Captive Rearing of Longfin Smelt Spirinchus thaleichthys: First Attempt of Weaning Cultured Juveniles to Dry Feed

The rapid decline of longfin smelt Spirinchus thaleichthys, a threatened euryhaline forage fish in California, is a serious concern for scientists and resource managers. To recover and conserve this species, a captive culture program was initiated, focusing on the collection, captive rearing and breeding of wild broodstock, and the rearing of their offspring. Although progress has been made in the collection of broodstock and the production and culturing of larvae, no studies have evaluated the rearing of juvenile life stages in captivity. The present study examines methodological considerations for culturing F1 juvenile longfin smelt, specifically, the first efforts toward weaning juveniles to a dry commercial pellet feed. Cultured juvenile longfin smelt were fed live Artemia only or co-fed Artemia and dry feed for 62 days, and the effects of feed type on juvenile survival, growth, body condition, and fatty acid profiles were examined. No significant differences were observed between feeding treatments, despite an 80% reduction in Artemia in the co-feeding treatment. Furthermore, examination of fish stomach contents at the end of the trial confirmed the transition to dry feed. This is the first study to indicate successful feeding by longfin smelt on dry commercial pellets, and suggests that juvenile longfin smelt can be fully weaned onto dry feeds. Results of this study are critical for closing the lifecycle of longfin smelt in captivity and developing a successful conservation culture program for this imperiled species.

Spinal paraganglioma at the conus medullaris mimicking schwannoma: A case report

Background

Paragangliomas of the spine are extremely rare, and they should be considered in the differential diagnosis of spinal tumors due to its overlapping clinical and radiological features with many spinal tumors.

Case report

In this article, we present a 30-year-old lady who presented with low back pain and radicular neuropathic pain at L1 dermatome which was intractable to medical surgery. Her magnetic resonance imaging (MRI) of the lumbosacral spine revealed a T1 isointense, T2 heterogeneously hyperintense intradural extramedullary lesion at the conus medullaris with strong homogenous enhancement on contrast administration. The lesion was surgically excised completely with L1 laminectomy, and the histopathological picture was suggestive of paraganglioma. The patient's complaints resolved fully postoperatively, and there was no evidence of recurrence on long-term follow-up.

Conclusion

Due to the absence of pathognomonic clinical or radiological features of paragangliomas, they should be taken into consideration in the differential diagnosis of spinal tumors. They share similar clinical and radiological features of schwannomas, ependymomas, and hemangioblastomas. The diagnosis is usually made postoperatively based on histopathological examination.

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Paragangliomas overlap the clinical and radiological features with other tumors.

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Diagnosis is made postoperatively based on histopathological examination.

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It should be considered in the differential diagnosis of spinal tumors.

Outcomes and technical issues of transcorporeal anterior cervical microforaminotomy in patients with cervical brachialgia

INTRODUCTION

Transcorporeal anterior cervical microforaminotomy is a motion-preserving surgery. It addresses directly to the prolapsed disc in contrast to posterior laminoforaminotomy and does not affect facet joints; in the transuncal approach, there is a chance of vertebral artery injury and it also decreases disc height; hence, may alter the motion of that segment.

OBJECTIVE

Aim is to assess the outcome of surgery and its effectiveness.

METHODS

A total of 40 patients were observed retrospectively of which 33 were male and 7 were female. A single study of transcorporeal anterior cervical microforaminotomy was analyzed in a private hospital (Comfort Hospital), Dhaka, Bangladesh. Patients having pure brachialgia who were not relieved by conservative treatment over 6-8 weeks in cervical disc prolapse were included in the study. Patients having more than one level of disease, features of myelopathy, or instability were excluded from the study.

RESULTS

All patients were pain-free postoperatively, although after one to two months 2 out of 40 patients developed brachialgia and required anterior cervical discectomy and fusion.

CONCLUSION

Transcorporeal microforaminotomy for brachialgia is a safe and effective approach that is motion preserving and minimally invasive as well.

The clinical aspects of septo-optic dysplasia: A narrative review with illustrative case report

INTRODUCTION AND IMPORTANCE

Septo-optic dysplasia (SOD) is a rare congenital disorder characterized by abnormal development of the optic nerve, pituitary gland, hypothalamus, and midline brain structures, with heterogeneous presentation among cases.

CASE PRESENTATION

We report a seven-month-old male infant presented with persistent vomiting and delayed developmental milestones. He had dysmorphic facial features, bilateral esotropia, a head circumference of 50 cm, and scoliosis. His muscle tone was high (clasp-knife spasticity) and his deep tendon reflexes were brisk in the four limbs. Clinical evaluation and brain MRI confirmed the diagnosis of SOD, for which, he was subjected for multidisciplinary evaluation. Genetic testing revealed an autosomal dominant TUBB gene mutation. On follow-up, at the age of three years, he presented with recurrent focal motor and generalized seizures, which were controlled with levetiracetam.

