Mass Mortality Research Articles

The emergence of multidrug-resistant Proteus vulgaris infection in cage reared Pangasianodon hypophthalmus: Molecular characterization and host-pathogen response

The study investigates the causative agent responsible for massive mortality in Pangasianodon hypophthalmus cage farms. The infected pangasius were lethargic, not taking feed, and had exophthalmia, deep ulceration, and hemorrhage on the ventral body surface. Pathogens were isolated from infected pangasius tissue samples, and the strain was preliminarily identified as Proteus vulgaris based on morphology, biochemical tests, 16S rRNA PCR sequencing, and phylogenetic analysis. The microbiological analysis revealed that P. vulgaris was associated with the disease outbreak and mortality of P. hypophthalmus, as confirmed by the biofilm formation, swimming activity, and survival assay results. The isolated P. vulgaris was resistant to several antibiotics, including Doxycycline, Dicloxacillin, Polymyxin B, Chloramphenicol, and Imipenem, exhibiting multiple antibiotic-resistant phenotypes. Furthermore, a host-pathogen model was developed to investigate the in vivo effect of emerging P. vulgaris infection in striped catfish. Results showed that P. vulgaris infection exhibited varying degrees of cellular changes in the kidney, liver, and gill tissues of infected P. hypophthalmus samples. The transcription analysis further highlights that P. vulgaris modulates the antioxidants, immune activation, growth regulator, homeostasis, degradation of invading DNA, and DNA damage-related gene expression in liver, kidney, spleen, skin, and gill tissue samples of infected P. hypophthalmus. The lessons learned from the study could be critical in understanding the P. vulgaris infection patterns and pathobiology necessary to enable risk assessment and develop management measures to control the bacterium's virulence.

Identification of cymothoid isopods probably responsible for mass mortality of hatchery-reared Pacific bluefin tuna Thunnus orientalis juveniles after transfer to sea cages

Identification of cymothoid isopods probably responsible for mass mortality of hatchery-reared Pacific bluefin tuna Thunnus orientalis juveniles after transfer to sea cages

Pathogenicity of Citrobacter freundii Causing Mass Mortalities of Macrobrachium rosenbergii and Its Induced Host Immune Response.

Citrobacter freundii is an opportunistic pathogen of freshwater aquatic animals, which severely restricts the sustainable development of the aquaculture industry. In this study, a dominant strain, named FSNM-1, was isolated from the hepatopancreas of diseased Macrobrachium rosenbergii. This strain was identified as C. freundii based on a comprehensive analysis of its morphological, physiological, and biochemical features and molecular identification. Challenge experiments were conducted to assess the pathogenicity of C. freundii to M. rosenbergii. The results showed that the FSNM-1 strain had high virulence to M. rosenbergii with a median lethal dose (LD50) of 1.1 × 106 CFU/mL. Histopathological analysis revealed that C. freundii infection caused different degrees of inflammation in the hepatopancreas, gills, and intestines of M. rosenbergii. The detection of virulence-related genes revealed that the FSNM-1 strain carried colonization factor antigen (cfa1, cfa2), ureases (ureG, ureF, ureD, ureE), and outer membrane protein (ompX), and virulence factor detection showed that the FSNM-1 strain had lecithinase, amylase, lipase, gelatinase, and hemolysin activities but did not produce protease and DNase activities. To investigate the immune response of M. rosenbergii to C. freundii, the expression levels of ALF3, MyD88, SOD, proPO, TRAF6, and TNF immune-related genes were monitored at different points of time in the hepatopancreas, gills, intestines, and hemocytes of M. rosenbergii after infection. The results demonstrated a significant upregulation in the expression levels of the ALF3, MyD88, SOD, proPO, TRAF6, and TNF genes in M. rosenbergii at the early stage of C. freundii infection. This study highlights C. freundii as a major pathogen causing mass mortality in M. rosenbergii and provides valuable insights into its virulence mechanisms and the host's immune response.

