Journal of aquatic animal health最新文献

{"title":"Histopathological effects of heavy metal on bivalves: Review and perspectives.","authors":"Jenny Carolina Rodríguez-Villalobos, Marcial Arellano-Martínez, Bertha Patricia Ceballos-Vázquez","doi":"10.1093/jahafs/vsaf012","DOIUrl":"10.1093/jahafs/vsaf012","url":null,"abstract":"<p><strong>Objective: </strong>We sought to establish a current understanding of the histopathology of bivalves following exposure to heavy metal and to standardize the related terminology and microscopic diagnostic techniques, highlight limitations that hinder understanding, and discuss future research perspectives.</p><p><strong>Methods: </strong>We conducted a literature review, looking for studies that implemented histopathological analyses to describe the damage that is caused by heavy metal bioaccumulation. For further description, we categorized lesions as regressive, defensive, or progressive.</p><p><strong>Results: </strong>We analyzed 49 articles that employed histopathological techniques to describe the morphological changes that are associated with heavy metal bioaccumulation in bivalves. Since the 1980s, a growing interest in understanding how heavy metals affect bivalves has been evident, given the increasing number of published articles. Most studies were descriptive, although some contained experimental methods. The descriptive studies described damage to the digestive gland, gonads, gills, and kidneys. Defensive lesions were the most common response in the literature, with inflammation events reported in most cases. Regressive and progressive lesions were also documented, with necrosis (regressive change) and fibrosis (progressive change) being the most commonly reported, although not always correctly identified using microscopy.</p><p><strong>Conclusions: </strong>Histopathological studies on the effects of heavy metals on bivalve health are abundant, and the resulting morphologic lesions have been described extensively. However, most studies on heavy metal accumulation in bivalves have not followed a microscopic approach, focusing instead on using bivalves solely as sentinel or bioindicator species. A histopathologic evaluation is a common and important facet of pathologic analyses; however, we identified inconsistencies among diagnoses and misleading use of pathological terms. Therefore, we highlight the need to establish a systematic and standardized characterization of lesions at the microscopical level and their subsequent categorization to reduce the ambiguity of pathological descriptions. Implementing other methodological approaches in combination with histopathological analysis will improve our understanding of how heavy metals affect the health of bivalves.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"155-169"},"PeriodicalIF":1.7,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Imaging-guided clinical approach to fishing line ingestion in a juvenile green sea turtle Chelonia mydas from southern Brazil.","authors":"Yohany Arnold Alfonso Pérez, Gustavo Martinez-Souza, Thayana Gião, Samara Rosolem Lima, Michel Abdalla Helayel, Eduarda Alexia Nunes Louzada Dias Cavalcanti, Raqueli Teresinha França, Eliane Teixeira Mársico, Kássia Valéria Gomes Coelho da Silva, Nayro Xavier de Alencar","doi":"10.1093/jahafs/vsaf015","DOIUrl":"10.1093/jahafs/vsaf015","url":null,"abstract":"<p><strong>Objective: </strong>This study presents a juvenile green sea turtle Chelonia mydas case of fishing line ingestion during artisanal fishing monitoring, highlighting the importance of imaging and complementary diagnostics in detecting clinical alterations and managing marine debris-related injuries.</p><p><strong>Methods: </strong>During artisanal fishing monitoring in Rio Grande do Sul, Brazil, a juvenile green sea turtle with a protruding fishing line was captured. Clinical evaluation included physical examination, ultrasonography, radiography, and hematological-biochemical analyses (e.g., red blood cell count, hemoglobin, white blood cell count, urea).</p><p><strong>Results: </strong>Radiography and ultrasonography revealed a fishing line extending consecutively through the oral cavity, esophagus, and stomach without associated hooks, enabling manual line removal. Hematological findings indicated systemic responses to gastrointestinal trauma-regenerative macrocytic anemia (red blood cell count = 0.18 × 10⁶/µL; hemoglobin = 8.3 g/dL; hematocrit = 25%; mean corpuscular volume = 1,388 fL), leukocytosis (white blood cell count = 10,600 cells/µL), and elevated urea (232.59 mg/dL), suggesting dehydration and catabolic stress. Coelomic fluid accumulation indicated localized inflammation, though intestinal motility remained intact. Successful manual extraction avoided surgical intervention.