农林科学最新文献

{"title":"Transcription of immune genes in ranched southern bluefin tuna show correlations to Cardicola spp. (Digenea: Aporocotylidae) infection","authors":"Maree Widdicombe ,&nbsp;Sarah Eastwood ,&nbsp;Bronwyn E. Campbell ,&nbsp;Cecilia Power ,&nbsp;Barbara F. Nowak ,&nbsp;Paul A. Ramsland ,&nbsp;Nathan J. Bott","doi":"10.1016/j.aquaculture.2025.742877","DOIUrl":"10.1016/j.aquaculture.2025.742877","url":null,"abstract":"<div><div><em>Cardicola forsteri</em> and <em>C. orientalis</em> (Digenea: Aporocotylidae) are significant pathogens affecting the Southern bluefin tuna (SBT), <em>Thunnus maccoyii</em>, aquaculture industry. The aims of this research were to identify a relationship between immune gene expression of SBT and <em>C. forsteri</em> and <em>C. orientalis</em> infection burdens; and to understand how immune gene expression changes over time during commercial ranching. SBT were collected during commercial operations in 2022 after 4, 8 and 10 weeks of ranching and the transcription of <em>interleukin 1 beta (il1b), interleukin 8 (il8), tumour necrosis factor 2 (tnf2), immunoglobulin m (igm), major histocompatibility complex 2 (mhc2)</em> and <em>t cell receptor beta (tcrb)</em> were measured from the anterior kidney and gills using reverse transcription quantitative polymerase chain reaction (RT-qPCR). <em>Cardicola forsteri</em> and <em>C. orientalis</em> infection was quantified as number of eggs/mm of SBT gill filament, number of adult flukes in SBT heart and <em>C. forsteri</em> and <em>C. orientalis</em> ITS-2 rDNA copy number/mg in SBT gills. Expression of <em>il8</em> and <em>igm</em> in anterior kidney was positively correlated to <em>C. forsteri</em> and <em>C. orientalis</em> eggs/mm of SBT gill filament and to the copy number of <em>C. forsteri</em> ITS-2 rDNA in SBT gills. Expression of <em>igm</em> and <em>mhc2</em> was higher in SBT positive for adult flukes and the expression of <em>igm, mhc2</em> and <em>tcrb</em> in the anterior kidney was positively correlated to the number of adult flukes in SBT heart. Expression of <em>tcrb</em> in gills was negatively correlated to the number of adult flukes in SBT heart and negatively correlated to the copy number of <em>C. orientalis</em> ITS-2 rDNA. Expression of the adaptive immune genes <em>igm</em>, <em>mhc2</em> and <em>tcrb</em> increased over the ranching duration in the kidney of SBT and the innate immune genes <em>il1b</em> and <em>il8</em> decreased over the ranching duration in SBT gills. Despite evidence of an immune response to <em>C. forsteri</em> and <em>C. orientalis,</em> SBT were not able to clear infections during the standard industry ranching timeline.</div></div>","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742877"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Achievement of prosperous nitrification cycle fosters diversity in freshwater microbiome within recirculating aquaculture systems after adjustment period","authors":"Jiho Yang ,&nbsp;Junhyuk Seo ,&nbsp;Jimin Choi ,&nbsp;Yehyeon Cha ,&nbsp;Yunhyeok Jang ,&nbsp;Ju-Ae Hwang ,&nbsp;Seung-Yoon Oh","doi":"10.1016/j.aquaculture.2025.742941","DOIUrl":"10.1016/j.aquaculture.2025.742941","url":null,"abstract":"<div><div>In recirculating aquaculture systems (RAS), a significant challenge involves managing the biological cycling of nitrogenous waste. As a result, there is worldwide focus on the diversity of biological groups involved in nitrogen cycling and their impacts. However, there is still a lack of information concerning the microbial diversity, particularly in relation to biological nitrogen cycling. We hypothesized that biological nitrification in RAS becomes fully established only after a distinct microbial adjustment period following microbial inoculant (MI) treatment, and that this phase features distinct shifts in microbiome composition and nitrogen compound dynamics. To test this, we monitored water chemistry and microbial community structure over an 8-week pre-treatment maturation phase in freshwater RAS for Japanese eel (<em>Anguilla japonica</em>) cultivation. Using 16S rRNA gene amplicon sequencing and qPCR targeting ammonia- and nitrite-oxidizing bacteria, we found