IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-02-05 DOI: 10.1016/j.aquaculture.2026.743739

Toshinao Ineno , Taisei Nozaki , Ryuhei Kinami

Induction of gonad development into ovaries in genetic male sterlets (Acipenser ruthenus) has previously been achieved by dietary supplementation with 1000 μg/g genistein (GS), a phytoestrogen. The present study aimed to determine the lowest effective GS dose capable of feminizing genetic male sterlets. Genetically male sterlets at 137 days post-hatch (DPH) were divided into four groups of 30 individuals (53.9 ± 1.87 g), orally administered GS at doses of 0, 500, 800, and 1000 μg/g diet for 180 days in in the group tanks with flow-through river water, and then fed a GS-free diet for approximately 200 days prior to sampling. The results revealed that GS did not affect survival or growth rates. Intersex gonads were observed in 15/25, 22/25, and 20/24 fish in the 0, 500, 800, and 1000 μg/g dietary GS groups, respectively, and the minimum GS dose required to induce ovarian tissue development in the testis was ≤500 μg/g diet. Furthermore, a novel classification system for ovarian tissue development within the testes was introduced that consists of stages 0 to 4 based on the histological analysis results. A significant correlation was observed between GS dose and gonadal stage (ordinal logistic regression analysis: p < 0.05, R² = 0.279), suggesting that GS increased the proportion of gonadal ovarian tissue in a dose-dependent manner. The results of this study suggest that administering an appropriate GS dosage could contribute towards the development of formulated feed that induces feminization in farmed sterlet.

通过在饲料中添加1000 μg/g染料木黄酮（一种植物雌激素），已成功诱导雄性遗传小鲟（ruthenus）的性腺发育进入卵巢。本研究旨在确定能使遗传雄性小体雌性化的最低有效GS剂量。将孵化后137天的遗传雄幼鱼分为4组，每组30尾（53.9±1.87 g），分别在有流动河水的组池中以0、500、800和1000 μg/g的剂量口服GS，饲喂180 d，然后在取样前饲喂不含GS的饲料约200 d。结果显示，GS不影响生存或生长速率。在饲料中添加0、500、800和1000 μg GS组，15/25、22/25和20/24鱼分别出现双性性腺，诱导睾丸卵巢组织发育所需的GS最低剂量≤500 μg。此外，本文还介绍了一种基于组织学分析结果的卵巢组织发育的新分类系统，包括0至4期。GS剂量与性腺分期显著相关（有序logistic回归分析：p <； 0.05, R2 = 0.279），提示GS增加卵巢性腺组织比例呈剂量依赖性。本研究结果表明，给予适当的GS剂量可能有助于开发诱导养殖小鲟雌性化的配方饲料。

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引用次数: 0

Differential growth and biochemical profiling of the red seaweed Gracilaria sp. under near-shore and pond-based environments: Insights from surface and on-bottom cultivation systems 近岸和池塘环境下红紫菜的差异生长和生化特征：来自水面和底部栽培系统的见解

IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-01-27 DOI: 10.1016/j.aquaculture.2026.743701

Joy Talapatra , Md. Ramzan Ali , Sayeda Afrin Busra , Sourav Chowdhury , Md Nayeem Hossain , Md Nahiduzzaman , Md Asaduzzaman

Gracilaria is a globally valuable red seaweed with applications in food, pharmaceuticals, and ecosystem-based aquaculture, yet its cultivation in Bangladesh remains largely confined to nearshore habitats. This study provides the first rigorous, side-by-side evaluation of Gracilaria sp. performance in a 2 × 2 factorial experiment in traditional nearshore systems and in underutilized coastal ponds, assessing how environment (near-shore vs ponds) and water cultivation layers (surface vs on-bottom) jointly shape growth dynamics, ecological drivers, and biochemical attributes. Nearshore systems consistently produced superior (p < 0.001) net weight biomass (up to 674% higher) and faster daily growth rate (DGR) (up to 482% higher), while surface-layer culture outperformed (p < 0.001) on-bottom culture across all metrics, underscoring the importance of light availability and hydrodynamic exposure. Multivariate analyses revealed that seasonal maxima occurred during December–February, driven by favorable thermal regimes, enhanced water clarity, and winter nutrient enrichment, while temperature elevation and turbidity strongly suppressed growth. Biochemical profiling revealed pronounced environmental differentiation. Nearshore-grown thalli of Gracilaria sp. exhibited significantly (p < 0.001) elevated protein, lipid, crude fiber, ash, and essential amino acids, reflecting enhanced nitrogen assimilation, stronger photosynthetic performance, and greater metabolic allocation toward structural and functional biomolecules under dynamic hydrodynamic conditions. Conversely, bottom-layer cultivation stimulated higher antioxidant and flavonoid concentrations (p < 0.001), indicating depth-specific activation of phenolic and oxidative defense pathways. These patterns were supported by FTIR spectra, which revealed distinct shifts in amino-acid–related and phenolic functional groups between environments and cultivation layers, underscoring the biochemical plasticity of Gracilaria in response to ecological gradients. Collectively, the findings show that while nearshore farming maximizes biomass and nutritional quality, coastal pond-based systems offer complementary benefits for carbon capture and seamless integration into existing aquaculture. By clarifying the mechanistic links between environmental variability, seasonal dynamics, and biochemical profiles, this study provides a foundation for resilient, high-value Gracilaria production and highlights how strategically managed coastal pond-based systems can transform underutilized shrimp ponds into multifunctional seaweed-aquaculture platforms that strengthen coastal livelihoods and advance Bangladesh's blue-economy agenda.