</p><p><strong>Conclusions: </strong>This case underscores the role of diagnostic tools (imaging, hematology) in assessing debris-related health impacts in aquatic species. The findings align with broader evidence of fishing gear as a pervasive stressor in marine ecosystems, contributing to anemia, metabolic dysregulation, and inflammatory sequelae. This work emphasizes the need to integrate clinical diagnostics into fisheries management and expand health-monitoring protocols to address anthropogenic threats across aquatic taxa.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"199-205"},"PeriodicalIF":1.7,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145587669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of static-bath and flowing-water Flavobacterium columnare challenge methods with juvenile Chinook Salmon.","authors":"J Scott Foott","doi":"10.1093/jahafs/vsaf003","DOIUrl":"10.1093/jahafs/vsaf003","url":null,"abstract":"<p><strong>Objective: </strong>Flavobacterium columnare is a common pathogen of Chinook Salmon Oncorhynchus tshawytscha in the Klamath River. Elevated water temperatures invoke congregation behavior within thermal refugia and are associated with columnaris disease. A flowing-water F. columnare challenge system was compared with the standard static-bath challenge as an initial step in simulating a riverine exposure.</p><p><strong>Methods: </strong>Juvenile Chinook Salmon were exposed to 103 CFU/mL F. columnare for 20 h either in an aerated static bath or within a recirculation swim chamber set at one body length per second. Fish were held at a constant 20°C or exposed to short-term temperature fluctuations to a maximum of 24°C prior to the challenge. Mucus and gill samples were collected at the end of the 20-h challenge and from fish held up to 96 h postchallenge. Samples were assayed for detection of F. columnare by quantitative PCR and conventional plate culture method.</p><p><strong>Results: </strong>In static-bath challenge groups, F. columnare was detected in asymptomatic (38%) and moribund Chinook Salmon (29%). In contrast, F. columnare was detected in only one asymptomatic (4%) and one moribund (4%) Chinook Salmon in the flowing-water challenge groups. Prechallenge temperature conditions had no effect on infection. Other yellow-pigmented bacteria were isolated from the Chinook Salmon (particularly static-bath challenge) but were not associated with morbidity or amplified in the F. columnare quantitative PCR.</p><p><strong>Conclusions: </strong>Low transmission of F. columnare occurred among juvenile Chinook Salmon under flowing-water conditions simulating a thermal refugia during early summer (20°C, flow of one body length per second, 20-h exposure to 103 CFU/mL). The flowing-water system is sufficient to examine the environmental factors (velocity, temperature, host density, duration, and bacterial concentration of exposure) of riverine exposures on F. columnare transmission to juvenile Chinook Salmon.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"147-153"},"PeriodicalIF":1.7,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144528142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution of viral hemorrhagic septicemia virus in the nearshore fish community of the St. Lawrence River.","authors":"Anna L Haws, Rodman G Getchell, John M Farrell","doi":"10.1093/jahafs/vsaf011","DOIUrl":"10.1093/jahafs/vsaf011","url":null,"abstract":"<p><strong>Objective: </strong>We investigated viral hemorrhagic septicemia virus dynamics in wild fish populations of the St. Lawrence River to compare host competency among five abundant native species and the invasive Round Goby Neogobius melanostomus following two decades of host-pathogen coevolution. To examine species' responses to the virus and identify principal hosts as viral reservoir species, we used viral surveillance among Round Gobies, Yellow Perch Perca flavescens, Rock Bass Ambloplites rupestris, Pumpkinseed Lepomis gibbosus, Bluegill L. macrochirus, and Brown Bullhead Ameiurus nebulosus collected from the nearshore fish community in the upper St. Lawrence River during spring 2020-2021.</p><p><strong>Methods: </strong>Reverse-transcription quantitative PCR was used to detect and quantify viral nucleoprotein gene genetic material in pooled organ (i.e., liver, kidney, and spleen) and brain tissues of wild fish belonging to several susceptible host species.</p><p><strong>Results: </strong>Reverse-transcription quantitative PCR detected viral hemorrhagic septicemia virus genetic material in each species during both sampling years. There was significant variation between species in both infection prevalence and median viral titer. Invasive Round Gobies exhibited significantly higher prevalence and titers compared to any of the native species. However, some native fishes (e.g., Yellow Perch and sunfishes Lepomis spp.) presented higher infection prevalence and viral concentrations compared to the others (e.g., Rock Bass and Brown Bullhead).</p><p><strong>Conclusions: </strong>Multiple species remain susceptible to viral hemorrhagic septicemia virus under enzootic conditions; however, viral infections are distributed unevenly among host species. Invasive Round Gobies have amplified reservoir competence compared to native fish species.