that nitrifier abundance increased sharply from week 3 post-treatment. Random forest analysis and structural equation modeling revealed that nitrate levels—serving as a proxy for complete nitrification—had the strongest direct influence on microbiome diversity. Diversity indices and beta-dispersion analyses confirmed that microbial communities during the adjustment period (weeks 0–3) were significantly different from those in the stabilization phase (weeks 4–8). These findings demonstrate the existence of a critical, temporally defined adjustment phase in RAS maturation, during which microbiome structure and nitrification processes co-develop. Our study provides mechanistic insights into microbiome assembly in RAS and highlights the importance of temporal monitoring in optimizing MI-based water treatment strategies.</div></div>","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742941"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic resonance imaging for rapid, noninvasive and accurate assessment of ovarian maturation in live Channa argus (Cantor, 1842)","authors":"Wenqian Sun ,&nbsp;Weiyin Vivian Liu ,&nbsp;Xingyu Chen ,&nbsp;Guangcan Lin ,&nbsp;Hao Li ,&nbsp;Yanting Song ,&nbsp;Chengdong Peng ,&nbsp;Wen Xiong ,&nbsp;Yu Peng ,&nbsp;Shangong Wu ,&nbsp;Shouqi Xie ,&nbsp;Sovan Lek ,&nbsp;Mette Sørensen ,&nbsp;Haokun Liu ,&nbsp;Dong Liu ,&nbsp;Lei Pan","doi":"10.1016/j.aquaculture.2025.742872","DOIUrl":"10.1016/j.aquaculture.2025.742872","url":null,"abstract":"<div><div>Current methods for the determination of ovarian maturation in fish have shortcomings. They are often time-consuming, inaccurate, and fish are sacrificed during the procedure. A novel noninvasive and accurate method to assess ovarian maturation can be to use magnetic resonance imaging (MRI). Long scanning time is a limitation for use in fish. A clinical MRI with a new sequence employing a shorter scanning time may be more feasible for the assessment of ovarian maturation in female fish. The aim of this study was to investigate ovarian maturation in <em>Channa argus</em> by clinical MRI with the three-dimensional fast spin echo Cube-flex (3D-FSE-Cube-Flex) T₂WI sequence, compared with two traditional sequences. The results demonstrated that compared with two traditional sequences, the 3D-FSE-Cube-Flex T₂WI sequence greatly reduced scanning time (only requiring 140 s per fish) without reducing the scanning quality. A significant correlation (R² = 0.985, <em>p</em> &lt; 0.001, <em>N</em> = 112) was found between the percentage volume of the ovary measured by MRI and the gonadosomatic index (GSI). Besides, ovarian maturation MRI images at different development stages were captured. These findings suggest that clinical MRI with the 3D-FSE-Cube-Flex T₂WI sequence is a rapid, accurate, and noninvasive method for assessing ovarian maturation, with great potential applications in sustainable aquaculture.</div></div>","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742872"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isolation and application of Bdellovibrio and like organisms (BALOs) for controlling Aeromonas hydrophila in the American eel (Anguilla rostrata) rearing water","authors":"Yanbiao Guo ,&nbsp;Bin Jiang ,&nbsp;Huixiang Chen ,&nbsp;Haifu Zhang ,&nbsp;Jingyin Liu ,&nbsp;Jintao lǚ ,&nbsp;Lingxiao Li ,&nbsp;Wenxi Zhong ,&nbsp;Shichao Wen ,&nbsp;Chunlan Liang ,&nbsp;Yi Huang ,&nbsp;Zhiping Liang ,&nbsp;Junpeng Cai","doi":"10.1016/j.aquaculture.2025.742912","DOIUrl":"10.1016/j.aquaculture.2025.742912","url":null,"abstract":"&lt;div&gt;&lt;div&gt;&lt;em&gt;Bdellovibrio&lt;/em&gt; is a kind of fast-moving bacteria that mainly preys on Gram-negative bacteria. &lt;em&gt;Aeromonas hydrophila&lt;/em&gt; is one of the most common pathogenic bacteria for many animals. However, the potential application of freshwater-derived &lt;em&gt;Bdellovibrio&lt;/em&gt; in protecting eels from &lt;em&gt;A. hydrophila&lt;/em&gt; infection is still unclear. In this study, &lt;em&gt;Klebsiella&lt;/em&gt; was used as the host bacteria, and &lt;em&gt;Bdellovibrio&lt;/em&gt;-and-like organisms (BALOs) were isolated by double-layer plate technique. 