Co-occurrence of white shrimp, Litopenaeus vannamei, mortalities and microcystin toxin in a southeastern USA shrimp facility

Various freshwater and marine algal toxins are known to affect plants, fishes, mammals, and invertebrates. During recent mortality events in Texas white shrimp aquaculture ponds, water and shrimp tissue samples were analyzed for cyanobacterial toxins and found to contain microcystin-LR. Cyanoprokaryota dominated the phytoplankton assemblage in water from the affected pond, particularly Microcystis aeruginosa and Anabaena sp. Water samples from the affected pond also contained high levels of microcystin-LR (45 μg/l), whereas adjacent ponds had a diatom-green algal assemblage and no measurable toxin. Unialgal isolates of M. aeruginosa from the affected pond produced microcystin-LR. Free microcystin-LR concentrations in dead shrimp hepatopancreas determined by HPLC were 55 μg/g total shrimp weight, whereas shrimp hepatopancreas from the adjacent pond without shrimp mortalities had no measurable toxin. Muscle toxin concentration was below 0.1 μg/g.     

Short-chain fatty acids protect gnotobiotic Artemia franciscana from pathogenic Vibrio campbellii

Infections caused by antibiotic resistant luminescent vibrios can cause considerable losses in aquaculture. In this study, different short-chain fatty acids were investigated as possible alternative biocontrol agents. The addition of 100 mM formic, acetic, propionic, butyric or valeric acid to the growth medium of a pathogenic Vibrio campbellii strain completely inhibited its growth at pH 6. At 10 mM, the growth of the pathogen was delayed, whereas at 1 mM, no effect could be observed. The growth-inhibitory effect was clearly pH-dependent and decreased with increasing pH. An in vivo challenge test with gnotobiotic Artemia franciscana nauplii revealed that all five short-chain fatty acids protected the shrimp from the pathogenic V. campbellii strain. The addition of 20 mM of the short-chain fatty acids to the culture water resulted in a significantly increased survival of infected nauplii, with no difference between the different fatty acids. In conclusion, our data indicate that short-chain fatty acids might be useful as alternative biocontrol agents to treat luminescent vibriosis.     

Design and performance of a low-cost,automated, large-scale photobioreactor for microalgae production

Microalgae feed production is a major cost in bivalve aquaculture. Its efficiency is increased by scaling it up under automated control of environmental conditions. The initial cost of commercially available systems can be prohibitive. Therefore, a large volume full-scale photobioreactor built of low-cost, readily available materials was developed and tested. A cone-bottom, polyethylene tank was internally illuminated with submersible fluorescent lamps and equipped with a monitoring and control system that measured temperature, pH and optical density of the microalgal culture. Injection of CO₂ was automated to maintain pH within a target range. System performance was evaluated by growing four batch cultures of Tetraselmis chuii. Temperature inside the photobioreactor was 29.5 ± 2.38 °C (mean ± SD, range 21−35 °C) and pH was 7.56 ± 0.87 (mean ± SD, range 5.29–8.97). Optimal harvest time was after 300 h (12.5 days) of growth, yielding 1700 L of microalgae at a density of 2500 cells/ μl (1200 cells/ μl/ m² illuminated surface area). With 24 h illumination, the fluorescent lights, air pump and monitoring/ control device consumed 14.9, 1.9 and 0.1kwh/ day, respectively. Assuming the microalgae are harvested at their optimal density after 12.5 days, each batch would consume 211kwh or 0.124kwh/ liter. The photobioreactor described provides an economical option for growing large amounts of microalgae for aquaculture feed and other purposes.     

Effects of dietary carbohydrate on growth of juvenile New Zealand rock lobsters, Jasus edwardsii

