Diógenes Henrique Siqueira-Silva

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• PhD in Animal Biology
• Professor at Federal University of Southern and Southeastern Pará

Fish sperm cryopreservation is an important technique for optimizing juvenile production in aquaculture stations and laboratories and contributing to the conservation of endangered species. Despite its benefits, the cryopreservation process can cause cellular damage, affecting spermatozoa quality and offspring viability. This study aimed to evaluat...

Chrysin (5,7‐dihydroxyflavone) is a natural flavonoid with potential anxiolytic‐like effects in preclinical models. Acute treatment with this molecule (0 – 10 mg/kg) produced a biphasic dose‐response in the zebrafish light/dark test (LDT), with anxiolytic‐like effect at low doses and anxiogenic‐like effects at high doses. Chrysin (1 mg/kg) decrease...

Piracanjuba (Brycon orbignyanus) is an endangered fish species from the Neotropical region. The establishment of a cryobank using spermatogonial stem cells (SSCs) and subsequent production of a germline chimera is thus a promising strategy for such species. In the present work, procedures for the isolation and cryopreservation of piracanjuba SSCs a...

Figure Flavonoids are natural secondary compounds of plants with a basic composition derived from polyphenols that can produce a plethora of different neurochemical effects, some of which are relevant to anxiety disorders. As such, many flavonoids have been evaluated in behavioral screens in preclinical research on anxiolytics. Given the many diffe...

Piracanjuba ( Brycon orbignyanus ) is an endangered fish species from the Neotropical region. The establishment of a cryobank using spermatogonial stem cells (SSCs) and subsequent production of a germline chimera is thus a promising strategy for such species. In the present work, procedures for the isolation and cryopreservation of piracanjuba SSCs...

Serotonin (5-HT) is involved in arousal and defensive responses, both of which represent modulators of attention and orienting. Orienting responses (ORs), considered as a unit of attentional processing, are elicited by novel innocuous stimuli, differ from defense reflexes, as the latter are elicited by painful and threatening stimuli. Under situati...

The reproductive cycle of Hemiodus unimaculatus in the upstream area of the Tucuruí reservoir in the Tocantins River was described. The animals were collected monthly for 1 year in the Tauiry Village, municipality of Itupiranga, Pará. The individuals had their biometry taken, the gonads removed and weighed to calculate the gonadossomatic index and...

The study of embryonic development in fish and how water temperature affects the life stage in this group is of pivotal importance to support works that aim at the conservation, management, and recovery of endangered or high economic valuable species. It allows a better evaluation of the species and the identification of morphophysiological changes...

Stress situations can be essential to trigger reproduction in fish; however, it may also inhibit it. One of those situations involves the release of the conspecific alarm substance (CAS), a natural stressor, into the water by specific fish epidermal cells after a predator attack. Little is known about the effects of that substance on fish reproduct...

Serotonin (5-HT) receptors have been implicated in social behavior in vertebrates. Zebrafish (Danio rerio) have been increasingly being used behavioral neuroscience to study the neurobiological correlates of behavior, including sociality. Nonetheless, the role of 5-HT2C receptors in different social functions were not yet studied in this species. Z...

Zebrafish is an important animal model, thousands lines have been developed, thus having a great need for their preservation. However, the cryopreservation of fish oocytes is still limited and needs improvement. The sodium alginate hydrogel, in addition to providing support for the cells, has been shown to be a potential cryoprotectant. Therefore,...

In this study, we assessed the effect of temperature on gonadal development and sex ratio in Brycon orbignyanus. The fish were kept at three different temperatures (20 °C, 23 °C, and 26 °C) from the beginning of exogenous feeding. At 420 days after fertilization, 10 individuals were collected per temperature regimen for histological and hormonal ev...

Currently, available fish anesthetics can produce important side effects, including respiratory arrest and distress. Easy-to-implement alternatives with low toxicity are needed to ensure fish health as well as to help artisanal fisheries and fish sellers in handling and transporting fishes, and native plants seems to be the best alternative. We aim...

