0.05) carcass lipid of fish fed the HF100 diet compared with the fish fed the RD and HND diets and a higher ( P  < 0.05) lipid gain (g/fish) of fish fed the HF100 diet compared with fish fed all the diets at the restricted feeding level. Restricting feeding resulted in significantly lower ( P  < 0.05) energy gain (kJ/fish) compared with fish fed at 100%. Increasing the DE and nutrient density of the diet had no effect on growth but improved feed efficiency and lowered solid wastes (g of solid wastes per kg of fish produced) while dissolved wastes were not affected by dietary ormulation.  相似文献   

12.
A feeding trial was conducted to study the effect of partial replacement of dietary monocalcium phosphate (MCP) with neutral phytase on growth performance and phosphorus digestibility in gibel carp, Carassius auratus gibelio (Bloch). Control diet was prepared with 2% MCP but without phytase (P0). Other three experimental diets were prepared by replacement of MCP by 25%, 50% and 75% respectively in comparison with control with supplementation of neutral phytase at 500 U kg?1 diet in each and designated as P25, P50 and P75 respectively. Gibel carp (initial body weight of 30.22 ± 1.98 g) were reared in twelve 300‐L cylindrical fibreglass tanks provided with filtered flow‐through tap water at 26–28°C. After 8‐week experiment, gibel carp fed with P50 had no obvious differences from the control group on weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency rate (PER) and survival rate. Phytase supplementation did not affect body compositions or muscle compositions. Crude protein and phosphorus (P) contents in the faeces of fish fed with the phytase‐supplemented diets were significantly lower than those of the control group. The apparent digestibility coefficients (ADCs) of crude protein and P in gibel carp were increased when fish fed with the diets in which MCP was replaced by neutral phytase. This study suggested that partial replacement of dietary MCP at 50% with neutral phytase was considered as a recommended dietary supplemental level and increased dietary P and protein availability.  相似文献   

13.
Two 8‐week feeding trials were conducted to evaluate soybean meal (SBM) as a fish meal substitute in diets for Japanese seabass, Lateolabrax japonicas. In trial I, a control diet (C) contained 400 g kg?1 fish meal, and 20%, 40%, 60% and 80% of the fish meal were replaced with SBM, supplied with 3 g kg?1 DL‐methionine and 2 g kg?1 L‐lysine (S20, S40, S60 and S80). In trial II, 60% and 80% of the fish meal in diet C were replaced with SBM, supplied with DL‐methionine at 3 g kg?1 (S60, S80) or 6 to 7 g kg?1 (RS60, RS80). The feed intake was lower in fish fed diet C than in fish fed diets S20, S40, S60 and S80 (trial I). No significant differences were found in the weight gain, nitrogen retention efficiency and body composition between fish fed diets C, S20, S40 and S60 (trial I), between fish fed diets S60 and RS60 or between fish fed diets S80 and RS80 (trial II). This study indicates that dietary fish meal level for Japanese seabass can be reduced to 160 g kg?1 by using SBM as a fish meal substitute.  相似文献   

