Identification of some skeletal deformities in freshwater teleosts raised in Egyptian aquaculture

Scale-based landmark for internal organs assessments of common carp (Cyprinus carpio) during digital radiography and ultrasonography imaging

Medical imaging techniques such as digital radiography and ultrasonography are non-invasive and provide precise results for examining internal organs and structures within fish. Their effectiveness can be further enhanced by using body parts like scales as markers for the organs beneath them. This study utilized the number of scales as landmarks in digital radiography and ultrasonography to non-invasively evaluate the muscles, bones, and images of internal and reproductive organs of common carp (Cyprinus carpio). Digital radiography was performed in the dorsoventral and lateral views of the fish, whereas ultrasonography was conducted in longitudinal and transverse views on sequence scale numbers with brightness and colour Doppler-modes. Digital radiography of the common carp revealed the whole-body morphology, including the bony parts from the head, pectoral fins, dorsal fins, pelvic fins, anal fins, and vertebrae to the tail that appeared radiopaque. Internal organs were also observed, with the swim bladder and heart appeared radiolucent, while the intestines, liver, testes, and ovaries appeared radiopaque. Ultrasonography in brightness mode displayed the digestive organs, reproductive organs, and muscle thickness. Additionally, colour Doppler mode demonstrated blood flow within the heart's ventricle.

Evaluation of Mitigation Role of L-Phenylalanine-Based Low-Molecular-Weight Gelator against Oil Pollution-Induced Nile Tilapia Toxicity

A lot of oil is leaked into aquatic environments, significantly impacting fish health and, consequently, human populations. This study aimed to introduce an L-phenylalanine-based low-molecular-weight gelator (expressed as Z-Phe-C18) as a smart remediation tool for oil spills. Several groups of Nile tilapia were allocated in aquaria exposed to different doses of crude engine oil with/without the organogelator for 4 weeks. The results revealed a significant increase in biochemical oxygen demand, chemical oxygen demand, electrical conductivity, and total dissolved solids in water samples of fish aquaria exposed to oil pollution. The antioxidant activity levels, micronucleus formation, and expression patterns of stress-related genes were significantly higher in the livers of fish exposed to crude oil than in those of control fish. On the contrary, fish groups exposed to oil pollution and treated with the organogelator indicated that antioxidant enzymes, micronucleus incidence, and gene expression alteration of stress-related genes declined compared with those exposed to oil pollution only. The results suggest that oil pollution can induce oxidative stress via the enhancement of oxygen free radical formation. On the contrary, oil removal by the organogelator decreases oxidative stress and consequently strengthens fish immunity. So, we can conclude that organogelator treatment is promoting oxidative resistance development by increasing the activities of antioxidant enzymes, which are important in protection against oil pollution and preventing peroxidation of fish tissues. Promisingly, the organogelator could be used as a tool for the remediation of oil pollution in aquatic environments.

The growth performance of pond-reared common carp (Cyprinus carpio) larvae propagated using cryopreserved sperm

The aim of our study was to determine the efficacy of utilizing cryopreserved common carp sperm (in comparison to fresh sperm) for propagation at a Hungarian aquaculture facility. The sperm was frozen in 5 mL straws using an extender method that was previously tested in common carp. Sperm motility was monitored using a computer-assisted sperm analysis system. The hatching and malformation rates among the specimens were recorded before the stocking of larvae in both groups. The growth (body weight, total length) and survival rates of the fish were measured during the pre-nursing (from May to June: between 1 and 26 days post hatching) and grow-out periods (from June to October: between 26 and 105 days post hatching) of the same year. The fresh sperm, which was collected and pooled prior to fertilization, showed high MOT (97%), pMOT (92%), VCL (106 µm s-1), LIN (75%), and ALH (1.84 µm). Prior to the fertilization trial of the cryopreserved sperm, low MOT (34%), pMOT (14%), and VCL (61 µm s-1) values were observed in frozen-thawed sperm. A significantly higher hatching rate was measured in the fresh sperm group (87%) when compared to the cryopreserved sperm group (42%). No significant difference in the overall malformation rate was observed in larvae originating from either the fresh or frozen sperm. A significant difference between the two test groups was observed in the incidence of deformed tails (fresh: 20%, cryopreserved: 55%). Except for one sampling period, no significant difference in the body weight and total length of the fish larvae was found between the two groups throughout the pre-nursing and grow-out periods. A significantly higher larvae survival rate was noted in the fresh sperm (72%) as compared to the cryopreserved group (43%) by the end of the pre-nursing stage. However, no significant difference in survival rate was observed for the cryopreserved sperm (96%) in comparison to the fresh sperm (95%) by the end of the grow-out stage. The results of this study showed, for the first time in large-scale pond culturing, an equal growth and viability in larvae propagated from cryopreserved sperm when compared to fresh sperm (despite the limited available rearing ponds provided by the commercial company).

