Visceral Cavity Research Articles

Seasonal fluctuations of heavy metal accumulation and gastrointestinal helminth induce oxidative stress and histological lesions in resident catfish Clarias gariepinus

The exposure of the African catfish (Clarias gariepinus) to various environmental contaminants leads to physiological and histological alterations. Therefore, the study aimed to assess the impact of seasonal variations of ecological contaminants as external stressors and internal stressors via helminth infections on oxidative stress and histopathology in resident C. gariepinus at EL-Salam Canal, Egypt. Seasonal water and sediment samples were collected to assess physicochemical parameters and heavy metals. The length, weight, and sex were recorded for each fish sample. The gastrointestinal tract was dissected from the visceral cavity, and the helminths were extracted and identified using SEM photos based on their morphological characteristics. The parasitic dominance in the gastrointestinal helminths was calculated. The heavy metal concentrations, bioaccumulation (BAF), and biosedimentation (BSF) factors were considered in the muscles and intestine. Specimens of muscles and intestines were removed to determine oxidative status. In addition, pieces of skin, muscles, stomachs, and intestines were subjected to light microscopy to determine the alterations. The calcium, magnesium, and potassium levels were within safe limits. Sulfate levels consistently remained below the maximum permissible thresholds throughout the seasons. Among the heavy metals examined, the highest accumulation was found in the intestinal tissues of C. gariepinus, while muscle tissues showed lower levels. The variability in metal concentrations across water, sediment, muscles, and intestines underscores the different capacities of these environments to accumulate heavy metals. The elevated metal levels in fish tissues raise concerns about potential health risks for humans who consume contaminated fish, highlighting significant bioaccumulation within the food chain. The result indicated that Cu in the sediment samples was associated with parasite abundance. The dual stress from environmental pollutants and parasitic infections exacerbates oxidative stress and causes notable histopathological changes in the tissues of the catfish. These results highlight the intricate interplay between external and internal stressors, emphasizing the need for continuous monitoring and management of aquatic ecosystems to safeguard the health of resident fish populations. It provides insight into how these factors affect fish health.

Nematodes in Trichomycterus nigromaculatus (Pisces: Trichomycteridae) from the Río Gaira, Sierra Nevada de Santa Marta, Colombia

Objective. To determine the prevalence of helminth infection in Trichomycterus nigromaculatus captured in environments defined from the physicochemistry of the Gaira River, in Minca, Sierra Nevada de Santa Marta, Colombia. Material and Methods. We collected 476 specimens of T. nigromaculatus covering both climatic periods of the area, which were dissected to analyze the visceral cavity. Isolated parasites were fixed in 10% formalin for subsequent clarification. The specimens were identified by observation of adult stages under a stereoscopic microscope after clarification. Results. Specimens were found exclusively from the genus Spirocamallanus (Nematoda), the species Spirocamallanus sp. parasitic prevalence ranged from 0% in August to 28.57% in April with an abundance of 1.09 worms/host. Environmental parameters such as dissolved oxygen (Mean:5.65 mg. L-1, Max:7.5 mg. L-1, Min:4.41 mg. L-1); pH (Mean:7.2, Max: 9.3, Min: 5.7) and conductivity (Mean:72.82 µs.cm-1, Max: 123.7 µs.cm-1, Min: 40 µs.cm-1) presented statistically significant differences, the environment is eutrophicated. Conclusions. Spirocamallanus sp. were described in the areas of presence of the parasitic association in T. nigromaculatus, which constitutes a new record for the Colombian Caribbean and an extension of the geographic distribution and host range of the nematode.

The potential of a combination of pungent spices as a novel supplement in gilthead seabream (Sparus aurata) diets to aid in the strategic use of fish oil in aquafeeds: a holistic perspective.

