Protein requirements of grass carp fry (Ctenopharyngodon idella Val.)

The study was aimed at determining the optimal level of protein in a casein diet for grass carp. There was a linear relationship between the percentage of protein in the diet and the increase in fish protein and weight up to optimal levels of 41 and 43%, respectively. No further increase in fish protein or weight was noted with diets containing up to 64% of protein. However, if the optimal level was defined by the parabolic curve with the formula y = 36.21 + 6.238x ? 0.0593x², it would equal 52.6 ± 1.93%. Net protein utilization (NPU) values for experimental diets were obtained using a formula which took the maintenance nitrogen metabolism on a non-protein diet into consideration. This NPU formula was related to the length of the experiment, difference in the weight of fish at the beginning of the experiment, and growth of fish fed protein diets. Both protein efficiency ratio (PER) and NPU decreased with the increase in protein content of the diets according to the formulae y = 1.966?0.018x and $\text{y = 40.8?0.327x +}\text{302.6}\text{x}$, respectively.     

Induced triploidy in grass carp, Ctenopharyngodon idella Val

Induction of triploidy in grass carp was accomplished by means of thermal shocks to eggs shortly after fertilization. Triploidy occurred most often with cold shocks at 5–7°C and at durations of 25–30 min starting 2.0–4.5 min after fertilization. Estimated percent triploid ranged from 50 to 100% on five occasions. With one exception, cold shocks of 5–7°C for less than 25 min did not induce triploidy, and cold shock durations of 30 min or longer generally resulted in 100% mortality. A heat shock of 40°C for 1 min, 4.75 min after activation, was the only heat treatment which produced triploidy (8%) with 81% surviving to the blastula stage. Fertilized eggs immersed in a solution of cytochalasin B (10 mg/l, 0.1% DMSO) for 10 min, 12 min after activation, resulted in 54% of the eggs surviving to the blastula stage with none found to be triploid.     

Intensive polyculture of common carp,Cyprinus carpio L., silver carp,Hypophthalmichthys molitrix (Val.) and black buffalo,Ictiobus niger (Raf.)

Intensive polyculture was carried out with common carp, silver carp and black buffalo fed a mixture of 60% pellets (with protein level of 25%) and 40% barley, along with mineral and organic fertilization. Two stocking patterns were tested. From pattern I, in pond 1 (total stocking density 4600 fish/ha), the yield of fish after 180 days was 3538 kg/ha, with standard weight (above 500 g), at a food conversion ratio of 2.36. From pattern II, in pond 2 (total stocking density 9200 fish/ha), the respective figures were 5022 kg/ha and 2.56.An economic comparison of several polyculture trials showed that buffalo fish (bigmouth and black) at a stocking rate of 2000 fish/ha, grown with common carp (2500 fish/ha) and silver carp (1200–1500 fish/ha), gave the best breeding and economic results (a profit of 962 levs/ha or 0.27 lev/kg). The buffalo fish have excellent organoleptic properties and are considered a delicacy favoured on the Bulgarian market.     

On the growth of grass carp, Ctenopharyngodon idella Val. in composite fish culture at Kalyani,West Bengal (India)

The Central Inland Fisheries Research Institute, Barrackpore, under its “All India Co-ordinated Research Project on Composite Culture of Indian and Exotic fishes” has been conducting experiments since 1971 in different parts of India to develop formulae of species combination of fishes whereby fishes feeding in different zones of pond water are selected and cultured together to increase production in pond culture operations. These experiments have indicated that grass carp not only controls aquatic weeds but also at the same time grows very fast and thus it is one of the best culturable fish if its feeds are available.     