紫菜是一种具有全球价值的红海藻，用于食品、制药和基于生态系统的水产养殖，但其在孟加拉国的种植仍主要局限于近岸栖息地。本研究首次在传统近岸系统和未充分利用的沿海池塘中进行了2 × 2因子实验，对江蓠的生长性能进行了严格的并排评估，评估了环境（近岸vs池塘）和水体栽培层（表层vs底层）如何共同影响生长动态、生态驱动因素和生化属性。近岸系统始终能产生更优的（p < 0.001）净重生物量（高出674%）和更快的日生长率（DGR）（高出482%），而表层培养在所有指标上都优于底层培养（p < 0.001），强调了光可用性和水动力暴露的重要性。多变量分析显示，由于有利的热环境、水的清晰度和冬季营养物质的富集，12月至2月出现了季节性最大值，而温度升高和浊度强烈抑制了生长。生化分析显示明显的环境分化。近岸生长的江蓠菌体的蛋白质、脂肪、粗纤维、灰分和必需氨基酸显著（p < 0.001）升高，反映了动态水动力条件下氮同化增强，光合性能增强，代谢分配向结构和功能生物分子方向发展。相反，底层培养刺激更高的抗氧化剂和类黄酮浓度（p < 0.001），表明酚和氧化防御途径的深度特异性激活。FTIR光谱支持了这些模式，揭示了江蓠在不同环境和栽培层之间氨基酸相关官能团和酚类官能团的明显变化，强调了江蓠对生态梯度的生化可塑性。总的来说，研究结果表明，虽然近岸养殖最大限度地提高了生物量和营养质量，但沿海池塘系统为碳捕获和与现有水产养殖的无缝整合提供了互补效益。通过阐明环境变化、季节动态和生化特征之间的机制联系，本研究为有弹性的高价值江蓠生产奠定了基础，并强调了战略性管理的沿海池塘系统如何将未充分利用的对虾池转变为多功能海藻养殖平台，从而加强沿海生计并推进孟加拉国的蓝色经济议程。

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引用次数: 0

Effects of SiO2NPs and CuONPs on the histoarchitecture and transcriptomic responses in the brain of Nile tilapia, Oreochromis niloticus SiO2NPs和CuONPs对尼罗罗非鱼脑组织组织结构和转录组反应的影响

IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-01-27 DOI: 10.1016/j.aquaculture.2026.743699

Ahmed E. Noreldin , Mustafa Shukry , Akram Ismael Shehata , Mohammed F. El Basuini , Hany M.R. Abdel-Latif

The widespread application of engineered nanomaterials, particularly silicon dioxide nanoparticles (SiO₂NPs) and copper oxide nanoparticles (CuONPs), has raised critical environmental concerns due to their increasing release into aquatic ecosystems. This study aimed to evaluate the sub-lethal neurotoxic effects of SiO₂NPs and CuONPs on the brain of Nile tilapia. Juvenile fish were exposed to SiO₂NPs (0, 20, 40, and 100 mg/L) and CuONPs (0, 10, 20, and 50 mg/L) for three weeks under controlled laboratory conditions. Histopathological examination revealed concentration-dependent neurodegenerative changes in the cerebellum and optic tectum, including neuronal shrinkage, edema, necrosis, and vacuolization, with significantly higher lesion scores at the highest concentrations. Transcriptomic analysis demonstrated a significant upregulation of oxidative stress-related gene metallothionein, and neuroendocrine regulator spexin at medium and high concentrations of both nanoparticles. Furthermore, key neurotransmission-related genes, including dopamine receptor 2, cholinergic receptor beta-2 subunit, acetylcholinesterase, and gamma-aminobutyric acid receptor gamma-3 subunit, were markedly downregulated in a dose-dependent manner, particularly at 100 mg/L SiO₂NPs and 50 mg/L CuONPs, indicating impaired synaptic signaling and potential behavioral dysfunction. In conclusion, the findings highlight the neurotoxic potential of SiO₂NPs and CuONPs in Nile tilapia, marked by histological deterioration and significant disruption of gene expression related to oxidative stress, inflammation, and neurotransmission. Notably, 50 mg/L for CuONPs and 100 mg/L for SiO₂NPs were identified as the highest concentrations that elicited significant adverse transcriptomic and histopathological responses, indicating these as critical levels for neurotoxicity. This study provides novel molecular evidence of nanoparticle-induced neurotoxicity and underscores the urgent need for environmental regulation to mitigate the risks of these nanomaterials in aquatic ecosystems.

