磁珠富集法制备大口鲶的微卫星分子标记

通过磁珠富集的方法分离大口鲶（Silurus meriaionalis）的微卫星分子标记。将基因组DNA酶切，梯度离心收集400～900bp片段并纯化，连接Brown接头，用生物素标记的寡核苷酸（CA）15作探针与其杂交，杂交复合物结合到包被有链霉亲和素的磁珠上，然后将这些片段洗脱，PCR扩增，进行克隆构建“基因组文库”，再通过同位素标记的探针（CA）15进行2次杂交筛选，所得到的阳性克隆测序。从所获得593个阳性克隆中选取178个经测序，97．19％（173个）含有微卫星序列，90．60％重复数在10以上，75．98％为完美型。除探针中使用的CA重复单元外，还观察到Cr、GA、ATG的重复序列。设计获得120对微卫星引物，合成40对经PCR筛选，结果31对引物扩增出多态性条带。显示出，磁珠富集法是获得微卫星分子标记的一种有效的方法，可成为今后发展该标记的主要方法。同时，制备出的微卫星标记可为今后研究大口鲶的分子遗传育种提供有用的遗传标记。     

磁珠富集法分离草鱼微卫星分子标记

磁珠富集法是一种快速、高效的分离微卫星分子标记的方法。本研究通过该方法分离草鱼的微卫星分子标记。将草鱼（Ctenopharyngodon idella）基因组DNA经Sau3AI酶切，同收纯化400～900bp片段，连上接头，构建“基因组PCR文库”。用生物素标记的简单重复序列（CA）15作探针与其杂交，杂交复合物结合到包被有链霉亲和素的磁珠上，经一系列的洗涤过程，去除磁珠表面不含有微卫星的片段。将吸附在磁珠上的片段洗脱，PCR扩增放大，再进行克隆和测序，根据微卫星两端的保守序列设计引物，即可得到微卫星分子标记。本研究义通过同位素标记的探针（CA）15进行二次杂交筛选，获得阳性克隆132个，所得到的阳性克隆经测序，86．36％含有微卫星序列，共获得130个微卫星DNA序列。用引物设计软件Primer Premier5．0没计引物83对。     

企鹅珍珠贝微卫星分子标记的筛选

运用生物素与链霉亲和素的强亲和性原理,用生物素-磁珠吸附微卫星富集法,筛选企鹅珍珠贝（Pteria penguin）的微卫星分子标记序列,进而对南海区企鹅珍珠贝的遗传多样性进行分析。对136个菌落中的85个阳性克隆进行微卫星测序,获得64个序列,达到85.93%。所得到的55个重复6次以上的微卫星序列中,除生物素探针中...     

哲罗鱼基因组微卫星富集文库的构建与分析

采用磁珠富集法构建哲罗鱼（Hucho taimen Pallas）荩因组微卫星文库。哲罗鱼基因组DNA经MboⅠ限制性内切酶消化后，选取400-900bp的片段，用生物素标记的简单重复序列（ACA）15作探针与其杂交，杂交复合物结合到包被有链霉亲和素的磁珠上，获得目的片段，连接T载体克隆，构建基因组微卫旱富集文库。再用同位素标记的（ACA）15探针进行二次筛选，筛选出686个阳性克隆，阳性克隆率为35．94％。对其中140个阳性克隆进行测序，共获得149个微卫星序列，4个小卫星序列，其GenBank Accession Number为DQ110955～DQ121108。其中perfect（完美型）62个，占41．61％；imperfect（非完美型）92个，占61．74％；compound（混合型）5个，占3．36％，重复次数主要分布于6～45（81．21％），平均重复次数为32．5，这表明（ACA／TGT）。在哲罗鱼基因组DNA中含最非常丰富。本研究旨为从DNA水平上研究哲岁鱼种群结构、遗传多样性及目前群体现状等方面提供有效工具。     

