Nanobubble applications in aquaculture industry for improving harvest yield, wastewater treatment, and disease control.

The ever-growing demand for aquaculture has led the industry to seek novel approaches for more sustainable practices. These attempts aim to increase aquaculture yield by increasing energy efficiency and decreasing footprint and chemical demand without compromising animal health. For this, emerging nanobubbles (NBs) aeration technology gained attention. NBs are gas-filled pockets suspended as sphere-like cavities (bulk NBs) or attached to surfaces (surface NBs) with diameters of <1 µm. Compared to macro bubbles and microbubbles, NBs have demonstrated unique characteristics such as long residence time in water, higher gas mass transfer efficiency and hydroxyl radical production. This paper focuses on reviewing NB technology in aquaculture systems by summarizing and discussing uses and implications. Three focus areas were targeted to review the applicability and effects of NBs in aquaculture: (i) NBs aeration to improve the aquaculture harvest yield and subsequent wastewater treatment; (ii) NB application for inactivation of harmful microorganisms; and (iii) NBs for reducing oxidative stress and improving animal health. Thus, this study reviews the research studies published in the last 10 years in which air, oxygen, ozone, and hydrogen NBs were tested to improve gas mass transfer, wastewater treatment and control of pathogenic microorganisms. The experimental results indicated that air and oxygen NBs yield significantly higher productivity, growth rate, total harvest, survival rate, and less oxygen consumption in fish and shrimp farming. Secondly, the application of air and ozone NBs demonstrated the ability of efficient pollutant degradation. Third, NB application demonstrated effective control of infectious bacteria and viruses, and thus increased fish survival, as well as different gene expression patterns that induce immune responses to infections. Reviewed studies lack robust comparative analyses of the efficacy of macro- and microbubble treatments. Also, potential health and safety implications, as well as economic feasibility through factors such as changes in capital infrastructure, routine maintenance and energy consumption need to be considered and evaluated in parallel to applicability. Therefore, even with a promising future, further studies are needed to confirm the benefits of NB treatment versus conventional aquaculture practices.

Deciphering patterns in whole fish nitrogen isotopes on a continental scale.

Nitrogen isotopes (δ15N) have been used as an indicator of anthropogenic nitrogen loading at local and regional scales. We examined δ15N in fish from estuaries across the continental United States. In the summer of 2015, the U.S. Environmental Protection Agency's National Coastal Condition Assessment (NCCA) collected fish in 136 coastal waterbodies throughout the United States. Whole fish were analyzed by NCCA for metals, organic contaminants, and lipids. For this study, we also analyzed these fish for isotopes of nitrogen (N). NCCA collected water quality, nutrients, chlorophyll a, and sediment chemistry at each site. We used these data, along with fish life history and watershed land use, to examine how whole fish δ15N was related to these environmental variables using random forest regression models at national and ecoregional scales. At the national scale, fish δ15N were negatively related to total N:total phosphorous (P) ratios (TN:TP) in surface water and reflected differences between the P-limited, δ15N depleted sites in the Floridian ecoregion to sites in other regions. δ15N was lower on the Atlantic relative to the Pacific coast. When considered by region, TN:TP was an important predictor of fish δ15N in 4 of 9 ecoregions, with higher δ15N observed with increasing N limitation (lower TN:TP) Fish life history was also an important predictor of fish δ15N at both the national and ecoregional scale. Whole fish δ15N was positively associated with bioaccumulative contaminants such as PCBs and mercury. Although land use was related to δ15N in fish, it was location specific. This study showed that N stable isotopes reflected ecological conditions at both regional and continental scales.

Biopesticide Spinosad: unraveling ecotoxicological effects on zebrafish, Danio rerio.

Biopesticides are natural compounds considered more safe and sustainable for the environment. Spinosad (SPI) is a bioinsecticide used in marketed worldwide, to eradicate a variety of pests. This study aimed to assess the impacts of the SPI on the non-target organism zebrafish (Danio rerio). Several concentrations of SPI were tested to evaluate the acute (0.07-1.0mg/L) and chronic (0.006-0.100mg/L) ecotoxicological effects. To evaluate sub-individual effects, antioxidant defense, lipid peroxidation, energy sources, and cholinergic biomarkers were quantified. In both exposures, SPI induced significant effects on antioxidant defense indicating oxidative stress, disrupting energy pathways, and exhibiting neurotoxic effects, under environmentally relevant conditions. Integrated Biomarker Response (IBRv2) showed that with increasing SPI concentrations, an increase in impacts on organisms was recorded. This study demonstrates the vulnerability of a non-target organism to SPI, a bioinsecticide considered environmentally safe. Further research is essential to fully understand the implications of spinosad to aquatic biota.

