枯草芽孢杆菌与腐植酸钠合剂净水效果的研究

养殖水体中高含量氨氮和亚硝酸盐对水产动物有害。试验通过不同配比腐植酸钠与枯草芽孢杆菌(Bacillus subtili)混合剂处理模拟养殖污水,结果表明养殖水体投入10 mg/L腐植酸钠与1.2×10~3 cfu/mL枯草芽孢杆菌混合剂对水体中氨氮和亚硝酸盐的处理效果较好。     

枯草芽孢杆菌对海水鱼塘生态因子的影响

为探讨枯草芽孢杆菌(Bacillus subtilis)在鱼类养殖池塘中的生态作用,采用直接往养殖水体中投放该制剂的方法,研究分析微生物数量及其与环境因子的相关关系。结果显示,枯草芽孢杆菌,实验池数量为0.35×10~3~1.45×10~3cfu/m L,对照池为0.04×10~3~0.08×10~3cfu/m L;浮游植物生物量,实验池为0.094~1.521 mg/L,对照池为0.103~0.763 mg/L,实验池中枯草芽孢杆菌数量和浮游植物生物量均高于对照组。试验鱼塘中枯草芽孢杆菌与硅藻数量呈显著正相关,相关系数0.844(P0.05);当溶氧≥6 mg/L时,枯草芽孢杆菌与亚硝酸盐氮含量呈显著负相关,相关系数-0.915(P0.05)。溶氧过低(2 mg/L)时,枯草芽孢杆菌对亚硝酸盐氮、氨氮没有明显的降解作用;溶氧≥6 mg/L时,对亚硝酸盐氮、氨氮的降解作用明显。研究表明,投放适量浓度的枯草芽孢杆菌能有效改善养殖水体状况,对水质起到进一步净化作用。     

产乳酸芽孢杆菌对对虾养殖水体水质的影响

在温度(28±1)℃、盐度28下,将产乳酸芽孢杆菌制剂添加到养殖10尾凡纳滨对虾、容水200L的0.3m~3室内玻璃钢桶中,使芽孢杆菌终密度为10~4、10~5、10~6 cfu/mL,以无益生菌添加组为对照组。定期测定养殖水体中的氨氮、亚硝酸盐氮和硝酸盐氮的含量,以及总异养菌、弧菌和芽孢杆菌的数量。试验结果显示,试验结束时,添加芽孢杆菌各试验组养殖水体中氨氮、亚硝酸盐氮和弧菌的含量显著低于对照组(P0.05);添加高密度芽孢杆菌试验组(10~6 cfu/mL)养殖水体中总异养菌的数量显著高于对照组(P0.05);添加芽孢杆菌对养殖水体中的硝酸盐氮含量未产生显著的影响(P0.05);添加芽孢杆菌后养殖水体中的芽孢杆菌数量在第4d后会出现下降趋势。试验还发现,在养殖后期初次投入芽孢杆菌时会引起养殖水体中氨氮含量的短期升高。试验结果表明,芽孢杆菌能改善对虾养殖水体水质,可作为益生菌用于对虾养殖中。     

枯草芽孢杆菌HAINUP40水质净化作用的研究

在筛选得到适宜枯草芽孢杆菌HAINUP40生长的最佳液体培养基基础上,探讨枯草芽孢杆菌HAINUP40对2种模拟废水及养殖废水的水质净化作用。生长曲线测定结果显示,枯草芽孢杆菌HAINUP40在不同培养基中的生长速度不同,由快到慢依次为普通淡水培养基细菌基础培养基2216E培养基普通海水培养基;氨氮降解筛选培养基试验表明,枯草芽孢杆菌HAINUP40对氨氮的降解效果显著,在试验的第4d时氨氮去除率达到最高值(57.58%);8.64×105cfu/mL、8.64×10~6 cfu/mL、8.64×10~7 cfu/mL 3种密度的枯草芽孢杆菌HAINUP40对模拟废水的净化试验结果显示,枯草芽孢杆菌HAINUP40均可显著降低模拟废水中的化学需氧量和pH值,在第24h,试验组化学需氧量去除率均超69%,而且pH均降至6.7~6.9(对照组为8.0);8.64×106 cfu/mL枯草芽孢杆菌HAINUP40对高含量氨氮和化学需氧量模拟废水的净化效果试验表明,该菌株在第7d时对化学需氧量的去除率达到90.37%。8.64×10~6cfu/mL枯草芽孢杆菌HAINUP40对养殖废水的净化效果试验表明,该菌株在第12h时对亚硝酸盐的去除率达到94.12%,在72h时对化学需氧量的去除率达到72.13%。试验结果显示,枯草芽孢杆菌HAINUP40可显著降低水体中的亚硝酸盐、氨氮和化学需氧量,具有较好水质净化效果。本试验为枯草芽孢杆菌HAINUP40在罗非鱼生产中作为潜在的水质改良剂提供了数据资料和科学依据。     