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"136-146"},"PeriodicalIF":1.7,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144992701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection and pathological effects of intestinal parasites in Spotted Scat Scatophagus argus: Filisoma spp. and Cryptosporidium spp. as infective agents and their roles in fish inflammatory response.","authors":"Watcharapol Suyapoh, Boonruen Thaweechart, Punnita Wae-Asae, Narissara Keawchana, Peerapon Sornying, Sareepah Manmoo, Pirayu Rakwong, Sasibha Jantrakajorn","doi":"10.1093/jahafs/vsaf009","DOIUrl":"10.1093/jahafs/vsaf009","url":null,"abstract":"<p><strong>Objective: </strong>The Spotted Scat Scatophagus argus, particularly in aquaculture, is commonly affected by intestinal parasitic infections that impact its health and growth. Filisoma spp., an acanthocephalan parasite, and Cryptosporidium spp. cause intestinal inflammation in various marine fish; however, infections with Cryptosporidium spp. or co-infection with these parasites have not been identified in Spotted Scat.</p><p><strong>Methods: </strong>Host-parasite interactions in fish, including the inflammatory responses of the intestine, were investigated in 32 cultured Spotted Scat from Songkhla, Thailand. The study used parasitological examination, including polymerase chain reaction and nucleotide sequencing of the ITS1 and ITS2 regions of the ribosomal RNA gene for acanthocephalans and the 18S ribosomal RNA gene for Cryptosporidium. Additionally, histopathology and immunohistochemistry for interleukin-4 expression were performed.</p><p><strong>Results: </strong>Most of the infected fish showed no significant clinical signs, with postmortem findings of hemorrhagic, congested, and edematous intestines. Parasitological analysis revealed that 84.37% of the fish were infected, with 9.37% having a single helminth infection, 40.62% being infected with coccidia, 34.37% having mixed infections with both parasites, and 15.62% of the fish being free from intestinal parasites. Polymerase chain reaction and nucleotide sequencing indicated that F. argusum and C. bollandi were the parasites involved. Histopathology showed increased inflammatory cell infiltrations, particularly eosinophilic granule cells and mononuclear cells, as well as higher levels of histopathological changes (vascular congestion, tissue necrosis, and epithelial desquamation) in the single F. argusum infection and co-infection with F. argusum and C. bollandi compared with C. bollandi infection alone. Similarly, significantly elevated interleukin-4 expression in the intestines, indicating a strong proinflammatory immune response, was observed in these groups.</p><p><strong>Conclusions: </strong>This study highlights the detrimental effects of F. argusum, regardless of whether it is a single or concomitant infection, which may impact the health of fish.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"122-135"},"PeriodicalIF":1.7,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144835210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced detection of Argulus and epizootic ulcerative syndrome in fish aquaculture through an improved deep learning model.","authors":"Mahdi Hamzaoui, Mohamed Ould-Elhassen Aoueileyine, Seifeddine Bouallegue, Ridha Bouallegue","doi":"10.1093/jahafs/vsaf001","DOIUrl":"10.1093/jahafs/vsaf001","url":null,"abstract":"<p><strong>Objective: </strong>Fish disease in aquaculture is a major risk to food safety. The identification of infected fish and disease categories present in fish farms remains difficult to determine at an early stage. Detecting infected fish in time is an essential step in preventing the spread of disease. The aim of this work was to detect fish infected with epizootic ulcerative syndrome and fish lice Argulus spp.</p><p><strong>Methods: </strong>An improved YOLO (You Only Look Once) version 5 (YOLOV5) model was developed. In the context of transfer learning, our improved model used a pretrained model on binary images. The improved model was deployed and integrated into a Raspberry Pi board.</p><p><strong>Results: </strong>The experimental results showed that it is more effective than a simple YOLOV5 model.</p><p><strong>Conclusions: </strong>Using the evaluation metrics of precision, recall, mAP50 (mean average precision at an intersection over union threshold of 0.50), and mAP50-95 (average of the mAP values calculated for intersection over union thresholds ranging from 0.50 to 0.95 in steps of 0.05), our new model achieved accuracy rates of 0.944, 0.969, 0.989, and 0.954, respectively.