Proteolytic digestive enzymes of carnivorous (Silurus glanis L.), herbivorous (Hypophthalmichthys molitrix Val.) and omnivorous (Cyprinus carpio L.) fishes

The authors studied the pH, temperature dependence, heat inactivation and the reactive groups of the active centers of proteolytic enzymes extracted from the alimentary canal of silver carp, common carp and sheatfish. In these three fish species activation energy values of enzymes, active in a pH range near neutral (7.5) were nearly identical, i.e.: silver carp: 14 kcal/mol; common carp: 15.4 kcal/mol; sheatfish: 15.7 kcal/mol. Differences were found in heat stability. At 55°C time values for 50% activity loss were 3.8: 1.3 and 14.6 min in the case of silver carp, common carp and sheatfish, respectively. Activities of enzymes, active in a pH range near neutral were inhibited by 82–94% by 10⁻³M PMSF, and by 2–5% by 10⁻³M EDTA. Proteolytic enzymes of the three fish species proved not to be homogeneous, but the largest part consisted of seryl-proteinases.     

Optimisation of Artemia feeding rate for carp larvae (Cyprinus carpio L.)

Carp (Cyprinus carpio) larvae were fed on measured numbers of Artemia nauplii, and daily growth of the larvae monitored for a period of 10 days in order to determine the effect of varying feeding levels. A 34% reduction in specific growth rate was observed over the experimental period. At a temperature of 24 ± 0.5° C, carp larvae were found to require 200–250% of their body weight of Artemia nauplii per day for optimal growth and food conversion during the first five days of feeding, reducing to 100–120%/day over the following five days. The significance of these results is discussed in relation to potential economies of Artemia cyst use in hatcheries.     

Growth,food intake and evacuation rates of grass carp, Ctenopharyngodon idella fry

Grass carp fry ranging in weight from 9 mg to 300 mg were used in experiments to determine their response to diets of coconut meal and a 1:3 mixture, by weight, of coconut meal and zooplankton at 28 and 33°C. The food intake was generally higher in those fry maintained on the mixed diet at 33°C. The rate of growth was always found to be higher in those fry maintained on a mixed diet at 28°C. The rate of weight increase of fry expressed as a percentage of the initial body weight tended to decrease in fry maintained on a diet of coconut meal, whilst the reverse was observed for others. A maximum food conversion ratio of 1.29 was recorded for fry maintained on a mixed diet of coconut meal and zooplankton at 28°C. Fry of grass carp changed from an almost exclusively carnivorous to a herbivorous one at a length of 25–30 mm. The evacuation time was both temperature- and weight-dependent, decreasing with increasing weight at a particular temperature.     

雌核发育草鱼的遗传结构分析和微卫星鉴别方法的建立

采用微卫星标记检测草鱼群体的遗传多样性,并根据纯合度的变化建立了雌核发育草鱼的鉴别技术。结果显示,8个位点共扩增出33个等位基因;在普通草鱼中,平均纯合度和PIC分别为0.203 1和0.552 8;在雌核发育群体中,则为0.716 1和0.357 2;2个群体间遗传相似度为0.873 3。其中,5个位点在雌核发育草鱼中纯合度明显提高,雌核发育草鱼在这5个位点的扩增总条带数为5~7个,普通草鱼则为8~10个,由此可100%区分2个草鱼群体。通过概率计算,理论鉴别概率达到99.92%。研究表明,雌核发育技术对草鱼的群体遗传结构改变较大,是快速建立纯系、固定优良性状的有效手段;根据群体遗传纯合度的改变、扩增条带数目差异,应用多态性微卫星分子标记可以简单、有效地区分雌核发育群体(或与之相似的高度近交群体)与普通群体。     

Intensive carp Cyprinus carpio (L.) rearing in a farm pond in southern Germany and its effects on water quality