This work studied the potential of a combination of pungent spices (capsicum, black pepper, ginger, and cinnamaldehyde) to be used as a supplement in diets of gilthead seabream (Sparus aurata; 44.1 ± 4.2g). During 90 days, fish were fed three experimental diets with low inclusion of fish oil and containing poultry fat as the main source of lipids, supplemented with graded levels of the tested supplement: 0 (control), 0.1 (SPICY0.1%), and 0.15% (SPICY0.15%). As a result, the pungent spices enhanced the growth performance, the activity of the bile-salt-activated lipase in the intestine, and decreased fat deposit levels within enterocytes. The SPICY0.1% diet reduced the feed conversion ratio and the perivisceral fat index and lipid deposits in the liver. Moreover, the ratio of docosahexaenoic acid/eicosapentaenoic acid in fillet increased in fish fed the SPICY0.1% diet, while the hepatic levels of docosahexaenoic acid and total n-3 polyunsaturated fatty acids increased in fish fed the SPICY0.15% diet. Furthermore, there was an effect on the expression of some biomarkers related to lipid metabolism in 2-h postprandial fish (fasn, elovl6, scd1b, cyp7a1, lpl, and pparβ), and in 48h fasted-fish fed with the SPICY0.1% diet, a regulation of the intestinal immune response was indicated. However, no significant differences were found in lipid apparent digestibility and proximate macronutrient composition. The spices did not affect biomarkers of hepatic or oxidative stress. No differences in microbial diversity were found, except for an increase in Simpson's Index in the posterior intestine of fish fed the SPICY0.1% diet, reflected in the increased relative abundance of the phylum Chloroflexi and lower relative abundances of the genera Campylobacter, Corynebacterium, and Peptoniphilus. In conclusion, the supplementation of gilthead seabream diets with pungent spices at an inclusion of 0.1% was beneficial to enhance growth performance and feed utilization; reduce fat accumulation in the visceral cavity, liver, and intestine; and improve the fish health status and condition. Results suggest that the tested supplement can be used as part of a nutritional strategy to promote a more judicious use of fish oil in fish diets due to its decreasing availability and rising costs.

The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones

Early Cretaceous (late Barremian – early Aptian) fissure fill deposits near Balve, North Rhine Westphalia, Germany, have yielded a rich continental vertebrate fauna over the course of the last two decades. More than 250 fragmentary specimens, including more than 150 osteoderms (i.e., granicones), represent the late Early Cretaceous helochelydrid Helochelydra nopcsai, which had previously been reported from the UK, France, and Spain. The new material mostly differs from that from the type section by exhibiting a reduced to absent entoplastral scute and by displaying distinct cranial scute sulci, both of which are interpreted as intraspecific variation. Although morphological insights are limited, the new material reveals that the visceral cavity extends anteriorly and posteriorly to the bridge, a relatively novel feature previously reported for an eclectic mix of compsemydids, pleurosternids, and other helochelydrids. The available sample of granicones reveals great shape diversity, but a morphometric analysis concludes that no distinct morphotypes exist.

Oxidative stress-related impairment of endothelial function in uncomplicated obesity

Purpose: Visceral obesity is associated with vascular oxidative stress and development of hypertension. Therefore, we tested the hypothesis that suppression of vascular oxidative stress in adults with visceral obesity would improve endothelium-dependent dilation. Methods: IV infusion of a water-soluble antioxidant (ascorbic acid) was performed in 15 middle-age obese adults (3 men/12 women) without diabetes or hypertension in a placebo-controlled, double-blinded, crossover study design. Ascorbic acid was infused at 0.06g/kg fat free mass in 100 ml saline at 5 mL/min over 20 min (bolus) followed by a drip infusion at 0.02 g/kg fat-free mass in 30 ml saline at 0.5 mL/min over 60 min. Endothelium-dependent dilation was assessed via brachial artery flow-mediated dilation (FMD) and expressed as % increase in diameter from baseline before forearm occlusion. Results: Android fat distribution in the visceral cavity (VAT%) was 39 ± 10% and body mass index (BMI) was 37 ± 6 kg/m2. IV infusion significantly increased plasma ascorbic acid concentrations (Baseline: 42 ± 2 vs. Bolus: 66 ± 6 vs. End: 62 ± 4 μmol/L, P<0.001). Compared with baseline, bolus infusion of ascorbic acid significantly increased FMD (Baseline: 5.8 ± 2.5 vs. Bolus: 9.0 ± 4.0 vs. End: 8.0 ± 4.2 %, P=0.01), which remained after statistically adjusting for the stimulus (shear rate area under the curve) via analysis of covariance (P=0.04). No significant change in FMD was observed following placebo (saline) during a separate study visit (Baseline: 8.0 ± 4.4 vs. Bolus: 8.3 ± 3.9 vs. End: 8.6 ± 2.9 %, P=0.86). Conclusions: These preliminary findings suggest that acute elevations in plasma ascorbic acid concentrations improve endothelium-dependent dilation in middle-aged adults with visceral obesity. Future studies should target mechanisms by which mediators of oxidative stress in obesity (e.g., hyperlipidemia, hyperinsulinemia) inhibit nitric oxide-mediated vasodilation. Funding and support: R01HL159370-01 (S.W.H.). This work was also supported by a CTSA grant from NCATS awarded to the University of Kansas for Frontiers: University of Kansas Clinical and Translational Science Institute (# UL1TR002366). The contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH or CTSA. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The effects of a structured physiotherapy program on pulmonary function and walking capacity in obese and non-obese adults undergoing cardiac surgery