工程纳米材料的广泛应用，特别是二氧化硅纳米颗粒（sio2nps）和氧化铜纳米颗粒（CuONPs），由于它们越来越多地释放到水生生态系统中，引起了严重的环境问题。本研究旨在评价sio2nps和CuONPs对尼罗罗非鱼脑的亚致死神经毒性作用。幼鱼在受控的实验室条件下暴露于SiO₂NPs（0、20、40和100 mg/L）和CuONPs（0、10、20和50 mg/L）三周。组织病理学检查显示，小脑和视神经顶盖出现浓度依赖性神经退行性改变，包括神经元萎缩、水肿、坏死和空泡化，在最高浓度下病变评分明显较高。转录组学分析表明，氧化应激相关基因金属硫蛋白和神经内分泌调节蛋白在中、高浓度下均显著上调。此外，关键的神经传递相关基因，包括多巴胺受体2、胆碱能受体β -2亚基、乙酰胆碱酯酶和γ -氨基丁酸受体γ -3亚基，以剂量依赖性的方式显着下调，特别是在100 mg/L SiO₂NPs和50 mg/L CuONPs时，表明突触信号传导受损和潜在的行为功能障碍。总之，这些发现强调了SiO₂NPs和CuONPs对尼罗罗非鱼的神经毒性潜力，其特征是组织学恶化和与氧化应激、炎症和神经传递相关的基因表达显著破坏。值得注意的是，50 mg/L的CuONPs和100 mg/L的SiO₂NPs被确定为引发显著不良转录组学和组织病理学反应的最高浓度，表明它们是神经毒性的临界水平。该研究为纳米颗粒诱导的神经毒性提供了新的分子证据，并强调了环境调控的迫切需要，以减轻这些纳米材料在水生生态系统中的风险。

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引用次数: 0

Crowding-induced physiological stress, not aggression, makes high stocking density more worthy of attention in aquaculture 群集引起的生理应激，而非攻击性，使得高放养密度在水产养殖中更值得重视

IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-01-27 DOI: 10.1016/j.aquaculture.2026.743700

Weijie Song , Qianjing Jiang , Yong He , Bin Ma , Yu Tang , Jian Zhao

Stocking density is a critical factor in aquaculture, and a long-standing debate persists regarding the relative detriments of high versus low densities to fish welfare. Moreover, the mechanistic pathways and contributions of physiological stress and aggression to welfare decline remain poorly quantified. In this study, we conducted a comprehensive meta-analysis spanning 108 fish species based on 2507 observations from 214 studies. Our analyses revealed that, in contrast to low stocking density, high stocking density significantly impeded growth performance, as evidenced by reduced specific growth rate (SGR) (-9.4%), lower daily feed intake (DFI) (-13.6%), and a higher feed conversion ratio (FCR) (+8.8%). Mechanistically, this is driven by a significant physiological stress response, including elevated cortisol levels (+11.3%) and impaired digestive function (-15.5%). Counterintuitively, frequency of aggressive behavior (FAB) decreased significantly (-38.6%), suggesting that crowding-induced physiological stress, rather than aggression, is the primary cause of welfare degradation. Furthermore, subgroup analyses indicated carnivorous fish demonstrated superior tolerance to high-density stress, with a relatively minor reduction in SGR (-7.6%), a pronounced decrease in FAB (-40.6%), and non-significant changes in cannibalism rate (CR), coefficient variation of final weight (CV), DFI, and cortisol levels. In contrast, omnivores suffered a more substantial SGR decline (-12.1%), accompanied by increases in CR (+469.5%), CV (+26.7%), and cortisol levels (+19.3%), and a significant reduction in DFI (-21.9%). Finally, we identified indoor culture system and precise feeding rate as viable mitigation strategies for high-density stress. These findings provide a mechanistic understanding and practical solutions for improving welfare in intensive aquaculture.

