The relationship between feeding preferences and consumption rates in grass carp and grass carp × bighead carp hybrids

The relationship between food preference hierarchy and consumption rate was examined for the grass carp, Ctenopharygodon idella , and its Fl hybrid (grass carp × bighead carp). Preferences of both types of fish were similar, although hybrids consumed vegetation at a much lower rate. For both, relative preference in feeding trials with mixed plant species was significantly correlated with consumption rate in monospecific feeding experiments. No correlations were found between preference and caloric content, protein content or relative water content. The hypothesis is proposed that preference hierarchies reflect relative handling times of different food types and that these fish maximize 'through-put' by preferentially consuming plant species which can be most rapidly ingested.     

Growth and energy budget in young grass carp, Ctenopharyngodon idella Val., fed plant and animal diets

Young grass carp held under laboratory conditions were fed either duckweed or tubificid worms. Food consumption ( C ), faecal production ( F ), excretion ( U ), metabolism ( R ) and growth ( G ) were estimated for fish fed both diets. Fish fed tubificid worms had higher growth rates than those fed duckweed, in terms of wet weight, dry matter, protein, lipid and energy. Fish fed duckweed consumed more wet and dry matter than did the fish fed tubificids, but rates of protein and lipid consumption were lower. The energy budget was estimated to be 100C = 9 F + 8 U + 61 R + 22 G for fish fed tubificids, and 100C = 35 F + 5 U + 51 R + 9 G for fish fed duckweed. Linear relationships existed between specific growth rate in wet weight and rate of food absorption (consumption minus faecal production) in dry matter, protein or energy. Food type did not have a significant effect on these relationships. It was concluded that differences in growth rate between grass carp fed different diets were mainly caused by differences in absorption rate.     

Utilization of grass carp faeces by the IsopodAsellus aquaticus (L.) in the laboratory

Grass carp (Ctenopharyngodon idella Val) faecal pellets derived fromElodea nutallii consumption were efficiently utilized by the detritivoreAsellus. Immature and adult individuals of 2.1–3.2 mm and 4.9–6.0 mm respectively, exhibited a high mean specific growth (9.03%/day and 3.33%/day) when offered faecal pellets as food during two weeks experimental trials. Individuals of the same groups, when fed onElodea which had been mechanically fragmented to simulate the macerating action of the grass carp pharyngeal teeth, grew at rates (9.57%/day and 4.06%/day) not significantly different from those fed on faecal pellets. However, the growth rates of animals fed on freshElodea (6.40%/day and 2.23%/day) were significantly lower than in the above trials, indicating that the morphological destruction of the plant tissue could be responsible for the higher observed growth. The control trials, including unfed animals, showed negative growth (– 0.49%/day and – 0.48%/day).Grass carp herbivory makes a new food resource available to benthic invertebrates by converting fresh plant material to small plant fragments.     

Intensive culture of grass carp, Ctenopharyngodon idella, in circular tanks

Fingerling grass carp ( Ctenopharyngodon idella ) were cultured in 380 1 circular fiberglass tanks at stocking densities of 0.53, 1.06, 1.59 and 2.11 fish/1. Fish were fed duckweed ( Lemna minima ) to satiation. Fish grew from 2.7 g to a maximum mean weight of 72.7 g in 88 days. Fish stocked at 0.53 fish/1 grow more rapidly than those stocked at higher densities. Mean daily consumption rates were strongly correlated with oxygen levels and when oxygen levels dropped below 4 mg/1 consumption was reduced approximately 40%. High biomass, growth, and survival rates obtained during this study indicate grass carp are well suited for intensive tank culture.     

Isolation of cellulose—producing microbes from the intestine of grass carp (<Emphasis Type="Italic">Ctenopharyngodon idellus</Emphasis>)

The cellulase activities of bacterial strains in the intestine of grass carp were analyzed, using filter paper and absorbent cotton as substrates and measuring the concentration of glucose by calorimetry. Six strains were isolated and determined high cellulase activity in all grass carp. Strains showed different abilities to produce cellulase, which suggests that they interact in the grass carp intestine to digest cellulose. The presence of cellulose activity suggests that grass carp have the ability to digest cellulose in the diet. The cellulase enzymatic activity increased dramatically after 6 days of culture and reached its peak at the 7th day. Microbes are probably the main source of cellulase in grass carp diets.     