14.
An experiment with 0.2‐kg Atlantic salmon, Salmo salar in saltwater was conducted to determine if the fish could grow normally, and maintain normal nitrogen (N) and mineral balance when fed a diet with the majority of the protein (75%) derived from soy‐protein concentrate (SPC). The two diets contained 50% SPC and 15% fish meal (FM) or 60% FM as the sources of protein. No calcium phosphate was added to the diets in order to assess the availability of P from the ingredients. A second aim was to investigate if whole‐body concentrations of essential elements and growth were related in individual salmon. Growth (SGR=0.88–0.89) was similar in salmon fed the two diets, and the fish nearly doubled their body weights during the 84 days of feeding. Feed conversion was more efficient for the FM diet (0.81 kg intake kg?1 gain) than for the SPC diet (0.89 kg kg?1). The intake of N was similar, faecal loss of N was lower, while the metabolic N excretion was greater in the fish fed the FM than the SPC diet. This resulted in a total excretion of 35.4 g N kg?1 gain for the salmon fed the FM diet and 35.5 g N for the fish fed the SPC diet. Both the intake, faecal and metabolic excretion of P were higher in the fish fed the FM diet than the SPC diet, resulting in a total excretion of 10.5 g P kg?1 gain for the FM diet and 7.2 g P for the SPC diet. Whole‐body concentrations of Ca, Mg, P and Zn were lower in the fish fed the SPC diet, while the Ca–P ratio was decreased, both when compared with the fish at the start of the experiment, and the fish fed the FM diet. The differences in elemental composition were ascribed to a combination of reduced availability of elements due to phytic acid and lower concentration of elements in the SPC than in the FM. No reduction in growth of individual fish, which could be ascribed to reduced availability of essential elements, was seen.  相似文献   

15.
D. Xie  D. Han  X. Zhu  Y. Yang  J. Jin  H. Liu  S. Xie 《Aquaculture Nutrition》2017,23(5):1104-1112
A nine‐week feeding experiment was conducted in flow‐through system with gibel carp (43.8 ± 0.2 g) to study the effects of dietary available phosphorus (P) on growth, phosphorous digestibility and intestinal enzyme activities. Seven semipurified diets were formulated to contain 0.8 (the basal), 2.4, 3.6, 6.1, 7.4, 10.1 and 15.8 g available phosphorus kg?1 diet. The results showed that specific growth rate and feed efficiency increased with increasing dietary available P from 0.8 to 7.4 g P kg?1. Fish body ash increased with increasing dietary available P, while moisture, protein content or energy content had no difference. Total phosphorus waste discharging (TPW) increased with increased dietary phosphorous. Plasma glucose was higher in the fish fed with 7.4 g kg?1 P. Plasma triglycerides was lower in fish fed diets containing 6.1–10.1 g kg?1 P. No significant effects were observed in plasma P and Ca (p > .05). The activities of intestinal amylase, lipase and trypsin showed no difference, while AKP and Na+, K+‐ATPase activities decreased with increasing dietary available P. In conclusion, based on the regression between specific growth rate (SGR), P retention efficiency, feed efficiency (FE) and dietary available P, the available P requirements for on‐growing gibel carp were 10.69, 8.22 and 6.72 g kg?1, respectively.  相似文献   

16.
An 8‐week feeding trial was conducted to evaluate the effects of replacing fish meal with soybean meal (SBM) on growth, feed utilization, and nitrogen (N) and phosphorus (P) excretion of juvenile Pseudobagrus ussuriensis (initial average weight 0.50 ± 0.00 g). Seven isonitrogenous and isolipidic diets were formulated to contain SBM to replace fish meal protein at 0% (S0), 10% (S10), 20% (S20), 30% (S30), 40% (S40), 50% (S50) and 60% (S60) respectively. To investigate the effects of supplementation with crystalline amino acid to balance diet S60, one diet was formulated to add 0.30% methionine (SM60). The results showed that there was no significant difference in weight gain among fish fed S0, S10, S20, S30 and S40 diets, however, a significant reduction in this variable occurred when 50% and 60% of fish meal protein was replaced by SBM (P < 0.05). Apparent digestibility coefficients of dry matter, crude protein and phosphorus of diets were affected by dietary SBM levels. N and P excretion indicate that fish meal replacement by SBM led to an increase in N excretion, but led to a reduction in P excretion. No differences were detected in growth, feed utilization and N and P excretion between fish feed diets S60 and SM60. The results of this study show that 40% of fish meal protein could be replaced by SBM in diets of juvenile P. ussuriensis without having a significant negative effect on growth or feed efficiency, but that higher dietary SBM levels reduce fish performance.  相似文献   