Isolation and characterization of Streptococcus agalactiae inducing mass mortalities in cultured Nile tilapia (Oreochromis niloticus) with trials for disease control using zinc oxide nanoparticles and ethanolic leaf extracts of some medicinal plants

BackgroundStreptococcus agalactiae (Group B streptococcus, GBS) induces a serious infection that can harm not only aquatic life but also humans and other animals. In a fish farm in southern Egypt, Nile tilapia (Oreochromis niloticus) has developed an epidemic with clinical symptoms resembling piscine streptococcosis.ResultsInitial microscopic inspection of the affected fish brain and kidney indicated the presence of Gram-positive cocci. S. agalactiae was effectively isolated and identified using nucleotide homology of the 16S rRNA and species-specific PCR. The partial 16S rRNA sequence was deposited in the GenBank database at the NCBI and given the accession number MW599202. Genotyping using RAPD analysis indicated that the isolates in the present study belonged to the same genotypes and had the same origin. The challenge test, via immersion (9.2 × 107, 9.2 × 106, and 9.2 × 105 CFU/ml for 1 h) or intraperitoneal injection (4.6 × 107, 4.6 × 106, and 4.6 × 105 CFU/fish), elicited clinical symptoms resembling those of naturally infected fish with a mortality rate as high as 80%. The ability to create a biofilm as one of the pathogen virulence factors was verified. Zinc oxide nanoparticles and the ethanolic leaf extracts of nine medicinal plants demonstrated considerable antibacterial activities against the tested S. agalactiae strain with low minimum bactericidal concentrations (MBC) and minimum inhibitory concentrations (MIC). The ethanolic leaf extracts from Lantana camara and Aberia caffra showed potent antibacterial activity with MBC values of 0.24 and 0.485 mg/ml, and MIC values of 0.12 & 0.24 mg/ml, respectively.ConclusionThis study isolated S. agalactiae from O. niloticus mortalities in a fish farm in Assiut, Egypt. The pathogen persists in fish environments and can escape through biofilm formation, suggesting it cannot be easily eliminated. However, promising findings were obtained with in vitro control employing zinc oxide nanoparticles and medicinal plant extracts. Nevertheless further in vivo research is needed.

Selective breeding enhances coral heat tolerance to marine heatwaves

Marine heatwaves are becoming more frequent, widespread and severe, causing mass coral bleaching and mortality. Natural adaptation may be insufficient to keep pace with climate warming, leading to calls for selective breeding interventions to enhance the ability of corals to survive such heatwaves, i.e., their heat tolerance. However, the heritability of this trait–a prerequisite for such approaches–remains unknown. We show that selecting parent colonies for high rather than low heat tolerance increased the tolerance of adult offspring (3–4-year-olds). This result held for the response to both 1-week +3.5 °C and 1-month +2.5 °C simulated marine heatwaves. In each case, narrow-sense heritability (h2) estimates are between 0.2 and 0.3, demonstrating a substantial genetic basis of heat tolerance. The phenotypic variability identified in this population could theoretically be leveraged to enhance heat tolerance by up to 1 °C-week within one generation. Concerningly, selective breeding for short-stress tolerance did not improve the ability of offspring to survive the long heat stress exposure. With no genetic correlation detected, these traits may be subject to independent genetic controls. Our finding on the heritability of coral heat tolerance indicates that selective breeding could be a viable tool to improve population resilience. Yet, the moderate levels of enhancement we found suggest that the effectiveness of such interventions also demands urgent climate action.

The association between changes in muscle mass and function and mortality in individuals receiving peritoneal dialysis.