华西雨屏区不同退耕模式细根(包括草根)分解过程中土壤酶动态

采用原状土芯(intact core)法, 探讨了四川洪雅柳江退耕模式——光皮桦(Betula luminifera)与扁穗牛鞭草(Hemarthria compressa)复合模式(HN)、扁穗牛鞭草草地模式(NC)、柳杉(Cryptameria fortunei)人工林模式(LS)、光皮桦人工林模式(H)细根(包括草根)分解过程中土壤酶动态。结果表明: 1) HN下的土壤脲酶、蔗糖酶、酸性磷酸酶活性较大, LS下的土壤脲酶、酸性磷酸酶活性最小, 显著低于其他模式(p < 0.05)。2) HN、NC和LS下的土壤脲酶与细根(包括草根)分解速率显著相关, HN的蔗糖酶、NC的酸性磷酸酶、LS的多酚氧化酶活性与细根(包括草根)分解速率也呈显著正相关关系(p < 0.05)。3) 除H外, 土壤脲酶活性与细根C/N、纤维素绝对含量呈显著负相关关系(p < 0.05); 除NC外, 多酚氧化酶活性与细根纤维素绝对含量呈显著负相关关系。4)土壤脲酶活性与需氧固氮细菌或与真菌数量显著相关, HN下的土壤蔗糖酶活性与细菌和纤维素分解菌数量呈正相关关系, H与NC下的土壤酸性磷酸酶还分别与细菌和纤维素分解菌数量呈正相关关系(p < 0.05)。以上结果显示: 由光皮桦与扁穗牛鞭草不同生活型植物构成的复合模式有利于土壤酶活性的提高; 土壤脲酶活性高低能够反映这几种退耕模式细根(包括草根)分解速率的快慢, 细根(包括草根)的C/N是影响土壤脲酶活性的一个重要因素; 土壤酶活性与土壤真菌、需氧固氮细菌、纤维分解菌及细菌数量有关。     

The relationship between specific dynamic action and growth in grass carp, Ctenophavyngodon idella (Val.)

Individual grass carp, Ctenopharyngodon idellu , were maintained in a respirometer for a month and fed pelleted diets containing various proportions of carbohydrate, fat and protein at different ration levels. Oxygen consumption was measured continuously, allowing the effects of consecutive daily feeding on respiration to be studied. The relationships established between daily food intake and oxygen consumption showed that, on average, 23.3% (high protein diet), 15.3% (high carbohydrate diet), 20.7% (high lipid diet) and 7.0% ( Lemnu diet ) of the absorbed energy was partitioned into specific dynamic action (SDA). (Here the term SDA is used to describe the oxygen consumption of a feeding fish in excess of the routine metabolic rate.) In terms of the overall energy budgets of growing fish, SDA represented between 12 and 58% of the total heat lost over the experimental period and was equivalent to between 14 and 33% of the consumed energy. Ration was positively correlated with heat loss due to total respiration ( r = 0.881) and with heat loss due to SDA ( r = 0.762). As ration increased, the size of SDA relative to total respiration increased. Significant positive correlations were found between oxygen consumption (total or due to SDA) and specific growth rate, and between oxygen consumption and the deposition of protein and energy. However, growth rate had a minimal influence on daily oxygen consumption when compared with food intake.     

草鱼肠道纤维素降解细菌的分离与鉴定

为更好地弄清草鱼（Ctenopharyngodon idella）肠道纤维素降解细菌的种类,采用羧甲基纤维素（CMC）作为唯一碳源的选择性培养基,分别从草鱼肠道内容物和肠道黏膜中分离到了40株产纤维素酶细菌。16S rRNA基因序列的分析结果显示,大多数产纤维素酶细菌为气单胞菌属（Aeromonas）的种类,其次为肠杆菌属（Enterobacter）的细菌以及未经分离纯培养的细菌（Uncultured bacterium）。进一步研究细菌产纤维素酶能力发现,纤维素酶活性显著性高于其他菌株的分别是A. veronii MC2、A. veronii BC6、肠杆菌科（Enterobacteriaceae）中一种未经分离纯培养的细菌BM3（Uncultured bacterium BM3）和A. jandaei HC9。草鱼肠道中简答气单胞菌（A. jandaei）、类志贺邻单胞菌（Plesiomonas shigelloides）、阴沟肠杆菌（E. cloacae）以及产气肠杆菌（E. aerogenes）是被作为产纤维素酶细菌的首次报道。       