Dried storage of sperm at supra-zero temperatures: an alternative for flow cytometric analysis under field conditions.

In biotechnological processes such as chromosomal manipulation studies, semen has become a reference in the ploidy verification of the evaluated material. However, the use of fresh samples is limited to the use at field conditions because the analysis is performed under laboratory conditions. Thus, this study aimed to develop a simpler procedure for storing dry semen at 28°C to reduce cold storage costs. For this, semen samples were evaluated according to established quality semen parameters, a protocol for dry, and 3 sterilization treatments of dry semen were applied to the store. The integrity of the DNA was evaluated every two months, using fresh semen, dry semen (untreated), and particles 3C to compare the peaks by flow cytometry. The results indicated that all samples evaluated before and after drying showed no significant difference in the DNA content. UV-treated semen showed a 1C peak in the histogram up to 180 days of storage and a non-significant difference (P > 0.05) from fresh control in the number of DNA particles up to 120 days and untreated only showed a 1C peak up to 120 days. The developed method may become an interesting procedure to serve as a reference peak for practical flow cytometric analysis, not only in the field of fish biology but also in biomedical and agricultural sciences. Furthermore, dried semen can become a tool for the preservation of genetic material and is a promising low-cost storage technique for biobanking.

Fish swim bladders as valve leaflets enhance the durability of transcatheter aortic valve replacement devices.

Transcatheter aortic valve replacement (TAVR) has emerged as an effective therapy for inoperable patients with severe aortic stenosis (AS). However, calcification-induced limited durability restricts its application. Fish swim bladders (FSB), which are resistant to calcific degeneration, offer a viable solution to this challenge. In this study, we developed a new TAVR device using FSB as the valve leaflet. Furthermore, the in vitro durability, in vivo performance, and size selection of this TAVR device were assessed by an experimental study and finite element analysis. A self-expandable TAVR device was fabricated by suturing the FSB films into a 23 mm nitinol alloy frame. Further, hemodynamic performance, such as effective orifice area, transvalvular pressure difference and regurgitant fraction, the durability was tested by the pulsatile flow test and accelerated fatigue test, according to the ISO 5840-3. The effect of release size on hydrodynamic performance was also investigated. Finally, the in vivo performance of the TAVR device were examined using a porcine implantation model. The results showed that the strength of the FSB films satisfied the requirements for valve leaflets. The hemodynamic performance of the FSB TAVR device met the requirements of ISO 5840-3 standards. After 400 million cycles, the FSB showed no fiber loss, torn, perforation, or other valve failure phenomena. In porcine models, the devices were well-positioned, functioned well with no stenosis immediately after the operation. Collectively, we successfully developed a TAVR device with FSB as valve leaflets that exhibited good fatigue resistance. STATEMENT OF SIGNIFICANCE: The source of material for the leaflets of commercialized biological heart valves (BHVs) is mainly bovine pericardium, but this material suffers the following problems: large and uneven thickness of the material, the presence of a-Gal and Ne5Gc antigens, and the susceptibility to structural valve degradation (SVD). New material for BHVs leaflets is rarely reported. In this study, we prepared a transcatheter aortic valve (TAV) and performed long-term in vitro and short-term in vivo studies using fish swim bladder (FSB) as the leaflets. The study confirmed that FSB TAV device can complete 400 million fatigue tests and maintain the good morphology of the leaflets, and that it still maintains good functionality after a certain amount of compression, indicating that FSB is a promising material for leaflets.

Effects of Nanomolar Methylmercury on developing Human Neural Stem Cells and Zebrafish Embryo.