32 strains of pathogenic bacteria from different sources including: one Gram-positive pathogenic stain of &lt;em&gt;Bacillus cereus&lt;/em&gt; and 31 Gram-negative pathogenic stains of &lt;em&gt;A. hydrophila, Escherichia coli&lt;/em&gt;, &lt;em&gt;Pantoea agglomerans&lt;/em&gt;, &lt;em&gt;Providencia rettgeri&lt;/em&gt;, &lt;em&gt;Pseudomonas aeruginosa&lt;/em&gt;, &lt;em&gt;Salmonella Choleraesuis&lt;/em&gt;, &lt;em&gt;Salmonella Typhimurium&lt;/em&gt;, &lt;em&gt;Serratia odorifera&lt;/em&gt;, &lt;em&gt;Shewanella Putrefaciens&lt;/em&gt;, &lt;em&gt;Vibrio parahaemolyticus&lt;/em&gt;, to name just a few. Moreover, 5 strains of potential probiotics including &lt;em&gt;Bacillus coagulans&lt;/em&gt;, &lt;em&gt;Lactobacillus plantarum&lt;/em&gt;, and &lt;em&gt;Lactobacillus salivarius&lt;/em&gt; were also used to select the &lt;em&gt;Bdellovibrio&lt;/em&gt; strain with a relatively wide lysis spectrum and no adverse effects on potential probiotics. Transmission electron microscopy and BALO-specific polymerase chain reaction [PCR] techniques were employed to identify BALOs strains. The application of BALOs strains in controlling &lt;em&gt;A. hydrophila&lt;/em&gt; infections of American eel (&lt;em&gt;Anguilla rostrata&lt;/em&gt;) was also conducted. Results showed that 8 strains of BALOs, viz. FSBD1, FSBD2, FSBD3, FSBD4, FSBD5, FSBD6, ZZBD1 and ZZBD2 were isolated. Lysis experiments on 32 potentially pathogens showed that FSBD1, FSBD2 FSBD3, FSBD4, FSBD5, FSBD6, ZZBD1 and ZZBD2 lysed 65.6%6 % (21/32), 65.6% (21/32), 65.6 % (21/32), 65.6 %6 % (21/32), 87.5 % (28/32), 75.0 % (24/32), 84.4 % (27/32) and 71.9 % (23/32) pathogens, respectively. Among of them, FSBD5 had the highest lysis rate of 87.5 % (28/32). It showed great lysis ability to 100.0 % (4/4) &lt;em&gt;Salmonella&lt;/em&gt; and 100.0 % (4/4) &lt;em&gt;Aeromonas&lt;/em&gt; tested. However, its lysis rate of potential 5 probiotics strains was 0 % (0/5). Surprisingly, ZZBD1 lysed one Gram-positive pathogenic stain of &lt;em&gt;B. cereus&lt;/em&gt;, with the Gram-positive lysis rate of 16.7 % (1/6). FSBD5 and ZZBD1 were identified as BALOs morphologically by transmission electron microscopy and partial &lt;em&gt;16S rDNA&lt;/em&gt; sequencing. Concerning the strain of FSBD5, compared with &lt;em&gt;A. hydrophila&lt;/em&gt; infection group (AHI), adding the cultured FSBD5 to the rearing water of American eel significantly reduced the number of &lt;em&gt;A. hydrophila&lt;/em&gt; in &lt;em&gt;Bdellovibrio&lt;/em&gt; treatment group (BDT, from 6.19 ± 0.01 log CFU/mL to 2.84 ± 0.08 log CFU/mL, &lt;em&gt;p&lt;/em&gt; &lt; 0.05), and also significantly improved the survival rate of American eel (at the end of 7 days experiment, the survival rate of AHI and BDT group was","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742912"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional characterization of CSAD and its genomic variations modulating taurine synthesis and heat adaptation between two congeneric oyster species","authors":"Meiqian Pang ,&nbsp;Haigang Qi ,&nbsp;Chaogang Wang ,&nbsp;Rihao Cong ,&nbsp;Mingyang Du ,&nbsp;Zhuxiang Jiang ,&nbsp;Min Wang ,&nbsp;Li Li ,&nbsp;Guofan Zhang","doi":"10.1016/j.aquaculture.2025.742933","DOIUrl":"10.1016/j.aquaculture.2025.742933","url":null,"abstract":"<div><div>Oysters are characterized by an extremely high taurine content, a feature that constitutes one of the key reasons for the nutritional and commercial value of these shellfish. Nevertheless, within these organisms, the functions of key metabolic genes and their regulatory mechanisms remain poorly understood. In the current study, we confirmed that cysteine sulfinic acid decarboxylase (CSAD) catalyzes taurine synthesis in two congeneric oyster species: the Pacific oyster <em>Crassostrea gigas</em> and the Portuguese oyster <em>Crassostrea angulata</em>. These oysters are notable for their high aquaculture yields and distinct thermal tolerance levels. <em>Csad</em> displayed distinct thermal response patterns in the two oyster species and significantly contributed to the enhancement of thermal tolerance. Three genomic variations in the <em>Csad</em> promoter region were identified. These variations enhanced the transcriptional activity by varying degrees under heat stress conditions, with the activity increasing from 2.52-fold to 3.19-fold, 2.81-fold and 4.30-fold respectively. Our findings establish Poly (ADP-ribose) polymerase 1 (PARP1) as a transcriptional coregulator mediating the species-divergent thermal response of <em>Csad</em>. This research fills a significant void in our understanding of the regulatory mechanisms of taurine metabolism in marine invertebrates and has the potential to lay a theoretical groundwork for the genetic improvement of oysters via molecular-based methodologies.