Experiments over three years, in a pond of approximately 1500 m², to intensify production at high stocking densities with controlled feeding resulted in a substantial increase in yield (weight gain per hectare and year: 2·6 tonne for C_3–4, 9·1 tonne for C_2–3, 15·4 tonne for C_1–2). At the same time water requirement could be reduced to 4 m³ kg^?1 fish produced. However, the stocking densities achieved resulted in a continuously increasing eutrophication effect which expressed itself in mass development of phytoplankton. This led to considerable diurnal fluctuations in oxygen concentration (0·5–20·0 mg O₂ litre^?1) and total ammonia (0–11·0 mg NH₃NH₄⁺ litre^?1; maximum of 1·5 mg NH₃ litre^?1). The high stocking density contributed indirectly to the diurnal fluctuations (fertilization through faeces and lost feeds). However, its contribution to the overall oxygen depletion amounted to less than 25% at night. The amplitude of the fluctuation was mainly determined by the photosynthetic and respiratory activity of the phytoplankton and by microbiological degradation processes. With increasing water temperature during summer, increasing feeding rate, continuous fish biomass increment, and decreasing light period per day and danger of total fish stock mortality was greatest in August. Only at maximum photosynthetic activity during daylight was the total ammonia production in the pond adequately counteracted and sufficient oxygen produced. Even heavy aeration could not always successfully provide for oxygen during night. In order to avoid a breakdown of the system, algae and nutrients had to be diluted from time to time by excessive water replacement. Despite the temporary overloading of the pond system, losses in numbers had been kept below 6·5% (normally: 10–20%).Pellets were offered via self-feeding devices. Food uptake was continuously recorded. No diurnal feeding rhythmic could be observed, but feeding activity was entirely dependent on oxygen levels in pond water. Feed conversion efficiencies reached values between 1·96 and 2·48.     

Study of a shallow carp (Cyprinus carpio L.) pond and its relevance to inland fish farming in Libyan Jamahiriya

Adult mirror carp (Cyprinus carpio), put into a small artificial pond (area 30 m²; volume about 6.5 m³) in the Al-Fateh University campus, in Tripoli, Libya, in autumn 1977, consumed all molluscs and higher plants and were feeding on Cyanophyta (Coelosphaerium and Lyngbia) prior to spawning in May 1978. The young grew to 136 mm fork length and yielded 2.2 kg (live weight) in 14 months (62.8 g/m² per year) without food or fertilisers being added. They stayed under cover for five winter months and at this time growth was not affected much. Quantitative or semi-quantitative data are given for water depths, salinity balance, maximum and minimum water and other temperatures, solar radiation, and for biomass of producer and consumer species, together with observations on algal species, carp and goldfish (Carassius auratus).     

The immune system of cyprinid fish. The immunosuppressive effect of the antibiotic oxytetracycline in carp (Cyprinus carpio L.)

The effect of oxytetracycline (oxyTC) upon the immune system of carp was investigated. OxyTC was administered by feeding with oxyTC-containing pellets or by intraperitoneal injection. In order to study cellular immunity, allogeneic scale transplantation was carried out. Oral administration of oxyTC had no influence upon the median survival time (MST) of the scales. However, injections with oxyTC significantly prolonged the MST from 8.5 to 11–20 days. Thus, cellular immunity was not affected by oral administration of oxyTC, but injections did have a dramatic immunosuppressive effect.To investigate the effect of oxyTC upon humoral immunity, animals were injected with rabbit red blood cells (RaRBC). During the primary and secondary response the number of rosette forming cells (RFC) in the spleen was determined. Control animals (not treated with oxyTC) developed an anti-RaRBC response up to 25000 RFC/10⁶ white spleen cells but oxyTC-treated animals always showed reduced RFC numbers. In some cases the RFC number in oxyTC-treated animals was comparable with background levels in non-immunized control animals (4000 RFC/10⁶ white spleen cells). Thus, irrespective of the route of administration, the humoral immune response is depressed by oxyTC. It is concluded that both humoral and cellular immune responses of carp are suppressed during treatment with oxyTC.Preliminary observations showed an increased number of granulocytes in the spleen of oxyTC-treated animals. It is tempting to speculate that in those cases where specific lymphoid defence mechanisms are blocked, the phagocytic defence system becomes more active.     