Data in terms of how dynamic changes of muscle mass and function affect mortality in end-stage kidney disease (ESKD) patients undergoing dialysis have led to inconclusive results. The main goal of this research was to determine the association between dynamic deterioration of muscle mass and function and all-cause mortality in ESKD patient on continuous ambulatory peritoneal dialysis (CAPD). Eligible ESKD patients on CAPD were prospectively included, and followed up at 3-month intervals in the tertiary care center for 2 years. Dynamic deterioration of muscle mass and function during a 12-month follow-up period before patients enrolled was the exposure of interest. The deterioration of muscle mass and function was identified utilizing the criteria set by the Asian Working Group on Sarcopenia in 2019 (AWGS 2019). Primary outcome was defined as the all-cause mortality during the next 2-year follow-up period. Kaplan-Meier analysis with log-rank test was used to compare overall survival between groups. Association of dynamic deterioration of muscle mass and function with all-cause mortality was examined by employing Cox proportional hazards models. A sensitivity analysis was also conducted to examine whether the potential association was modified. A total of 217 eligible patients on CAPD were included. The prevalence of dynamic deterioration of muscle mass and function was 42.9% (93/217), of which that evolving to sarcopenia (nonsevere sarcopenia or severe sarcopenia) from nonsarcopenia was 24.9% (54/217) and that evolving to severe sarcopenia from nonsevere sarcopenia was 18.0% (39/217). A total of 35.0% (76/217) participants died during the 2-year follow-up period, of which the group with deterioration of muscle mass and function was 50.5% (47/93), and the group without deterioration was 23.4% (29/124), with an absolute difference of 27.1% (95%CI 14.5%-39.7%). Kaplan-Meier survival curve revealed that the participants with dynamic deterioration of muscle mass and function had a worse survival rate than those without deterioration (log-rank test, χ2 = 17.46, p < 0.001). After adjustment for potential confounding factors, the dynamic deterioration of muscle mass and function was still significantly associated with increased risk of all-cause mortality (hazard ratio [HR] = 2.40, 95%CI 1.44-4.00, p = 0.001). In sensitivity analysis, the relationship between dynamic deterioration of muscle mass and function (nonsarcopenia to sarcopenia vs without deterioration) and all-cause mortality was consistent (HR = 4.01, 95%CI 2.22-7.22, p < 0.001). Nevertheless, no significant relationship was found in participants who evolved to severe sarcopenia from nonsevere sarcopenia (HR = 1.41, 95%CI 0.72-2.74, p = 0.313). This research demonstrated a significant association between dynamic deterioration of muscle mass and function and higher risk of mortality in ESKD patients on CAPD, and we recommend individualized lifestyle intervention that may be implemented to intervene in the progression of their muscle mass and function across the health care spectrum.

Impact of Global Warming

In present time climate change has been recognized as the foremost environmental problem of the twenty first century and has become a subject of considerable debates. It is predicted to lead to adverse, irreversible impact on earth and the ecosystem as a whole. Although it is difficult to connect specific weather events to global warming, increase in global temperatures has been predicted to cause border changes, including glacial retreat, arctic shrinkage, and worldwide sea level rise. Climate change has been implicated in mass mortalities of mail, aquatic species, including plants. Climate change is an emerging threat to global public health in many ways including heat stress, air pollution, food scarcity and spread of infectious diseases and intensity of disease outbreaks. Thus, ‘Global Climate Change’ has been a major issue that has created global concern and this has been highlighted by awarding the 2007 Nobel Peace Prize for this cause, on the Inter-Governmental Panel of Climatic Change (IPCC) and Albert Arnold (M) Gore JR., the former American Vice-President, jointly. Global warming is being proven as the major reason behind the climate change. Fossil fuels are being continuously used to produce electricity. The burning of these fuels produces gases like carbon dioxide, methane and nitrous oxides which lead to global warming. Deforestation is also leading to warmer temperatures. The hazard of global warming is continuously causing major damage to the earth’s environment. The present paper focuses on different aspects of ‘Global Climate Change’; the causes, predicted impacts. Probable steps for mitigation and the need for greater understanding of climate change and bringing global awareness on the issue.