CLINICAL DISCUSSION

The ophthalmic manifestations of SOD include optic nerve hypoplasia, which can lead to visual impairments such as nystagmus, strabismus, and reduced visual acuity. Midline brain anomalies involve structures like the corpus callosum and septum pellucidum, and can result in cognitive and neurological deficits. Hypothalamic-pituitary axis abnormalities can cause endocrine dysfunction and growth abnormalities. The clinical heterogeneity of SOD is attributed to variable phenotypic penetration and genetic mutations. Environmental risk factors may also contribute to the development of the syndrome.

CONCLUSION

SOD is a complex disorder with diverse clinical manifestations. Early diagnosis and multidisciplinary management are crucial for optimizing patient outcomes. Further research is needed to understand the underlying genetic and environmental factors involved in SOD and to develop targeted treatments.

Anterior cervical microforaminotomy for persistent brachialgia in a patient with multilevel cervical spondylosis; comparing PROMIS with Nurick score for outcome of surgery

Introduction and importance

The primal instinct of neurosurgeons has been to maintain spinal stability and motion since the beginning of spinal procedures. Conventional anterior approaches without fusion eliminate motion in time as fusion invariably sets in and hampers the vertebral column's normal dynamic physiology.

Case presentation

We reported a 60 years old male patient who presented with signs of myelopathy, but his primary complaint was brachialgia. He had myelopathic features for eight years, for which he offered fusion surgery at multiple levels years ago, and he denied it. He was static since then, and the disease did not progress further. For intolerable pain, he agreed to minimally invasive surgery. Therefore, we operated for a right C6 transcorporeal microforaminotomy and removed the inciting disc material.

Clinical discussion

Clinical implication for anterior cervical microforaminotomy for this patient was successful where there was acute disc prolapse in cervical spondylotic myelopathy.

Conclusion

Finally, functional preservation of the cervical spine in multilevel spondylosis can optimize the fusion. In this case, the report authors have explored the comparison between the PROMIS score and the Nurick score, reporting for the first time.

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Functional retention of cervical spine can boost fusion in multilevel spondylosis.

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Clinical efficacy of cervical microforaminotomy in acute disc prolapse is effective.

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The case report shows comparison of PROMIS score and Nurick score for the first time.

A rare case of pituicytoma-related hyperprolactinemia due to mass effect on infundibular stalk-Case report

INTRODUCTION AND IMPORTANCE

Pituicytomas are extremely rare cancers of the sellar and suprasellar region that appear from the infundibulum or posterior pituitary. World Health Organization in 2007, described pituicytoma as a low-grade tumour (Grade I) in the taxonomy of CNS cancers. The tumour can frequently simulate a pituitary adenoma and is also linked with hormonal disorders. Distinguishing a pituitary adenoma from a pituicytoma can be challenging. We present a rare case report where an elderly female showed high levels of prolactin mainly due to mass effects along with diagnostic, imaging, and immunohistochemical characteristics of pituicytoma.

CASE PRESENTATION

A 50-year-old female known case of hypothyroidism, complained of headache associated with dizziness and blurry vision. Her prolactin levels were high which led to the suspicion of pituitary involvement and underwent MRI. The imaging study revealed a well-defined, completely suprasellar, homogenously enhancing mass lesion arising from the left lateral aspect of the pituitary infundibulum. The initial differential diagnosis from the imaging included an ectopic pituitary gland, adenoma, pituicytoma, or hypothalamic glioma. She underwent a right supra-orbital craniotomy for debulking of the pituitary stalk lesion. The histopathological diagnosis was pituicytoma, WHO grade I.

CLINICAL DISCUSSION

The clinical manifestations are mostly depended upon the tumour mass and position. They typically present due to mass effects leading to hormonal disorders. The imaging studies are the backbone of the clinical diagnosis along with the histopathological findings. Surgical resection is the preferred treatment for pituicytoma, with an exceptionally low recurrence rate (4.3 %) following complete removal.

CONCLUSION

Pituicytomas are slow-growing, benign glial growths. It is challenging to diagnose before surgery as its clinical manifestations and imaging findings look like those of non-functional pituitary adenomas. The effective treatment for pituicytoma is gross total resection by the endoscopic method or transcranial technique.