BACKGROUND: Obesity is thought to be a risk factor for cardiopulmonary diseases due to changed pulmonary mechanics. It also drastically lowers functional capability in both males and females. A routine physiotherapy program has been shown to be effective in the prevention and treatment of cardiopulmonary diseases. It also significantly increases functional capacity following coronary artery bypass grafting. However, the effect of a structured physiotherapy program in obese and non-obese patients has not been well explored. As such, the objective of this study is to determine the effect of a standardized physiotherapy program on pulmonary function and walking capacity in obese and non-obese patients undergoing coronary artery bypass grafting. METHODS: A prospective study was conducted on 50 obese (age 57.2 ± 6.3 Y) and non-obese (age 56.6 ± 5.7 Y) adults who were schedule for coronary artery bypass grafting. Their body mass index was used to separate them into two groups. Both groups followed a structured physiotherapy program from day 1 to day 7 post cardiac surgery. Both groups underwent spirometry test at baseline (preoperatively) and after day 4 and day 7 postoperatively as well as a six-minute walk test at baseline and on day 7 postoperatively. RESULTS: At baseline, obese individuals had significantly lower pulmonary and physical functioning. On postoperative day 4, both groups deteriorated, although the obese group deterioration was worse, in most of the pulmonary parameters. On postoperative day 7, both groups improved, though the non-obese group improved at a faster rate. In contrary, it was observed that the obese group improved more rapidly in terms of functional capacity. CONCLUSIONS: The study indicated that the outcomes of a structured physiotherapy program following coronary artery bypass grafting were different for persons who were obese compared to those who were not. Adipose tissue variations surrounding the rib cage, diaphragm, and visceral cavity may account for the observed rate of change between the two groups. Therefore, it is apparent that a new strategy for managing obese individuals who have undergone CABG is required.

In vitro culture of the zoonotic nematode Anisakis pegreffii (Nematoda, Anisakidae)

BackgroundAnisakiasis is a foodborne disease caused by the third-stage larvae (L3) of two species belonging to the genus Anisakis: Anisakis pegreffii and Anisakis simplex sensu stricto. Both species have been the subject of different -omics studies undertaken in the past decade, but a reliable in vitro culture protocol that would enable a more versatile approach to functional studies has never been devised. In nature, A. pegreffii shows a polyxenous life-cycle. It reproduces in toothed whales (final host) and disseminates embryonated eggs via cetacean faeces in the water column. In the environment, a first- (L1) and second-stage larva (L2) develops inside the egg, and subsequently hatched L2 is ingested by a planktonic crustacean or small fish (intermediate host). In the crustacean pseudocoelom, the larva moults to the third stage (L3) and grows until the host is eaten by a fish or cephalopod (paratenic host). Infective L3 migrates into the visceral cavity of its paratenic host and remains in the state of paratenesis until a final host preys on the former. Once in the final host’s gastric chambers, L3 attaches to mucosa, moults in the fourth stage (L4) and closes its life-cycle by becoming reproductively mature.MethodsTesting two commercially available media (RPMI 1640, Schneider’s Drosophila) in combination with each of the six different heat-inactivated sera, namely foetal bovine, rabbit, chicken, donkey, porcine and human serum, we have obtained the first reliable, fast and simple in vitro cultivation protocol for A. pegreffii.ResultsSchneider’s Drosophila insect media supplemented with 10% chicken serum allowed high reproducibility and survival of adult A. pegreffii. The maturity was reached already at the beginning of the third week in culture. From collected eggs, hatched L2 were maintained in culture for 2 weeks. The protocol also enabled the description of undocumented morphological and ultrastructural features of the parasite developmental stages.ConclusionsClosing of the A. pegreffii life-cycle from L3 to reproducing adults is an important step from many research perspectives (e.g., vaccine and drug–target research, transgenesis, pathogenesis), but further effort is necessary to optimise the efficient moulting of L2 to infective L3.Graphical

Occurrence of Eustrongylides sp. (Nematoda: Dioctophymatidae) in Fish Species Collected in the Peruvian Amazonia and Its Implications for Public Health.