Exposure to mercury and its organic form methylmercury (MeHg), is of great concern for the developing nervous system. Despite available literature on MeHg neurotoxicity, there is still uncertainty about its mechanisms of action and the doses that trigger developmental effects. Our study combines two alternative methodologies, the human neural stem cells (NSC) and the zebrafish (ZF) embryo, to address the neurotoxic effects of early exposure to nanomolar concentrations of MeHg. Our results show linear or nonmonotonic (hormetic) responses depending on studied parameters. In ZF, we observed a hormetic response in locomotion and larval rotation, but a concentration-dependent response for sensory organ size and habituation. We also observed a possible delayed response as MeHg had greater effects on larval activity at 5 days than at 24 hours. In NSC cells, some parameters show a clear dose dependence, such as increased apoptosis and differentiation to glial cells or decreased neuronal precursors; while others show a hormetic response: neuronal differentiation or cell proliferation. This study shows that the ZF model was more susceptible than NSC to MeHg neurotoxicity. The combination of different models has improved the understanding of the underlying mechanisms of toxicity and possible compensatory mechanisms at the cellular and organismal level.

Ocular fish hook injuries.

PURPOSE: Fishing stands out as a widely enjoyed leisure pursuit. While ocular fishing injuries are infrequent, they carry the potential for severe ocular trauma, and safe extraction of a fish hook can pose challenges. We here in report a series of 21 cases of penetrating injury to the cornea by fish hook, detailing successful surgical interventions employed for their management. The report not only outlines different techniques for the removal of fish hooks but also provides clarification on terminologies associated with various components of a fish hook. METHODS: This was a retrospective study conducted at tertiary eye care centers in South India. Our hospitals cater to the states of Telangana, Andhra Pradesh, and Odisha. All medical records of patients who attended the emergency department from the period of 2003 to 2023 were evaluated and all patients with fish hook injury were included in the study. This is the longest and largest study in India. RESULTS: Twenty-one cases of ocular fish-hook injuries were presented to the emergency room between 2003 and 2023. Patients were between the ages of 9 and 59 years (mean, 29.4 years), and 90.4 % (19 out of 21) were males. Patient demographics, injury characteristics, surgical interventions, and visual outcomes were meticulously documented. Out of 21 cases, three cases (14.3 %) had blunt trauma, 17 cases (80.9 %) had penetrating injury and one case had lid laceration. Patients had better visual outcomes after the second surgery. Out of 21 cases, 7 (33.3 %) had post-operative visual acuity (VA) between 20/20 and 20/40. Three (14.3 %) had post-operative VA between 20/60 and 20/125. Five (23.8 %) had post-operative VA between 20/200 and 20/600. Six cases (28.6 %) had poor visual outcomes of which two had no perception of light (NPL), two had Hand movements and the other two had the perception of light present and projection of rays inaccurate CONCLUSION: This extensive case series underscores the complexity of ocular injuries caused by fish hooks and emphasizes significance of tailored surgical approaches for optimal visual outcomes. The hook can be successfully removed with minimal trauma to ocular structures by understanding structure of fish hook and by employing appropriate method of extraction.

Identification and florfenicol-treatment of pseudomonas putida infection in gilthead seabream (Sparus aurata) fed on tilapia-trash-feed.

The present study aimed to determine the major cause of the high mortality affecting farmed gilthead seabream (Sparus aurata) and controlling this disease condition. Fifteen diseased S. aurata were sampled from a private fish farm located at Eldeba Triangle, Damietta, fish showed external skin hemorrhages, and ulceration. Bacterial isolates retrieved from the diseased fish were identified biochemically as Pseudomonas putida and then confirmed by phylogenetic analysis of the 16 S rRNA gene sequence. P. putida was also isolated from three batches of tilapia-trash feed given to S. aurata. Biofilm and hemolytic assay indicated that all P. putida isolates produced biofilm, but 61.11% can haemolyse red blood cells. Based on the antibiotic susceptibility test results, P. putida was sensitive to florfenicol with minimum inhibitory concentrations ranging between 0.25 and 1.0 µg mL- 1, but all isolates were resistant to ampicillin and sulfamethoxazole-trimethoprim. Pathogenicity test revealed that P. putida isolate (recovered from the tilapia-trash feed) was virulent for S. aurata with LD50 equal to 4.67 × 107 colony forming unit (CFU) fish- 1. After intraperitoneal (IP) challenge, fish treated with 10 mg kg- 1 of florfenicol showed 16.7% mortality, while no mortality was recorded for the fish group that received 20 mg kg- 1. The non-treated fish group showed 46.7% mortality after bacterial challenge. HPLC analysis of serum florfenicol levels reached 1.07 and 2.52 µg mL- 1 at the 5th -day post-drug administration in the fish groups received 10 and 20 mg kg- 1, respectively. In conclusion, P. putida was responsible for the high mortality affecting cultured S. aurata, in-feed administration of florfenicol (20 mg kg- 1) effectively protected the challenged fish.