The commercial aquaculture of spiny lobsters is impeded by the development of effective practical diets, which is partly due to a lack of knowledge of the digestive capabilities and nutritional needs of these species. Carbohydrates have the potential to provide a low cost energy source in practical diets for spiny lobsters. This research investigated the effect of algal carbohydrates, on the growth of juvenile rock lobsters. Juvenile lobsters, Jasus edwardsii, (10-12 mm carapace length) were provided with one of five diets; blue mussel, squid (Nototodarus gouldii), or a mussel diet partially substituted with algal carbohydrates, either agar, carrageenan or alginate over 80 days in culture. In all treatments, diet consumption and lobster growth were maintained or increased over time. Growth was highest for the mussel diet followed by the agar diet. Similar lobster growth occurred on the carrageenan and alginate diets, with the least on the squid diet. After 80 d there were significant differences in the percent lipid and glycogen stored in the mid-gut gland with highest levels of glycogen in lobsters fed the mussel only diet. Percent protein in the tail muscle was greatest for mussel fed lobsters. The mid-gut index (mid-gut weight/whole wet weight) was highest for the mussel only diet and this was similar to control lobsters at the start of the experiment. The results indicate that glycogen from mussels and agar could be used as carbohydrate source in the future development of a practical diet for spiny lobsters.     

The effects of light and temperature on the photosynthesis of the Asparagopsis armata tetrasporophyte (Falkenbergia rufolanosa), cultivated in tanks

The integrated aquaculture of the tetrasporophyte of Asparagopsis armata Harvey (Falkenbergia rufolanosa) using fish farm effluents may be viable due to the species high capacity of removing nutrients and its content of halogenated organic compounds with applications on the pharmaceutical and chemical industries. In order to optimize the integrated aquaculture of F. rufolanosa, we followed the daily variation of the potential quantum yield (F_v/F_m) of PSII on plants cultivated at different biomass densities and different total ammonia nitrogen (TAN) fluxes to check if they are photoinhibited at any time of the day. Moreover, the photoinhibition under continuous exposure to highly saturating irradiance and its potential for subsequent recovery in the shade was assessed. The potential for year round cultivation was evaluated by measuring rates of O₂ evolution of plants acclimated at temperatures ranging from 15 to 29 °C, the temperature range of a fish farm effluent in southern Portugal where an integrated aquaculture system of F. rufolanosa was constructed.Photoinhibition does not seem to be a major constrain for the integrated aquaculture of F. rufolanosa. Only when cultivated at a very low density of 1.5 g fresh weight (FW) l^− 1 that there was a midday decrease in maximal quantum yield (F_v/F_m). At densities higher than 4 g FW l^− 1, no photoinhibition was observed. When exposed to full solar irradiance for 1 h, F. rufolanosa showed a 33% decrease in F_v/F_m, recovering to 86% of the initial value after 2 h in the shade. A midday decline of the F. rufolanosa F_v/F_m was also observed under the lowest TAN flux tested (∼6 μM h^− 1), suggesting that this fast and easy measurement of fluorescence may be used as a convenient diagnostic tool to detect nutrient-starved unbalance conditions of the cultures. Maximum net photosynthesis peaked at 15 °C with 9.7 mg O₂ g dry weight (DW)^− 1 h^− 1 and remained high until 24 °C. At 29 °C, the net oxygen production was significantly reduced due to a dramatic increase of respiration, suggesting this to be the species' lethal temperature threshold.Results indicate that F. rufolanosa has a considerable photosynthetic plasticity and confirm it as a good candidate for integrated aquaculture at temperatures up to 24° C and cultivation densities of at least 5 g FW l^− 1. When cultivated at these densities, light does not penetrate below the first few centimetres of the surface zone. Plants circulate within the tanks, spending around 10% of the time in the first few centimetres where they are able to use efficiently the saturating light levels without damaging their photosynthetic apparatus.     

Enhanced production of the sea urchin Paracentrotus lividus in integrated open-water cultivation with Atlantic salmon Salmo salar