The present study aims to report the occurrence of Eustrongylides sp. in some neotropical fish species commercialized in the Peruvian Amazonia. Samples of young farmed Arapaima gigas were collected from a fish farmer; young Brachyplatystoma tigrinum were acquired from a fish exporter and samples of adult specimens of Acestrorhynchus falcirostris, Pseudoplatystoma punctifer, Cichla monoculus, Hoplias malabaricus, Hydrolycus scomberoides, Raphiodon vulpinus, and Serrasalmus rhombeus were acquired from a fish market of Iquitos, Loreto-Peru. Samples were transported to the "Laboratorio de Parasiología y Sanidad Acuícola" from "Instituto de Investigaciones de la Amazonía Peruana" located in Iquitos, Peru. Larvae L4 of Eustrongylides sp. were found in the host body, in the muscle, and in the visceral cavity of studied fish species. Notorious damages were reported in young A. gigas (lumps in the muscle, inflammation and severe redness of the skin) and in young B. tigrinum (perforation of the abdominal cavity), while in adult specimens of the remaining species, no external damage was reported. The presence of Eustrongylides sp. in various fish species collected in the city of Iquitos-Peru contributes to the distribution of this parasite in the Peruvian Amazon, reporting it, for the first time in this country. Its presence in the muscle of various fish species commercialized in fish markets, warm a possible public health concern and implications for their marketability in the city of Iquitos, Peru.

A severe microsporidian disease in cultured Atlantic Bluefin Tuna (Thunnus thynnus)

One of the most promising aquaculture species is the Atlantic bluefin tuna (Thunnus thynnus) with high market value; disease control is crucial to prevent and reduce mortality and monetary losses. Microsporidia (Fungi) are a potential source of damage to bluefin tuna aquaculture. A new microsporidian species is described from farmed bluefin tunas from the Spanish Mediterranean. This new pathogen is described in a juvenile associated with a highly severe pathology of the visceral cavity. Whitish xenomas from this microsporidian species were mostly located at the caecal mass and ranged from 0.2 to 7.5 mm. Light and transmission electron microscopy of the spores revealed mature spores with an average size of 2.2 × 3.9 μm in size and a polar filament with 13–14 coils arranged in one single layer. Phylogenetic analysis clustered this species with the Glugea spp. clade. The morphological characteristics and molecular comparison confirm that this is a novel microsporidian species, Glugea thunni. The direct life-cycle and the severe pathologies observed makes this parasite a hard risk for bluefin tuna cultures.

Infection Rate in Seabasses Fed with Viscera Parasitised by Anisakid Larvae.

It has been suggested that the removal of infected viscera on board is responsible for the high prevalence of anisakid larvae present in wild fish species. The aim of this work is to assess the re-infection capacity of anisakid larvae in European seabasses, a natural host species for the parasite by feeding with pieces of parasitised hake liver under controlled experimental conditions. To prove this potential link between manipulation and re-infestation, 50 farmed seabasses free of anisakid nematodes were fed with fresh hake liver pieces naturally infested with anisakid larvae. After digestion periods from 4 to 21days, the seabasses showed a prevalence of Anisakis of 6%, and a low retention rate of 0.11 larvae/seabass after four days' digestion, and 0.0021 after 21day digestion. Two nematodes were found in the intestine and in the visceral cavity, and 13 Anisakis were found partially digested in the stomach of one same individual after 4day digestion. Results showed that only a small number of Anisakis ingested with the viscera were able to reinfect the seabasses, as most of the larvae seemed to be quickly digested or defecated. it seems that the availability of larvae that could re-enter the life cycle and re-infect a fish after the removal and discarding the infected viscera on board could be much less important than commonly believed.

Detection of pathogenic Aeromonas hydrophila from two rainbow trout (Oncorhynchus mykiss) farms in Peru.