兰州鲇（CAG）n、（GATA）n微卫星文库构建与鉴定

应用磁珠富集法构建兰州鲇（ Silurus lanzhouensis） CAG重复和GATA重复的微卫星文库，并分析其序列特征。兰州鲇基因组DNA经MseI酶切，选取200～800 bp的片段与生物素标记的探针（CAG）8和（GATA）6杂交，捕获到含有微卫星序列的目的DNA片段连接到pMD19-T载体，转化到大肠杆菌DH5α菌株中构建微卫星富集文库，经PCR检测筛选出阳性克隆进行测序。从126个阳性克隆中随机选取96个进行测序，获得59个微卫星序列（ GenBank登录号： KJ545973～KJ545998， KJ598088～KJ598120）。其中完美型31个（52.54％）、非完美型20个（33.9％）、混合型为8个（13.56％）。根据侧翼序列，成功设计48对引物，选取25对微卫星引物在10个个体进行扩增与多态性筛选，共获得10对多态性引物。结果表明，经优化的磁珠富集法能够高效地获得兰州鲇微卫星标记，这些标记将为兰州鲇种质资源保护、微卫星连锁图谱构建、经济性状的QTL定位及分子标记辅助选育奠定基础。     

FIASCO法筛选鳜鱼微卫星标记

通过FIASCO(Fast Isolation by AFLP Sequences Containing repeats)法构建鳜鱼(Siniperca chuatsi)基因组微卫星富集文库,分离微卫星DNA序列并对其特征进行分析。鳜鱼基因组DNA经MseⅠ限制性内切酶消化后,选取200~800 bp的片段与MseⅠ接头连接,用生物素标记的寡核苷酸探针(AC)8、(CT)8、(AT)7、(GATA)8、(GATT)7与其杂交,杂交复合物结合到包被有链霉亲和素的磁珠上,变性洗脱获得单链目的片段,经PCR扩增形成双链,然后克隆到pGEM-T载体上,转化至DH5α中,首次成功构建鳜鱼基因组微卫星富集文库。对其中100个阳性克隆进行测序,60个(60%)含有微卫星序列(GenBank Accession Number:DQ789247~DQ789306)。成功设计了47对鳜鱼微卫星引物,并合成21对引物进行PCR扩增,结果筛选出18个多态性微卫星标记。结果表明:FIASCO法能有效提高筛选微卫星标记的效率。本研究筛选的微卫星标记可以用于鳜鱼遗传背景分析和遗传连锁图谱构建,并将为鳜鱼基因组结构分析、标记辅助育种以及数量性状位点(QTL)基因的定位等研究提供候选微卫星标记。     

团头鲂微卫星标记的快速制备

采用磁珠富集法与放射性杂交相结合开发团头鲂（Megalobrama amblycephala）基因组微卫星资源。以团头鲂基因组DNA为材料，经Sau 3AⅠ限制性内切酶消化后，选取400～900bp的片段进行PCR全基因组扩增，并利用生物素标记的（CA）15探针进行微卫星片段的富集。将得到的片段与T载体连接后转入DH5α大肠杆菌中，然后利用γ-32P标记的放射性同位素探针进行第二轮杂交。结果表明，共获得微卫星基因组文库2000个菌，杂交前菌落PCR检测阳性克隆率为50％；杂交后得到的阳性克隆为230个，占11．5％。从得到的230个阳性克隆中挑出120个进行测序，有94个克隆含有重复次数大于5次的微卫星序列，其中46个（48．94％）有随机侧翼区，可以设计引物；14个缺乏足够的侧翼序列。在得到的微卫星序列中，重复单元除CA／GT外，还观察到CT、AG、CG、CAA、CTCA等重复单元。在单一型标记中，完美础占53．15％，非完美型为37．84％；混合型标记占9．01％。另外，微卫星重复次数主要集中在5-30次，占75．68％。本研究旨在对团头鲂基因组资源的开发利用起到一定的促进作用，并为团头鲂养殖品系的优化、遗传多样性的检测及遗传图谱的构建等奠定基础。     