Global warming and glyphosate toxicity (II): Offspring zebrafish modelling with behavioral, morphological and immunohistochemical approaches

The increase in temperature due to global warming greatly affects the toxicity produced by pesticides in the aquatic ecosystem. Studies investigating the effects of such environmental stress factors on next generations are important in terms of the sustainability of ecosystems. In this study, the effects of parental synergistic exposure to glyphosate and temperature increase on the next generation were investigated in a zebrafish model. For this purpose, adult zebrafish were exposed to 1 ppm and 5 ppm glyphosate for 96 h at four different temperatures (28.5, 29.0, 29.5, 30.0 °C). At the end of this period, some of the fish were subjected to the recovery process for 10 days. At the end of both treatments, a new generation was taken from the fish and morphological, physiological, molecular and behavioral analysis were performed on the offspring. According to the results, in parallel with the 0.5-degree temperature increase applied to the parents with glyphosate exposure, lower survival rate, delay in hatching, increased body malformations and lower blood flow and heart rate were detected in the offspring. In addition, according to the results of whole mouth larva staining, increased apoptosis, free oxygen radical formation and lipid accumulation were detected in the offspring. Moreover, it has been observed that the temperature increases to which the parents are exposed affects the light signal transmission and serotonin pathways in the offspring, resulting in more dark/light locomotor activity and increased thigmotaxis.

Spinal malformations in a naturally isolated Neotropical fish population

Fish populations that reside in completely isolated freshwater ecosystems are rare worldwide. The Vila Velha State Park (VVSP), located in southern Brazil, is recognized for its arenitic formations called sinkholes (furnas), which are completely isolated. Fish populations within, such as those of Psalidodon aff. fasciatus, often develop vertebral malformations due to this isolation from other conspecifics and other species. In this study, we analyzed geometric morphology in digital radiographs to identify congenital deformations of Psalidodon aff. fasciatus in Furna 2 of VVSP. We found many fish with spinal deformities, including wide variation in the number of caudal vertebrae and corporal deformations related to a flattened body and spinal curvature. Females were more affected than males. We also demonstrated that these deformations reflect inbreeding and an absence of gene flow in the population. In conclusion, isolated populations such as fish species in furnas are potential models for evo-devo research.

Comparative Toxicity Assessment of Kratom Decoction, Mitragynine and Speciociliatine Versus Morphine on Zebrafish (Danio rerio) Embryos

Background: Kratom (Mitragyna speciosa Korth), a popular opioid-like plant holds its therapeutic potential in pain management and opioid dependence. However, there are growing concerns about the safety or potential toxicity risk of kratom after prolonged use.

Aim of the study: The study aimed to assess the possible toxic effects of kratom decoction and its major alkaloids, mitragynine, and speciociliatine in comparison to morphine in an embryonic zebrafish model.

Methods: The zebrafish embryos were exposed to kratom decoction (1,000–62.5 μg/ml), mitragynine, speciociliatine, and morphine (100–3.125 μg/ml) for 96 h post-fertilization (hpf). The toxicity parameters, namely mortality, hatching rate, heart rate, and morphological malformations were examined at 24, 48, 72, and 96 hpf, respectively.

Results: Kratom decoction at a concentration range of ≥500 μg/ml caused 100% mortality of zebrafish embryos and decreased the hatching rate in a concentration-dependent manner. Meanwhile, mitragynine and speciociliatine exposure resulted in 100% mortality of zebrafish embryos at 100 μg/ml. Both alkaloids caused significant alterations in the morphological development of zebrafish embryos including hatching inhibition and spinal curvature (scoliosis) at the highest concentration. While exposure to morphine induced significant morphological malformations such as pericardial oedema, spinal curvature (lordosis), and yolk edema in zebrafish embryos.