Fish farms are one of the principal food industries located in peri-urban and rural communities that use available resources to ensure the quality of their products. However, trout can suffer from bacterial infections affecting the sector and being a key component of human health risk. We aimed to identify and characterize Enterobacteriaceae in 46 trout (Oncorhynchus mykiss) in two fish farms in Lima, Peru. Adult trouts older than seven weeks (> 200 grams weight) were included. Cultures were performed in duplicate (n=192 trials) with swabs from the squamous surface and visceral cavity. The isolates were identified with the Vitek® 2 Compact system, and the minimum inhibitory concentrations (MIC) were interpreted with the CLSI VET 03-A guide. At El Molino and El Angelito fish farms, 66 (68.8%) and 57 (59.4%) isolates were obtained. The most frequently isolated species were Escherichia coli (56.8%), Proteus sp. (4.2%) and Klebsiella pneumoniae (2.6%). E. coli was present in all sampling areas, and Aeromonas hydrophila was only present in one open viscera sample at El Angelito fish farm. A. hydrophila showed antibiotic resistance to Ampicillin/Sulbactam (≥32 MIC), Oxytetracycline (>8 MIC), Imipenem (8 MIC), Levofloxacin (>8 MIC), and Ceftazidime (≥64 MIC). Our results suggest the presence of multi-resistant A. hydrophila in O. mykiss. Further studies are needed to understand the developmental context of A. hydrophila, which is crucial to the food industry, aquaculture and public health.

Brown adipose tissue prevents glucose intolerance and cardiac remodeling in high-fat-fed mice after a mild myocardial infarction

BackgroundObesity increases the risk of developing impaired glucose tolerance (IGT) and type 2 diabetes (T2D) after myocardial infarction (MI). Brown adipose tissue (BAT) is important to combat obesity and T2D, and increasing BAT mass by transplantation improves glucose metabolism and cardiac function. The objective of this study was to determine if BAT had a protective effect on glucose tolerance and cardiac function in high-fat diet (HFD) fed mice subjected to a mild MI.MethodsMale C57BL/6 mice were fed a HFD for eight weeks and then divided into Sham (Sham-operated) and +BAT (mice receiving 0.1 g BAT into their visceral cavity). Sixteen weeks post-transplantation, mice were further subdivided into ±MI (Sham; Sham-MI; +BAT; +BAT-MI) and maintained on a HFD. Cardiac (echocardiography) and metabolic function (glucose and insulin tolerance tests, body composition and exercise tolerance) were assessed throughout 22 weeks post-MI. Quantitative PCR (qPCR) was performed to determine the expression of genes related to metabolic function of perigonadal adipose tissue (pgWAT), subcutaneous white adipose tissue (scWAT), liver, heart, tibialis anterior skeletal muscle (TA); and BAT.Results+BAT prevented the increase in left ventricle mass (LVM) and exercise intolerance in response to MI. Similar to what is observed in humans, Sham-MI mice developed IGT post-MI, but this was negated in +BAT-MI mice. IGT was independent of changes in body composition. Genes involved in inflammation, insulin resistance, and metabolism were significantly altered in pgWAT, scWAT, and liver in Sham-MI mice compared to all other groups.ConclusionsBAT transplantation prevents IGT, the increase in LVM, and exercise intolerance following MI. MI alters the expression of several metabolic-related genes in WAT and liver in Sham-MI mice, suggesting that these tissues may contribute to the impaired metabolic response. Increasing BAT may be an important intervention to prevent the development of IGT or T2D and cardiac remodeling in obese patients post-MI.

Abstract P002: Associations Of Bone Fracture Outcomes With Body Compositions Measurements In A Fragility Fracture Clinic Population

Introduction: While preoperative bone health optimization is typical in the fragile population, objective assessment is limited. Among the aged, localized discordance in bone loss is prevalent and may not be assessed properly with traditional diagnostic measures. Etiology for bone loss discordance is unknown, but may be attributed to aging, disease state, habitus, or activity. This study investigated the association between body composition measures and common fragility fractures. Hypothesis: We hypothesized that each different fracture outcome would associate differently with measures of body composition. Methods: The Fragility Fracture Clinic at the University of Michigan provides comprehensive care to promote bone health, accelerate healing, and reduce fracture risk in those with and at-risk for fractures. Participants (N=344) included those who enrolled at the clinic between 2013 and 2020 and received an abdomen and/or pelvis computed tomography (CT) scan up to 120 days prior to initial enrollment date. Fracture categorizations included acute vs. non-acute, intensity (high vs. low energy), and location (thoracic vs. lumbar vertebral). Retrospective CT-scans were obtained from the University of Michigan Picture Archive and Communication System. Analytic Morphomics was used to obtain granular vertebral-indexed measurements of vertebral bone density, fascia, adipose tissue, muscle, vasculature, and interior body dimensions. Relevant measures include bone mineral density (BMD) [vertebral body trabecular bone density in Hounsfield Units (HU)], lower muscle group density in HU (DMG) (cross sectional area of DMG in HU range of 31-100), cortical bone density [anterior cortical half-maximum (in HU)], and fascial width (in mm). Measurements were divided by their standard deviation to ease interpretation of odds ratios. Multivariable logistic regression was used to evaluate the relationship between body measures and fracture type. Coefficients are reported as odds ratio (OR) and 95% confidence interval (CI). An alpha level of 0.05 determine statistical significance. Results: Associations were observed between acute fracture and BMD at L3 [OR 0.58, 95% CI 0.36-0.85]; high energy fracture and DMG at L3 [OR 2.08, 1.05-4.64]; low energy fracture and BMD at T8 [OR 0.39, 0.17-0.81]; thoracic vertebral fractures and BMD at T11 [OR 0.39, 0.17-0.81], cortical bone density at T11 [OR 0.64, 0.40-0.95], and fascial width at L4 [OR 0.67, 0.43-0.98]; lumbar vertebral fracture and BMD at L3 [OR 0.44, 95% CI 0.20-0.88]. Conclusion: Body composition measures uniquely associated with fracture outcomes. Lower vertebral trabecular bone density was associated with acute, high energy, thoracic vertebral, and lumbar vertebral fractures; lower lean muscle with high energy fractures; cortical bone density and facial (i.e. visceral cavity) width with thoracic vertebral fractures.