Effects of protein or energy restriction with subsequent realimentation on performance parameters of carp (Cyprinus carpio L.)

The influence of a limited crude protein or energy supply followed by an adequate supply was investigated and compared to continuous feeding of carp over a live weight range of 150–440 g for various performance parameters. Throughout the trial the control group (treatment C) was given a feed containing 18.8 kJ gross energy/g fresh matter (FM) and 38.8% crude protein in the FM at a level of 2% of the live weight. During the restriction phase (up to 250 g live weight) either the crude protein supply was reduced by about 30% with constant energy supply (treatment P), or the gross energy supply was reduced by about 37% with constant crude protein supply (treatment E). In the realimentation phase all carp were fed as the control group.In the phase of the protein restriction and during realimentation this group (P) digested the feed less well than the carp of the control group. Digestibility was somewhat improved as a result of the energy restriction. The restricted protein or energy supplies clearly slowed the growth (duration of the restriction phase 49 (P) and 47 days (E) in comparison to 35 days (C)), but only in treatment P could an increased feed expenditure per g gain be observed. In the realimentation phase the carp of treatments P (42 days) and E (41 days) showed similar weight gains to the control carp (42 days). No compensatory growth effect occurred. Treatment E, however, tended to improve feed expenditure.As compared to the control group, the carp under protein restriction had carcasses richer in dry matter, fat and energy. After energy restriction the carcasses were poorer in dry matter, fat and energy, but richer in protein than the control carp. In the course of realimentation, the differences, especially between treatments P and C, diminished, but the carcasses of treatment P carp were still fattiest. The carcasses of treatment E fish contained least fat, even after realimentation.     

变性淀粉对鲢鱼糜冻结速率及凝胶特性的影响

为了比较4种变性淀粉与商业抗冻剂(4%蔗糖+4%山梨醇)对鲢鱼糜在冻结过程(-20、-80℃下静止冻结)中的影响,对冻结速率、冻结相变热特性参数、凝胶强度和持水性能进行了测定。结果表明,鱼糜在-80℃下的冻结速率均显著高于-20℃下;同一冻结温度下,几种添加物均会降低鱼糜的冻结速率及冻结相变焓,而提高冷冻鱼糜凝胶的持水性能,且变性淀粉组的持水性都显著高于商业抗冻剂组(P0.05)。在-80℃冻结时,添加交联酯化淀粉与醋酸酯化淀粉的鱼糜的冻结速率相近,且均显著小于其他组(P0.05)。在2种冻结温度下,醋酸酯化淀粉组的凝胶强度均与商业抗冻剂组无显著性差异,而显著高于其他实验组(P0.05)。研究表明,4%蔗糖+4%醋酸酯化淀粉可有效地防止鱼糜在冻结过程中的品质变化,可代替商业抗冻剂应用在冷冻鱼糜中。     

氟苯尼考在鲫和草鱼体内的药代/药效动力学联合参数及其临床给药方案的研究

为研究氟苯尼考在鲫和草鱼体内的药代学、药效动力学联合参数,并制定氟苯尼考对鲫、草鱼的精确用药方案,本实验结合氟苯尼考对致病性嗜水气单胞菌CAAh01的体外药效学研究和口灌不同剂量的氟苯尼考在鲫、草鱼体内药代动力学研究,确定了氟苯尼考防治该致病菌引起的鲫和草鱼细菌性败血症的给药方案。研究结果显示,氟苯尼考对CAAh01菌株的最小抑菌浓度(MIC)为0.5μg/mL,最小杀菌浓度(MBC)为1.0μg/mL,防细菌耐药突变浓度(MPC)为6.0μg/mL,防耐药突变选择窗(MSW)为0.5~6.0μg/mL。按10、20、30 mg/kg体质量剂量对鲫、草鱼口灌氟苯尼考后,在鲫体内,血药浓度大于MPC的维持时间分别为5、8、24 h;AUC24/MIC分别为177.06、265.90、426.50;Cmax/MIC分别为15.59、21.32、31.24。在草鱼体内,血药浓度大于MPC的维持时间分别为0、0、3 h;AUC24/MIC分别为38.60、75.08、121.94;Cmax/MIC分别为4.75、10.08、19.99。研究表明,综合血药浓度维持MPC以上的时间、AUC24/MIC或Cmax/MIC指标,氟苯尼考适用于鲫细菌性疾病的防治,其防突变用药方案为剂量30 mg/kg,每日1次给药,休药期不低于20 d。对于草鱼细菌性疾病的防治,氟苯尼考不宜连续使用。     