Discriminating Between Biotic and Abiotic Stress in Poplar Forests Using Hyperspectral and LiDAR Data

Sustainable forest management faces challenges from various biotic and abiotic stresses. The Asian longhorned beetle (ALB) and drought stress both induce water shortages in poplar trees, but require different management strategies. In northwestern China, ALB and drought stress caused massive mortality in poplar shelterbelts, which seriously affected the ecological functions of poplars. Developing a large-scale detection method for discriminating them is crucial for applying targeted management. This study integrated UAV-hyperspectral and LiDAR data to distinguish between ALB and drought stress in poplars of China’s Three-North Shelterbelt. These data were analyzed using a Partial Least Squares-Support Vector Machine (PLS-SVM). The results showed that the LiDAR metric (elev_sqrt_mean_sq) was key in detecting drought, while the hyperspectral band (R970) was key in ALB detection, underscoring the necessity of integrating both sensors. Detection of ALB in poplars improved when the poplars were well watered. The classification accuracy was 94.85% for distinguishing well-watered from water-deficient trees, and 80.81% for detecting ALB damage. Overall classification accuracy was 78.79% when classifying four stress types: healthy, only ALB affected, only drought affected, and combined stress of ALB and drought. The results demonstrate the effectiveness of UAV-hyperspectral and LiDAR data in distinguishing ALB and drought stress in poplar forests, which contribute to apply targeted treatments based on the specific stress in poplars in northwest China.

Characterization of the ferric uptake regulator VaFur regulon and its role in Vibrio anguillarum pathogenesis.

The Gram-negative marine bacterium Vibrio anguillarum is able to cause vibriosis with hemorrhagic septicemia in many fish species, and iron acquisition is a critical step for virulence. Despite the fact that genes specific to certain processes of iron transport have been studied, the iron-regulated circuits of the V. anguillarum strains remain poorly understood. In this study, we showed that in V. anguillarum strain 775, iron could affect the expression of a number of critical metabolic pathways and virulence factors. The global iron uptake regulator VaFur is the major actor to control these processes for the bacterium to respond to different iron conditions. A VaFur binding motif was identified to distinguish directly and indirectly regulated targets. The absence of VaFur resulted in the aberrant expression of most iron acquisition determinants under rich-iron conditions. A similar regulation pattern was also observed in the transcription of genes coding for the type VI secretion system. The expression of peroxidase genes is positively controlled by VaFur to prevent iron toxicity, and the deletion of Vafur caused impaired growth in the presence of iron and H2O2. VaFur also upregulates some virulence factors under limited-iron conditions, including metalloprotease EmpA and motility, which are likely critical for the high virulence of V. anguillarum 775. The deletion of VaFur led to reduced swimming motility and decreased extracellular protease activity under limited-iron conditions, thereby leading to attenuated pathogenicity. Our study provides more evidence to better understand the VaFur regulon and its role in the pathogenesis of V. anguillarum.IMPORTANCEVibriosis, the most common disease caused by marine bacteria belonging to the genus Vibrio, leads to massive mortality of economical aquatic organisms in Asia. Iron is one of the most important trace elements, and its acquisition is a critical battle occurring between the host and the pathogen. However, excess iron is harmful to cells, so iron utilization needs to be strictly controlled to adapt to different conditions. This process is mediated by the global iron uptake regulator Fur, which acts as a repressor when iron is replete. On the other hand, free iron in the host is limited, so the reduced virulence of the Δfur mutant should not be directly caused by abnormally regulated iron uptake. The significance of this work lies in uncovering the mechanism by which the deletion of Fur causes reduced virulence in Vibrio anguillarum and identifying the critical virulence factors that function under limited-iron conditions.