Evaluate effects of the dilution medium and holding time on various motility parameters of delta smelt semen

Sperm preservation is an efficient technique used for the recovery, conservation, and management of some endangered fish species. The present study was conducted to explore how preservation time would affect sperm and spawning performance in the endangered delta smelt (Hypomesus transpacificus). Sperm were preserved with the modified Hanks balanced salt solution at 14.7-16.9 °C. The Kruskal-Wallis test of sperm parameters using OpenCASA plugin in ImageJ software showed that sperm (n = 33♂) had significantly higher velocity and motility within the first 5 s after activation than that of other time points, while sperm had the lowest velocity and motility after 3 min post activation (P < 0.001). The findings (n = 30♂) also showed fresh sperm had higher velocity and motility than preserved sperm, while the sperm preserved for over 24 h showed a significantly low performance (P < 0.001). The nonlinear mixed effects models of fertilization results (n = 14♂ × 70♀) indicated the fresh sperm and sperm preserved for 1 h had higher fertilization rates than other preservation times (P < 0.001). The hatching rate (n = 14♂ × 70♀) also showed the fresh sperm and sperm preserved for 3 min and 1 h had higher hatching rates than other preservation times (P < 0.001). Overall, the study showed the best sperm performance in delta smelt was found within the first 5 s post activation, and the best fertilization and hatching rates were found when the sperm were fresh and preserved for 1 h. The findings of this study provide information for the first time about how long the delta smelt's sperm are motile for quality analysis, and how the preservation time can affect sperm quality, fertility, and hatching of this species for future applications.

Cryopreservation Studies on Silver Carp (Hypophthalmichthys molitrix) Embryos

BACKGROUND

Cryopreservation is an effective tool for the preservation of live biological materials.

OBJECTIVE

This study examined the suitability of cryopreservation protocols and the effectiveness of ultrasound for silver carp embryos.

MATERIALS AND METHODS

Embryos at three developmental stages were exposed to 10, 15, 20, and 25% of five cryoprotectants (CPAs), namely propylene glycol (PG), dimethylformamide (DFA), DMSO, MeOH, and ethylene glycol (EG) for 20 min. Embryos were exposed to twelve vitrification solutions (VSs) for 10 (five steps of 2 min), 15 (five steps of 3 min), 20 (five steps of 4 min) min. Embryos were also exposed to ultrasound in VSs prior to cooling for cryopreservation.

RESULTS

Hatching rates decreased with increasing CPA concentrations while toxicity varied in the order of PG < DMSO < EG < MeOH < DFA. Tail elongation stage was more tolerant to CPA than 6-somites and morula stages. The survival of embryos exposed to ultrasound in VS was remarkably lower than in water. Embryos exposed to ultrasound in VSs under the best conditions did not response well after attempted vitrification.

CONCLUSION

Ultrasound-mediated CPA impregnation could be effective but other innovative methods may be needed to attain successful cryopreservation.

Evolutionary History and Taxonomic Reappraisal of Coral Reef Rabbitfishes (Siganidae): Patterns of Lineage Diversification and Speciation

Simple Summary

Herbivorous fish are recognized as being ecologically important to the health and survival of coral reef ecosystems because they remove algal turfs growing on corals. Apart from being one of the major components of herbivorous fish communities, rabbitfish are also characterized by possessing rabbit-like mouths. A total of 29 species of rabbitfish are confined to a single genus, Siganus, fish that are highly sought after for the aquarium trade and for food by humans. Natural hybridization between some species that have parapatric distributions across the Indo-West Pacific region may have homogenized their genotypic and morphological features. Relatively little is known, however, about how environmental factors may affect phylogenetic relationships among these siganid species. Based on sequencing of eight siganid species collected from the South China Sea and meta-analysis of sequences from ten siganid species retrieved from the NCBI database, we applied an integrated morphological–molecular approach to elucidate phylogenetic relationships and demographic histories of these species. Our results highlight that diversification and speciation of siganid species were influenced by a series of paleo-climatic events, changes to natural geographical distributions, and associated environmental changes. The target species were differentiated by body shape, and two morphometric parameters, notably body depth and snout length. Our results provide considerable baseline knowledge for strategizing improvement of both breeding and conservation programs for rabbitfish.

Abstract

Rabbitfish (Siganidae) are coral reef fish that are distributed across diverse habitats that include estuaries, mangroves, reefs, and even seaweed mats. Given their ecological diversity and natural widespread distributions across the Indo-Pacific region, we were interested to investigate the evolutionary history of this group and patterns of divergence that have contributed to their present-day distributions. In the present study, samples were collected from the South China Sea to study taxonomic and phylogenetic relationships, and divergence times. We investigated the taxonomic relationships among modern rabbitfish species, reconstructed their molecular phylogeny, and estimated divergence times among selected lineages based on a fragment of the mtDNA cytochrome oxidase I (COI) and sequences of the nuclear rhodopsin retrogene (RHO). Our results indicate that modern rabbitfish likely originated in the Indo-West Pacific during the late Eocene [37.4 million years ago (mya)], following which they diverged into three major clades during the Pliocene/Pleistocene. Subsequent diversification and origins of the majority of siganids may likely be associated with episodes of paleo-oceanographic events, including greenhouse and glaciation events (Eocene–Miocene) as well as major plate tectonic events (Pliocene–Pleistocene). Some modern siganid species may naturally hybridize with congeneric species where their geographical ranges overlap. A comprehensive taxonomic analysis revealed that the phylogeny of Siganidae (cladogenesis of Clades I, II, and III) is characterized by divergence in several external morphological characters and morphometric parameters. Our study demonstrates that morphological characteristics, geographical heterogeneity, and environmental change have contributed to siganids’ historical diversification.