The Chinese grass carp, Ctenopharyngodon idella, its biology,introduction, control of aquatic macrophytes and breeding in the Sudan

The paper describes the distribution and biology of the grass carp following its introduction into Sudan. It provides aspects on the culture of the grass carp and its breeding under Sudanese conditions with emphasis on future research.     

鲤和草鱼IL17受体基因家族的全基因组识别、起源进化及表达分析

为了研究鲤科鱼类最具代表性的二个物种—鲤和草鱼IL17受体基因家族的起源进化,实验采用比较基因组学和生物信息学的方法,分别在鲤和草鱼基因组数据库进行序列比对和注释,然后对得到的基因进行结构域和系统发育学分析,最后在12个不同组织中进行基因表达分析研究。结果显示,在鲤和草鱼中分别注释得到9个和5个IL17受体基因家族成员。系统发育分析显示,该基因家族不存在鱼类特有的基因,在硬骨鱼类中具有一定的保守性。比较基因组学结果显示,与四足动物相比,大多数硬骨鱼类中IL17受体基因没有明显增多。鲤与草鱼等其他硬骨鱼类相比,除IL17RB以外,其余IL17受体基因家族成员均加倍。不同组织的表达分析结果显示全基因组复制后不同基因拷贝的功能发生了分化。研究表明,虽然硬骨鱼经历第三轮全基因组复制,但是由于复制发生时间久远,大多数基因已经发生改变或退化,进而在基因组中丢失。而鲤第四轮基因组复制时间发生在820万年前,复制发生时间较近,故复制后的基因基本得以保留。但是对于一些具有特殊功能的高度保守基因(例如IL17RB),也会发生在极短时间内出现丢失现象。鲤和草鱼健康组织的表达谱分析结果同样表明,鲤IL17受体基因的不同拷贝之间已经发生了快速进化及亚功能化,并且这种现象在鲤四倍体基因组中普遍存在。     

Effects of introduction of common carp, Cyprinus carpio (L.), on the pond ecology and growth of fish in polyculture

The effects of introduction of common carp, Cyprinus carpio (L.). in polyculture with major Indian carps and silver carp were studied in fertilized and fed earthen ponds in Mymensingh, Bangladesh. Bottom-dwelling common carp were found to exert an influence on the quality and quantity of planktonic food organisms. The presence of common carp significantly increased (P < 0.05) the growth of other carps including the bottom-feeder mrigal. Cirrhinus mrigala (Hamilton). A significantly higher fish yield (P < 0.05) was observed in the fish ponds containing common carp when the combined yields of all species in three treatments were compared.     

In situ studies on the bioaccumulation of microcystins in the phytoplanktivorous silver carp (Hypophthalmichthys molitrix) stocked in Lake Taihu with dense toxic Microcystis blooms