Изменения литоральных популяций рачков-балянусов Semibalanus balanoides (L.) Кольского залива и Восточного Мурмана в период потепления климата в Арктике

Methods for bioindication of early climate impacts in the marine ecosystem are unknown and being developed for the first time. The high rate of changes in the littoral barnacle Semibalanus balanoides (L.) populations is of key importance for bioindication. Mass mortality and significant decrease in the abundance over 1–3 years were observed in estuaries only and mainly associated with an increase of spring floods during the period of ongoing climate warming in the Arctic. The survival of the juveniles appeared in 2023 (up to 8000 sp/m2) fully depends on further climate changes.

Geographic, ecological, and temporal patterns of seabird mortality during the 2022 HPAI H5N1 outbreak on the island of Newfoundland

Highly pathogenic avian influenza H5N1 caused mass mortality of wildlife across the North Atlantic in 2022. Following European outbreaks, the first North American case was detected on the island of Newfoundland, Canada in November 2021, before spreading throughout North America. During the following summer, Newfoundland and surrounding islands (NFLD) experienced one of the most significant mortalities in Canadian provinces, with seabirds being the most affected taxa. From surveys and citizen reports, we estimate that 13517 mortalities that can be attributed to HPAI occurred in NFLD from April to September 2022. Most estimated mortalities were among Northern Gannets (Morus bassanus, Linnaeus, 1758) (6596), Common Murres (Uria aalge, Pontoppidan, 1763) (5992), Atlantic Puffins (Fratercula arctica, Linnaeus, 1758) (282), and Black-legged Kittiwakes (Rissa tridactyla, Linnaeus, 1758) (217). Mortality reports moved from west to east along the southern then eastern NFLD coast and peaked in July and August. We formulated exploratory hypotheses regarding traits that could contribute to infection and mortality. Species differences in mortality most strongly associated with inter-nest distance, breeding phenology, and at-sea overlap with allospecifics from other colonies. Unprecedented seabird mortality and ongoing transmission within the circulating avian influenza viruses highlight the need for continued monitoring and development of conservation strategies.

Regime shift of skeletal δ13C after 1997/1998 El Nino event in Porites coral from Green Island, Taiwan

The 1997/1998 El Niño event caused mass coral bleaching and mortality in many tropical and subtropical regions, including corals on Green Island, Taiwan, in the northwestern Pacific Ocean. This study analyzed coral carbon isotope ratios (δ13C), oxygen isotope ratios (δ18O), and Sr/Ca ratios for 29 years, including the 1997/1998 El Niño period, to examine how high water temperature events are recorded in coral geochemical indicators. Sr/Ca ratios in coral skeletons from Green Island show the lowest peak, means the highest temperature during the 1997/1998 El Niño period. However, we couldn’t observe high-temperature events on δ18O. Furthermore, a negative δ13C shift was observed after El Niño events. The regime shift of δ13C might have been caused by temporal bleaching and/or a decrease in symbiotic algae due to high water temperature stress under the continuous decrease in δ13C in DIC due to the Suess effect.

Evaluation of a DNA vaccine with self-designed CpG sequences against J genotype IHNV infection in rainbow trout (Oncorhynchus mykiss)

Rainbow trout suffer from infectious hematopoietic necrosis virus (IHNV) outbreaks, which lead to massive mortality and huge economic loss worldwide. The approved commercial vaccine is used for the prevention of IHN in Canada. Given that Chinese domestic J-genotype isolates are different from North American IHNV isolates, the development of an effective DNA vaccine against Chinese J-genotype isolates is urgent. In this study, we developed a DNA vaccine encoding glycoprotein based on our previously isolated IHNV GS21 strain and self-designed CpG sequences were supplemented as molecular adjuvants. The vaccinated rainbow trout were significantly protected against IHNV with approximately a relative percent survival (RPS) of 94.74 % compared to the unvaccinated group. Moreover, the specific antibody of IgM and neutralizing antibody (NAb) was significantly provoked after the vaccination. Particularly, the antiviral immune response was rapidly evoked in the early stage of vaccination including the up-regulation of Mx-1, IFN-Ⅰ, and IFN-γ. The IHNV load in vaccinated fish was apparently lower than that in the unvaccinated group. Furthermore, the integration of exogenous genes into the host chromosome and the spread of antimicrobial-resistant genes were not found. These results suggested that our vaccine enhances robust immune responses and evokes considerable protection against IHNV with limited genetically modified risk, which is an effective and promising vaccine candidate for further prevention of IHNV outbreaks.