Survivorship and performance was investigated for two size classes of the sea urchin Paracentrotus lividus grown adjacent to open-water Atlantic salmon (Salmo salar) cultivation on the north-west coast of Scotland. Juvenile P. lividus were maintained for 12 months at 0 m, 50 m and 2.5 km from the mariculture activity. The sea urchins at the 0 m station showed higher survivorship than at the 50 m and 2.5 km stations and had significantly greater test diameter than at the 50 m station. Only urchins at 0 m developed gonads and, although small, these were of acceptable or excellent colouration in terms of their marketability. Adult P. lividus were maintained for 3 months at 0 m and 15 m from the mariculture activity, either with or without additional macroalgae Laminaria spp. Sea urchins at the 0 m station and fed additional macroalgae showed higher gonadal growth than sea urchins at the 15 m station held without additional food. Gonad colouration in the adult urchins, irrespective of the treatment, was acceptable or excellent. The 0 m station also received significantly greater quantities of particulate organic matter (POM) than the other stations in both the juvenile and adult experiments. At the 0 m station, the presence of the fatty acid 22:1n-11 and elevated levels of the long chain n-3 fatty acid DHA 22:6n-3 in the gonadal tissue of the urchins confirmed the consumption of fish farm derived POM and highlighted the potential human health benefits from consuming sea urchin roe.The results show that P. lividus can thrive in the salmon culture environment and suggests that the integration of P. lividus with Atlantic salmon can provide a viable means to culture this species, even at this northerly latitude. Salmon-sea urchin co-culture would enable fish farms to diversify into producing a second highly valuable product and would reduce the increasing worldwide pressure of sea urchin fisheries on wild stocks.     

Do strain differences in microalgae alter their relative quality as a food for the rotifer Brachionus plicatilis?

Brachionus plicatilis is used in aquaculture to feed larval fish and crustaceans. It is well established that different prey species alter rotifer productivity. Isochrysis galbana is one microalgal prey that is commonly fed to rotifers, and there are several strains of this flagellate available to aquaculturists. As microalgae strains may differ in their composition and growth attributes, we rigorously examined if growth and biochemical differences in I. galbana strains elicit differences in the growth and biochemical attributes of B. plicatilis. Four I. galbana strains and one strain of the flagellate Nanochloropsis were grown under standard conditions. Growth rate, cell volume, production, and composition (dry weight, carbohydrate, protein, lipid) were measured. Significant differences occurred between strains in all of these attributes (at times 2 to 3 fold), but no clear pattern emerged that one strain was superior. Of note was that for some measurements, strain differences were significantly greater than differences between species. The strains were then fed to rotifers, and a number of parameters were measured: growth rate, reproductive rate, fecundity attributes, a number of developmental rates, and composition (dry weight, carbohydrate, protein, lipid). There were significant effects of prey strain on some of these attributes, but none was dramatic (rarely more than 10% and occasionally up to 30%), suggesting that aquaculturists need not be too concerned regarding which I. galbana strain they use. However, we do indicate subtle differences, induced by different prey strains and suggest that for maximum productivity these differences should be considered.     

不同施肥方法对鱼蚌综合养殖池塘浮游植物群落结构的影响

通过155 d围隔实验检验了不同施肥条件下鱼蚌综合养殖水体中的浮游植物群落结构。实验设3个处理:施鸭粪、施化肥、兼施鸭粪和化肥。放养种类为三角帆蚌、草鱼、鲫、鲢和鳙,放养量分别为每围隔20、15、5、5和5个。结果发现,围隔内浮游植物生物量平均值为(2.1~6.0)×108个/L。不同施肥方法对浮游植物种类组成和优势种、叶绿素a(Chl.a)、生物量以及蓝藻在浮游植物生物量中的比例无显著影响。浮游植物群落变化表现出较明显的季节性特点,影响围隔浮游植物群落的理化因子为TN、NH3-N和DO。研究表明,采用不同施肥方法的围隔内浮游植物群落结构未表现出显著差异,难以从浮游植物角度解释兼施鸭粪和化肥的围隔珍珠产量高于施鸭粪或施化肥的围隔的事实,也难以确定珍珠产量与浮游植物群落结构之间存在必然的联系。     

Suspension-feeding aquaculture systems: Effects of phytoplankton concentration and temperature on growth of the bay scallop

The growth rate of the bay scallop Argopecten irradians was studied in relation to temperature and phytoplankton concentration. Results suggest that normal variations in phytoplankton concentration do not influence the growth rate of scallops in their natural habitat. Increasing the concentration of phytoplankton above natural levels did not result in increased growth rates while decreasing the phytoplankton concentration resulted in a decrease in growth rate of the scallops. Under extremely low phytoplankton concentrations, such as those that characterize ‘clean water’ effluent from a culture system, the animals ceased growing. A mathematical model of scallop growth rate as a function of phytoplankton concentration is proposed as a tool for comparing the functioning of different suspension feeders in aquaculture systems.     