A Juvenile Specimen of Archaeorhynchus Sheds New Light on the Ontogeny of Basal Euornithines

The ontogenetic development of extant birds is characterized by rapid growth, bone fusion and an early onset of flight ability. In contrast, little is known about how these ontogenetic traits evolved in the bird stem lineage, and the available data pertains primarily to Enantiornithes. Here, we describe an almost complete skeleton of a juvenile euornithine bird (LNTU-WLMP-18) from the Early Cretaceous Jiufotang Formation (Aptian), which was discovered near Lamadong Town (Jianchang County, Liaoning, China). Despite its completeness, bone preservation is rather poor. Thus, to increase the contrast between bone tissue and matrix, we used cyan-red-based autofluorescence photography. The specimen is more or less articulated and exposed in ventral aspect. The jaws are edentulous, the coracoid bears a procoracoid process, and the ischium lacks a proximodorsal process. The pedal unguals are short and barely curved, indicating a ground-dwelling lifestyle. Feathers, including long primaries, are present as carbonized traces. Several characters indicate that LNTU-WLMP-18 is a juvenile: the bone surface has a coarsely striated texture and no fusion is evident between the carpals and metacarpals, between the tibia and the astragalus and calcaneum, or among the metatarsals. Although juvenile characters have the potential to impede accurate identification of the specimen, morphological comparisons and cladistic analysis identify LNTU-WLMP-18 as most likely referable to the basal euornithineArchaeorhynchus, which would make the specimen the first juvenile bird from the Jehol Group that could be assigned to a specific taxon. Based on its size and the incomplete ossification of the bone surface, LNTU-WLMP-18 represents the smallest and therefore youngest known individual of this genus. A statistical comparison of limb proportions shows that the forelimbs of LNTU-WLMP-18 are significantly shorter than the hindlimbs, while the forelimbs are longer than the hindlimbs in subadult and adult individuals. This is different from the situation in some Enantiornithes, in which the forelimbs exceed the length of the hindlimbs even in hatchlings. Similar to Enantiornithes,Archaeorhynchusprobably exhibit an early onset of flight ability, as indicated by the extensive wing plumage in LNTU-WLMP-18. Finally, the lack of gastroliths in the visceral cavity might indicate a dietary shift inArchaeorhynchusduring ontogeny. As a small-bodied, ground-dwelling, seed-eating bird with a precocial ontogeny,Archaeorhynchusfilled an ecological niche that later allowed early crown birds to survive the K-Pg mass extinction.

Effectiveness of Gutting Blue Whiting (Micromesistius poutassou, Risso, 1827), in Spanish Supermarkets as an Anisakidosis Safety Measure.