Albinism is a condition in which an animal’s skin, feathers, or fur is lighter in color than that of other animals of that species. We report a unique case of complete albinism in a red-brocket deer in the Brazilian Amazon rainforest. The individual, which we called a “magical creature,” lives inside a conservation area in one of the most deforeste...

Serotonin (5-HT) receptors have been implicated in social behavior in vertebrates. Zebrafish (Danio rerio) have been increasingly being used behavioral neuroscience to study the neurobiological correlates of behavior, including sociality. Nonetheless, the role of 5-HT2C receptors in different social functions were not yet studied in this species. Z...

This study describes important components of the reproductive biology of the Amazonian amphibian fish Copella arnoldi. The species sex ratio biased to female 1.8 to 1 male and the length‐weight relationship also shown differences between sexes (b value = 1.854 for females and 2.235 for males), although both presented allometric growth (b < 3), “bei...

Rivers in the Amazon have among the greatest biodiversity in the world. The Xingu River, one of the tributaries of the Amazon River, has a length of 1640 km, draining 510,000 km2 in one of the most protected regions on the planet. The Middle Xingu region in Brazil has been highly impacted by mining and livestock farming, leading to habitat fragment...

In order to meet the agricultural sector growing demand for sustainable alternatives, this work was developed to explore the bioherbicide and anesthetic potential of Aniba Canelilla essential oil, a natural Amazon resource. Leaves and fine branches, collected in two seasons of the year, were subjected to hydrodistillation and the essential oils obt...

Zebrafish anxiety-like behavior was assessed in the novel tank test after the formation of dominant-subordinate hierarchies. Ten pairs of animals were subjected to dyadic interactions for 5 days, and compared with control animals. After this period, a clear dominance hierarchy was established across all dyads, irrespective of sex. Social status aff...

The levels of reproductive hormones for fish stocked in fish farming ponds can be varying with respect to age and sex. Piracanjuba is an endangered species and broodstock are raised to be used in stocking programs. Therefore, we aimed to describe the plasma levels of the major sex steroids, 17β-estradiol (E2), 17α-hydroxyprogesterone (17α-OHP), tes...

Individuals of the same species may present different reproductive tactics depending on the environment in which they develop and mature. The present study aimed to define the gonadal development phases of males and females of Astyanax rivularis and to carry out a comparative analysis of the reproductive development of specimens captured in two iso...

Individuals of the same species may present different reproductive tactics depending on the environment in which they develop and mature. The present study aimed to define the gonadal development phases of males and females of Astyanax rivularis and to carry out a comparative analysis of the reproductive development of specimens captured in two iso...

We aimed to develop a simplified protocol for transplantation of Brycon orbignyanus spermatogonial stem cells (SSCs) into Astyanax altiparanae testes. Brycon orbignyanus testes were enzymatically digested and SSC purified by a discontinuous density gradient. Endogenous spermatogenesis was suppressed in A. altiparanae using busulfan or by incubation...

This study interrogated factors which affect the appearance of secondary sexual characteristics, namely , fin spinelets (rigid dimorphic structure empirically associated with male sexual maturity in characids), in Astyanax altiparanae. Many variables such as the season of the year and several biotic components, including organism length, sex, phase...

In view of the established climate change scenario and the consequent changes in global temperature, it is essential to study its effects on animal spermatogenesis. Therefore, the aim of this study was to verify the duration of spermatogenesis at different temperatures. For this purpose, 96 male and adult specimens of Astyanax altiparanae were kept...

This study describes the embryonic development of Moenkhausia oligolepis in laboratory conditions. After fertilization, the embryos were collected every 10 min up to 2 h, then every 20 min up to 4 h, and afterwards every 30 min until hatching. The fertilized eggs of M. oligolepis measured approximately 0.85 ± 0.5 mm and had an adhesive surface. Emb...

Rivulidae comprises a family of fish largely distributed in Brazil that includes 201 species, of which 125 are considered endangered. This fact emphasizes the need for development of conservation strategies including studies on genetics and reproduction. In this paper, we describe aspects of biology and reproduction of the rivuliid species Hypsoleb...