水族箱气单胞菌的鉴定及致病特性分析

为了确定南京市某渔场发病鱼感染的病原,本研究采集患鱼脏器,采用平板培养、生化实验和特异性gyrB基因扩增测序等方法进行细菌的分离鉴定;利用PCR技术检测分离株毒力基因的分布,分析其生物学特性,并进一步通过动物实验确定菌株致病力.结果分离到1株水族箱气单胞菌,命名为LK-25.该菌株携带5种主要毒力基因:气溶素(aer)、细胞毒性肠毒素(act)、细胞兴奋性肠毒素(alt)、温敏胞外蛋白酶(epr)和丝氨酸蛋白酶(ahp),其溶血性和溶蛋白能力较强,对斑马鱼的半数致死量为1.02×103 CFU/尾,确定为强毒株.进化树分析表明,水族箱气单胞菌与嗜水气单胞菌达卡亚种亲缘关系较近.本研究在国内首次报道发现水族箱气单胞菌,为进一步预防该菌所引起的相关疾病的发生和传播提供理论基础.     

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.     

Organic flocculants for the removal of phytoplankton biomass

The formation of noxious phytoplankton blooms causes deterioration of water quality in aquaculture ponds and reservoirs, but also in swimming pools and aquaria. We have studied the effects of selected cationic polyacrylamides on natural phytoplankton community, which was investigated by a decrease of chlorophyll a content in the water column and photosynthetic activity of phytoplankton floccules. Results indicate that cationic polyacrylamides are able to remove more than 80% of phytoplankton biomass. Moreover, no cell damage or lysis was observed by microscopic observation after flocculation. To our knowledge, this is the first report suggesting the removal of cyanobacterial blooms by organic flocculants. Cationic polyacrylamides are biodegradable organic flocculants with low toxicity to aquatic organisms, and seem to be a prospective tool with a possibility for algal or cyanobacterial bloom management in aquaculture.     

吉富罗非鱼与奥利亚罗非鱼自繁与杂交 F1遗传特性与抗病力分析

以吉富罗非鱼与奥利亚罗非鱼为繁育亲本,采用完全双列杂交繁育4组F1,将初始规格基本一致的4组罗非鱼饲养100 d后,运用“加性-显性”遗传分析模型,分析了4组F1罗非鱼8个生长相关性状杂种优势、遗传效应以及与性状间的相关性.结果表明:(1)F1群体平均优势为0.129 4～0.368 4.除尾柄长超亲优势较大外,其他性状的群体超亲优势较小或表现出负向超亲优势.(2)8个性状的广义遗传率(HB)为0.714 2～0.995 3,表明加性效应和显性效应对性状的遗传变异影响极显著(P＜0.01).除尾柄长外,其他性状的狭义遗传率(HN)介于0.469 4～0.737 9,表明加性遗传方差在表型方差中所占比率较高.(3)体质量、全长、体长、体高、体宽、头长、尾柄长、尾柄高性状之间表型相关在0.776 6～0.999 7范围内,而遗传相关在0.994 1～1.000 0之间,表明这些性状间都存在极显著的正相关.取样结束后,采用3.95×106 CFU/mL的海豚链球菌菌液进行腹腔感染,吉富罗非鱼自繁组F1代12 h后出现死亡,而奥利亚罗非鱼自繁组F1192 h后才出现死亡.384 h后,吉富罗非鱼自繁组F1死亡率为40％,正反交组F1分别为20％和23.3％,奥利亚罗非鱼自繁组F1死亡率最低,为6.67％.研究结果表明,除尾柄长外,杂交F1的其他性状不具备超亲优势,然而杂交可以提高选育后代的抗病力.     

Optimization of chitosan flocculation for phytoplankton removal in shrimp culture ponds

The removal of phytoplankton cells from aquaculture systems generally results in the reduction of nitrogenous waste and improves water quality. With this study, the effects of chitosan concentration, environmental condition and pH adjustment on flocculation of phytoplankton in marine shrimp (Litopenaeus vannamei) culture tanks were investigated. The remaining phytoplankton and suspended solids in the system were indicators for evaluating the efficiency of chitosan on flocculation. The results indicate that the flocculation efficiency of chitosan was highest (>85%) and remained fairly constant at a chitosan concentration of 40–80 mg L^?1 and a pH range of 7–9 after chitosan addition. With this novel technique including 40 mg L^?1 chitosan addition, pH adjustment to 6.5 and then to 8.5, high efficiency and consistency of flocculation were achieved. This technique could also be applied with various water alkalinity up to 400 mg CaCO₃ L^?1. The experiment for phytoplankton removal by chitosan flocculation in the recirculating aquaculture system showed that flocculation efficiency remained constant even though flocculation was repeated several times.     