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"97-109"},"PeriodicalIF":1.7,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144637136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Florfenicol- and erythromycin-medicated feeds are similarly efficacious in reducing mortality from Lactococcus petauri infections in Rainbow Trout.","authors":"Taylor I Heckman, Ruth Milston-Clements, Zeinab Yazdi, Alvin C Camus, Kelsey M Anenson, Hugh Mitchell, Mark A Adkison, Esteban Soto","doi":"10.1093/jahafs/vsaf008","DOIUrl":"10.1093/jahafs/vsaf008","url":null,"abstract":"<p><strong>Objective: </strong>Piscine lactococcosis associated with Lactococcus petauri is a serious emerging threat to fish populations in the Americas. This bacterial disease commonly presents as a hemorrhagic septicemia, resulting in high mortality rates and substantial financial losses. There are no commercial vaccines in the United States, and treatment options are limited and understudied. Florfenicol (Aquaflor) is a broad-spectrum antibiotic approved for finfish aquaculture, and erythromycin (Aquamycin 100) is an investigational new animal drug. This study aimed to compare the effectiveness of florfenicol- and erythromycin-medicated feed against lactococcosis through cohabitation challenges in Rainbow Trout Oncorhynchus mykiss.</p><p><strong>Methods: </strong>Shedder fish were intracoelomically injected with L. petauri (∼1.5 × 104 CFU) and introduced to naïve populations at 13°C or 18°C. Treatments were initiated immediately after observation of mortality, with fish receiving florfenicol at 15 mg/kg for 10 d, erythromycin at 100 mg/kg for 21 d, or the control diet.</p><p><strong>Results: </strong>At 18°C, cohabitant survival was significantly higher in florfenicol-treated (100%) and erythromycin-treated (93%) tanks compared to untreated positive controls (60%). There were no mortalities at 13°C or in the negative control tanks. In sampled survivors, L. petauri was detected by quantitative PCR in 29% of positive control fish, 14% of erythromycin-treated fish, and 14% of florfenicol-treated fish at 18°C compared to 21, 7, and 0%, respectively, at 13°C. Culturable bacteria were only recovered from 14% of positive control fish at both temperatures.</p><p><strong>Conclusions: </strong>These results indicate that early intervention with florfenicol or erythromycin can limit the spread of L. petauri and that lower water temperatures reduce disease onset, improving options for managing lactococcosis in aquaculture.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"110-121"},"PeriodicalIF":1.7,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144642640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Psychoactive drug propranolol modulates behavioral, acetylcholinesterase, and oxidative stress parameters in freshwater African Sharptooth Catfish Clarias gariepinus.","authors":"Temitope Dadewura Melefa, Felix Atawal Andong, Funmilayo Faith Hinmikaiye, Edwin Ejike Ozota, Mary-Claret Nwoko, Venatius Chiamaka Steve Ubah, Gladys Ndidiamaka Ugwu, Christopher Didigwu Nwani","doi":"10.1093/jahafs/vsaf004","DOIUrl":"10.1093/jahafs/vsaf004","url":null,"abstract":"<p><strong>Objective: </strong>Propranolol is a beta-blocker psychoactive drug used for the management of high blood pressure, tremors, atrial fibrillation, and migraine headaches. This study investigated the effect of propranolol on behavior, acetylcholinesterase, lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in the brain of African Sharptooth Catfish Clarias gariepinus juveniles.</p><p><strong>Methods: </strong>A total of 180 African Sharptooth Catfish were exposed to 7.00-, 9.00-, 11.00-, 13.00-, and 15.00-mg/L acute propranolol concentrations and a control (0.00 mg/L) for 24, 48, 72, and 96 h, and the 96-h LC50 value was 9.48 mg/L. For sublethal study, 120 juvenile African Sharptooth Catfish were divided into four groups of 30 fish each and exposed to 1.90-, 0.95-, and 0.47-mg/L propranolol concentrations and a control for 21 d and allowed to recover for 7 d. All the treatment groups and control were set in triplicates, with 10 fish in each. The behavioral changes due to propranolol exposure were monitored by direct observation and scoring during the exposure and withdrawal period. The brains of fish were sampled every week for 4 weeks in order to evaluate the effects of propranolol on acetylcholinesterase, lipid peroxidation, and oxidative stress parameters.</p><p><strong>Results: </strong>Behavioral changes were evidenced by alterations in swimming rates, air gulping activities, and opercula beats in the propranolol-exposed fish during the acute exposure. Sublethal exposure resulted in a significant decrease in superoxide dismutase and catalase but increase in glutathione peroxidase and reductase values. Significant increase in lipid peroxidation and acetylcholinesterase enzyme levels were observed as exposure duration increased from day 7 compared with the control. The effects of propranolol on the observed parameters appeared to wane after fish withdrawal from the drug for 7 d.</p><p><strong>Conclusions: </strong>The drug propranolol, as demonstrated by these alterations, may negatively impact nontarget aquatic species and may have ecological consequences.