</div></div>","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742933"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heart rate variability as a neurophysiological biomarker of stress and welfare in olive flounder (Paralichthys olivaceus) under varying stocking densities","authors":"Inyeong Kwon ,&nbsp;Ju-Ae Hwang","doi":"10.1016/j.aquaculture.2025.742931","DOIUrl":"10.1016/j.aquaculture.2025.742931","url":null,"abstract":"<div><div>This study sought to evaluate the physiological stress responses of olive flounder (<em>Paralichthys olivaceus</em>) to varying stocking densities by analyzing heart rate and heart rate variability (HRV). All experiments were conducted in flow-through tanks under both normal- and high-density conditions. Bio-loggers were implanted in the fish to continuously monitor their heart rates and HRV over a 25-day period. The collected data were processed using the Mercury software, using only high-quality heart rate data. To evaluate HRV, the coefficient of variation (CV) was calculated, offering a standardized measure of heart rate variability. The fish in the high-density environments exhibited significantly higher heart rates and lower HRVs than those in normal-density environments. Elevated plasma cortisol levels in the high-density group (<em>p</em> &lt; 0.05) further validated the stress responses indicated by heart rate and HRV. These findings suggest that high-density conditions induce significant stress in olive flounder, potentially reducing physiological adaptability and autonomic nervous system balance due to sympathetic dominance. This underscores the importance of density management in aquaculture to enhance fish welfare and highlights HRV analysis as a reliable, non-invasive tool for stress assessment.</div></div>","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742931"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population pharmacokinetic modelling of oxytetracycline in rainbow trout (Oncorhynchus mykiss): Effects of route of administration, temperature and ploidy","authors":"Alexis Viel ,&nbsp;Florine Bachelet ,&nbsp;Annaëlle Chailleux ,&nbsp;Céline David ,&nbsp;Lionel Pineau ,&nbsp;Ségolène Calvez ,&nbsp;Antoine Rostang","doi":"10.1016/j.aquaculture.2025.742917","DOIUrl":"10.1016/j.aquaculture.2025.742917","url":null,"abstract":"<div><div>The aim of this study was to perform a pharmacokinetic (PK) study of oxytetracycline (OTC) in rainbow trout using different routes of administration and different doses, and to investigate the influence of the bodyweight, the ploidy status (diploid <em>versus</em> triploid) and the water temperature (10 °C <em>versus</em> 16 °C).</div><div>A cross-over design was used with 361 trout (median bodyweight: 389 g), each fish receiving OTC intravenously (8–30 mg/kg) and orally (50–150 mg/kg), by gavage or by spontaneous intake <em>via</em> a coating of OTC on the feed to mimic farming practice. Each fish, for each modality, was sampled 3–4 times over a period of 11 days, to establish its individual PK profile. Coated feed and plasma samples were assayed using a sensitive HPLC-MS/MS method. A population PK modelling approach was used to analyse plasma data and estimate key PK parameters and their variability.</div><div>A bi-compartmental PK model best described the plasma data. The absolute oral bioavailability appeared to be very low (around 3 %) and the elimination of OTC was slow and strongly influenced by temperature (elimination half-life approximately 79 h at 16 °C <em>versus</em> 113 h at 10 °C). A comparison of spontaneous intake and gavage showed a significant loss of antibiotic due to leaching (about 30 %). Bodyweight and water temperature were the most influential covariates affecting the PK of OTC compared to the effect of ploidy. Pharmacodynamic (PD) studies with OTC against the major trout pathogens are now required to allow a more robust assessment of the expected efficacy thanks to a PK/PD approach.