Ursolic Acid Restores Redox Homeostasis and Pro-inflammatory Cytokine Production in Denervation-Induced Skeletal Muscle Atrophy.

Skeletal muscle (SkM) atrophy results from metabolic disorders causing body and muscle mass loss, affecting morbidity and mortality. Increased oxidative stress, inflammation, and poor prognosis are the leading causes of involuntary weight loss. Ursolic acid (UA), known for its antioxidant and anti-inflammatory properties, can potentially reduce oxidative stress and inflammation in muscles, but its effects on muscle mass regulation are still unknown. Therefore, the present study investigated the medicinal efficacy of UA and its mode of action against the murine model of SkM atrophy over 7days of UA supplementation. Denervation-induced SkM atrophy significantly impacts overall body weight and the weight of individual muscles (p < 0.05). However, supplementation with UA can effectively counteract these effects by promoting the synthesis of the slow-myosin heavy chain, thereby restoring body weight and myotube diameter. Moreover, UA also plays a crucial role in reducing the production levels of reactive oxygen species (ROS), lipid peroxidation (LPO), and caspase-3-like activity in atrophied muscles. UA also prevents the leakage of creatine kinase (CK) through the upregulation of superoxide dismutase (SOD) and glutathione peroxidase (GPx) expression. Furthermore, the results obtained from qRT-PCR demonstrated a significant decrease in the levels of pro-inflammatory markers, namely IL-1β, IL-6, TNF-α, and TWEAK, up to four-fold after the third day of the UA intervention. UA also upregulated PGC-1α, Bcl2, and p-Aktser473 expression towards the regulation of redox homeostasis.

Pathogenomic profiling: Decoding the pathogenic potential of virulent Bacillus cereus associated with mortality of farmed Labeo rohita (Hamilton, 1822), in India

Bacillus cereus is widely used as probiotics in aquaculture. However, present research work identified B. cereus from diseased fish (Labeo rohita) associated with mass mortality in Hooghly, West Bengal, India. The bacterium was identified based on morphological, biochemical characterization and molecular identification, which comprise 16S rRNA gene and housekeeping gene sequencing analysis. Furthermore, the pathogenic potential of the isolates was confirmed by the presence of different toxin-encoding genes viz. hemolytic enterotoxin (hblA, hblC, hblD), non-hemolytic enterotoxin (nheA, nheB, nheC), cytotoxin K (cytK) and enterotoxin FM (entFM), Diarrheal enterotoxin (bceT) and Cereolysin AB. All these toxin-encoding genes were regulated by a master virulence regulating transcription factor plcr, which is also present in this isolate. Additionally, this bacterium also secretes caseinase and lecithinase, which helps the bacteria to invade the host tissue. The intraperitoneal injection of B. cereus at a dose of 3.6× 106 CFU ml−1 resulted in 100 % mortality of L. rohita. The histopathological changes revealed that the bacterium induces severe damage and necrosis in the liver and kidney of the infected fish. To understand the innate immune response once bacteria invade the host, a quantitative gene expression study was carried out using different immune-related genes and stress-related genes viz. Complement factor 3a (C3a), Toll-like receptor (TLR), Myeloid differentiation primary response 88 (Mydd88), Interleukin 6 (IL6), Nucleotide oligomerization domain (NOD)-like receptor, Catalase (CAT), Glutathione peroxidase (GPx) and Superoxide dismutase (SOD) in the hepatic and renal tissue. The over-expression of TLR, NOD and Mydd88 shared a common downstream inflammatory signaling pathway and the upregulation of antioxidant enzymes SOD, CAT and GPx was evident for combating strategies as well as safeguarding the host's cells from oxidative damage. Overall, this study showed that an isolated strain of B. cereus exhibits high pathogenicity, which may be attributed to climate change, urbanization or horizontal gene transfer. This presents a potential threat to the aquaculture industry and raises concerns about the possibility of cross-contamination within the human population.