放养密度是水产养殖的一个关键因素，关于高密度与低密度对鱼类福利的相对危害的争论一直存在。此外，生理压力和攻击性对福利下降的机制途径和贡献仍然缺乏量化。在这项研究中，我们基于214项研究的2507项观察结果，对108种鱼类进行了全面的meta分析。结果表明，与低放养密度相比，高放养密度显著影响了黄鳝的生长性能，具体表现为特定生长率（SGR）降低（-9.4%），日采食量（DFI）降低（-13.6%），饲料系数（FCR）升高（+8.8%）。从机制上讲，这是由显著的生理应激反应驱动的，包括皮质醇水平升高（+11.3%）和消化功能受损（-15.5%）。与直觉相反，攻击行为（FAB）的频率显著下降（-38.6%），这表明拥挤导致的生理压力，而不是攻击，是福利退化的主要原因。此外，亚组分析表明，肉食性鱼对高密度应激的耐受性较好，SGR降低相对较小（-7.6%），FAB显著降低（-40.6%），而同类相食率（CR）、最终体重变异系数（CV）、DFI和皮质醇水平变化不显著。相比之下，杂食动物的SGR下降幅度更大（-12.1%），CR增加（+469.5%），CV增加（+26.7%），皮质醇水平增加（+19.3%），DFI显著降低（-21.9%）。最后，我们确定了室内培养系统和精确的饲养速率作为高密度应激的可行缓解策略。这些发现为提高集约化水产养殖的福利提供了机制理解和实际解决方案。

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引用次数: 0

A single PCR-based sex marker, Sj-SexI, from conserved SDR gametologue genes: Enhancing efficiency and cross-species applicability in kelp 基于pcr的SDR配子体基因性别标记Sj-SexI：提高海藻的效率和跨物种适用性

IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-01-27 DOI: 10.1016/j.aquaculture.2026.743702

Liping Liu , Zihan Gai , Yan Li , Yanling Liu , Shuxiu Chen , Xiaojie Li , Weiwei Wang , Linan Zhang

The brown alga Saccharina japonica is a commercially important species in global seaweed aquaculture, with a haploid UV-type sex determination system operating at the gametophyte stage. Reliable sex identification is critical for germplasm resource management and genetic breeding; however, fully validated morphological traits for this purpose are currently lacking. Existing sex-specific molecular markers for S. japonica also have limitations, such as low efficiency (requiring dual markers) and insufficient specificity or interspecific universality. In this study, we developed a single PCR-based sex marker (designated Sj-SexI) derived from a pair of conserved gametologue genes—SjaF_32G0008590 (female-associated) and Sja_32G0004800 (male-associated)—localized within the sex-determining region (SDR) of S. japonica. These two gametologues encode putative Ste20-like serine/threonine kinases, sharing conserved exon sequences but exhibiting distinct intron lengths. This length polymorphism enabled the design of a degenerate primer pair to discriminate between male and female amplification products. Using a single PCR reaction, Sj-SexI amplified a 670 bp product in female gametophytes and a 391 bp product in male gametophytes, allowing for both rapid sex identification and detection of sex mixing in gametophytes. Validation experiments confirmed three key functionalities of Sj-SexI: (1) accurate identification of the genetic sex of aposporous gametophytes; (2) distinction between sporophytes derived from sexual reproduction (showing both male and female amplification bands) and those from asexual reproduction (displaying a single sex-specific band); and (3) broad cross-species applicability. Specifically, Sj-SexI successfully amplified sex-specific bands in multiple kelp species, including S. longissima, S. angustata, S. latissima, S. gyrata, Kjellmaniella crassifolia, and even Undaria pinnatifida (a species from a different family, Alariaceae). Compared with previously reported sex markers for S. japonica, Sj-SexI significantly improves identification efficiency and enhances both specificity and universality. This marker thus serves as a reliable tool for large-scale germplasm management, research on reproductive development mechanisms, and genetic breeding in S. japonica and related kelp species.

褐藻Saccharina japonica是全球海藻养殖中重要的商业物种，在配子体阶段具有单倍体uv型性别决定系统。可靠的性别鉴定对种质资源管理和遗传育种至关重要；然而，目前还缺乏完全有效的形态学特征。现有的粳稻性别特异性分子标记也存在效率低（需要双标记）、特异性或种间普适性不足等局限性。在本研究中，我们从日本稻性别决定区（SDR）内的一对保守配子学基因sjaf_32g0008590（雌性相关）和Sja_32G0004800（雄性相关）中开发了一个基于pcr的性别标记（命名为Sj-SexI）。这两种配子体编码假定的ste20样丝氨酸/苏氨酸激酶，共享保守的外显子序列，但具有不同的内含子长度。这种长度多态性使得简并引物对的设计能够区分雄性和雌性扩增产物。通过单次PCR扩增，Sj-SexI在雌性配子体中扩增了670 bp的产物，在雄性配子体中扩增了391 bp的产物，从而实现了快速的性别鉴定和配子体性别混合检测。验证实验证实了Sj-SexI的三个关键功能：(1)准确识别无孢子配子体的遗传性别；(2)有性生殖产生的孢子体（显示雄性和雌性扩增带）与无性生殖产生的孢子体（显示单一性别特异性扩增带）的区别；(3)广泛的跨物种适用性。具体来说，Sj-SexI成功扩增了多个海带物种的性别特异性条带，包括S. longissima、S. angustata、S. latissima、S. gyrata、Kjellmaniella crassifolia，甚至是Undaria pinnatifida（来自不同科的海带科物种）。与已有报道的粳稻性别标记相比，Sj-SexI显著提高了粳稻的鉴定效率，增强了特异性和普遍性。因此，该标记可作为大规模种质资源管理、生殖发育机制研究和海带及其相关物种遗传育种的可靠工具。