17.
Two digestibility trials and two growth trials were carried out to evaluate the influence of top‐sprayed phytase on apparent digestibility coefficients (ADCs) of protein and mineral and utilization in rainbow trout fed with soybean meal‐based diets. In Trial 1, a semi‐purified diet containing 50% soybean meal was supplemented with graded levels of phytase (0, 500, 1000, 2000 and 4000 U kg?1 diet), and fed to triplicate groups of fish. In Trial 2, commercial‐type extruded feeds containing 36% soybean meal with either 0 or 2000 U phytase kg?1 were fed to five replicate groups of fish. Phytase clearly decreased phytic acid content of feces from 35 to 5 mg and from 34 to 14 mg phytic acid per g faecal dry matter in Trials 1 and 2 respectively. Apparent digestibility coefficient of P improved from 23% to 83% in Trial 1 and from 35% to 54% in Trial 2 by phytase. Apparent protein increased by 1.2% and 3.2%‐units by phytase in Trials 1 and 2. Zinc digestibility was significantly increased in Trial 1, but not in Trial 2. Trials 3 and 4 were conducted to evaluate the influence of phytase on dietary P (Trial 3) and lysine (Trial 4) utilization. Three diets were prepared for each trial: P (Trial 3)‐ or lysine (Trial 4)‐deficient basal diets, basal diets with phytase supplementation (2000 U kg?1) and P (Trial 3)‐ or lysine (Trial 4)‐fortified diets. Rainbow trout (initial weight 20 g) were fed for 10 weeks using four and six replicates for Trials 3 and 4 respectively. Phytase increased P utilization in Trial 3 as demonstrated by an increase in vertebra ash from 24.1% to 45.4%, and by an increase in weight gain from 243% to 459% of the initial weight. Phytase did not increase lysine utilization, since neither protein retention nor weight gain were enhanced by phytase. Supplemental lysine increased protein retention and weight gain to 43.1% and 514%, respectively, and also decreased whole‐body lipid contents significantly from 120 to 123 g kg?1 in fish fed the basal diet and phytase‐supplemented diet to 106 g kg?1 in fish fed with lysine‐fortified diet.  相似文献   

18.
A feeding trial was conducted for 8 weeks to evaluate the effects of supplemental phytic acid (PA) on the apparent digestibility and utilization of dietary amino acids (AAs) and minerals in juvenile grass carp. Five experimental diets consisted of graded levels of PA (0.2, 4.7, 9.5, 19.1 and 38.3 g kg?1, named as P0, P5, P10, P20 and P40). Triplicate groups of fish (initial weight, 22.37 ± 0.16 g) were fed twice daily (08:00 and 16:00 h). The crude protein content in whole body significantly (p < .05) decreased in fish fed with 19.1 and 38.3 g PA kg?1 diet. Supplemental PA (>4.7 g kg?1) significantly reduced the apparent digestibility coefficient (ADC) of AAs (Asp, Thr, Ser, Glu, Gly, Ala, Cys, Val, Met, Ile, Leu, Phe, Lys, Pro, His and Arg) and the ADC of minerals (P, Ca, Mg, Zn, Cu, Fe and Mn) in grass carp. The contents of minerals (P, Ca, Mg and Zn) in whole body and bone were also found to be significantly reduced in dietary PA > 4.7 g kg?1, while the bone ash, serum Alkp and Zn contents were found to be significantly decreased when the PA supplementation level was above 9.5 g kg?1, and the contents of serum Ca and Mg were found to be markedly altered in higher PA‐supplemented groups. The results indicated that supplemental PA decreased the apparent digestibility and utilization of AAs and minerals, and thus reduced the feed utilization of grass carp, suggesting that the level of total PA should be below 4.7 g kg?1 in grass carp diet.  相似文献   