A sarcoptic mange outbreak drives long-term patterns of a fitness trait in an exotic ungulate

Species phenotypes are driven by persistent selective pressures that condition their adaptation to the environment. However, stochastic critical events, such as disease outbreaks, may also act as selective pressures because of drastic population decline. External structures like horns of ungulate species may reflect the consequences of these selective pressures on animal fitness. Using a generalized linear model approach, we analysed how a massive mortality event caused by a sarcoptic mange outbreak in 1992 affected the horn size of an Iberian aoudad population (dataset from 1980 to 2014) by comparing horn length before and after the outbreak. We found that this episodic, albeit massive, outbreak changed long-term trends in age-size horn relations. Both females and males presented shorter horns after the sarcoptic mange outbreak, although more marked in males. Even when animals reached mature ages, horn length did not increase with age to the same degree as before the outbreak. We consider that two processes may have acted on the population: a bottleneck favoured “shorter horns” phenotype and a post-mange enzootic period limited horn growth, as infected animals may invest more resources in the immune system. Overall, our results show a top-down regulation of a fitness trait for an ungulate population mediated by a parasite. This disease outbreak showed long-lasting effects on the ungulate population, with ecological and management implications.Graphical

REPRODUCCIÓN Y CULTIVO LARVARIO DEL PEZ PAYASO MARRÓN (Premnas biaculeatus) BAJO CONDICIONES CONTROLADAS

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Interest in ornamental marine fish, especially species associated with coral reefs, is rapidly growing. Most of the fish traded come from the wild, and collection methods harm coral reefs and cause massive mortalities in non-target species. To make the activity sustainable, it is necessary to develop aquaculture biotechnologies to reduce the collection of wild organisms and lessen the pressure on their natural environment. &lt;strong&gt;Objective:&lt;/strong&gt; To develop protocols for the reproduction and larval rearing of the maroon clownfish (&lt;em&gt;Premnas biaculeatus&lt;/em&gt;) for the sustained production of juveniles in captivity. &lt;strong&gt;Methodology:&lt;/strong&gt; Two pairs of &lt;em&gt;P. biaculeatus&lt;/em&gt; were placed in two aquariums of a recirculating system with filtered seawater. The obtained eggs were incubated in 100 L tanks. The larvae were fed with rotifers &lt;em&gt;Brachionus rotundiformis&lt;/em&gt;, &lt;em&gt;Artemia&lt;/em&gt; sp. nauplii, and weaned onto a commercial diet. The larvae were measured at hatching and every four days until weaning. &lt;strong&gt;Results:&lt;/strong&gt; The clownfish pairs began spawning 4-5 months after being placed in the recirculating system and continued spawning every 15-20 days. The eggs hatched 6-7 days after fertilization (DAF), and the hatched larvae measured 3.4±0.06 mm in total length (TL). At 19 days after hatching (DAH), after completing weaning, they measured between 9.8 to 11.5 mm in TL; at 26 DAH, they measured between 10.8 to 13.1 mm. After one month, between 800 to 1,000 juveniles were obtained for commercialization. &lt;strong&gt;Implications:&lt;/strong&gt; The reproduction and larval rearing protocols of the maroon clownfish &lt;em&gt;P. biaculeatus&lt;/em&gt; described in this work can be used to obtain juveniles in captivity for commercialization; additionally, they can serve as a basis for developing other protocols for obtaining juveniles of other ornamental marine fish species for commercialization, contributing to the protection of their natural environment. &lt;strong&gt;Conclusion:&lt;/strong&gt; The results obtained demonstrated the viability of maintaining &lt;em&gt;P. biaculeatus&lt;/em&gt; breeders in captivity and achieving their natural reproduction, larval rearing, and mass production of juveniles throughout the year.&lt;/p&gt;

