Aquaculture Research最新文献

The biofloc technology (BFT) in sea cucumber (Apostichopus japonicus) farming utilizes nutrient cycling, driven by heterotrophic microorganisms, to improve water quality and promote sustainable aquaculture. This study explored the potential of sodium bicarbonate and sodium acetate as novel carbon sources, which may offer advantages in maintaining water stability and enhancing microbial diversity compared to traditional carbon sources. Juvenile sea cucumbers were cultured in a 64-day trial and assigned to five treatment groups: S (sucrose), SSa (S + sodium acetate), SSb (S + sodium bicarbonate), Nc (no carbon source), and Cg (control group), each treatment group was repeated three times (n = 3). The inclusion of sodium bicarbonate and sodium acetate significantly improved water quality parameters. The group SSb exhibited a higher pH (8.28), and significantly lower ammonia nitrogen (0.501 mg L⁻¹), and nitrite levels (0.031 mg L⁻¹) compared to other groups. Additionally, the biofloc volume (BFV; 17 mL L⁻¹), total suspended solids (TSSs; 238 mg L⁻¹), and protein content (13.9%) in the group SSb were all within the tolerance range for sea cucumbers. Group SSb also showed the significantly highest weight gain rate (WGR; 78.5%) and specific growth rate (SGR; 0.91%), alongside increased enzyme activities, including superoxide dismutase (SOD; 179 U mL⁻¹) and peroxidase (POD; 1.59 U mL⁻¹), which were significantly higher than those in other groups. Furthermore, the group SSb demonstrated enhanced gut microbiota diversity, characterized by a higher abundance of beneficial Bacillus and lower levels of harmful Vibrio and Pseudomonas. The addition of SSb significantly improved water quality by maintaining optimal pH and reducing harmful nitrogen compounds, which in turn supported enhanced physiological growth and increased gut microbiota diversity, indicating its potential as a superior carbon source in biofloc systems.

The present study assessed the effect of common hop (Humulus lupulus L.) extract on common carp (Cyprinus carpio L.). Fish (initial weight of 32.22 ± 0.65 g) were divided into three groups and fed diets containing 0 (control), 0.75 g (H_0.75), and 1.5 g (H_1.5) of common hop extract per kg of isonitrogenous, isolipidic, and isoenergetic commercial diet for 8 weeks. No significant differences in growth performance across treatments were observed (p > 0.05). Protein content in whole-body proximate composition increased significantly in H_1.5 compared to the control (p < 0.05). The H_0.75 showed a significant increase in lipid peroxidation (LPO) and reduced glutathione (GSH) levels compared to the control (p  < 0.05). While H_1.5 had higher acetylcholinesterase (AChE) than group H_0.75 (p  < 0.05), no significant change was observed in AChE, catalase (CAT), and superoxide dismutase (SOD) activities in treated groups compared to the control (p  > 0.05). Blood biochemical indices, alanine aminotransferase (ALT), and alkaline phosphatase (ALP) were significantly lower in H_0.75 and H_1.5 than in the control (p < 0.05), while lactate dehydrogenase (LDH) increased significantly in H_1.5 compared to the control (p < 0.05). Cholesterol, triglyceride (TG), and the number of white blood cells (WBCs) showed no significant differences across treatments (p > 0.05). H_0.75 significantly increased the proportion of polyunsaturated fatty acids (PUFAs) like α-linolenic acid, docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA; p < 0.05), and both H_0.75 and H_1.5 raised considerably the value of oleic acid and eicosatrienoic acid compared with the control (p < 0.05); in contrast, eicosapentaenoic acid (EPA) was decreased significantly by H_1.5 compared to the control (p < 0.05). Supplementation of the common hop at 0.75 and 1.5 g kg⁻¹ positively affected farmed carp.