This protocol, modified from OECD 203 (Acute toxicity test, adult fish), tests toxic (lethal and nonlethal) effects of substances that have been injected intraperitoneally in adult fish. While OECD 203 is appropriate for testing the effects of waterborne substances (e.g., sewage effluents, pesticides, and other toxicants that can reach water bodies...

Orienting responses (ORs) are whole-organism reflexes that are elicited by innocuous stimuli, and which decrease in magnitude after stimulus repetition. ORs represent relatively simple responses that can be used to study attentional processes, and are modulated by the organism’s state, including arousal and activation levels, as well as by emotiona...

The seminal characteristics of Moenkhausia oligolepis are described. Three males were induced with a single dose of carp pituitary. Semen was collected 6 h after induction, and diluted in dibasic sodium phosphate extender solution. For motility analysis, 1 μl of diluted semen was added to 10 μl of distilled water to achieve gamete activation. The a...

This study describes the embryonic development of Moenkhausia oligolepis in captive conditions. After fertilization, the embryos were collected every 10 min up to 2 h, every 20 min up to 4 h, and every 30 min until hatching. The fertilized eggs of M. oligolepis measured approximately 0.85 mm and have an adhesive surface. The embryonic development l...

Reproduction in the family Phallostethidae is an area that has long been of interest especially in gonadal structure and gametogenesis. However, no published data concerning as mentioned above in Neostethus lankesteri Regan, 1916 from Thailand is noted. This fish is important for rural livelihood in the estuarine fisheries of Pranburi River estuary...

Albinism is a genetic condition that results in total hypopigmentation of the eyes, fur, skin, hair, scales, and feathers of an organism. Albinism might result in a selective disadvantage for affected animals. Cases of albinism have been previously recorded in Neotropical vertebrates, such as reptiles, mammals, birds, and fish. However, observing a...

Albinism is a genetic condition that results in total hypopigmentation of the eyes, fur, skin, hair, scales, and feathers of an organism. Albinism might result in a selective disadvantage for affected animals. Cases of albinism have been previously recorded in Neotropical vertebrates, such as reptiles, mammals, birds, and fish. However, observing a...

Triploidization is a technique to produce sterile fish on a large scale. In the spotted catfish Pimelodus maculatus, sterile fish serve as a host of germ cell transplantation for subsequent reconstitution of endangered catfish species. This study aimed to establish an efficient protocol for triploidization in P. maculatus using temperature shock. I...

This protocol describes the method to obtaining crude alcoholic extracts from plant organs, such leaves and inflorescences. The used plants were the popularly called “João Brandinho” Piper Callosum and “Jambu” Spilanthes acmella. The crude extracts were used in our laboratory to anesthetize the native silver tetra fish Ctenobrycon sp. and Zebrafish...

This protocol describes the method to obtaining crude alcoholic extracts from plant organs, such leaves and inflorescences. The used plants were the popularly called “João Brandinho” Piper Callosum and “Jambu” Spilanthes acmella. The crude extracts were used in our laboratory to anesthetize the native silver tetra fish Ctenobrycon sp. and Zebrafish...

Orienting responses (ORs) are whole-organism reflexes that are elicited by innocuous stimuli, and which decrease in magnitude after stimulus repetition. ORs represent relatively simple responses that can be used to study attentional processes, and are modulated by the organism's state, including arousal and activation levels, as well as by emotiona...

A histological characterization of gonadal development in the tetra Astyanax bimaculatus was performed, aimed at determining its reproductive cycle in streams localized inside the Amazonian forest. Collections were carried out monthly from August 2017 to July 2018 at the Zoobotânica Foundation of Marabá, PA. Collected specimens were weighed and mea...

Although the potential of surrogate propagation technology for aquaculture and conservation of Neotropical fish, the poor understanding of the host immune system may results in rejection and destruction of the donor material. Thus, it is necessary to study and to develop methods to evaluate the effects of immunosuppressive drugs employment and to e...

This work aimed to analyze factors affecting secondary sexual characteristics in the yellowtail tetra Astyanax altiparanae. For this, seventy-five specimens were first separated into three different size classes (small, medium and large groups) between two seasons, summer and winter. In all groups, male fish were consistently bigger in the summer....