Acellular fish skin grafts in the treatment of diabetic wounds: Advantages and clinical translation.

Diabetic wounds cannot undergo normal wound healing due to changes in the concentration of hyperglycemia in the body and soon evolve into chronic wounds causing amputation or even death of patients. Diabetic wounds directly affect the quality of patients and social medical management; thus researchers started to focus on skin transplantation technology. The acellular fish skin grafts (AFSGs) are derived from wild fish, which avoids the influence of human immune function and the spread of the virus through low-cost decellularization. AFSGs contain a large amount of collagen and omega-3 polyunsaturated fatty acids and they have an amazing effect on wound regeneration. However, after our search in major databases, we found that there were few research trials in this field, and only one was clinically approved. Therefore, we summarized the advantages of AFSGs and listed the problems faced in clinical use. The purpose of this paper is to enable researchers to better carry out original experiments at various stages.

Polystyrene nanoplastic and engine oil synergistically intensify toxicity in Nile tilapia, Oreochromis niloticus : Polystyrene nanoplastic and engine oil toxicity in Nile tilapia.

Polystyrene nanoplastic (PS-NPs) and Engine oil (EO) pose multiple ecotoxic effects with increasing threat to fish ecosystems. The current study investigated the toxicity of 15 days exposure to PS-NPs and / or EO to explore their combined synergistic effects on Nile tilapia, Oreochromis niloticus (O. niloticus). Hematobiochemical parameters, proinflammatory cytokines, and oxidative stress biomarkers as well as histological alterations were evaluated. The experimental design contained 120 acclimated Nile tilapia distributed into four groups, control, PS-NPs (5 mg/L), EO (1%) and their combination (PS-NPs + EO). After 15-days of exposure, blood and tissue samples were collected from all fish experimental groups. Results indicated that Nile tilapia exposed to PS-NPs and / or EO revealed a significant decrease in almost all the measured hematological parameters in comparison to the control, whereas WBCs and lymphocyte counts were significantly increased in the combined group only. Results clarified that the combined PS-NPs + EO group showed the maximum decrease in RBCs, Hb, MCH and MCHC, and showed the maximum significant rise in interleukin-1ß (IL-1ß), and interleukin-6 (IL-6) in comparison to all other exposed groups. Meanwhile, total antioxidant capacity (TAC) showed a significant (p < 0.05) decline only in the combination group, whereas reduced glutathione (GSH) showed a significant decline in all exposed groups in comparison to the control. Both malondialdehyde (MDA) and aspartate aminotransferase (AST) showed a significant elevation only in the combination group. Uric acid showed the maximum elevation in the combination group than all other groups, whereas creatinine showed significant elevation in the EO and combination group when compared to the control. Furthermore, the present experiment proved that exposure to these toxicants either individually or in combination is accompanied by pronounced histomorpholgical damage characterized by severe necrosis and hemorrhage of the vital organs of Nile tilapia, additionally extensively inflammatory conditions with leucocytes infiltration. We concluded that combination exposure to both PS-NPs and EO caused severe anemia, extreme inflammatory response, oxidative stress, and lipid peroxidation effects, thus they can synergize with each other to intensify toxicity in fish.

Assessment of deltamethrin-induced DNA damage, neurotoxic and neuroimmune effects in the brain tissue of brown trout (Salmo trutta fario).

This study investigated the impact of deltamethrin (DM) toxicity on brown trout (Salmo trutta fario), examining its effects on the immune system, including the white blood cell (WBC), lymphocyte (Lym), total immunoglobulin (T. Ig), and lysozyme levels, as well as its neurotoxic consequences on the brain tissue. The neurotoxic effects encompassed oxidative stress, the activity of the antioxidant enzymes, such as the superoxide dismutase (SOD) and catalase (CAT), acetylcholinesterase (AChE) activity, and DNA damage using 8-hydroxy-2-deoxyguanosine (8-OHdG). The DM exposure led to elevated levels of malondialdehyde (MDA), and 8-OHdG, while concurrently causing a reduction in the AChE activity, protein and lipid content, WBC count, Lym, lysozyme activity, T. Ig levels, as well as the SOD and CAT levels in the brain tissues of groups 2 and 3 when compared to those in group 1. In summary, the findings of this study strongly indicate that DM induces DNA damage, immunotoxicity, and neurotoxicity in the brain tissue of brown trout, primarily due to the excessive production of reactive oxygen species (ROS). Moreover, the observed dose-dependent responses of DM to the environmental concentrations on all the investigated parameters suggest its potential utility in aquaculture risk assessment.