This article presents the recent advancements in recirculating aquaculture systems (RAS). The review explores new developments and potential future breakthroughs in RAS systems across leading countries. It highlights technical and technological advancement in plant management aimed at improving water quality, production efficiency, and animal welfare. A significant aspect of recent progress is the integration of artificial intelligence (AI), which is being used to optimize system performance, enhance monitoring, and support more precise and predictive management strategies. The review also addresses advancements in pathogen control and the prevention of disease outbreaks. Specific case studies of cutting-edge RAS systems from different parts of the world are discussed. The review also investigates how the improvements in RAS technology can help mitigate environmental impact. Finally, the paper focuses on advancements in the production of six fish species farmed in Europe, namely Atlantic salmon (Salmo salar), European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), yellowtail kingfish (Seriola lalandi), arctic charr (Salvelinus alpinus), and rainbow trout (Oncorhynchus mykiss). This review is part of the ERA-NET BlueBio cofound-funded project titled “Optimizing land-based fish production in next generation digital recirculating aquaculture systems,” which is focusing on the above-mentioned fish species.

This study examines the dietary application of probiotic Bacillus licheniformis and phytobiotic Cinnamomum verum concerning growth, immunity, gene expression, and disease resistance in Labeo rohita fish. A controlled experiment was conducted over 12 weeks involving 800 fingerlings, which were divided into seven groups: one control group and three groups each receiving varying doses of B. licheniformis (D1 = 10⁵, D2 = 10⁷, and D3 = 10⁹ CFU/g) and C. verum (D4 = 25, D5 = 50, and D6 = 75 mg/kg) individually, along with a group with no additions (control). Growth was measured in terms of weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER) alongside hematology and immunology. To evaluate resistance of the test organisms, pathogenic challenge with Aeromonas hydrophila was performed. The findings indicated that fish in the D3 group achieved the highest average final weight of 125.40 ± 0.1 g, a weight increment of 86.40 ± 0.53 g, and the most favorable FCR of 0.81 ± 0.01. The D6 group followed, in contrast to the control group, which had a body weight of 95.20 ± 0.2 g, a WG of 56.73 ± 0.05 g, and a FCR of 1.03 ± 0.06. The survival rates following the challenge were analyzed, revealing that group D3 exhibited the highest effectiveness (p < 0.001). The evaluation of immunological parameters in D3 indicated increased levels of total protein, immunoglobulin M (IgM), complement component 3 (C3), and lysozyme activity relative to D1 and D2. Analysis of gene expression revealed that interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α) were upregulated in the liver and head kidney tissues of fish in the D3 and D6 groups. Bacillus licheniformis, when administered at 10⁹ CFU/g, enhances growth, feed utilization efficiency, immunity, and disease resistance in L. rohita. Cinnamomum verum at a dosage of 75 mg/kg improved the immune response. This study supports the consumption of probiotics and phytobiotics as substitutes for antibiotics in aquaculture.

The demand for the purple sea urchin Paracentrotus lividus has led to the decline of its wild populations, increasing interest in cultivating this species for commercial purposes and ecological restoration purposes. Consequently, there is a need to expand knowledge about the optimal conditions for sea urchin aquaculture, particularly regarding food regimes. Here, we evaluate the effects of several vegetable diets on the survival and growth of early juveniles of P. lividus. Using an outdoor experimental assay, we fed early juveniles (5–6.5 mm) various diets: fresh algae (Ulva sp.), aquaculture pellets, and vegetables (carrot, spinach, and maize) presented as individual or mixed diets (equal mass proportions). All diets were provided ad libitum in equal mass proportions. After 120 days, the pellet-fed urchins showed good growth but a high mortality rate (>40%). The Ulva sp. diet, considered the control regime mimicking wild sea urchin diet, resulted in low mortality but poor growth performance (maximum of 10.92 ± 1.94 mm in diameter and 0.68 ± 0.26 g in weight). In contrast, plant-based diets, especially those containing maize, led to the highest growth and lowest mortality rates (<5%). Notably, the triple mixed diet (carrot–spinach–maize) resulted in a threefold size increase, as the P. lividus juveniles reached 15 mm in 4 months. This study demonstrates the effectiveness of inexpensive, ready-to-use vegetable-based diets in optimizing rearing protocols for early juveniles of P. lividus. It offers preliminary insights into dietary preferences to rapidly attain an adequate release size for purple urchin aimed at restocking wild populations and balancing aquaculture and ecological restoration needs.