Effects of Salinity on Fertilization, Hatching, and Larval Performance of Longfin Smelt Spirinchus thaleichthys

Understanding the spawning and rearing habitats of fishes is critical to effective fisheries management and conservation. Longfin smelt Spirinchus thaleichthys is an imperiled migratory fish that is believed to spawn and rear in habitats of varying salinities; however, optimal conditions for each stage remain unknown. Here, we examined the effects of variation in salinity on egg fertilization, hatch success, and larval growth and survival. Eggs that were fertilized in freshwater (0.4 ppt) exhibited a significantly higher fertilization rate (81%) than those fertilized in brackish water (62% at 5 ppt), with no detectible effects of fish origin or female size. In contrast to fertilization rates, once the eggs were fertilized, their hatching rates were not affected by the fertilization salinity, incubation salinity, nor their interaction; however, hatching success and larval survival both increased with increasing maternal body mass. Larval growth rate appeared to be independent of salinity and maternal size. Taken together, the results indicate that fertilization is possible at a range of salinities, but optimal at lower salinities for longfin smelt; however, embryos and larvae can perform well across a range of salinities. Furthermore, results indicated that larger mothers produced high-quality offspring, a finding that supports the “bigger is better” paradigm in fisheries science and management. These results likely explain, in part, the spawning and rearing behaviors of wild longfin smelt and suggest that the conservation culture program would likely be optimized by utilizing freshwater fertilization and larger females as broodstock.

Land- and Water-Based Adaptive Farming Practices to Cope with Waterlogging in Variably Elevated Homesteads

Waterlogging is a major problem in the south-western region of Bangladesh; this study was conducted in the eight most affected areas in order to enhance agricultural production by applying Land- and Water-based adaptive and alternative Farming Practices (LWFP). The study was designed to support target (research) farmers by raising one part of their homestead to use for living and agricultural farming, with the other part excavated to store rainwater and use for aquaculture. The study selected two groups of control farmers: those with ponds and those without. The study was conducted in two phases (i.e., phase 1—pilot phase and phase 2—extended phase), with each year divided into three cropping seasons: summer, rainy, and winter. The study found that the research farmers’ income was significantly higher from vegetables (both pilot and extended phases: p < 0.001), dike crops (both pilot and extended phases: p < 0.001), fish (both pilot and extended phases: p < 0.001), livestock (pilot phase: p < 0.01 and extended phase: p < 0.001), and poultry (pilot phase: p < 0.05 and extended phase: p < 0.001) compared to the control farmers. Moreover, the research supported the empowerment of women, which was not found in the control farms. Overall, the research program was embraced by the local communities as a very successful model. Furthermore, the study showed how waterlogging marginally affects very poor people, and that they can cope with this severe problem by adopting various farming practices. Therefore, the application of this research approach is suggested for similarly affected areas.

Long-term Exposure to Predation Threat Can Modulate the Expression of Sexually Selected Traits in Male Guppy (Poecilia reticulata)

The expression of sexual traits can be affected by different environmental factors among which predation may be particularly important life-history traits. This study investigated the effects of predation risk on courtship behavior, growth and sexual color patterns in male guppy (Poecilia reticulata). In the study, juvenile male guppies were randomly assigned to two treatments, namely T1 (predation threat) and T2 (no predation threat). The courtship performances were visually observed and recorded, while color patterns and morphological traits were measured by using the ImageJ software from the captured photos. The courtship behavioral trials revealed that predation threatened males performed significantly lower number of sigmoid displays than those of no-predation group. Further, the predation scared group had significantly shorter standard length, body area and a reduced number and area of orange spots than their counter group. However, the predation threat did not affect significantly the gonopodial thrusts, and black and iridescent color components (spot number and area). The reduction of costly traits (e.g. behavior, color patterns and body size) is common anti-predator response which presumably reduces predation risks. Male guppies are probably using this form of defence in response to the increased predation risk. The overall result suggests that growth and sexually selected trait expression are sensitive to predation risk and thereby aid in our understanding to predict the evolution of phenotypic variation in natural systems.