Betaine improves appetite regulation and glucose-lipid metabolism in mandarin fish (Siniperca chuatsi) fed a high-carbohydrate-diet by regulating the AMPK/mTOR signaling.

Diets with high carbohydrate (HC) was reported to have influence on appetite and intermediary metabolism in fish. To illustrate whether betaine could improve appetite and glucose-lipid metabolism in aquatic animals, mandarin fish (Siniperca chuatsi) were fed with the HC diets with or without betaine for 8 weeks. The results suggested that betaine enhanced feed intake by regulating the hypothalamic appetite genes. The HC diet-induced downregulation of AMPK and appetite genes was also positively correlated with the decreased autophagy genes, suggesting a possible mechanism that AMPK/mTOR signaling might regulate appetite through autophagy. The HC diet remarkably elevated transcriptional levels of genes related to lipogenesis, while betaine alleviated the HC-induced hepatic lipid deposition. Additionally, betaine supplementation tended to store the energy storage as hepatic glycogen. Our findings proposed the possible mechanism for appetite regulation through autophagy via AMPK/mTOR, and demonstrated the feasibility of betaine as an aquafeed additive to regulate appetite and intermediary metabolism in fish.

From little things big things grow: enhancement of an acoustic telemetry network to monitor broad-scale movements of marine species along Australia's east coast.

BACKGROUND: Acoustic telemetry has become a fundamental tool to monitor the movement of aquatic species. Advances in technology, in particular the development of batteries with lives of > 10 years, have increased our ability to track the long-term movement patterns of many species. However, logistics and financial constraints often dictate the locations and deployment duration of acoustic receivers. Consequently, there is often a compromise between optimal array design and affordability. Such constraints can hinder the ability to track marine animals over large spatial and temporal scales. Continental-scale receiver networks have increased the ability to study large-scale movements, but significant gaps in coverage often remain. METHODS: Since 2007, the Integrated Marine Observing System's Animal Tracking Facility (IMOS ATF) has maintained permanent receiver installations on the eastern Australian seaboard. In this study, we present the recent enhancement of the IMOS ATF acoustic tracking infrastructure in Queensland to collect data on large-scale movements of marine species in the northeast extent of the national array. Securing a relatively small initial investment for expanding receiver deployment and tagging activities in Queensland served as a catalyst, bringing together a diverse group of stakeholders (research institutes, universities, government departments, port corporations, industries, Indigenous ranger groups and tourism operators) to create an extensive collaborative network that could sustain the extended receiver coverage into the future. To fill gaps between existing installations and maximise the monitoring footprint, the new initiative has an atypical design, deploying many single receivers spread across 2,100 km of Queensland waters. RESULTS: The approach revealed previously unknown broad-scale movements for some species and highlights that clusters of receivers are not always required to enhance data collection. However, array designs using predominantly single receiver deployments are more vulnerable to data gaps when receivers are lost or fail, and therefore "redundancy" is a critical consideration when designing this type of array. CONCLUSION: Initial results suggest that our array enhancement, if sustained over many years, will uncover a range of previously unknown movements that will assist in addressing ecological, fisheries, and conservation questions for multiple species.

Location and elimination of Anisakis simplex third stage larvae in Atlantic herring Clupea harengus L.