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引用次数: 0

Genomic insights into Priestia megaterium H403: A kelp endophyte with growth-promoting potential for microbe-assisted aquaculture 巨藻Priestia megaterium H403的基因组分析：一种具有促进微生物辅助水产养殖生长潜力的海带内生菌

IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-01-25 DOI: 10.1016/j.aquaculture.2026.743696

XiaoKun Yang , Xiaowen Zhang , Tianle Xi , Yitao Wang , Min Jiao , Ning Niu , Hua Xu , Chengwei Liang , Naihao Ye

Kelp (Saccharina japonica) is a commercially significant seaweed worldwide, yet its indoor seedling cultivation process remains time-consuming and costly. In this study, we isolated an endophytic bacterium, Priestia megaterium Strain H403, from healthy kelp S.japonica tissue of co-culture experiments demonstrated that H403 significantly promoted S. japonica seedling growth. Seedlings treated with H403 (at 1.4 × 10⁷ cfu) exhibited a 3.6-fold increase in length compared to control group. Whole-genome sequencing of P. megaterium H403 identified 5458 protein coding genes, including several associated with plant growth-promoting traits, such as nitrogen fixation, phosphate solubilization, siderophore production, and indole-3-acetic acid biosynthesis. Additionally, Strain H403 showed strong adaptability to kelp seedling conditions and lacked alginate lyase activity, indicating its potential to colonize kelp seedings without causing host tissue damage. To our knowledge, this is the first report elucidating the molecular mechanisms underlying kelp growth promotion by P. megaterium, highlighting its promise for application in microbe-assisted seedling cultivation to support seaweed aquaculture.

海带（Saccharina japonica）是世界范围内具有重要商业价值的海藻，但其室内育苗过程仍然耗时且成本高昂。在本研究中，我们从健康的海带S.japonica共培养组织中分离到一株内生细菌，巨型Priestia megaterium菌株H403，实验证明H403显著促进S.japonica幼苗的生长。H403处理（1.4 × 107 cfu）的幼苗长度比对照组增加了3.6倍。megaterium H403的全基因组测序鉴定出5458个蛋白质编码基因，其中包括几个与植物生长促进性状相关的基因，如固氮、磷酸增溶、铁载体生产和吲哚-3-乙酸生物合成。此外，菌株H403对海带幼苗条件具有较强的适应性，缺乏海藻酸解酶活性，表明其可能在不造成寄主组织损伤的情况下定植海带幼苗。据我们所知，这是第一篇阐明巨型藻促进海带生长的分子机制的报告，强调了其在微生物辅助育苗以支持海藻养殖中的应用前景。

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引用次数: 0

Fasting-refeeding reshapes diurnal behavior, digestive physiology, and gut microbiota in Pacific abalone (Haliotis discus hannai) via the brain-gut-microbiome axis 禁食-再喂食通过脑-肠-微生物组轴重塑太平洋鲍鱼（Haliotis discus hannai）的日常行为、消化生理和肠道微生物群

IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-01-24 DOI: 10.1016/j.aquaculture.2026.743682