Anisakidosis is a parasitic zoonotic disease which can cause gastroallergic reactions in humans. In 2010, the European Food Safety Agency estimated that approximately 20,000 cases of anisakiasis had been reported across the world, with Spain having the highest number of infections in Europe. The blue whiting (Micromesistius poutassou, Risso, 1827) is one of the most widely fished species worldwide and represents around 25% of the white fish eaten in Spain. The Spanish Food Safety Authority requires obligatory evisceration of certain fish species before commercialization, but not for blue whiting. Nevertheless, some supermarkets carry this out themselves to prevent human infections and negative customer reactions deriving from the presence of ascaridoid larvae. To assess the effectiveness of eviscerations at supermarkets, a total of 320 blue whiting specimens were examined. The risk of larval migration from the visceral cavity to the musculature in gutted and ungutted fish was also assessed. Our results showed a total prevalence (25%) of ascaridoids in fish gutted at the supermarket, and a direct relationship was found between the presence of larvae in the muscle and time until evisceration. In ungutted fish, the standard length and weight were higher for infected than for non-infected fish. Also, massive infections had a higher prevalence in these larger specimens, in which the viability of larvae was also high. Larval viability was not found to be affected by a 24-h refrigeration period. Anisakis was the most prevalent genus identified in the fish examined. The results indicate that gutting at the supermarket is not an effective method for the total removal of ascaridoid larvae and that additional safety measures are advisable.

Description of the unusual digestive tract of Platax orbicularis and the potential impact of Tenacibaculum maritimum infection.

BackgroundEphippidae fish are characterized by a discoid shape with a very small visceral cavity. Among them Platax orbicularis has a high economic potential due to its flesh quality and flesh to carcass ratio. Nonetheless, the development of its aquaculture is limited by high mortality rates, especially due to Tenacibaculum maritimum infection, occurring one to three weeks after the transfer of fishes from bio-secure land-based aquaculture system to the lagoon cages for growth. Among the lines of defense against this microbial infection, the gastrointestinal tract (GIT) is less studied. The knowledge about the morphofunctional anatomy of this organ in P. orbicularis is still scarce. Therefore, the aims of this study are to characterize the GIT in non-infected P. orbicularis juveniles to then investigate the impact of T. maritimum on this multifunctional organ.MethodsIn the first place, the morpho-anatomy of the GIT in non-infected individuals was characterized using various histological techniques. Then, infected individuals, experimentally challenged by T. maritimum were analysed and compared to the previously established GIT reference.ResultsThe overlapped shape of the GIT of P. orbicularis is probably due to its constrained compaction in a narrow visceral cavity. Firstly, the GIT was divided into 10 sections, from the esophagus to the rectum. For each section, the structure of the walls was characterized, with a focus on mucus secretions and the presence of the Na+/K+ ATPase pump. An identification key allowing the characterization of the GIT sections using in toto histology is given. Secondly, individuals challenged with T. maritimum exhibited differences in mucus type and proportion and, modifications in the mucosal and muscle layers. These changes could induce an imbalance in the trade-off between the GIT functions which may be in favour of protection and immunity to the disadvantage of nutrition capacities.

Taxonomy and 18S rDNA-based phylogeny of Henneguya multiradiatus n. sp. (Cnidaria: Myxobolidae) a parasite of Brochis multiradiatus from Peruvian Amazon

A new myxozoan species belonging to the genus Henneguya was isolated from the serous membrane of the visceral cavity of the hognosed catfish Brochis multiradiatus from Peruvian Amazon. Whitish plasmodia, macroscopically visible, were found in four of the thirty examined fishes. Mature myxospores were ellipsoidal in shape in frontal view and had a total length of 44.5 ± 0.6 μm (43.9–45.1), spore body measured 18.7 ± 0.9 μm (16.8–19.6) in length, 7.1 ± 0.2 μm (6.6–7.4) in width and 5.5 ± 0.3 μm (4.9–5.6) in thickness. The two polar capsules were elongated and equal in size, measuring 9.1 ± 0.1 μm (8.8–9.4) in length and 1.7 ± 0.1 μm (1.6–1.8) in width, occupying half of the myxospore body. Polar tubules coiled in 10–11 turns perpendicular to the long axis of the polar capsule. The caudal appendage was not bifurcated and measured 25.8 ± 0.6 μm (24.7–26.5) in length. The sequencing of the 18S rDNA gene resulted in 1400 bp and this sequence did not match any of the myxozoans available in GenBank. Phylogenetic analysis placed the new species in a well-supported subclade of Henneguya spp. infecting callichthyid fishes, with Henneguya loretoensis being the closest species. This study is the first description of a myxozoan species, Henneguya multiradiatus n. sp. from a fish of the genus Brochis.

First Occurrence of Eustrongylides spp. (Nematoda: Dioctophymatidae) in a Subalpine Lake in Northwest Italy: New Data on Distribution and Host Range.