American shad Alosa sapidissima is an important exotic farmed fish species in China. Recently, skin ulcers associated with significant morbidity and mortality have severely affected American shad culture in Spring. In this study, a bacterial strain C8 was isolated from diseased A. sapidissima and was identified as A. hydrophila based on traditional phenotypic typing and 16S rDNA sequence analyses. Drug susceptibility test revealed the isolate was sensitive to Quinolones and Amphenicols but resistance to Aminoglycosides, Sulfonamides, and Tetracyclines. Experimental infection with the isolate C8 showed the typical symptoms of acute sepsis caused by A. hydrophila infection and 100% mortality. Histopathological observation revealed that substantial inflammatory cell infiltration occurred in the skin lesion of diseased fish, and extensive degenerative and necrosis was observed in the parenchymal cells of the liver and kidney. This study is the first report on the histopathology of cultured A. sapidissima caused by A. hydrophila and provides useful information for health management.

Research on the synergistic effect of combined antibacterial agents has contributed significantly to addressing microbiological challenges, particularly bacterial resistance mutations. This study employed a combination of enrofloxacin (ENR) and sulfamonomethoxine (SMM) to conduct in vitro antimicrobial susceptibility tests and assess postantibiotic effects (PAEs) against three primary pathogens, Edwardsiella ictaluri, Aeromonas veronii, and Aeromonas hydrophila, known to afflict yellow catfish (Pelteobagrus fulvidraco). The results indicated that the minimum inhibitory concentrations (MICs) of ENR against E. ictaluri, A. veronii, and A. hydrophila were 0.25, 0.125, and 0.125 μg/mL, respectively. The MICs of SMM against these pathogens were 800, 700, and 700 μg/mL, respectively. Notably, the combination of ENR and SMM exhibited synergistic effects across all tested strains, increasing the PAE duration compared to ENR or SMM alone at the same concentration (p  < 0.05). In addition, the increase in PAE duration and enhanced antibacterial efficacy observed with the ENR–SMM combination demonstrated a positive correlation with the total drug concentration. These results suggest that the combination of ENR and SMM reduced the dosage of individual antibacterial agents while ensuring an efficient antibacterial effect. This approach holds promise for the treatment of bacterial infections in the yellow catfish.

Gibelion catla is an economically important fish species in Asian fish industry due to its suitability in polyculture system and high market value. Despite a valued market fish in Pakistan and serious threats of bacterial infections this fish is facing, studies concerning health status and disease resistance of G. catla are rare. Therefore, this study used label-free quantification liquid chromatography-mass spectrometry (LFQ—LC-MS/MS) and identified infection-biased expression of the protein in the skin mucus of G. catla after Aeromonas hydrophila infection. In total, 1545 proteins in the skin mucus of nontreated fish and 1400 proteins in the treated fish were identified, of which 1335 proteins overlapped between the two groups, 137 differentially expressed proteins (DEPs) were found, where 71 proteins were downregulated and 66 proteins were upregulated. Functionally, the 137 DEPs were immune-related, bactericidal, and cytoskeleton proteins. The most significant and upregulated protein in the skin mucus of treated fish were ribosomal proteins (40S ribosomal protein S19 (20-fold change (FC)), 60S ribosomal L7a (20-FC), 60S ribosomal L12 isoform X1 (21-FC), and 60S acidic ribosomal P0), beta-actin (24-FC), immunoglobulin mu heavy chain (20-FC), glucose-regulated protein 78 (GRP78; 20-FC), epithelial cell adhesion molecule-like protein (20-FC), putative complement c 3.3 (20-FC), 14 kDa apolipo (19-FC), hemoglobin subunit beta-like protein (19.3-FC), annexin A1-like protein (19-FC), proliferating cell nuclear antigen (18-FC), G-type lysozyme (18-FC), and keratins such as type I cytoskeletal 47 kDa-like isoform X1 (23-FC), and type II cytoskeletal 8 (23-FC). In short, our study highlighted the proteins in the skin mucus of fish involved against bacterial infection, which could be possible biomarkers for further functional-based studies. Particularly, the study elaborates the mucosal immune response of G. catla against A. hydrophila infection, which may help in the strategies of prevention and control of bacterial diseases in this fish.