Conclusion: Our findings provide evidence for embryonic developmental toxicity of kratom decoction and its alkaloids both mitragynine and speciociliatine at the highest concentration, hence suggesting that kratom consumption may have potential teratogenicity risk during pregnancy and thereby warrants further investigations.

Prevalence, Virulence Gene Distribution and Alarming the Multidrug Resistance of Aeromonas hydrophila Associated with Disease Outbreaks in Freshwater Aquaculture

The study aims to evaluate the infection prevalence, virulence gene distribution and antimicrobial resistance of Aeromonas hydrophila associated in diseased outbreaks of cultured freshwater fish in Northern Vietnam. The confirmed A. hydrophila were screened for the presence of the five pitutative-virulence genes including aerolysin (aerA), hemolysin (hlyA), cytotonic enterotoxin (act), heat-labile cytotonic enterotoxin (alt), and heat-stable enterotoxin (ast), and examined the susceptibility to 16 antibiotics. A total of 236 A. hydrophila isolates were recovered and confirmed from 506 diseased fish by phenotypic tests, PCR assays, and gyrB, rpoB sequenced analyses, corresponding to the infection prevalence at 46.4%. A total of 88.9% of A. hydrophila isolates harbored at least one of the tested virulence genes. The genes aerA and act were most frequently found (80.5% and 80.1%, respectively) while the ast gene was absent in all isolates. The resistance to oxacillin, amoxicillin and vancomycin exhibited the highest frequencies (>70%), followed by erythromycin, oxytetracycline, florfenicol, and sulfamethoxazole/trimethoprim (9.3–47.2%). The multiple antibiotic resistance (MAR) index ranged between 0.13–0.88 with 74.7% of the isolates having MAR values higher than 0.2. The results present a warning for aquaculture farmers and managers in preventing the spread of A. hydrophila and minimizing antibiotic resistance of this pathogen in fish farming systems.

Axial Skeletal Malformations in Genetically Modified Xenopus laevis and Xenopus tropicalis

Skeletal malformations in captive-bred, adult Xenopus spp., have not previously been reported. Here we describe 10 sexually mature, genetically modified laboratory frogs (6 Xenopus laevis and 4 Xenopus tropicalis) with axial skeletal abnormalities. The young adult frogs were described by veterinary staff as presenting with "hunchbacks," but were otherwise considered to be in good health. All affected frogs were genetically engineered using various techniques: transcription activator-like effector nucleases (TALEN) editing using thyroid hormone receptor α TALEN mRNA, restriction enzyme-mediated integration methods involving insertion of the inducible transgene pCAR/TRDN, or via I-SceI meganuclease transgenesis using either pDRTREdpTR-HS4 or pDPCrtTA-TREG-HS4 plasmid sequences. Radiographic findings (6 frogs) and gross necropsy (10 frogs) revealed vertebral column malformations and sacroiliac deformities that resulted in moderate to severe kyphosis and kyphoscoliosis. These findings were confirmed and additional skeletal abnormalities were identified using computed tomography to create a 3D reconstruction of 4 frogs. Additional findings visible on the 3D reconstructions included incomplete vertebral segmentation, malformed transverse processes, and a short and/or curved urostyle. Histopathologic findings included misshapen intervertebral joints with nonconforming articular surfaces, narrowed joint cavities, flattened or irregularly-formed articular cartilage, irregular maturation lines and nonpolarized chondrocytes, excess fibrocartilage, and evidence of irregular bone resorption and growth. While the specific etiology of the vertebral skeletal abnormalities remains unclear, possibilities include: 1) egg/oocyte physical manipulation (dejellying, microinjection, fertilization, etc.), 2) induction and expression of the transgenes, 3) inactivation (knockout) of existing genes by insertional mutagenesis, or 4) a combination of the above. Furthermore, the possibility of undetected changes in the macro or microenvironment, or a feature of the genetic background of the affected frogs cannot be ruled out.