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"66-74"},"PeriodicalIF":1.7,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143993179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Edwardsiella ictaluri type III and type VI secretion system mutant strains as candidates for live attenuated vaccines.","authors":"Matthew L Rogge, Ahmad A Elkamel, Ronald L Thune","doi":"10.1093/jahafs/vsaf005","DOIUrl":"10.1093/jahafs/vsaf005","url":null,"abstract":"<p><strong>Objective: </strong>Edwardsiella ictaluri, the causative agent of enteric septicemia of catfish, causes substantial economic losses to Channel Catfish Ictalurus punctatus producers in the United States. This study evaluates three E. ictaluri strains, each carrying a markerless deletion mutation in a type III or type VI secretion system gene, as candidates for a live attenuated vaccine against enteric septicemia of catfish in Channel Catfish. Replication in Channel Catfish cells, in vivo invasion and persistence, virulence, and the ability to provide single-dose protection against a wild-type E. ictaluri strain were evaluated for each mutant.</p><p><strong>Methods: </strong>In this study, three isogenic mutants were constructed that introduced deletions in esrC, eseG, and evpC. EsrC is a T3SS-encoded protein that regulates expression of multiple virulence genes, including the T3SS effector EseG and the T6SS structural protein EvpC. Each mutant strain was evaluated for its ability to replicate in Channel Catfish ovary cells and head-kidney-derived macrophage cells. Channel Catfish were also challenged with the mutant strains to evaluate if mutation affected invasion, colonization, or persistence within the head kidney, attenuated mortalities in Channel Catfish, or induced protection against disease following subsequent wild-type E. ictaluri exposure.</p><p><strong>Results: </strong>Each mutant maintained the ability to replicate within head-kidney-derived macrophage cells and Channel Catfish ovary cells, as well as invade and colonize the head kidney. Although able to replicate intracellularly and successfully colonize catfish tissue, all three mutants were significantly attenuated in their ability to persist in tissues and cause mortality. A single immersion in mutant strains 28 d prior to exposure to wild-type E. ictaluri resulted in significantly lower mortality than fish immersed in sterile broth, with relative percent survival ranging from 95% to 100%.</p><p><strong>Conclusions: </strong>The findings demonstrate the potential for the development of live attenuated E. ictaluri vaccine strains through the targeted mutation of one or more E. ictaluri T3SS and T6SS genes.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"75-84"},"PeriodicalIF":1.7,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144011542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low thiamine concentrations are associated with altered cardiac morphology across reproductive life histories of spawning Chinook Salmon.","authors":"K A Adeli, T E Pitcher, J M Ludwig, J Rinchard, B D Neff","doi":"10.1093/jahafs/vsaf007","DOIUrl":"10.1093/jahafs/vsaf007","url":null,"abstract":"<p><strong>Objective: </strong>Thiamine deficiency is a widespread issue in salmonine species and has been reported to induce changes in cardiac morphology and cardiac dysfunction in Lake Trout Salvelinus namaycush. Here, we assess the effects of thiamine concentration on the ventricular morphology of three reproductive life histories (jack males, hooknose males, and females) of wild spawning Chinook Salmon Oncorhynchus tshawytscha.</p><p><strong>Methods: </strong>Fish were sampled from the Credit River (a Lake Ontario tributary), and skeletal muscle, ventricle, and liver thiamine concentrations were quantified using high-performance liquid chromatography. A subset of ventricles was retained for histological analyses. Hematoxylin and eosin-stained slides were used to measure cardiomyocyte width and compact myocardium thickness, and Masson's trichrome-stained slides were used to measure levels of cardiac fibrosis. Level of spawning senescence was quantified based on a qualitative score.</p><p><strong>Results: </strong>Thiamine levels did not differ significantly among life histories, except that hooknose males had significantly greater skeletal muscle thiamine concentrations than females. Thiamine concentrations in skeletal muscle and the ventricle were positively correlated. Across all life histories, lower concentrations of thiamine in skeletal muscle were associated with increased levels of cardiomyocyte hypertrophy and cardiac fibrosis, independent of their relationships with ventricle mass and level of spawning senescence. No significant relationships were observed with compact myocardium thickness.</p><p><strong>Conclusions: </strong>Low thiamine concentrations are associated with pathological alterations in cardiac morphology across reproductive life histories in spawning Chinook Salmon.</p>","PeriodicalId":15235,"journal":{"name":"Journal of aquatic animal health","volume":" ","pages":"55-65"},"PeriodicalIF":1.7,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144159245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}