Social plasticity, defined as the ability to adaptively change the expression of social behavior according to previous experience and to social context, is a key ecological performance trait that should be viewed as crucial for Darwinian fitness. The neural mechanisms for social plasticity are poorly understood, in part due to skewed reliance on ro...

This protocol describes the dissection, fixation, and histological processing of gonadal tissue of small and medium-sized fish. It has been used in our lab to describe the microanatomy of the gonads of Amazonian Characidae, as well as of ornamental fish such as zebrafish.

Social plasticity, defined as the ability to adaptively change the expression of social behavior according to previous experience and to social context, is a key ecological performance trait that should be viewed as crucial for Darwinian fitness. The neural mechanisms for social plasticity are poorly understood, in part due to skewed reliance on ro...

O desenvolvimento de métodos pedagógicos tem sido essencial no processo de ensino-aprendizagem da pessoa com deficiência, mas ainda é difícil identificar, avaliar e socializar o grau de aprovação, impactos e possibilidades destas metodologias. A prospecção tecnológica é uma ferramenta usada para mapear as tecnologias existentes, visando contribuir...

Chemical communication of predation risk has evolved multiple times in fish species, with conspecific alarm substance (CAS) being the most well understood mechanism. CAS is released after epithelial damage, usually when prey fish are captured by a predator and elicits neurobehavioural adjustments in conspecifics which increase the probability of av...

This review discusses the new biotechnological tools that are arising and promising for conservation and enhancement of fish production, mainly regarding the endangered and the most economically important species. Two main techniques, in particular, are available to avoid extinction of endangered fish species and to improve the production of commer...

Social plasticity, defined as the ability to adaptively change the expression of social behavior according to previous experience and to social context, is a key ecological performance trait that should be viewed as crucial for Darwinian fitness. The neural mechanisms for social plasticity are poorly understood, in part due to skewed reliance on ro...

Neotropical icthyofauna represents one of the most diverse and extreme ecosystems in the world. Likewise, reproduction showed enormous diversity with different reproductive systems, modes and behavior. On the other hand, information on Neotropical fish species, in particular on male reproductive physiology is restricted to few species. This mini-re...

O presente trabalho teve como objetivo avaliar o potencial anestésico de extratos vegetais da planta Spilhantes acmella (jambu) na espécie de peixe Serrapinnus heterodon. Os espécimes de S. heterodon foram coletados na Fundação Zoobotanica de Marabá-PA e aclimatados por 15 dias. Para a extração vegetal as folhas e flores de jambu foram lavadas, cor...

Chemical communication of predation risk has evolved multiple times in fish species, with the conspecific alarm substance (CAS) contemporaneously being the most well understood mechanism. CAS is released after epithelial damage, usually when prey fish is captured by a predator, and elicits neurobehavioral adjustments in conspecifics which increase...

Environmental and housing conditions experienced by laboratory animals exert profound effects on their biology, physiology, and behavior. These parameters are important and often overlooked sources of potential variation in experiments, and should be reported in peer-reviewed publications in order to promote scientific reproducibility. To that end,...

Contents We aimed to vitrify embryos of Prochilodus lineatus in a high‐osmolarity cryoprotectant solution, evaluating, after the vitrification–thawing process, their morphological changes. Thus, 240 embryos in the 20‐somite phase (20S) were exposed for 20 min to one main internal cryoprotectant solution (1,2‐propanediol—PROP), divided into four imm...

This study aimed to evaluate the vitellogenic transference and incorporation of long‐chain polyunsaturated fatty acids (LC‐PUFA) into the membranes of Prochilodus lineatus embryos, aiming to increase the permeability to cryoprotectants and resistance to electric fields. One hundred thirty broodstock of P. lineatus were fed with control (C) or fish...

Synchronizing developmental stages in Neotropical catfishes for application in germ cell transplantation - CORRIGENDUM - Volume 26 Issue 3 - Dilberto Ribeiro Arashiro, George Shigueki Yasui, Leonardo Luiz Calado, Nivaldo Ferreira do Nascimento, Matheus Pereira dos Santos, Silvio Carlos Alves do Santos, Nycolas Levy-Pereira, Paulo Sérgio Monzani, Di...