Pug-Headedness Anomaly in a Wild and Isolated Population of Native Mediterranean Trout Salmo trutta L., 1758 Complex (Osteichthyes: Salmonidae)

Skeletal anomalies are commonplace among farmed fish. The pug-headedness anomaly is an osteological condition that results in the deformation of the maxilla, pre-maxilla, and infraorbital bones. Here, we report the first record of pug-headedness in an isolated population of the critically endangered native Mediterranean trout Salmo trutta L., 1758 complex from Sardinia, Italy. Fin clips were collected for the molecular analyses (D-loop, LDH-C1* locus. and 11 microsatellites). A jaw index (JI) was used to classify jaw deformities. Ratios between the values of morphometric measurements of the head and body length were calculated and plotted against values of body length to identify the ratios that best discriminated between malformed and normal trout. Haplotypes belonging to the AD lineage and the genotype LDH-C1*100/100 were observed in all samples, suggesting high genetic integrity of the population. The analysis of 11 microsatellites revealed that observed heterozygosity was similar to the expected one, suggesting the absence of inbreeding or outbreeding depression. The frequency of occurrence of pug-headedness was 12.5% (two out of 16). One specimen had a strongly blunted forehead and an abnormally short upper jaw, while another had a slightly anomaly asymmetrical jaw. Although sample size was limited, variation in environmental factors during larval development seemed to be the most likely factors to trigger the deformities.

First record of pughead deformity in Cichla kelberi (Teleostei: Cichlidae), an invasive species in an estuarine system in south-eastern Brazil

The first record of pughead deformity in a Neotropical freshwater fish not raised in captivity is provided, based on an adult male of Cichla kelberi introduced into an estuary of Rio de Janeiro State, south-eastern Brazil. A general biological characterization of the specimen is provided and aspects of its aberrant anatomy are described. Environmental and biological factors that may cause pughead deformity in fishes are discussed.

Toxicomorphomics and toxicokinetics of quinalphos on embryonic development of zebrafish (Danio rerio) and its binding affinity towards hatching enzyme, ZHE1

This study outlines the toxic effects of Quinalphos (QP), an organophosphrous insecticide on the development of zebrafish (Danio rerio) embryos, with special emphasis on toxicomorphomics and toxicokinetics of target enzyme, AChE. A range of concentrations was used to elucidate the median lethal concentration (LC₅₀) of Quinalphos. Furthermore, embryos were exposed to two sub-lethal concentrations LC₁₀ (0.66mg/L) and LC₂₀ (1.12mg/L) along with a median lethal concentration (3.0mg/L) for 96h. Several morphological aberrations like lordosis, kyphosis, scoliosis, heart edema, breaks in the neuronal tube and underdeveloped facial parts were noticed, which were of concentration and time dependent. The QP has adequately hindered hatching process during the course of exposure which was upheld by the in silico docking studies with hatching enzyme, ZHE1. The length of hatchlings at 96h in LC₅₀ concentration was significantly reduced to 47% compared to control. A significant pericardial effusion (5 to 16 fold) was observed in >90% of LC₅₀ treated groups. Morphological changes in heart lead to the bradycardia, which ultimately leading to heart failure in some cases. The swimming behavior was significantly diminished in relation to the inhibition of AChE levels. From the in vitro kinetic studies, the kinetic constants K_m, V_max and inhibitory concentration K_i (4.45×10^-5M) was determined which supported the competitive nature of QP.

Morphological re-description and new geographical records for three digenean parasites infecting African sharptooth catfish Clarias gariepinus (Pisces: Clariidae) in Egypt

Sixty specimens of African sharptooth catfish Clarias gariepinus (Clariidae) were collected during the period of March 2014-February 2015 from boat landing sites and fishermen of the River Nile at Beni Suef Governorate, Egypt, and examined for the presence of digenean parasites. The morphology of these parasites was studied by using light microscopy to describe morphological and morphometrically measurements for different body parts. Three digenean species belonging to three different genera were collected from various organs within the examined fish species. A certain degree of site specificity was also observed, with Thaparotrema botswanensis being found only in the gall bladder of C. gariepinus, while both Pseudoholorchis clarii and Glossidium pedatum were found only in the intestine and thus seem to occupy a certain niche within their host. This study represent as the first record of T. botswanensis and G. pedatum from C. gariepinus, as well as the first report of the genera from the River Nile in Egypt. In addition, re-description of P. clarii clarifies measurements for some body parts.