The phytoplanktivorous silver carp is an important biomanipulation fish to control cyanobacterial blooms and is also a food fish with the greatest production in China. The accumulation of the hepatotoxic microcystins (MCs) determined by LC-MS in various organs of silver carp was studied monthly in Lake Taihu dominated by toxic Microcystis aeruginosa. Average recoveries of spiked fish samples were 78% for MC-RR and 81% for MC-LR. The highest content of MCs was found in the intestine (97.48 μg g^− 1 DW), followed by liver (6.84 μg g^− 1 DW), kidney (4.88 μg g^− 1 DW) and blood (1.54 μg g^− 1 DW), and the annual mean MC content was in the order of intestine > liver > kidney > blood > muscle > spleen > gallbladder > gill. Silver carp could effectively ingest toxic Microcystis cells (up to 84.4% of total phytoplankton in gut contents), but showed fast growth (from 141 g to 1759 g in 1 year in mean weight). Silver carp accumulated less microcystins in liver than other animals in the same site or other fish from different water bodies at similar level of toxin ingestion. There was possible inhibition of the transportation of the most toxic MC-LR across the gutwall. Muscle of silver carp in Lake Taihu should not be consumed during period of dense Microcystis blooms while viscera were risky for consumption in more months.     

Gut contents of silver carp — Hypophthalmichthys molitrix (Val.) — and some trophic relations to other fish species in a polyculture system

This work is a continuation of the studies conducted in the ponds of the Fish and Aquaculture Research Station, Dor, in 1975 concerning the components of fish feed under conditions of polyculture, with additional food and intensive fertilization.A study was made of the food eaten by the silver carp, Hypophthalmichthys molitrix (Val.), grown with or without supplementary food in ponds that had previously been used for storage of fish fed on pellets (ponds Types 1 and 3), or which had been kept dry for various periods of time (ponds Types 2 and 4).The special pattern of its gills, which are adapted to retain suspended organisms and particles of sizes less than 20 μm, enables the silver carp to filter enormous quantities of phytoplankton and organic particles.A comparative study was made of the trophic relations existing between Hypophthalmichthys molitrix (Val.), Cyprinus carpio (L.) and Tilapia aurea Steindachner, which were the principal species in the polyculture system, and of the influence of the type of pond used on the growth of the fish.     

Effects of silver carp and the small indigenous fish mola Amblypharyngodon mola and punti Puntius sophore on fish polyculture production

A sustainable semi-intensive pond aquaculture technology including major carp species as cash-crop and small indigenous fish species (SIS) as food for the farmers' families is being optimized in Bangladesh. The inclusion of silver carp (Hypophthalmichthys molitrix), a cheap large species affordable by poor farmers, is now being considered. As part of a study on the effects of this filter feeder on polycultures including the large carps rohu (Labeo rohita), catla (Catla catla) and common carp (Cyprinus carpio) and the SIS punti (Puntius sophore) and mola (Amblypharyngodon mola), an experiment was carried out under farm conditions to test the effects of silver carp and of each SIS species on the growth, survival and yield of the large and small species and on pond ecology.The experiment was performed in 38 farmers' fishponds of different sizes, from 220 m² to 1200 m². The results show that the larger the fish pond the better rohu performance, the larger punti fry weight and the lower punti fry harvested biomass. Pond size did not affect other fish species. The addition of 250 mola and/or punti per 100 m² fishponds affected rohu and catla and did not affect common and silver carps. The addition of mola alone reduced rohu's parameters by 15%. The addition of SIS in the three combinations tested (250 mola, 250 punti, 125 of each species) reduced catla's parameters by 20-24%. Punti fry were larger when both SIS were stocked and punti fry biomass was larger when only punti were present. Total mola harvested biomass and yield were larger when the entire SIS stocked were only mola.The addition of 10 silver carp over the 99 large carps stocked per 100 m² fishponds negatively affected rohu and catla growth and yield by about 15-21% and 45-50% respectively but not their survival, did not affect common carp performance, did not affect punti and mola reproduction in the ponds, reduced punti yields by 25%, reduced mola performance by about 35%, and silver carp own biomass increased total yield and total income in about 12% each. These effects are explained and discussed considering fish interactions through the food web. The decreased income from selling the more expensive large carps is more than compensated by that obtained from silver carp, which allows the option to the farmer to sell part of the silver carp to complete the cash income that would have been obtained from large carps only if silver carp would not be stocked, and consume the rest with the family.