枯草芽孢杆菌改善水质提高凡纳滨对虾幼体抗逆性的研究

投放不同浓度梯度的枯草芽孢杆菌于凡纳滨对虾幼体养殖环境中,监测不同枯草芽孢杆菌使用浓度下与养殖环境相关的水质因子（氨氮、亚硝酸盐氮、化学需氧量）的变化;观察不同枯草芽孢杆菌使用浓度下凡纳滨对虾幼体对人工制造的胁迫环境的抗逆性;观测不同枯草芽孢杆菌使用浓度下凡纳滨对虾幼体的成活率与体重增长率。研究枯草芽孢杆菌对水质改善和凡纳滨对虾幼体抗逆性的影响。结果表明,枯草芽孢杆菌能显著（P〈0.05）降低化学需氧量、氨氮含量,抑制亚硝酸盐氮的产生;当枯草芽孢杆菌投放浓度为1.25×10^4cfu/ml时,水体中化学需氧量、氨态氮、亚硝酸盐氮含量均值比对照组分别降低了65.30%、59.70%、88.64%,成活率比对照组提高了10.00%,体重增长率是对照组的2.44倍;当枯草芽孢杆菌使用浓度为1.25×10^4～1.25×10^6cfu/ml时,对虾抗逆性显著（P〈0.05）增强,对虾在氨氮、亚硝酸盐氮、高锰酸钾、甲醛胁迫下24小时的成活率均值分别比对照组提高了16.94%、24.44%、44.17%、18.61%。     

竹子填料海水曝气生物滤器除氮性能

生物滤器是循环水养殖系统的关键水处理单元,主要用于去除水体中水溶性的氮化物.采用人工模拟海水养殖废水,在系统运行的水力停留时间HRT为1h,水温为18～25 ℃,气水比为3∶1,初始C/N＝3∶1,pH为8.05～8.53条件下,对竹子填料浸没式生物滤器的挂膜过程和稳定运行阶段系统去除氨氮的运行特性,以及挂膜过程中的硝化细菌群落变化进行了实验研究.结果表明,在较低的NH+4-N浓度条件下,采用竹子填料的生物滤器有较快的挂膜速度,挂膜成功后滤料表面上生长的氨氧化细菌和亚硝酸氧化细菌的数量分别为4.5×105、1.5×105(光面)和1.1×106 CFU/ml(粗面).具有较高且稳定的氨氮去除效果,氨氮去除效率达到80%,出水浓度小于0.06 mg/L,满足海水循环养殖系统中的应用要求.     

不同浓度的枯草芽孢杆菌对罗非鱼鱼苗的养殖水体水质及其抗病力的影响

罗非鱼鱼苗的养殖水体中引入不同浓度的枯草芽孢杆菌,检测水体的水质指标、鱼苗体内与免疫相关酶的酶活力、鱼苗的生长率和成活率。实验结束时,引入1.0×10^4 cfu/mL枯草芽孢杆菌实验组,氨氮和亚硝酸盐氮含量分别为2.72 mg/L、0.15 mg/L,显著低于对照组（P〈0.05）;AKP活力、抗菌活力分别达249.9 U/g prot、0.59μg/mL,显著高于对照组（P〈0.05）;鱼苗成活率也显著高于对照组（P〈0.05）,比对照组提高了11.0%。结果显示：适合浓度的枯草芽孢杆菌能有效地改善鱼苗养殖水体的水质,提高机体免疫力和成活率。     

不同流向对曝气生物滤池处理对对虾养殖污水效果的影响

采用上流式和下流式曝气生物滤池处理凡纳滨对虾(Litopenaeus vannamei)养殖污水,连续进行30 d,分析出水水质,并观察系统运行情况和装置污染状况。研究了养殖污水中化学需氧量、氨氮、硝酸盐氮、亚硝酸盐氮、无机氮及活性磷酸盐6项指标的去除效果。实验结果表明:从养殖污水主要污染物指标的去除效果和稳定性上看,上流式优于下流式曝气生物滤池。在系统进水化学需氧量质量浓度为7.62～8.20 mg/L、氨氮质量浓度为0.62～0.65 mg/L、硝酸盐氮质量浓度为0.54～0.59 mg/L、亚硝酸盐氮质量浓度为0.23～0.27 mg/L、无机氮质量浓度为1.40～1.47 mg/L、活性磷酸盐质量浓度为0.24～0.29 mg/L,水温为25℃～30℃时,上流式曝气生物滤池对养殖污水中6项指标的去除率分别为:45.2%、88.9%、58.5%、78.8%、75.3%和25.1%。可见,对氨氮的去除效果最佳,亚硝酸盐氮和无机氮次之,化学需氧量和硝酸盐氮的去除效果较差,活性磷酸盐去除率最低。     

微生物对水产养殖水质调控作用研究

正本实验研究了光合细菌、放线菌、枯草芽孢杆菌三种细菌优化配比成的复合功能菌去除养殖水体有机氮效果。结果表明,光合细菌、放线菌、枯草芽孢杆菌混合培养生态制剂能有效去除养殖水体中的有机氮,对高浓度的氨氮、亚硝酸盐氮的去除率可达99.6%和94%。     

养殖水体中微生物全程自养脱氮初步研究

利用3种微生物对养殖水体的不同脱氮特性,研究了微生物对养殖水体的全自养脱氮.结果表明,水温25～30 ℃、pH 7.0～7.3及最大DO 3.5 mg/L时,光合细菌、枯草芽孢杆菌以1:1的接种水平,养殖水体中氨氮、亚硝酸盐氮的去除率分别为85.4%、89.5%,可以很好地实现对养殖水体的全自养脱氮.     

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.