饲料氧化鱼油对草鱼肝胰脏结构和功能的损伤

为了探讨饲料氧化鱼油对草鱼(Ctenopharyngodon idellus)肝胰脏组织结构及其功能的影响, 研究以豆油、鱼油及氧化鱼油作为饲料脂肪源, 分别设计鱼油组(6F)、豆油组(6S)、2%氧化鱼油(4S2OF)、4%氧化鱼油(2S4OF)及6%氧化鱼油(6OF)5组等氮、等能的半纯化饲料, 在池塘网箱中养殖72d。结果显示: 氧化鱼油显著增加草鱼血清ALB、GLB、MDA和GSH含量(P0.05), 显著降低肝胰脏GSH和SOD含量(P0.05); 氧化鱼油会显著增加草鱼肝胰脏指数及肝胰脏脂肪含量(P0.05), 且草鱼血清TG含量显著上升(P0.05), HDL/LDL显著下降(P0.05); 氧化鱼油使血清及肝胰脏TC含量显著增加(P0.05), 血清TBA显著下降(P0.05), 肝胰脏TBA显著上升(P0.05); 氧化鱼油会引起草鱼脂肪肝, 损伤肝胰脏细胞线粒体, 并导致肝胰脏细胞纤维化和组织萎缩。结果表明: 饲料添加氧化鱼油会引起草鱼氧化应激, 并降低草鱼肝胰脏抗氧化能力; 扰乱草鱼肝胰脏脂肪代谢, 引起脂肪肝; 影响胆汁酸肝肠循环, 使胆汁酸在肝胰脏中堆积, 并损伤肝胰脏细胞线粒体, 最终增加草鱼肝胰脏脂肪性肝炎发生率。     

Cold hardiness and water relations parameters in Rhododendron cv. Catawbiense Boursault subjected to drought episodes

We determined whether increase in cold hardiness of Rhododendron cv. Catawbiense Boursault induced by water stress was correlated with changes in tissue water relations. Water content of the growing medium was either maintained near field capacity for the duration of the study or plants were subjected to drought episodes at different times between 15 July and 19 February. Watering during a drought episode was delayed until soil water content decreased below 0.4 m³ m⁻³ then watering was resumed at a level to maintain soil water content between 0.3 and 0.4 m³ m⁻³. Cold hardiness was evaluated in the laboratory with freeze tolerance tests on detached leaves. Water relations parameters were determined using pressure-volume analysis. Exposure to drought episodes increased cold hardiness during the cold acclimation stage in late summer and fall but not during the winter. When water-stressed plants were re-watered to field capacity, the previous gain in cold hardiness gradually disappeared. Water relations parameters correlating with seasonal changes of cold hardiness included dry matter content (r =−0.67). apoplastic water content (r =−0.60), and water potential at the turgor loss point (r = 0.40). Changes of cold hardiness in water-stressed plants in reference to well-watered plants were correlated with changes of all water relations parameters, except for osmotic potential at full turgor (r = 0.13). It is proposed that water stress reduced the hydration of cell walls, thereby increasing their rigidity. Increased rigidity of cell walls could result in a development of greater negative turgor pressures at subfreezing temperatures and therefore increased resistance to freeze dehydration.     

鲫幼鱼游泳运动能力的个体变异与表型关联

为考察鲤科鱼类运动能力的个体变异和表型关联及不同加速度对匀加速游泳能力的影响, 研究在(25±0.5)℃条件下测定鲫(Carassius auratus)幼鱼的静止代谢率(Resting metabolic rate, RMR), 通过临界游泳速度(Critical swimming speed, U_crit)法和过量耗氧(EPOC)法获取实验鱼的最大代谢率(Maximum metabolic rate, MMR)、代谢空间(Aerobic scope, AS=MMR-RMR)、相对代谢空间(Factorial aerobic scope, FAS=MMR/RMR)、U_crit及步法转换速度(Gait transition speed, U_gt), 并在不同加速度(0.083、0.167、0.250、0.333 cm/s2)下测定鲫幼鱼的匀加速游泳能力(Constant accelerated test, U_cat)和U_gt。研究发现: 鲫幼鱼的MMR和AS与U_crit均呈正相关, 但RMR与U_crit不相关; 能量代谢参数(MMR、AS、RMR)与U_gt不相关。U_crit法获取的MMR、AS、FAS与EPOC法均无平均值的显著性差异, 但2种方法获得的上述参数具有较高的个体重复性; 鲫幼鱼的能量代谢参数之间存在表型关联并且关联方向不尽相同。鲫幼鱼的U_crit和U_gt均小于各加速度下的U_cat和U_gt, 加速度对U_cat测定无影响但对U_gt有影响。鲫幼鱼的U_gt与U_crit或U_cat呈正相关, 并且其匀加速游泳能力参数在不同加速度下保持较高的重复性。除0.333 cm/s2外, 其他加速度下鲫幼鱼U_cat的无氧代谢组分(U_cat-U_gt)与U_cat呈正相关; 然而, 鲫幼鱼的有氧代谢组分(U_gt)与无氧代谢组分(U_cat-U_gt)呈负相关。研究表明: U_crit法和EPOC法诱导鲫幼鱼的有氧代谢能力无方法学差异; 鲫幼鱼的能量代谢存在表型关联, 其匀加速游泳能力具有稳定个体差异, 并且该种鱼的有氧代谢与无氧代谢存在权衡。     