Chronic alcohol use induces adaptations and toxicity that can induce symptoms of anxiety, autonomic hyperarousal, and epileptic seizures when alcohol is removed (withdrawal syndrome). Zebrafish has recently gained wide attention as a behavioral model to study the neurobehavioral effects of acute and chronic alcohol use, including withdrawal. The li...

Chemical communication of predation risk has evolved multiple times in fish species, with the conspecific alarm substance (CAS) contemporaneously being the most well understood mechanism. CAS is released after epithelial damage, usually when prey fish is captured by a predator, and elicits neurobehavioral adjustments in conspecifics which increase...

The aim of this study was to describe the effect of temperature on the fertilization, early developmental stages, and survival rate of two Neotropical catfishes Pimelodus maculatus and Pseudopimelodus mangurus . After fertilization, the eggs were incubated at 22°C, 26°C, and 30°C, which resulted in fertilization rates of 96.95 ± 1.79%, 98.74 ± 0.76...

Chronic alcohol use induces adaptations and toxicity that can induce symptoms of anxiety, autonomic hyperarousal, and epileptic seizures when alcohol is removed (withdrawal syndrome). Zebrafish has recently gained wide attention as a behavioral model to study the neurobehavioral effects of acute and chronic alcohol use, including withdrawal. The li...

Fish nocifensive behavior can be studied and understood similarly to the way pain is studied and understood in more advanced vertebrates. Nocifensive behavior is a behavioral and physiological response to a noxious stimulus that leads to the fish avoiding it in the future. This behavioral flexibility is an important criterion for inferring pain sen...

This work was aimed at developing an effective procedure to obtain sterile ideal host fish in mass scale with no endogenous germ cells in the germinal epithelium, owning permanent stem-cell niches able to be colonized by transplanted germ cells in surrogate technology experiments. Thus, triploids, diploid hybrids, and triploid hybrids were produced...

This study aimed to examine the gonadal morphology of diploid and triploid fish through stereological analysis. Triploid individuals were obtained after temperature shock (40°C for 2 min) at 2 min post-fertilization and reared until 175 days post-fertilization (dpf). Intact eggs were used to obtain the diploids. Gonads were collected for histologic...

This stereological analysis of the types of germ cells and the number of Sertoli cells per cyst in Astyanax altiparanae testes during spermatogenesis is the first such report in Characiformes. Testes of 25 male A. altiparanae were examined. Based on the number of spermatogonia B per cyst (469.2 ± 9.92), we estimated that spermatogonia undergo at le...

This study aimed to describe testicular and its main ducts structure in the yellowtail tetra Astyanax altiparanae, contributing to the knowledge of the region in which semen is produced, storage and released, focusing mainly on the dynamic of germinal epithelium and Sertoli cells during germ cell maturation. Ten sexually mature male A. altiparanae...

Interest in reproductively sterile fish in aquaculture has prompted research into their production. Several methods are available for inducing sterility and optimizing its application in the global fishery industry. Sterilization can potentially be accomplished through irradiation, surgery, or chemical and hormonal treatment. Alternative approaches...

We aimed to analyze the oogenesis of adult females of the cichlid fish Laetacara araguaiae . The specimens’ gonads were removed and processed for light and transmission electron microscopy. Oogenesis in L. araguaiae showed the following characteristics: a germinal epithelium with three types of oogonia (A-undifferentiated, A-differentiated and B-oo...

The histological description of the urogenital papilla is an important tool to comprehension of the reproductive mechanisms in fish, as well as a pre-requisite to germ cell transplantation in adult fish, besides to be a good biological indicator to environmental changes. Was performed the histological description of the urogenital papilla and its c...

We aimed to standardize a protocol to suppress spermatogenesis in the characiform fish Astyanax altiparanae, for future use as a host in germ cell transplant research, opening opportunities for a range of studies, such as spermatogenesis analyses and transgenesis, since this species presents livestock characteristics to be used as a biological mode...