壳聚糖和益生菌对暗纹东方鲀抗病力和免疫功能的影响

为了解壳聚糖和益生菌刺激和增强免疫应答的可能作用,本试验在基础饲料中添加0.2%、0.5%、1.0%的壳聚糖,0.1%、0.2%、0.4%的益生菌,甘露聚糖与益生菌混合物,壳聚糖与益生菌的混合物,在室内水泥池中喂养暗纹东方鲀(3.15±0.05)g 2个月,根据抗菌活力筛选出免疫增强饲料组(0.2%壳聚糖,0.1%、益生菌,甘露聚糖与益生菌混合物,壳聚糖与益生菌混合物)测定免疫功能。结果表明,甘露聚糖与益生菌混合物仅提高头肾T淋巴细胞转化,壳聚糖与益生菌混合物显著增强头肾T、B淋巴细胞转化和脾脏B淋巴细胞体外培养时分泌的IgM。筛选出的四种免疫增强饲料均能使头肾B淋巴细胞体外培养时分泌的IgM显著增加。无论是脾脏B淋巴细胞还是头肾B淋巴细胞,体外培养时所分泌的IFN-α都不同程度地受抑制。     

浅析维生素C、E混合物以及免疫多糖对暗纹东方鲀生长及抗病力的影响

免疫增强剂的研究已成为当前鱼病学研究和新鱼药开发的一个热点。作为一种新型的绿色渔药,免疫增强剂以其种类多、应用广、使用方便等优点,日渐受到人们的青睐。研究表明,免疫增强剂在鱼类疾病控制上具有十分重要的意义。因此,免疫增强剂添加在暗纹东方鲀饲料中的应用将成为生态、绿色、健康养殖的趋势。本试验主要研究了维生素C、维生素E以及免疫多糖等免疫增强剂在暗纹东方鲀上的应用。     

玉米蛋白粉替代鱼粉对暗纹东方鲀溶菌酶活性及c型溶菌酶mRNA表达的影响

以初重为(41.26±1.09)g的暗纹东方鲀为实验鱼,配制5种玉米蛋白粉使用量为0%、5%、10%、15%、20%的实验饲料,玉米蛋白粉对饲料中鱼粉的替代水平分别为0%、7.4%、14.8%、22.2%和29.6%。用实验饲料饲养暗纹东方鲀60d,研究玉米蛋白粉替代鱼粉对暗纹东方鲀肝胰脏、头肾和脾脏组织的溶菌酶活性及其c-型溶菌酶mRNA相对表达量的影响。结果表明,(1)暗纹东方鲀肝胰脏、头肾和脾脏的溶菌酶比活力分别为9.14、42.12和40.49U/mgprot,头肾和脾脏组织中c-型溶菌酶mRNA相对表达量分别是肝胰脏的3.76和3.24倍。(2)玉米蛋白粉替代鱼粉显著影响暗纹东方鲀溶菌酶比活力。5%和10%组的肝胰脏和头肾组织溶菌酶比活力显著高于对照组(P<0.05),而15%和20%组肝胰脏和头肾组织溶菌酶比活力则显著低于对照组(P<0.05);5%和10%组的脾脏组织溶菌酶活力与对照组无显著性差异(P>0.05),而15%和20%组显著低于对照组和5%组(P<0.05)。(3)玉米蛋白粉对暗纹东方鲀c型溶菌酶基因mRNA相对表达量有显著影响(P<0.05)。肝胰脏组织中5%和10%组表达量显著高...     

壳聚糖投喂方式对草鱼抗饥饿胁迫能力的影响

在基础饲料中添加0.5%的壳聚糖,采用3种不同的投喂方式(方式A:连续投喂基础饲料,对照组;方式B:连续投喂添加0.5%壳聚糖的饲料,连续组;方式C:先投喂0.5%壳聚糖饲料再投喂基础饲料且每15天间隔投喂,不连续组)饲喂初始体重(19.46±0.04)g的草鱼60d后,对草鱼进行饥饿胁迫处理[各投喂方式分为投喂组(feeding,F)和饥饿组(starvation,S)],以生长、一氧化氮(nitrogenoxide,NO)含量和溶菌酶(lysozyme,LSZ)活性为指标考察壳聚糖不同投喂方式对草鱼抗饥饿胁迫处理的能力。结果显示,(1)连续组和不连续组60d时草鱼增长率和增重率显著高于对照组(P<0.05),15d饥饿处理后也呈现投喂组和饥饿组的增长率和增重率高于对照组的趋势(P>0.05);(2)对照组头肾、肝胰脏NO含量和血清、头肾溶菌酶活性饥饿组显著高于投喂组(P<0.05),连续组除头肾外NO含量和各组织溶菌酶活性饥饿组显著低于投喂组(P<0.05)或与投喂组无显著差异(P>0.05),不连续组除脾脏外NO含量和除肝胰脏外的溶菌酶活性饥饿组显著低于投喂组(P<0.05)或与投喂组无显著差异(P>0...     