The genus Eustrongylides includes nematodes that infect fish species and fish-eating birds inhabiting freshwater ecosystems. Nematodes belonging to the genus Eustrongylides are potentially pathogenic for humans; infection occurs after the consumption of raw or undercooked fish. In the two-year period 2019–2020, a total of 292 fish belonging to eight species were examined for the occurrence of Eustrongylides spp. from Lake San Michele, a small subalpine lake in northwest Italy. The prevalence of infestation was 18.3% in Lepomis gibbosus, 16.7% in Micropterus salmoides, and 10% in Perca fluviatilis. The other five fish species (Ameiurus melas, Ictalurus punctatus, Squalius cephalus, Carassius carassius, and Scardinius erythrophthalmus) were all negative for parasite presence. There were no significant differences in prevalence between the three fish species (Fisher’s exact test; p = 0.744). The mean intensity of infestation ranged from 1 (M. salmoides and P. fluviatilis) to 1.15 (L. gibbosus), and the mean abundance ranged from 0.1 (P. fluviatilis) to 0.28 (L. gibbosus). There were significant differences in the infestation site between the four muscle quadrants (anterior ventral, anterior dorsal, posterior ventral, and posterior dorsal) and the visceral cavity (Kruskal–Wallis test; p = 0.0008). The study findings advance our knowledge about the distribution and host range of this parasite in Italy.

Anatomy of the visceral cavity of Eugerres mexicanus (Teleostei: Gerreidae)

Introduction. The visceral cavity of teleostean fishes contains the kidneys, digestive tube and annexed glands, gas bladder, gonads, and spleen. Objective: To analyze and describe the anatomic relationships of the organs of the visceral cavity of the Mexican mojarra, Eugerres mexicanus. Methods: By means of dissections, we analyzed, described and illustrated the splanchnology of the visceral cavity of 10 adult specimens from the State of Chiapas, Mexico. Results: The visceral cavity is delimited by the precaudal vertebrae, the scapular and pelvic girdles, the pleural ribs, the first anal pterygiophore and several myotomes. Both kidneys, with extraperitoneal character are partially fused each other, and contact the neurocranium, the precaudal vertebrae, and the gas bladder. The digestive tube does not present a stomach nor pyloric caeca, and it is 1.3 the standard length of the fish. The liver has two short right lobes. Both ovaries and testes are wide and reach the liver. The spleen is ovoid and is located on the left side of the duodenum. The gas bladder has two anterior lobes, its posterior end is in direct contact with the floor of the visceral cavity, and contain the urinary bladder. Discussion: The organization of the organs in the visceral cavity is in the anatomical pattern of the teleostean fishes, however, the organ that shows the highest number of special characters is the gas bladder, which as in other species of Eugerres is large and shows two notable anterior lobes, reinforced by epipleural ribs. Compared with other species of Eugerres, the Mexican mojarra shows, as exclusive characters: a) the union of the posterior end of the gas bladder with the floor of the visceral cavity, and, b) the location of the urinary bladder within the gas bladder.

A rare bird of Czechia: Case of homozygous female Fabry disease patient

A new myxozoan species belonging to the genus Henneguya was isolated from the serous membrane of the visceral cavity of the hognosed catfish Brochis multiradiatus from Peruvian Amazon. Whitish plasmodia, macroscopically visible, were found in four of the thirty examined fishes. Mature myxospores were ellipsoidal in shape in frontal view and had a total length of 44.5 ± 0.6 μm (43.9–45.1), spore body measured 18.7 ± 0.9 μm (16.8–19.6) in length, 7.1 ± 0.2 μm (6.6–7.4) in width and 5.5 ± 0.3 μm (4.9–5.6) in thickness. The two polar capsules were elongated and equal in size, measuring 9.1 ± 0.1 μm (8.8–9.4) in length and 1.7 ± 0.1 μm (1.6–1.8) in width, occupying half of the myxospore body. Polar tubules coiled in 10–11 turns perpendicular to the long axis of the polar capsule. The caudal appendage was not bifurcated and measured 25.8 ± 0.6 μm (24.7–26.5) in length. The sequencing of the 18S rDNA gene resulted in 1400 bp and this sequence did not match any of the myxozoans available in GenBank. Phylogenetic analysis placed the new species in a well-supported subclade of Henneguya spp. infecting callichthyid fishes, with Henneguya loretoensis being the closest species. This study is the first description of a myxozoan species, Henneguya multiradiatus n. sp. from a fish of the genus Brochis.