Haowei Cai , Xiaolong Gao , Mo Zhang , Rui Gao , Ying Liu

The Pacific abalone (Haliotis discus hannai), a typically nocturnal species, primarily engages in movement and feeding behaviors at night, while seeking shelter in dark areas during the day to avoid light. To explore how feeding frequency affects the behavior and physiological rhythms of this nocturnal mollusk during the high-temperature summer period, three feeding regimens were applied: continuous fasting (DJ), fasting followed by refeeding (DF), and intermittent feeding every three days (CF). The CF group showed significantly higher survival rates and specific growth rates in weight compared to the LS group. Within 24 h, the DJ group had significantly shorter movement durations than the continuous feeding group (LS) (P < 0.05). After refeeding, the DF group exhibited a significantly longer cumulative feeding duration compared to the LS group (P < 0.05). The CF group had the shortest cumulative movement distance, though its cumulative feeding duration after refeeding did not significantly differ from that of the LS group. However, fasting followed by refeeding did not significantly alter the diurnal rhythms of abalone movement and feeding compared to the LS group (P > 0.05). In the DF group, α-amylase activity in the gut was significantly higher than in the other three groups, and the peak phase of enzyme activity shifted forward from ZT00:34 in the LS group to ZT19:48 (P < 0.05). In the LS group, expression of the leptin receptor gene in the cerebral ganglia remained high during the day but low at night, while expression levels in the DJ and DF groups were significantly lower than in the LS group (P < 0.05). The dominant gut microbiota, Proteobacteria and Firmicutes, exhibited rhythmic diurnal changes in relative abundance, with significant differences observed in key genera, including Vibrio, Psychrilyobacter, Ruegeria, and Mycoplasma (P < 0.05). Fasting followed by refeeding significantly reduced the α-diversity of the gut microbiota (P < 0.05), with notable changes in the relative abundance of key genera such as Bacteroides, Sphaerochaeta, Vibrio, Ruegeria, Persicobacter, and Acinetobacter among the treatment groups (P < 0.05). Therefore, under controlled laboratory conditions, a three-day fasting and refeeding regimen can promote growth efficiency in abalone during high-temperature stress with limited natural food availability, though its long-term benefits and field applicability need to be validated. This dietary management induces a restructuring of behavior and physiological rhythms, with coordinated shifts in neuroendocrine and microbiota profiles supporting the involvement of the brain-gut-microbiome axis. These results provide a theoretical basis for developing scientific aquaculture practices to lower production costs.

太平洋鲍鱼（Haliotis discus hannai）是一种典型的夜行动物，主要在夜间活动和觅食，而在白天则在黑暗的地方寻找庇护所以躲避光线。为探讨高温夏季摄食频率对夜行软体动物行为和生理节律的影响，采用连续禁食（DJ）、禁食后再摄食（DF）和每三天间歇性摄食（CF）三种摄食方案。与LS组相比，CF组的存活率和体重特定生长率显著高于LS组。24 h内，DJ组的运动时间显著短于连续喂养组（LS）（P < 0.05）。复饲后，DF组的累计摄食时间显著长于LS组（P < 0.05）。CF组的累计运动距离最短，但再喂后的累计摄食时间与LS组无显著差异。然而，与LS组相比，禁食后再喂食对鲍鱼运动和摄食的日节律没有显著影响（P > 0.05）。DF组肠道α-淀粉酶活性显著高于其他3组，酶活性峰相由LS组的ZT00:34提前至ZT19:48 （P < 0.05）。LS组脑神经节瘦素受体基因白天表达量高，夜间表达量低，DJ组和DF组表达量显著低于LS组（P < 0.05）。优势肠道菌群变形菌门和厚壁菌门的相对丰度呈现出节律性的昼夜变化，关键属包括弧菌、精神杆菌、鲁氏菌和支原体（P < 0.05）。禁食后再饲喂显著降低了肠道菌群α-多样性（P < 0.05），关键属如拟杆菌属（Bacteroides）、藻毛纲（Sphaerochaeta）、弧菌属（Vibrio）、鲁氏菌属（Ruegeria）、persicobacterter)和不动杆菌属（Acinetobacter）的相对丰度在各处理组之间变化显著（P < 0.05）。因此，在受控的实验室条件下，在天然食物供应有限的高温胁迫下，三天禁食再饲喂方案可以提高鲍鱼的生长效率，但其长期效益和现场适用性有待验证。这种饮食管理诱导了行为和生理节律的重组，神经内分泌和微生物群的协调变化支持脑-肠-微生物群轴的参与。这些结果为制定科学的养殖方法以降低生产成本提供了理论依据。

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引用次数: 0

Evaluating the practicability of Oreochromis niloticus farming with mixing strategy in recycled old and new biofloc 评价新老生物群落循环利用混合策略养殖尼罗褐虾的可行性

IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-01-23 DOI: 10.1016/j.aquaculture.2026.743695