Optimization of chitosan flocculation for phytoplankton removal in shrimp culture ponds

The removal of phytoplankton cells from aquaculture systems generally results in the reduction of nitrogenous waste and improves water quality. With this study, the effects of chitosan concentration, environmental condition and pH adjustment on flocculation of phytoplankton in marine shrimp (Litopenaeus vannamei) culture tanks were investigated. The remaining phytoplankton and suspended solids in the system were indicators for evaluating the efficiency of chitosan on flocculation. The results indicate that the flocculation efficiency of chitosan was highest (>85%) and remained fairly constant at a chitosan concentration of 40–80 mg L⁻¹ and a pH range of 7–9 after chitosan addition. With this novel technique including 40 mg L⁻¹ chitosan addition, pH adjustment to 6.5 and then to 8.5, high efficiency and consistency of flocculation were achieved. This technique could also be applied with various water alkalinity up to 400 mg CaCO₃ L⁻¹. The experiment for phytoplankton removal by chitosan flocculation in the recirculating aquaculture system showed that flocculation efficiency remained constant even though flocculation was repeated several times.     

Exploring Northeast American and Asian species of Porphyra for use in an integrated finfish-algal aquaculture system

Many aquaculture industries generate a nutrient-rich waste stream that can lead to eutrophication of coastal waters. To address this environmental issue, the bioremediation potential of several native Northeast American species of Porphyra was assessed and compared to the well-known Asian species. Porphyra thalli were cultured over 4 weeks at 15 °C at a stocking density of 0.4 g FW L^− 1. At 3- to 4-day intervals nutrient uptake, tissue N accumulation and phycobiliprotein concentration (PBP) were determined as functions of nitrogen (N) concentration (25-300 μM) and N source (nitrate vs. ammonium). Growth rates were measured weekly. Growth and tissue N reached maximal levels at inorganic N concentrations of 150-300 μM. Maximum growth rates ranged from 10% to 25% day^− 1, although induction of archeospores reduced average growth rates in many cases. No evidence of ammonium toxicity (reductions in growth rate) was observed; in fact, similar values were found with both N sources. Ammonium generally yielded higher PBP and tissue N contents than nitrate. Porphyra amplissima presented the highest growth rate, followed by the Asian Porphyra yezoensis. Under the experimental conditions, Porphyra spp. removed 70-100% of N within 3-4 days at N concentrations up to 150 μM, but was less efficient in removing inorganic phosphorus (35-91% removal). The highest tissue N and PBP concentrations were found at 150-300 μM of N, with N values close to 7% DW. Overall, Porphyra appears to be an excellent choice for bioremediation of moderately eutrophic effluents, with the added benefit that tissue may be harvested for sale.     

The food value of Phaeodactylum tricornutum Bohlin to the larvae of Ostrea edulis L. and Crassostrea gigas Thunberg

The food value of three cultures of Phaeodactylum tricornutum composed of three different cell forms was measured for the larvae of the bivalve molluscs Ostrea edulis and Crassostrea gigas. While all three types supported good growth of both species of larvae, there were no significant differences in food value between the three and the Isochrysis galbana controls. Increasing the feeding rate of one type of P. tricornutum culture had no marked effect on the growth rates, survival or settlement of C. gigas larvae in the range equivalent in terms of dry weight to 25–200 cells I. galbana/μl.     