</div></div>","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742917"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of enrofloxacin exposure on energy metabolism and the ARGs transmission in grass carp: Potential contribution of microbiota-gut-liver axis","authors":"Ping Li ,&nbsp;Bianhao Zeng ,&nbsp;Xuqian Cao ,&nbsp;Bin Liu ,&nbsp;Ling Liu ,&nbsp;Yi Chai ,&nbsp;Zhi-Hua Li","doi":"10.1016/j.aquaculture.2025.742889","DOIUrl":"10.1016/j.aquaculture.2025.742889","url":null,"abstract":"<div><div>Enrofloxacin is one of the antibiotics commonly used in aquaculture. Nevertheless, the precise mechanisms underlying its toxicological effects on the energy metabolism of organisms remain elusive. Therefore, we conducted experiments employing grass carp (<em>Ctenopharyngodon idellus</em>) as our model organism, subjecting them to varying concentrations of ENR for a duration of 21 days followed by a 14-day purification period. Our results revealed that ENR exposure led to disturbances in the intestinal flora of grass carp, inducing hypoglycemia by impeding gluconeogenesis while promoting glycolysis and aerobic metabolism. Additionally, it curtailed lipid utilization and catabolism in grass carp, resulting in hepatic function impairment and metabolic disorders. The effects were partially alleviated after a 14-day purification period, but the damage to the grass carp continued. Furthermore, our investigation unveiled a significant association between the top 20 abundant genera and biomarkers of energy metabolism, providing further insights into the intricate interplay of the microbial-gut-liver axis. Concurrently, we detected 6 common quinolone resistance genes in the experimental group, indicating a potential risk of antimicrobial resistance genes (ARGs) transmission, which could lead to environmental pollution and pose threats to human health.</div></div>","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742889"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of freshwater rearing on saltwater performance: A genotype-environment interaction study in Atlantic Salmon (Salmo salar)","authors":"Mette J. Tollervey ,&nbsp;Saif Agha ,&nbsp;Michaël Bekaert ,&nbsp;Almas A. Gheyas ,&nbsp;Ross D. Houston ,&nbsp;Andrea Doeschl-Wilson ,&nbsp;Ashie Norris ,&nbsp;Herve Migaud ,&nbsp;Alejandro P. Gutierrez ,&nbsp;Monica B. Betancor","doi":"10.1016/j.aquaculture.2025.742892","DOIUrl":"10.1016/j.aquaculture.2025.742892","url":null,"abstract":"<div><div>Atlantic salmon, <em>Salmo salar,</em> have traditionally been reared in net-pens in freshwater (FW) lochs up to smoltification, with subsequent transfer to saltwater (SW) cages for grow-out. Recently, interest in recirculating aquaculture systems (RAS) has grown due to environmental and husbandry benefits. To investigate the impact of RAS on their production cycle, we conducted an experiment under commercial conditions, raising a group of salmon in either a FW-RAS or -loch system. The study evaluated the effects of FW-rearing on SW performance by investigating phenotypic performance, genetic architecture, and genotype-environment interactions (GxE), which describe how the effects of different genotypes on traits change with environmental variation, potentially impacting performance across systems. We co-reared salmon for approximately nine-months before splitting them: half remained in FW-RAS and half transferred to FW-loch, where they were separated for about eight weeks. Both groups were then transferred to a SW cage-site. We sampled fish at the end of FW-rearing as smolts and three-months post-SW transfer as post-smolts, taking fin clips for genotyping. Results indicate that RAS-reared smolts were smaller in FW but demonstrated enhanced growth and lower trait variance post-transfer. Sexually dimorphic growth was observed in the loch population. Heritability of