Aquarium studies on the selectivity of 16 aquatic plants as food by fingerling hybrids of the cross between Ctenopharyngodon idella ♂ and Cyprinus carpio ♀

Fish hybrids of the cross Ctenopharyngodon idella ♂ (grass carp) and Cyprinus carpio ♀ (Israeli carp), averaging 124 mm total length and 20 g in weight were stocked in aquaria along with 16 different aquatic plants to determine which plants they would eat. Observations showed that one group of plants was highly utilized (Azolla caroliniana, Lemna spp., Cladophora sp., Spirogyra sp., Nymphaea odorata); another group was moderately utilized (Pistia stratiotes, Ruppia maritima, Najas flexilis, Limnobium spongia, Potamogeton pecti-natus). Two other groups were only poorly utilized (Ceratophyllum demersum, Eichhornia crassipes, Elodea sp.) , or not utilized (Cabomba caroliniana, Sigittaria sp., Myriophyllum pinnatum).     

Formation of cluster roots and mycorrhizal status of Comptonia peregrina and Myrica pensylvanica in Maine, USA

Extent of cluster (proteoid) root formation in the field was examined in relation to availability of P and successional status of the site in two actinorhizal, N₂-fixing shrubs. Comptonia peregrina (L.) Coult. and Myrica pensylvanica Loisel. In C. peregrina cluster roots were present at all 13 sites and comprised between 0.2 and 19% of total fine root dry weight. Cluster root formation was most extensive at recently disturbed sites and was negatively correlated with cover of associated woody species (r =−0.85), litter depth (r =−0.81) and available (extractable) soil P (r =−0.75). In M. pensylvanica cluster roots were present at all 11 sites and comprised between 6 and 20% of total fine root dry weight. On mineral soils (n = 6), extent of cluster root formation was negatively correlated (r =−0.86) with cover of associated woody species and with litter depth (r =−0.78; P = 0.07). Comptonia peregrina and M. pensylvanica lack functional mycorrhizae at these sites because only intracellular infections were found and these lacked arbuscules. None of 22 non-N₂-fixing, dominant woody species associated with C. peregrina and M. pensylvanica formed cluster roots. Cluster roots probably allow C. peregrina and M. pensylvanica to obtain sufficient P from nutrient-poor soils in the absence of functional mycorrhizae. Extensive cluster root formation on disturbed, early successional sites may aid these species in colonizing these sites because they have to form only one symbiosis (with Frankia ) and not two (with Frankia and a mycorrhizal fungus).     

Karyotype variability in successive generations after hybridization between the great sturgeon, Huso huso (L.), and the sterlet, Acipenser ruthenus L.

Effects of particle size, fish size and temperature on the filtration rate of silver carp were determined. When feeding at 20°C on zooplankton and spherical particles (yeast, micronic beads and pollen), 32-g silver carp filter particles larger than 70 urn at a maximum rate of 18.251 h⁻¹. For particles smaller than 70 μm, filtration rates decrease with decreasing particle size until there is no measured filtration for particles smaller than 10 μm. Filtering rates ( FR ) for particles between 10 and 50 μm are described by the equation, FR =−20.8 + 21.7 × log particle diameter. Filtration rates rise as fish size, particle size and temperature increase. Filtration rates per unit biomass, however, fall as fish size increases: FR = 1.54 W^0.713, where FR is the maximum filtration rate in ¹ h ¹ fish ¹ and W is weight of fish in grammes. The results of these trials are consistent with the hypothesis that particle selection by silver carp is a mechanical, passive function of gill raker morphology.     