Forecasting the impact of marine heat waves on farmed bivalves Nodipecten nodosus and Magallana gigas

Marine heat waves are considered a threat to the cultivation of commercially important species because exposure to thermal stress may lead to mass mortalities of organisms. Investigating the upper thermal limits of marine species and their capacity for shifting these limits can contribute to securing the sustainability of aquaculture activities as exposure to heat extremes is increasing in frequency. The scallop Nodipecten nodosus and oyster Magallana [Crassostrea] gigas are two bivalve species commercially farmed in Brazil and production of spat is undertaken mainly at two hatcheries located in different regions subjected to distinct climate and seawater temperature conditions over the year. This study investigated the upper thermal tolerance of populations of N. nodosus and M. gigas sourced from temperate and tropical farming areas. Groups of N. nodosus and M. gigas farmed under warmer temperature regimes exhibited lower mortality rates when exposed to elevated temperatures compared to groups sourced from cooler waters and consequently displayed higher values of lethal temperature 50 (LT50). N. nodosus exhibited superior thermal tolerance than was previously known, however, commercial cultivation of this species is still at risk of mass mortalities depending on the duration and intensity of forecasted heat waves in both cultivation regions. M. gigas showed a high capacity to endure acute thermal stress at the resting stage of the reproductive cycle. To enhance the aquaculture sector's resilience to climate change, we recommend the development of cultivation methods that account for marine and atmospheric heat wave events, alongside continuous monitoring of abiotic factors at farming sites.

Antibiofilm activity of Morganella morganii JB8F and Pseudomonas fluorescens JB3B compound to control single and multi-species of aquaculture pathogens

BackgroundIndonesia is a country that uses half or more aquatic foods as protein intake. The increased production in aquaculture industries might cause several problems, such as bacterial disease resulting in mass mortality and economic losses. Antibiotics are no longer effective because aquaculture pathogens can form biofilm. Biofilm is a microbial community that aggregates and firmly attaches to living or non-living surfaces. Biofilm formation can be caused by environmental stress, the presence of antibiotics, and limited nutrients. Therefore, it is important to explore antibiofilm to inhibit biofilm formation and/or eradicate mature biofilm. Phyllosphere bacteria can produce bioactive compounds for antimicrobial, antibiofilm, and anti-quorum sensing. Three aquaculture pathogens were used in this study, such as Aeromonas hydrophila, Streptococcus agalactiae, and Vibrio harveyi.ResultsPseudomonas fluorescens JB3B and Morganella morganii JB8F extracts could disrupt single and multi-species biofilms. Both extracts could inhibit single biofilm formation from one to seven days of incubation time. We confirmed the destruction activity on multi-species biofilm using light microscope and scanning electron microscope. Using GC-MS analysis, indole was the most active fraction of the P. fluorescens JB3B extracts and octacosane from the M. morganii JB8F extract. We also conducted a toxicity test using brine shrimp lethality assay on P. fluorescens JB3B and M. morganii JB8F extracts. P. fluorescens JB3B, M. morganii JB8F, and a mixture of both extracts were confirmed non-toxic according to the LC50 value of the brine shrimp lethality test.ConclusionsP. fluorescens JB3B and M. morganii JB8F phyllosphere extracts had antibiofilm activity to inhibit single biofilm and disrupt single and multi-species biofilm of aquaculture pathogens. Both extracts could inhibit single species biofilm until seven days of incubation. Bioactive compounds that might contribute to antibiofilm properties were found in both extracts, such as indole and phenol. P. fluorescens JB3B, M. morganii JB8F extracts, and mixture of both extracts were non-toxic against Artemia salina.

Body mass index and mortality in critically ill patients

Body mass index and mortality in critically ill patients