Xin Hu , Sixing Xu , Shuhui Liu , Wenchang Liu , Hongxin Tan , Guozhi Luo

Despite its potential for sustainable aquaculture, biofloc technology faces persistent challenges in the effective management of old biofloc and the establishment of a stable system start-up. This study systematically evaluated the comparative performance and reuse feasibility of old biofloc (Old) against new biofloc (New) and a 1:1 mixture (Mix) over a 6-week tilapia (Oreochromis niloticus) farming trial. Results showed that total ammonia nitrogen peaked in the New group, whereas nitrite nitrogen was highest in the Old group. The Mix group demonstrated a synergistic effect, combining the initial stability of old biofloc with the superior late-phase water quality control of new biofloc. Although the tilapia survival rate was highest in the New group, specific growth rate and final body weight were significantly higher in Mix group than Old and New groups (p < 0.05). No significant differences were observed in antioxidant and immune enzymes among groups except for lysozyme, where the Old group showed significantly higher levels than New and Mix groups (p < 0.05). No significant differences were observed in nutritional component of tilapia muscle among groups (p > 0.05). Gut microbiome analysis showed significantly higher microbial richness in Mix and New groups (p < 0.05). Correlation analysis revealed a significant negative correlation between biofloc volume and the survival rate of tilapia. These findings demonstrate that mixing old and new biofloc could enhance growth performance while abating drawbacks of old biofloc. This study validates a practical waste-valorization strategy to advance sustainable tilapia aquaculture by optimizing biofloc resource efficiency.

尽管具有可持续水产养殖的潜力，但生物絮团技术在有效管理旧生物絮团和建立稳定的系统启动方面面临着持续的挑战。在为期6周的罗非鱼（Oreochromis niloticus）养殖试验中，本研究系统地评估了旧生物絮团（old）与新生物絮团（new）和1:1混合物（Mix）的性能和重复使用的可行性。结果表明，总氨氮以新组最高，亚硝酸盐氮以老组最高。Mix组表现出协同效应，将旧生物絮团的初始稳定性与新生物絮团的后期优良水质控制相结合。新组罗非鱼成活率最高，但混合组特定生长率和末重显著高于新、老组（p < 0.05）。除溶菌酶外，各组抗氧化酶和免疫酶水平无显著差异（p < 0.05），其中老组显著高于新组和混合组。各组罗非鱼肌肉营养成分无显著差异（p > 0.05）。肠道微生物组分析显示，Mix组和New组微生物丰富度显著高于对照组（p < 0.05）。相关分析显示，生物絮团体积与罗非鱼成活率呈显著负相关。综上所述，新旧生物絮团混合可以提高生长性能，同时减少旧生物絮团的缺陷。本研究通过优化生物絮团资源效率，验证了一种切实可行的废物增值策略，以促进可持续罗非鱼养殖。

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引用次数: 0

Blue mussels (genus Mytilus) as a biofilter against sea lice around aquaculture farms 蓝贻贝（贻贝属）在水产养殖场周围作为防止海虱的生物过滤器

IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-01-22 DOI: 10.1016/j.aquaculture.2026.743694

Christian Stolz , Michael Chambers , Lars Christian Gansel , Stig Atle Tuene

The ectoparasitic copepods of the family Caligidae are well known for their impact on modern sea cage aquaculture of salmonids. A rather overlooked approach to sea lice management is to use the natural filter-feeding ability of bivalves. In this study, on the example of mussels in the genus Mytilus, we explore the feasibility and expected size of a bivalve biofilter against planktonic stages of sea lice. We measured the filtration of planktonic Lepeophtheirus salmonis larvae by blue mussels (M. edulis) in laboratory experiments and combined the measured filtration rates with filtration rates calculated from raw data from comparable studies. The combined results suggest that 50 mm mussels filter sea lice nauplii with a mean rate of 1.66 L

\cdot

h^-1 and copepodids with a mean rate of 0.46 L

\cdot

h^-1. The observed differences in filtration amongst larval stages indicate that a mussel biofilter will be more effective at preventing the release of sea lice larvae from a salmonid farm than at preventing the entry of the infective stage. Upscaling to a typical salmonid aquaculture setting, we estimate that several million blue mussels would be needed to filter 10% of all passing copepodids and 30% of all passing nauplii, corresponding to more than 10 000 m of mussel rope per open-net cage. In smaller settings, around 1 million mussels corresponding to more than 1 000 m of mussel rope would be needed. Our estimates may be used in future modelling and planning of combined salmonid-mussel farms.

蝶科的外寄生桡足类动物因其对现代海洋网箱养殖鲑鱼的影响而闻名。海虱管理的一个相当被忽视的方法是利用双壳类动物的天然滤食能力。在本研究中，我们以贻贝为例，探讨了双壳类生物过滤器对海虱浮游阶段的可行性和预期尺寸。我们在实验室实验中测量了蓝贻贝（M. edulis）对浮游Lepeophtheirus salmonis幼虫的过滤率，并将测量的过滤率与从可比研究的原始数据计算的过滤率相结合。综合结果表明，50 mm贻贝对海虱的平均过滤率为1.66 L⋅h-1，对桡足类的平均过滤率为0.46 L⋅h-1。观察到的不同幼虫阶段的过滤差异表明，贻贝生物过滤器在防止鲑鱼养殖场释放海虱幼虫方面比在防止感染阶段进入方面更有效。升级到典型的鲑鱼养殖环境，我们估计需要数百万蓝贻贝来过滤10%的通过的桡足类和30%的通过的nauplii，相当于每个开网箱需要超过10,000米的贻贝绳。在较小的环境中，大约需要100万个贻贝，相当于1000多米的贻贝绳。我们的估计可用于未来的建模和规划鲑鱼-贻贝联合养殖场。