We here describe the location of anisakid third stage larvae in Atlantic herring Clupea harengus L. caught in the North Sea in August 2023. We further demonstrate how industrial processing (mechanical gutting, removal of entrails, head, tail, hypaxial anterior musculature and vertebral column) reduces the overall infection and worm load in the musculature. The isolated anisakid larvae were identified as Anisakis simplex sensu stricto by a combination of morphometrics and molecular methods (PCR of rDNA and mtDNA, sequencing, BLAST analysis). As a baseline we examined a total of 75 specimens of freshly caught and ungutted herring and showed a positive correlation between host size (fish length and weight) and infection level. The overall prevalence of infection was 84 %, the mean intensity 11.3 (range 1-38 parasites per fish) and the abundance 9.52. The main part of the overall worm population was associated with stomach and pyloric caeca in the body cavity (77 %) and only 5 % was found in the musculature. Larvae occurred in the hypaxial part of the musculature (21), the epaxial part (7 worms) and the caudal part (5 worms). The prevalence of muscle infection was 28 % and the mean intensity 1.6 (range 1-5) parasites per fish and abundance 0.44 parasites per fish. In order to assess the effect of industrial processing on worm occurrence in the fish we examined a total of 67 specimens of herring, from exactly the same batch, but following processing. This included removal of organs in the body cavity, cutting the lower part of the hypaxial segment but leaving the right and left musculature connected by dorsal connective tissue. Five out of these fish carried one larva (prevalence 7.5%, mean intensity 1, abundance 0.07 larvae per fish), and these worms were located in the ventral part of the anterior musculature (2), in the central part of the anterior musculature (2) and one larva in the central part of the caudal musculature. The industrial processing reduced the overall occurrence (abundance) of worms in the fish from 9.52 to 0.07 (136 times reduction) and the occurrence in the musculature from 0.44 to 0.07 (6.28 times reduction). The overall prevalence was reduced from 84 % to 7.5 % (11.2 times reduction). Muscle infection prevalence fell from 28 % to 7.5 % (3.7 times reduction). We then followed another batch of herring following a marinating process (11% NaCl for 24 h and subsequent incubation in acetic acid and vinegar) by artificially digesting the flaps during week 1-8. Although a total of 31 larvae were recovered from 144 fish examined no live nematode larvae were isolated. The importance of fish handling, processing and marination for consumer safety is discussed.

Selective social interactions and speed-induced leadership in schooling fish.

Animals moving together in groups are believed to interact among each other with effective social forces, such as attraction, repulsion, and alignment. Such forces can be inferred using "force maps," i.e., by analyzing the dependency of the acceleration of a focal individual on relevant variables. Here, we introduce a force map technique suitable for the analysis of the alignment forces experienced by individuals. After validating it using an agent-based model, we apply the force map to experimental data of schooling fish. We observe signatures of an effective alignment force with faster neighbors and an unexpected antialignment with slower neighbors. Instead of an explicit antialignment behavior, we suggest that the observed pattern is the result of a selective attention mechanism, where fish pay less attention to slower neighbors. This mechanism implies the existence of temporal leadership interactions based on relative speeds between neighbors. We present support for this hypothesis both from agent-based modeling as well as from exploring leader-follower relationships in the experimental data.

Bioaccumulation of Perfluoroalkyl Sulfonamides (FASA).

Hundreds of sites across the United States have high concentrations of perfluoroalkyl sulfonamides (FASA), but little is known about their propensity to accumulate in fish. FASA are precursors to terminal per- and polyfluoroalkyl substances (PFAS) that are abundant in diverse consumer products and aqueous film-forming foams manufactured using electrochemical fluorination (ECF AFFF). In this study, FASA with C3-C8 carbon chain lengths were detected in all fish samples from surface waters up to 8 km downstream of source zones with ECF AFFF contamination. Short-chain FASA ≤ C6 have rarely been included in routine screening for PFAS, but availability of new standards makes such analyses more feasible. Bioaccumulation factors (BAF) for FASA were between 1 and 3 orders of magnitude greater than their terminal perfluoroalkyl sulfonates. Across fish species, BAF for FASA were greater than for perfluorooctanesulfonate (PFOS), which is presently the focus of national advisory programs. Similar concentrations of the C6 FASA (<0.36-175 ng g-1) and PFOS (0.65-222 ng g-1) were detected in all fish species. No safety thresholds have been established for FASA. However, high concentrations in fish next to contaminated sites and preliminary findings on toxicity suggest an urgent need for consideration by fish advisory programs.

Effects of metformin on wild fathead minnows (Pimephales promelas) using in-lake mesocosms in a boreal lake ecosystem.