壳聚糖和益生菌对异育银鲫非特异免疫功能及血清甲状腺激素、皮质醇水平的影响

为探讨壳聚糖和益生菌是否通过甲状腺激素、皮质醇对异育银鲫的非特异免疫功能的进行调控,试验以基础饲料为对照,在基础饲料中分别添加0.50%壳聚糖A、0.50%壳聚糖B、0.20%益生菌以及0.50%壳聚糖A与0.05%益生菌的混合物制备试验饲料,饲养异育银鲫64d后,测定各组鱼外周血白细胞数量及其分类、白细胞吞噬活性、脾脏溶菌酶活性、脾脏淋巴细胞转化能力;同时采用放射免疫分析法测定异育银鲫血清中三碘甲腺原氨酸(T3)、甲状腺素(T4)及皮质醇含量。结果表明,饲料中添加壳聚糖、益生菌或其混合物对异育银鲫白细胞总数无显著影响,但是可显著提高异育银鲫外周血淋巴细胞数量、白细胞吞噬活性和脾脏溶菌酶活性(P<0.05),显著降低外周血多形核细胞数量(P<0.05)。除了壳聚糖A能够显著提高异育银鲫脾脏B淋巴细胞转化能力之外,其余试验组的脾脏T、B淋巴细胞转化能力均与对照组无显著差异(P>0.05)。同时发现饲料中添加壳聚糖、益生菌或其混合物可以显著提高异育银鲫血清中T3的含量(P<0.05)、显著降低异育银鲫血清中皮质醇的含量(P<0.05),除了壳聚糖B对异育银鲫血清中T4的含量无显著影响(P>0.05)之外,其余均可...     

暗纹东方鲀血细胞发生的观察

通过对暗纹东方鲀(Takifugu obscurus)血液涂片及头肾、体肾、脾脏和肝脏四种脏器印片的光镜观察,发现血细胞的发育大致经过三个阶段,即原始阶段、幼稚阶段、成熟阶段。实验对不同发育阶段的红血细胞、淋巴细胞、单核细胞、粒细胞进行了观察和测量,并对暗纹东方鲀血细胞的发生过程做了初步探讨。实验结果表明暗纹东方鲀血细胞的发育主要在头肾和体肾,肝脏印片未观察到原始造血细胞,提示肝脏可能不是暗纹东方鲀的造血器官。     

壳聚糖通过甲状腺激素对草鱼免疫功能的调节

以初始体质量为（1.04&#177;0.01）g的草鱼（Ctenopharyngodon idella）为对象,在探讨内分泌激素—甲状腺激素对草鱼免疫功能影响的基础上,研究壳聚糖对草鱼免疫功能的内分泌调控。实验分别制作含甲状腺激素饲料（在基础饲料中分别添加0mg/kg、1mg/kg、5mg/kg、10mg/kg饲料的甲状腺激素）和含壳聚糖饲料（在基础饲料中分别添加0、0.25%、0.50%、0.75%、1.00%的壳聚糖）,在循环水族箱中饲养草鱼70d。实验结束后测定试验鱼血清中的甲状腺激素（T3和T4）含量和非特异性免疫功能。结果表明,饲料中添加甲状腺激素对草鱼血清中甲状腺激素含量和非特异性免疫功能（头肾和脾脏溶菌酶活性、头肾NO含量）有显著影响（P〈0.05）,且两者变化趋势相似。故认为甲状腺激素能够调控草鱼的非特异性免疫功能。壳聚糖对草鱼血清中甲状腺素含量和非特异性免疫功能（吞噬活性、头肾和脾脏溶菌酶活性、头肾NO含量）也有显著影响（P〈0.05）,而且在各实验组有较为相似的变化趋势。综合以上结果认为,壳聚糖可以通过内分泌途径甲状腺激素水平的变化实现对草鱼非特异性免疫功能的调控。鉴于0.50%壳聚糖组具有最强的非特异性免疫功能,认为在本实验条件下,壳聚糖在草鱼饲料中的适宜添加量为0.50%。     

暗纹东方鲀江水漂养高效试验

为了提高暗纹东方鲀的养殖效益和品质,我们从2012年4月至10月,在泰兴市长江渔场进行暗纹东方鲀江水漂养试验。试验共使用3口鱼池,9亩水面,每口鱼池3亩。每亩放养暗纹东方鲀1000尾,搭配鲢鱼200尾,投喂粗蛋白45%粉状饲料和蚌肉、小鱼等鲜活饵料,取得了良好的效益。现将试验情况总结如下:     

一种复合免疫增强剂对大菱鲆和血鹦鹉鱼酶活性及抗病力的影响

在饲料中对自制复合免疫增强剂设计了四个添加剂量(投喂免疫增强剂浓度0‰、投喂免疫增强剂浓度1‰、投喂免疫增强剂浓度2‰、投喂免疫增强剂浓度3‰)分别投喂大菱鲆和血鹦鹉鱼。30d后测定各组试验鱼血清的溶菌酶活性、碱性磷酸酶活性和总超氧化物歧化酶活性,并分别进行攻毒试验。结果表明投喂免疫增强剂浓度1‰、2‰的大菱鲆的溶菌酶活性、碱性磷酸酶活性和总超氧化物歧化酶活性皆显著高于对照组(P0.05);三个实验组鱼的人工感染死亡率分别为50%、45%和100%,方差分析表明两个实验组皆显著低于对照组(P0.05)。投喂血鹦鹉鱼试验各测定酶指标都是2‰组最高,并且显著高于对照组(P0.05),攻毒试验死亡率投喂投喂免疫增强剂浓度2‰组最低。因此可以证明投喂本复合制剂可以明显提高大菱鲆和血鹦鹉鱼的酶活性及抗应激能力,并且适宜投喂比例为2‰。     

几种免疫增强剂对草鱼SOD、CAT及AKP活性的影响

将草鱼放入网箱中,投喂在基础饲料中分别添加不同剂量的黄芪多糖、枸杞多糖和金丝桃素的饲料,研究其对草鱼血清中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)及碱性磷酸酶(AKP)活性的影响。结果表明:投喂添加中药免疫增强剂的饲料60d后,与对照组相比,血清中CAT和AKP活性变化不明显(P0.05);血清中SOD活性显著高于对照组(P0.05),说明中药免疫增强剂对增强草鱼免疫活性具有一定的作用。     

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.