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引用次数: 0

Colouration, growth performance and health status of ornamental koi carp (Cyprinus carpio var. koi) reared in variable stocking density under biofloc system 不同放养密度下观赏锦鲤（Cyprinus carpio var. koi）着色、生长性能及健康状况

IF 3.9 1区农林科学 Q1 FISHERIES

Aquaculture

Pub Date : 2026-01-22 DOI: 10.1016/j.aquaculture.2026.743666

Amandeep Kaur , Amit Mandal , Sasmita Barik , Gurpreet Kaur , Devendra Pathak

The eco-friendly biofloc technology enhances colouration, growth, and health status of ornamental fish by efficiently managing water quality. However, maintaining species-specific stocking density remains a major challenge to minimize stress and ensure fish well-being. This study optimized stocking density (SD) for ornamental koi carp (Cyprinus carpio var. koi) in biofloc systems by assessing colouration, performance, and health, using eighteen fiberglass-reinforced plastic (1000−L) tanks arranged in randomly designed six treatments with triplicates: two controls at 30 fish m⁻³ (SD30C1 without biofloc and SD30C2 with biofloc), and four other biofloc groups at 40, 50, 60, and 70 (SD40-SD70). A C:N ratio of 15:1 was maintained in biofloc treatments using jaggery, and fish were fed a 27% protein diet (1 mm pellet size) at 2.5% biomass for 120 days. Improved water and floc quality, overall fish performance, and health status were observed in biofloc treatments compared to the control group (SD30C1). Water quality parameters improved up to SD50 but deteriorated at higher stocking densities. Biofloc volume, microbial composition, and bacterial abundance improved up to SD50, dominated by Aeromonas hydrophila (biofloc formation) and also, Pseudomonas aeruginosa and Acinetobacter junii (pigmentation). Growth performance (weight, length, SGR, PER, FCR), carotenoid content, colour indices (RGB, L*a*b*), haematological and biochemical parameters, antioxidant responses, and metabolic enzymes were significantly improved up to SD50, with no difference between SD40 and SD60. Expression of colour related genes Mc1r and Tyr was downregulated in SD40–SD60, particularly in SD50. Histological assessment indicated better skeletal muscle integrity, gill structure, intestinal villi, and hepatic organization in SD50 fish. Economic performance also favored higher SD. Overall; the study indicated that the optimum stocking density for koi carp was 50 fish m⁻³, ensuring superior colouration, growth performance, and production, while a density range of 40–60 fish m⁻³ was found suitable under biofloc systems.

生态友好型生物絮团技术通过有效管理水质，提高观赏鱼的着色、生长和健康状况。然而，维持特定物种的放养密度仍然是减少压力和确保鱼类健康的主要挑战。本研究利用18个玻璃纤维增强塑料（1000 - L）水族箱，随机分为6个处理组，每组3个，分别为30鱼m - 3 （SD30C1不含生物絮团，SD30C2含生物絮团）和4个其他生物絮团组，分别为40、50、60和70 (SD40-SD70)，通过评估其颜色、性能和健康状况，优化观赏锦鲤（Cyprinus carpio var. koi）在生物絮团系统中的放养密度（SD）。在生物絮团处理中，投喂生物量为2.5%、蛋白质含量为27%（颗粒大小为1 mm）的饲料，碳氮比维持在15:1，饲喂120 d。与对照组（SD30C1）相比，生物絮团处理改善了水和絮团质量、鱼的整体性能和健康状况。在SD50之前，水质参数有所改善，但在较高的放养密度下，水质参数恶化。生物絮团的体积、微生物组成和细菌丰度提高到SD50，以嗜水气单胞菌（生物絮团形成）、铜绿假单胞菌和朱尼不动杆菌（色素沉着）为主。生长性能（体重、体长、SGR、PER、FCR）、类胡萝卜素含量、颜色指数（RGB、L*a*b*）、血液学和生化参数、抗氧化反应和代谢酶在SD50前均有显著提高，SD40与SD60之间无显著差异。颜色相关基因Mc1r和Tyr在SD40-SD60中表达下调，尤其是在SD50中。组织学评估显示SD50鱼的骨骼肌完整性、鳃结构、肠绒毛和肝脏组织较好。经济表现也有利于提高标准差。整体;研究表明，锦鲤的最佳放养密度为50鱼m−3，可保证较好的显色、生长性能和产量，而在生物群落系统下，密度为40-60鱼m−3较为适宜。

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