Effect of temperature on copper toxicity and hematological responses in the neotropical fish Prochilodus scrofa at low and high pH

Copper sulfate has been widely used to control algae and pathogens in fish culture ponds. However, its toxic effects on fish depend not only on its concentration in water but also on water quality. The susceptibility of the neotropical freshwater fish Prochilodus scrofa to copper was evaluated at two temperatures with low and high water pH. Juvenile fish were acclimated at 20 and 30 °C and exposed to copper (static bioassay system) in water with pH 4.5 and 8.0. The 96 h-LC₅₀ were determined at each temperature and pH, as were the hematological parameters. The 96 h-LC₅₀ for copper (98 and 88 μg Cu L^− 1 in water with pH 4.5 and 16 and 14 μg Cu L^− 1 in water with pH 8.0 for fish kept at 20 and 30 °C, respectively) was significantly dissimilar in pH 4.5 and 8.0, but no difference was found between 20 and 30 °C in the same water pH. At 20 °C, regardless of the water pH, the hematocrit (Hct) increased while the red blood cells (RBC) and hemoglobin (Hb) concentration decreased compared to control pH 7.0. Copper exposure in water pH 4.5 and 8.0 causes an increase on the Hct, RBC and Hb concentrations in relation to the controls pH 4.5 and 8.0. At 30 °C, the changes on the blood parameters depended on the water pH and, after copper exposure at low and high pH, the blood changes indicated more complex responses. The changes in hematological parameters of the fish, regardless of the pH and water temperature, indicate ionoregulatory or respiratory disturbances that imply an increase in energy consumption to restore homeostasis instead of other physiological functions such as weight gain and growth.     

Selective particle feeding by the Chilean oyster, Ostrea chilensis; implications for nursery culture and broodstock conditioning

Hatchery broodstock conditioning and nursery culture of the Chilean flat oyster Ostrea chilensis have been hampered by the poor performance of oysters fed typical microalgal hatchery diets. To determine the feeding capabilities of this species the selective removal and consumption of natural planktonic assemblages and artificial inert particles (polystyrene beads) by juvenile and adult oysters were examined experimentally. The arrangement of the eulaterofrontal cirri of the ctenidia was also examined to infer their potential efficiency of particle selection for feeding. Polystyrene beads of 45 and 15 μm in diameter had high rates of removal from suspensions by both juvenile (45 μm = 70%, 15 μm = 73%) and adult (45 μm = 88%, 15 μm = 87%) oysters. In contrast, beads of 6 μm diameter had lower rates of removal (adults = 68%, juveniles = 53%), while 1 μm beads were not removed at all. Both adult and juvenile oysters feeding upon natural plankton assemblages removed only microphytoplankton (20-75 μm in size) despite the presence of nanophytoplankton (2-20 μm), picophytoplankton (< 2 μm), cyanobacterium Synechoccocus spp. (< 2 μm), and bacterial cells (< 75 μm) in the experimental suspensions. Eulaterofrontal cirri of both juvenile (15.2 μm ± 0.9 SE) and adult oysters (18.9 μm ± 0.3 SE) are the shortest that have been reported for any ostreid species which helps to explain the inability of this species to retain small food particles. The clearance rates for oysters feeding on microphytoplankton only were 1.49 (± 0.05 SE) and 7.1 (± 1.2 SE) l h^− 1g^− 1 for juveniles and adults respectively. These values are much higher than previously reported for this species being fed smaller sized cultured microalgae. Our results strongly suggest that the difficulties in the nursery and broodstock hatchery culture of this oyster may be due to inappropriate phytoplankton diets. We recommend the provision of cultured microalgae of 20-75 μm in diameter for improving the performance of hatchery maintained juvenile and adult O. chilensis.     

团头鲂营养需求与健康研究进展

团头鲂是我国主要的大宗淡水养殖品种之一,其养殖规模在近10年不断扩大。团头鲂的营养物质需求主要以生长和营养缺乏症为评价指标。而营养物质对鱼类健康,如免疫反应和抗病力等影响的研究尚不充分。一般认为,饲料中营养物质搭配合理、品质优良有利于维持鱼类生理健康,并能保护养殖水环境。此外,一些营养物质如维生素,在鱼类的免疫机制中发挥重要作用。未来水产饲料应具有促进水产动物生长和维持健康的双重作用,通过营养调控预防鱼类疾病是保证水产养殖可持续发展的重要策略之一。本研究综述了团头鲂对蛋白质、脂肪、碳水化合物、维生素和矿物质营养需求的研究进展,以及饲料营养元素对团头鲂免疫力及抗病力影响的最新报道,以期为团头鲂高效配合饲料的开发提供科学参考。