19.
This study focuses on reducing total phosphorus loading (T-P) from carp culture through improved feed formulation. Since phosphorus (P) contained in fish meal (FM) mainly in the form of tricalcium phosphate is not available to carp, which lack a stomach, the reduction of FM from their diets is effective for lowering T-P. Thus in this experiment, six diets (crude protein < 35%, digestible energy > 3.5 kcal g−1) were designed by substituting FM (10%−25%) with alternate protein ingredients such as poultry feather meal (PFM; 5%−10%), blood meal (BM; 5%−7%) and defatted soybean meal (dSBM; 4%−9%). All diets followed the Kasumigaura ‘Feed Standard’. The total dietary P was 1.0%−1.4% and water extractable P available to carp was 0.66%−0.71%, the levels meeting the dietary requirement of carp. A feeding trial was conducted with juvenile carp (4.6 ± 0.7 g) for 12 weeks at a mean water temperature of 23.7°C. The T-P loading from fish fed the different diets was estimated based on absorption and retention of dietary P. Growth performance corresponded to increasing levels of FM inclusion, being highest in the fish fed 25% FM diet; however, the decrease in T-P was achieved at the lower FM levels. The T-P (based on P retention) ranged from 8.9 to 11.7 kg t−1 production, much lower than that from the commercial diets (9.1–26.4 kg t−1 production). These results indicated that the reduction of FM levels in carp diets to 15%−20% through the combined use of PFM, BM and dSBM effectively lowered T-P. Moreover, the formulated diets were also found to be better than commercial diets in lowering the N loading from carp culture.  相似文献   

20.
A study was conducted to evaluate the effect of partial replacement of dietary fish meal by crystalline amino acids on growth performance, feed utilization, body composition and nitrogen utilization of turbot juveniles.

Four diets were formulated to be isolipidic (12% DM) and isonitrogenous (8% DM). A fish meal based diet was used as control. In the experimental diets, a crystalline amino acid (AA) mixture was used to partially replace fish meal, corresponding to a non-protein nitrogen content of 19, 37 and 56%, respectively (diets 19AA, 37AA and 56AA, respectively). The overall amino acid profile of the experimental diets resembled that of the whole-body protein of turbot. Each experimental diet was fed to triplicate groups of 20 fish (initial body weight of 31.8 g) twice daily to apparent satiation for 42 days. During the trial water temperature averaged 18 °C.

Final body weight, weight gain (g kg ABW− 1 day− 1) and specific growth rate were not different between the control and 19AA diet but significantly decreased with the increase of crystalline-AA inclusion from 19 to 56%. Feed intake and feed efficiency of fish fed the control and diet 19AA were similar and significantly higher than those of fish fed the 56AA diet. At the end of the growth trial, there were no significant differences in whole-body composition among groups. Hepatosomatic index was also unaffected by dietary treatments.

Nitrogen retention (g kg ABW− 1 day− 1) of fish fed the control and the 19AA diets were similar and significantly higher than that of fish fed the other diets. Expressed as a percentage of the nitrogen intake, N retention was significantly higher with the control than with the 37AA and 56AA diets.

Daily ammonia excretion (mg kg ABW− 1 day− 1) of fish fed the control diet was significantly higher than that of fish fed the 37AA and 56AA diets, while daily urea excretion (mg kg ABW− 1 day− 1) did not significantly differ among treatments. Non-fecal nitrogen (ammonia + urea) excretion (mg kg ABW− 1 day− 1) was significantly higher for fish fed the control diet than in those fed the 37AA and 56AA diets. However, as percent of N intake, ammonia excretion and non-fecal N excretion were significantly higher in fish fed the 56AA diet than in those fed the control and 19AA diets.

Specific activity of glutamate dehydrogenase, alanine and aspartate aminotransferases did not significantly differ among experimental groups.

In conclusion, in diets with an overall amino acid profile resembling that of the whole-body protein of turbot, crystalline-AA may replace 19% of dietary protein without negatively affecting growth performances or feed utilization efficiency. However, higher protein replacement levels of protein-bound-AA by crystalline-AA severely depressed growth performance.  相似文献   


设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号