Due to its widespread use for the treatment of Type-2 diabetes, metformin is routinely detected in surface waters globally. Laboratory studies have shown that environmentally relevant concentrations of metformin can adversely affect the health of adult fish, with effects observed more frequently in males. However, the potential risk to wild fish populations has yet to be fully elucidated and remains a topic of debate. To explore whether environmentally relevant metformin exposure poses a risk to wild fish populations, the present study exposed wild fathead minnows (Pimephales promelas) to 5 or 50 µg/L metformin via 2 m diameter in-lake mesocosms deployed in a natural boreal lake in Northern Ontario at the International Institute for Sustainable Development - Experimental Lakes Area (IISD-ELA). Environmental monitoring was performed at regular intervals for 8-weeks, with fish length, weight (body, liver and gonad), condition factor, gonadosomatic index, liver-somatic index, body composition (water and biomolecules) and hematocrit levels evaluated at test termination. Metabolic endpoints were also evaluated using liver, brain and muscle tissue, and gonads were evaluated histologically. Results indicate that current environmental exposure scenarios may be sufficient to adversely impact the health of wild fish populations. Adult male fish exposed to metformin had significantly reduced whole body weight and condition factor and several male fish from the high-dose metformin had oocytes in their testes. Metformin-exposed fish had altered moisture and lipid (decrease) content in their tissues. Further, brain (increase) and liver (decrease) glycogen were altered in fish exposed to high-dose metformin. To our knowledge, this study constitutes the first effort to understand metformin's effects on a wild small-bodied fish population under environmentally relevant field exposure conditions.

Re-evaluation of certain aspects of the EFSA Scientific Opinion of April 2010 on risk assessment of parasites in fishery products, based on new scientific data. Part 1: ToRs1-3.

Surveillance data published since 2010, although limited, showed that there is no evidence of zoonotic parasite infection in market quality Atlantic salmon, marine rainbow trout, gilthead seabream, turbot, meagre, Atlantic halibut, common carp and European catfish. No studies were found for greater amberjack, brown trout, African catfish, European eel and pikeperch. Anisakis pegreffii, A. simplex (s. s.) and Cryptocotyle lingua were found in European seabass, Atlantic bluefin tuna and/or cod, and Pseudamphistomum truncatum and Paracoenogonimus ovatus in tench, produced in open offshore cages or flow-through ponds or tanks. It is almost certain that fish produced in closed recirculating aquaculture systems (RAS) or flow-through facilities with filtered water intake and exclusively fed heat-treated feed are free of zoonotic parasites. Since the last EFSA opinion, the UV-press and artificial digestion methods have been developed into ISO standards to detect parasites in fish, while new UV-scanning, optical, molecular and OMICs technologies and methodologies have been developed for the detection, visualisation, isolation and/or identification of zoonotic parasites in fish. Freezing and heating continue to be the most efficient methods to kill parasites in fishery products. High-pressure processing may be suitable for some specific products. Pulsed electric field is a promising technology although further development is needed. Ultrasound treatments were not effective. Traditional dry salting of anchovies successfully inactivated Anisakis. Studies on other traditional processes - air-drying and double salting (brine salting plus dry salting) - suggest that anisakids are successfully inactivated, but more data covering these and other parasites in more fish species and products is required to determine if these processes are always effective. Marinade combinations with anchovies have not effectively inactivated anisakids. Natural products, essential oils and plant extracts, may kill parasites but safety and organoleptic data are lacking. Advanced processing techniques for intelligent gutting and trimming are being developed to remove parasites from fish.

Zebrafish Feed Intake: A Systematic Review for Standardizing Feeding Management in Laboratory Conditions.

Zebrafish are one of the most used animal models in biological research and a cost-effective alternative to rodents. Despite this, nutritional requirements and standardized feeding protocols have not yet been established for this species. This is important to avoid nutritional effects on experimental outcomes, and especially when zebrafish models are used in preclinical studies, as many diseases have nutritional confounding factors. A key aspect of zebrafish nutrition is related to feed intake, the amount of feed ingested by each fish daily. With the goal of standardizing feeding protocols among the zebrafish community, this paper systematically reviews the available data from 73 studies on zebrafish feed intake, feeding regimes (levels), and diet composition. Great variability was observed regarding diet composition, especially regarding crude protein (mean 44.98 ± 9.87%) and lipid content (9.91 ± 5.40%). Interestingly, the gross energy levels of the zebrafish diets were similar across the reviewed studies (20.39 ± 2.10 kilojoules/g of feed). In most of the reviewed papers, fish received a predetermined quantity of feed (feed supplied). The authors fed the fish according to the voluntary intake and then calculated feed intake (FI) in only 17 papers. From a quantitative point of view, FI was higher than when a fixed quantity (pre-defined) of feed was supplied. Also, the literature showed that many biotic and abiotic factors may affect zebrafish FI. Finally, based on the FI data gathered from the literature, a new feeding protocol is proposed. In summary, a daily feeding rate of 9-10% of body weight is proposed for larvae, whereas these values are equal to 6-8% for juveniles and 5% for adults when a dry feed with a proper protein and energy content is used.