An Anomalous Hatchery-Reared Biwa Rock Catfish, Silurus lithophilus (Teleostei: Siluridae),with an Adipose Fin-Like Projection

An anomalous individual with an adipose fin-like projection was discovered during seedling production of Biwa rock catfish, Silurus lithophilus (Teleostei: Siluridae). The external shape of the projection resembled an adipose fin, but soft rays were clearly observed within it. The projection was proximally supported by a series of pterygiophores and by 14 soft rays. The projection can be explained as: I, homologous with a primitive adipose fin, which occurred as a result of localized ontogenetic reversion; II, an extra fin that occurred as a result of abnormal expression of a regeneration mechanism; III, a remnant of a dorsal fin and/or a second dorsal fin; and IV, an inversion phenomenon of the polarity in the formation process of the anal fin.

Spinal deformities in a wild line of Poecilia wingei bred in captivity: report of cases and review of the literature

OBJECTIVE

To describe the occurrence of various spinal deformations in a captive-bred wild line of Poecilia wingei (P. wingei).

METHODS

Fish belonging to a wild line of P. wingei caught from Laguna de Los Patos, Venezuela, were bred in an aquarium home-breeding system during a period of three years (2006-2009). The spinal curvature was observed to study spinal deformities in P. wingei.

RESULTS

Out of a total of 600 fish, 22 showed different types of deformities (scoliosis, lordosis, kyphosis), with a higher incidence in females. Growth, swimming and breeding of deformed fish were generally normal.

CONCLUSIONS

Possible causes for spinal curvature in fish are discussed on the basis of the current literature. While it is not possible to determine the exact cause(s) of spinal deformities observed in the present study, traumatic injuries, nutritional imbalances, genetic defects or a combination of these factors can be supposed to be involved in the pathogenesis of such lesions.

Pathology survey on a captive-bred colony of the Mexican Goodeid, nearly extinct in the wild, Zoogoneticus tequila (Webb & Miller 1998)

The Mexican Goodeid, Zoogoneticus tequila, is considered nearly extinct in the wild and it is maintained in captivity by the nonprofit international “Goodeid Working Group.” The unique Italian colony has produced about 180 fish so far. The observable diseases were registered and some fish were submitted, immediately after spontaneous death, to necroscopic and histopathologic exams. Encountered diseases included the following: 7 cases of scoliosis (2 males and 5 females); 2 fish with a similar congenital deviation of ocular axis; 1 adult male with left corneal opacity, presumably of traumatic origin; 1 female fish with a large subocular fluid-filled sac, histologically referable to a lymphatic cyst, similarly to the eye sacs of a Goldfish variety (Carassius auratus) called bubble eye; and 1 female fish with recurrent abdominal distension consequent to distal bowel dilation and thinning, associated with complete mucosal atrophy, and comparable to intestinal pseudo-obstruction syndromes described in humans and various animal species. The absence of infectious or parasitic diseases, as well as the low incidence of diseases potentially related to environmental alterations or nutritional disorders such as spinal deformities, suggests the adequacy of breeding management techniques of Z. tequila for its conservation and reintroduction in to the original habitat in the near future.

Skeletal ossification impairment in Nile Tilapia (Oreochromis niloticus) after exposure to lead acetate

Heavy metal pollution represents a serious problem facing many of the aquatic organisms. Lead is one of the most toxic elements found in many industrial effluents which are metabolized inside bodies and can cause skeletal deformities by impairing developmental processes and bone formation. This study was undertaken to determine the LC50 of Pb-acetate and detect the effect of 1/10 LC50 exposure on fingerlings of Nile Tilapia (Oreochromis niloticus). Modern and accurate diagnostic methods were used; Scanning Electron Microscopy (SEM) of gills, plain X-ray and Energy-dispersive X-ray Spectroscopy (EDX) of the spinal column to explain the elemental analysis. The results indicated that the 96 h LC50 of lead acetate was 146.8 mg L(-1). SEM showed a distinct degeneration in gill filaments and pavement cells with increasing of mucus secretion after lead exposure. X-ray revealed slight dorsal spinal curvature. EDX analysis of the spinal column of treated fish showed decrease in calcium and phosphorus weight percents, on the other hand Pb appeared in treated fish but not in control ones. Finally this study can spot a light on the dangerous effects of lead toxicity in developing of fish and impairment of their skeletal ossification which may lead to skeletal deformities.