Siniperca chuatsi is an economically important carnivorous fish. The efficient commercial culture of this fish is hindered by suboptimal nutrient utilization and the emergence of diseases, specifically viral diseases. Compound Chinese herbal medicine (CCHM) and probiotics can be used to enhance disease resistance and improve digestion. We have previously isolated Bacillus velezensis, a probiotic with a desirable effect on S. chuatsi. In this study, we aimed to evaluate the antiviral effect of a CCHM compound at the cellular level by conducting animal tests to investigate the synergistic effect of CCHM and B. velezensis GY65 in a simulated S. chuatsi culture. The animal experiments were divided into four groups: control group (G0); CCHM group (G1); B. velezensis GY65 group (G2); and Chinese herbal medicine compound probiotic group (CHCP) (G3). CCHM showed significant blocking and killing effects on the largemouth bass virus (LMBV) (p < 0.05), while the inhibiting effect was not significant. In animal tests, CCHM significantly improved S. chuatsi growth, while CHCP reduced S. chuatsi mortality. Regarding biochemical and nonspecific immune parameters, CHCP reduced serum lipid and hepatic malondialdehyde levels and increased serum lysozyme and hepatic catalase activities (p < 0.05). CCHM and B. velezensis GY65 increased the serum glutathione transaminase levels (p < 0.05). Digestive enzymes in the intestine of S. chuatsi improved in all groups, and the best result was observed in the CHCP group. Additionally, the intestinal development improved in all groups, but the best intestinal development was observed in the CCHM group. However, in the kidney, only TNF-α was significantly upregulated in the CHCP group (p < 0.05). In conclusion, CCHM exerted significant blocking and killing effects on LMBV. CHCP effectively protected the growth and immunity of S. chuatsi. Our findings provide preliminary data and lay the foundation for the practical application of herbal medicines and probiotics in aquaculture.

Previously, dietary humic substances (HSs) or protease complexes (PCs) in fingerling channel catfish Ictalurus punctatus (Rafinesque) have demonstrated potential for health enhancement. Two trials were conducted to elucidate an optimal HS or PC administration plan for growth and health promotion. The first feeding trial was conducted within a recirculating aquaculture system. Catfish fingerlings were fed a commercial control (28% protein) or supplemented diet (control + PC or HS). Diets were administered through four feeding regimens of either HS, or PC-supplemented diet. After 60 days, continuous feeding of diets with HS or PC contributed to improved feed efficiency and weight gain of the fish. Similarly, catfish growth was enhanced following the application of HS or PC for the final 4 weeks. Serum lysozyme activity was relatively improved in catfish when a PC or HS diets were offered for 60 days. Feeding either of the supplements for the final 4 weeks improved skin lysozyme activity compared to the control group. In the second trial, catfish were fed either the commercial control diet, PC-supplemented diet, or HS-supplemented diet in an outdoor production environment for 60 days. Both HS and PC catfish groups had higher survival rates than the control group. Furthermore, growth performance was superior in additive-fed groups. After HS or PC application, gut microbiota analysis from catfish fecal at two time points revealed significant variation in alpha diversity, community abundance, and beta diversity. However, the association of dietary HS or PC on improved survival, immunity, and gut microbiota modulations presents their importance as functional immunostimulants in catfish aquaculture.