草鱼雌核发育后代不同群体的微卫星遗传分析及指纹识别

以紫外线灭活的团头鲂精子激活草鱼卵子,冷休克抑制第二极体排出的方法诱导出长江水系优良F2代草鱼减数雌核发育子代。在后代中不仅存在雌核发育后代,还存在草鲂杂交后代,雌核发育后代的体型与草鱼一致,而草鲂杂交后代的体型介于草鱼与团头鲂之间。Partec CyFlow倍性分析仪测定结果显示:普通草鱼与雌核发育草鱼的相对DNA含量分别为23.01和22.72,二者的DNA含量接近;而高体型子代的相对DNA含量为25.38,介于草鱼与团头鲂（DNA含量28.21）之间,属于草鲂杂交后代。选取17个微卫星标记对草鱼群体、雌核发育草鱼群体和草鲂杂交后代的遗传多样性进行了检测,共检测出59个等位基因,其中43.18个有效等位基因。草鱼对照群体、草鲂杂交后代和雌核发育草鱼群体的平均等位基因依次为3.57、2.86和2.79,平均有效等位基因依次为2.93、2.37和1.96,平均期望杂合度在依次为0.6502、0.5573和0.3775,多态信息含量（PIC）平均值依次为0.5738、0.4649和0.3791。与草鱼对照群体相比,雌核发育草鱼群体的遗传多样性显著下降,表明通过减数雌核发育方法可获得纯合性较高的草鱼个体。构建了草鱼后代不同群体的DNA指纹模式图,筛选到不同群体的9个特异微卫星标记,为草鱼优良群体的选育提供了基础资料。     

Intraspecific mass scaling of metabolic rates in grass carp (Ctenopharyngodon idellus)

We assessed the intraspecific mass scaling of standard metabolic rate (SMR), maximum metabolic rate (MMR), excess post-exercise oxygen consumption (EPOC), and erythrocyte size in grass carp (Ctenopharyngodon idellus), with body masses ranging from 4.0 to 459 g. SMR and MMR scaled with body mass with similar exponents, but neither exponent matched the expected value of 0.75 or 1, respectively. Erythrocyte size scaled with body mass with a very low exponent (0.090), suggests that while both cell number and cell size contribute to the increase in body mass, cell size plays a smaller role. The similar slopes of MMR and SMR in grass carp suggest a constant factorial aerobic scope (FAS) as the body grows. SMR was negatively correlated with FAS, indicating a tradeoff between SMR and FAS. Smaller fish recovered faster from the exhaustive exercises, and the scaling exponent of EPOC was 1.075, suggesting a nearly isometric increase in anaerobic capacity. Our results provide support for the cell size model and suggest that variations of erythrocyte size may partly contribute to the intraspecific scaling of SMR. The scaling exponent of MMR was 0.863, suggesting that the metabolism of non-athletic fish species is less reliant on muscular energy expenditure, even during strenuous exercise.     

The cooperative relation between non-hydraulic root signals and osmotic adjustment under water stress improves grain formation for spring wheat varieties

Non-hydraulic root signals (nHRS) and osmotic adjustment (OA) are two important adaptive responses of plants to water stress. There is little understanding of their relationships during water stress. The threshold range of soil water potential to occurrence of nHRS, the capacity for OA, grain yield and water use efficiency (WUE) were examined in three spring wheat ( Triticum aestivum L.) varieties (two bred after 1975 and one bred before 1900) under water stress conditions. The threshold range of nHRS was significantly correlated with the maintenance rate of grain yield (MRGY) ( r  = 0.99, P  < 0.05) under moderate drought (−0.49 to −0.55 MPa) but not under severe drought (−0.70 to −0.76 MPa). There were similar correlations between OA and the MRGY. However, regulation of nHRS precedes OA during gradual water stress. The threshold range of nHRS and OA was positively correlated ( r  = 0.93, P  < 0.05), suggesting a mechanism for adapting to drought. WUE was higher for modern than for old varieties and was correlated with the root efficiency (full biomass weight including root per root weight, r  = 0.78, P  < 0.05) and the root water uptake efficiency (water consumption per root weight, r  = 0.72, P  < 0.05). However, there was a significant negative correlation between WUE and root weight ( r  = –0.84, P  < 0.01). The cooperative relationship between the threshold range of nHRS and OA under water stress was beneficial for improving grain formation for spring wheat varieties.     