morphological traits increased post-SW transfer in the loch population but decreased in RAS. GxE for SW morphological traits were minimal, though significant genotype re-ranking was observed for SW growth. Genetic correlations between FW and SW morphological traits were high, except for whole-body weight in the loch population. These findings indicate that RAS-origin post-smolts, despite smaller FW size, showed faster growth and reduced phenotypic variance in SW compared to loch-origin fish. Differences in heritability estimates and genotype re-ranking for SW growth suggest that breeding programs may need to refine selection strategies for varied rearing environments.</div></div>","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742892"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and characterization of the PAAR-1 gene in Pseudomonas plecoglossicida: Insights into bacterial phenotypes and host immune responses in Large Yellow Croaker (Larimichthys crocea)","authors":"Baoyu Zhang ,&nbsp;Youshen Li ,&nbsp;Jianxin Li ,&nbsp;Yu Zhai ,&nbsp;Ziyu Meng ,&nbsp;Xiyue Huang ,&nbsp;Yuanyuan Zhou ,&nbsp;Jingqun Ao ,&nbsp;Ruoyu Liu ,&nbsp;Xinhua Chen","doi":"10.1016/j.aquaculture.2025.742925","DOIUrl":"10.1016/j.aquaculture.2025.742925","url":null,"abstract":"<div><div><em>Pseudomonas plecoglossicida</em> is a pathogen bacterium responsible for visceral white spot disease (VWND) in Large Yellow Croakers (<em>Larimichthys crocea</em>), causing significant economic losses in commercial fish farms. The proline-alanine-alanine-arginine repeats protein (PAAR) is a core component of the spike structure in the type VI secretion system (T6SS), which injects toxic effectors into host and contributes to bacterial virulence. However, the role of the <em>PAAR</em> gene in <em>P. plecoglossicida</em> and its impact on bacterial infection and host immune responses remain unexplored. In this study, <em>PAAR-1</em> was identified for the first time in <em>P. plecoglossicida</em> as an effector gene within the T6SS-1 gene cluster, which is regulated and secreted by T6SS-1. The <em>P. plecoglossicida</em> mutant strain (Δ<em>PAAR-1</em>) and its complementary strain (C-Δ<em>PAAR-1</em>) were constructed for subsequent investigation. Compared to the wild-type strain, Δ<em>PAAR-1</em> exhibited reduced biofilm formation, adhesion, total antioxidant capacity, and secretion of T6SS core protein Hcp-1. In vitro, Δ<em>PAAR-1</em> showed decreased survival rates in Large Yellow Croaker macrophage cell line (LYC-FM) due to impaired oxidative stress tolerance. In vivo, infection with Δ<em>PAAR-1</em> led to a significant reduction in mortality, bacterial colonization, and the formation of spleen nodules in Large Yellow Croakers. Comparative transcriptome analysis revealed that <em>PAAR-1</em> predominantly influences the host Toll-like receptor (TLR) signaling pathway and apoptosis by upregulating the expression of plasma membrane-associated TLRs, including <em>TLR1</em>, <em>TLR2</em>, and <em>TLR5</em>, while downregulating the expression of endosomal TLRs like <em>TLR3</em>, <em>TLR7</em>, <em>TLR8</em>, and <em>TLR9</em>, along with its downstream molecules such as <em>MyD88</em> and <em>TRAF3.</em> Additionally, knockout <em>PAAR-1</em> downregulates apoptosis-related genes including <em>AP-1, NF-κB, FAS-L TNFα, Caspase8,</em> and <em>FAS-L</em>. Real-time quantitative polymerase chain reaction (RT-qPCR) further confirmed these findings. Furthermore, the proportion of apoptotic cells was significantly lower in the Δ<em>PAAR-1</em> infected LYC-PKM cells. These results indicate that <em>PAAR-1</em> is involved in regulating TLR signaling pathway and apoptosis in Large Yellow Croaker. This study provides the first identification of the core T6SS-1 gene <em>PAAR-1</em> in <em>P. plecoglossicida</em>, offering valuable insights into its pathogenic mechanisms and presenting a potential target for attenuated vaccine development.</div></div>","PeriodicalId":8375,"journal":{"name":"Aquaculture","volume":"610 ","pages":"Article 742925"},"PeriodicalIF":3.9,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144557228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}