企鹅珍珠贝微卫星分子标记的筛选

运用生物素与链霉亲和素的强亲和性原理,用生物素-磁珠吸附微卫星富集法,筛选企鹅珍珠贝(Pteria penguin)的微卫星分子标记序列,进而对南海区企鹅珍珠贝的遗传多样性进行分析。对136个菌落中的85个阳性克隆进行微卫星测序,获得64个序列,达到85.93%。所得到的55个重复6次以上的微卫星序列中,除生物素探针中使用的CA重复外,还得到TG、TC、GA的重复序列。重复序列中完美型36个,占65.5%;不完美型14个,占25.5%;混合型5个,占9.1%。利用Primer Premier5.0设计引物40对,合成其中的20对并进行PCR筛选,15对可扩增出特异性条带。研究表明,筛选出的企鹅珍珠贝微卫星分子标记可用于进一步的遗传多样性分析。     

方正银鲫微卫星序列的筛选及PCR扩增产物的初步检测

采用小片段克隆法构建了方正银鲫[（Carassius auratus gibelio（Block）]部分基因组文库，并采用非影印的方法将转化子转移到硝酸纤维素滤膜上。用人工合成、并经放射性同位素[γ-^32P]ATP标记的（CA）15探针对构建的基因组文库进行筛选，获得137个阳性克隆，经测序得到微卫星序列130个，其中完美型、非完美型、混合型分别占64．3％、16．9％和18.8％。应用引物设计软件Primer Prmmer5．0进行引物设计，得到引物103对。合成30对引物，随机选取其中5对进行PCR扩增。结果表明，这5对引物均可以稳定扩增，并且观测杂合度均较高。     

日本蟳微卫星富集文库的建立与多态性标记的筛选

采用磁珠富集法筛选日本蟳微卫星分子标记。日本蟳基因组DNA经Sau3 AⅠ酶切后,收集400~1 200 bp大小的片段并纯化,利用生物素标记的寡核苷酸探针(AC)¹⁵从中筛选出含有微卫星序列的DNA片段,连接到pMD18-T载体中,构建富集微卫星序列的基因组文库,经PCR检测筛选出阳性克隆进行测序。从随机挑选的970个菌落中筛选出369个阳性克隆进行测序,结果86.99%(321个)含有微卫星序列,其中完美型占80.54%,非完美型占15.95%,混合型占4.28%。除使用的探针AC重复外,还得到GA、CT等重复序列。共设计出102对微卫星引物,其中65对能扩增出清晰条带,27对具有多态性。同时筛选出的微卫星标记可为今后研究日本蟳的分子遗传育种提供有效的遗传标记。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Production of diatom–bacteria biofilm isolated from Seriola lalandi cultures for aquaculture application

Controlled incorporation of selected microalgae and bacteria in aquaculture systems can be beneficial because they can act as microbiological control. That is why the characteristics of biofilm generated naturally in Seriola lalandi culture cages were analysed, their potential benefit to the growth of larvae was studied, and their controlled use for improving the larval viability and as a vector to improve incorporation of previously studied probiotic bacteria was tested. According to biodiversity results, these biofilms are composed of a diatom–bacteria mix showing a decrease in biodiversity in laboratory culture conditions being dominated by Navicula phyllepta and bacteria of the family Rhodobacteraceae. This can be produced on mesh substrates incorporated in bioreactors with rapid growth rate and adhesiveness. Preliminary results from the addition of substrates with this specific biofilm in larvae culture systems showed that it is consumed by the larvae without negative effects, while positive effects on the viability of larvae in combination with probiotics were observed. Considering preliminary results, the addition of these specific substrates with diatom–bacteria biofilms could be a good improvement for aquaculture systems and together with the use of probiotics can contribute to maintaining a stable and controlled system improving the viability of the larval fish culture in its early stages.