The enigmas of bone without osteocytes

One of the hallmarks of tetrapod bone is the presence of numerous cells (osteocytes) within the matrix. Osteocytes are vital components of tetrapod bone, orchestrating the processes of bone building, reshaping and repairing (modeling and remodeling), and probably also participating in calcium-phosphorus homeostasis via both the local process of osteocytic osteolysis, and systemic effect on the kidneys. Given these critical roles of osteocytes, it is thought-provoking that the entire skeleton of many fishes consists of bone material that does not contain osteocytes. This raises the intriguing question of how the skeleton of these animals accomplishes the various essential functions attributed to osteocytes in other vertebrates, and raises the possibility that in acellular bone some of these functions are either accomplished by non-osteocytic routes or not necessary at all. In this review, we outline evidence for and against the fact that primary functions normally ascribed to osteocytes, such as mechanosensation, regulation of osteoblast/clast activity and mineral metabolism, also occur in fish bone devoid of these cells, and therefore must be carried out through alternative and perhaps ancient pathways. To enable meaningful comparisons with mammalian bone, we suggest thorough, phylogenetic examinations of regulatory pathways, studies of structure and mechanical properties and surveys of the presence/absence of bone cells in fishes. Insights gained into the micro-/nanolevel structure and architecture of fish bone, its mechanical properties and its physiology in health and disease will contribute to the discipline of fish skeletal biology, but may also help answer questions of basic bone biology.

A major QTL controls susceptibility to spinal curvature in the curveback guppy

Background

Understanding the genetic basis of heritable spinal curvature would benefit medicine and aquaculture. Heritable spinal curvature among otherwise healthy children (i.e. Idiopathic Scoliosis and Scheuermann kyphosis) accounts for more than 80% of all spinal curvatures and imposes a substantial healthcare cost through bracing, hospitalizations, surgery, and chronic back pain. In aquaculture, the prevalence of heritable spinal curvature can reach as high as 80% of a stock, and thus imposes a substantial cost through production losses. The genetic basis of heritable spinal curvature is unknown and so the objective of this work is to identify quantitative trait loci (QTL) affecting heritable spinal curvature in the curveback guppy. Prior work with curveback has demonstrated phenotypic parallels to human idiopathic-type scoliosis, suggesting shared biological pathways for the deformity.

Results

A major effect QTL that acts in a recessive manner and accounts for curve susceptibility was detected in an initial mapping cross on LG 14. In a second cross, we confirmed this susceptibility locus and fine mapped it to a 5 cM region that explains 82.6% of the total phenotypic variance.

Conclusions

We identify a major QTL that controls susceptibility to curvature. This locus contains over 100 genes, including MTNR1B, a candidate gene for human idiopathic scoliosis. The identification of genes associated with heritable spinal curvature in the curveback guppy has the potential to elucidate the biological basis of spinal curvature among humans and economically important teleosts.

Spinal deformities in the black-striped pipefish Syngnathus abaster (Pisces, Syngnathidae) from the Tunis North Lake, Tunisia

Spinal deformities are seen in fishes. Deformities in the family Syngnathidae is rarely reported. Spine curvatures in natural population of pipefish, Syngnathus abaster are reported from the Tunis North Lake. The species is euryhaline and occurs along the Mediterranean coasts. Four hundred specimens of S. abaster were collected from January 2006 to December 2007 from the Tunis North Lake. Two specimens with skeletal abnormalities were described for the first time. X-rays radiographies revealed several vertebral deformities for each deformed specimen, especially at five curvation places of the caudal part. Several factors are believed to be the cause of spinal deformities of S. abaster in the Tunis North Lake, such as environmental disturbances, parasitism infection and nutritional factors.