Biology and management of grass carp (Ctenopharyngodon idella,Cyprinidae) for vegetation control: a North American perspective

Summary The grass carp is one of the largest members of the family Cyprinidae. In their native habitat, grass carp typically reach weights of 30–36 kg, but fish have been reported up to 181 kg. Successful reproduction is a function of temperature, age/size, and water conditions. Fish reach maturity when about 4 years old (4–5 kg). Spawning occurs when water temperature rises above 20°C. Because grass carp eggs are semipelagic, current during spawning is required to keep eggs in suspension while they incubate. In general, successful spawning takes place under rising water conditions in very long rivers. Fecundity is very high in normal diploid individuals; females may produce over one million eggs in a season. In triploid fish, eggs and sperm are produced, but the incidence of viable offspring (even when mated with diploids) is very low.Grass carp fry begin feeding on microscopic animals and gradually switch to plant material as they grow. Adult diploids, triploids, and hybrids ( grass carp x bighead carp (Hypophthalmichthys nobilis, Cyprinidae)) are all herbivorous. Feeding is strongly affected by temperature. Active feeding begins as temperatures rise above 7–8°C and consumption peaks at 20–26°C. Whereas triploids feed at nearly the same rate as diploids, hybrids feed at substantially lower rates. Therefore, vegetation control is most efficiently achieved with diploid or triploid fish. These fish may consume more than their own weight in plant material each day. However, feeding rate (and hence vegetation control) is affected by the forage that is available. Grass carp exhibit strong preferences for different macrophyte species depending on the aquatic system (i.e. the same plant species is not always the most preferred). Hydrilla verticillata and similar species are almost always among the most preferred species, and control or elimination is usually assured if adequate stocking densities are used. Vegetation control has been reported with stocking densities as low as six fish per vegetated ha.Grass carp currently appear to be the most effective biological control on aquatic vegetation. However, in order to avoid ecological disaster, care should be taken to limit their use to sterile forms and to prevent their invasion of ecologically sensitive areas, such as waterfowl staging areas and threatened or endangered species habitat.     

Effect of meal size on excess post-exercise oxygen consumption in fishes with different locomotive and digestive performance

Effects of feeding on pre-exercise VO₂ and excess post-exercise oxygen consumption (EPOC) after exhaustive exercise were investigated in sedentary southern catfish, active herbivorous grass carp, omnivorous crucian carp, and sluggish omnivorous darkbarbel catfish to test whether feeding had different effects on EPOC and to compare EPOC in fishes with different ecological habits. For fasting fish, the pre-exercise and peak post-exercise VO₂ were higher and recovery rates were faster in crucian carp and grass carp compared to those of darkbarbel catfish and southern catfish. EPOC magnitudes of grass carp and southern catfish were significantly larger than those of crucian carp and darkbarbel catfish. Feeding had no significant effect on peak post-exercise VO₂, recovery rate, and EPOC magnitude in grass carp. Both the pre-exercise and peak post-exercise VO₂ increased with meal size, while the EPOC magnitude and duration decreased significantly in the larger meal size groups of crucian carp and southern catfish. In darkbarbel catfish, both the pre-exercise and peak post-exercise VO₂ increased with meal size, but the VO₂ increment elicited by exercise was larger in feeding groups compared with the fasting group. These results suggest that (1) the characteristics of the post-exercise VO₂ profile, such as peak post-exercise VO₂ and recovery rate, were closely related to the activity of fishes, whereas the EPOC magnitude was not and (2) the effects of feeding on EPOC were more closely related to the postprandial increase in VO₂.     

不同草鱼池塘混养系统结构优化的实验研究

研究采用陆基围隔实验法,对草鱼(Ctenopharyngodon idellus)、鲢鱼(Hypophythalmichthys molitrix)、鲤鱼(Cyprinus carpio)和凡纳滨对虾(Litopenaeus vannamei)不同混养系统的养殖产量、投入产出比、氮磷利用率和综合养殖效果进行了研究。实验设置6个处理组,分别为草鱼单养(G)、草鱼和鲢鱼二元混养(GS)、草鱼、鲢鱼和鲤鱼按照不同比例放养的三元混养(GSC1和GSC2)和草鱼、鲢鱼和凡纳滨对虾按照不同比例放养的三元混养(GSL1和GSL2)。研究结果表明,各处理组总产量在770480—11492.50 kg/hm2之间;饲料系数在1.00—1.38之间,以GSC1最低,各处理组之间差异显著(P<0.05)。N、P总相对利用率在2.01—7.37之间,以GSL2最高,G最低;投入产出比在1:1.41—1:2.12之间,以GSL2最高,G最低;综合效果指标在0.59—1.39之间,以GSL2最高,G最小。研究结果表明,混养组能显著提高养殖系统的产量,降低饲料系数,提高N、P利用率,从而有效提高草鱼养殖的经济效益和生态效益。