Danilo Pedro Streit Jr

@ufrgs.br

Professor of the Department and Postgraduate of Animal Science
Federal University of Rio Grande do Sul (UFRGS)

Danilo Pedro Streit Jr


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https://researchid.co/streitjr
108

Scopus Publications

Scopus Publications

  • A stepwise methodology for developing fish sperm cryopreservation protocols: application to the endangered Pogonias courbina
    Jhony Lisbôa Benato, Nathalia dos Santos Teixeira, Rômulo Batista Rodrigues, Karel Torres Lozano, Renata Villar Dantas, et al.
    Cryobiology, 2026
  • Reproductive biology characterization of violinha Loricariichthys anus
    Douglas C. Selle, Raquel S. dos Santos, Thaiza R. de Freitas, Jhony L. Benato, Thales de S. França, et al.
    Reproductive Biology, 2026
  • Cryopreservation toxicity and morphological outcomes in Piaractus brachypomus oocytes and embryos
    Melanie Digmayer, Darci Carlos Fornari, Lis Santos Marques, Jayme Aparecido Povh, Ricardo Pereira Ribeiro, et al.
    Animal Reproduction, 2026
    This study evaluated the toxicity of cryoprotectants and the performance of low-rate freezing protocols for oocytes and embryos of Piaractus brachypomus, a Neotropical fish of increasing relevant for Brazilian aquaculture and genetic conservation. Eight cryoprotectant solutions based on methanol (MeOH) or dimethyl sulfoxide (Me2SO), combined with 0.25 M sucrose in L-15 or HBSS media, were tested for oocytes toxicity at 28 °C and post-freezing viability. In spite of histological and scanning electron microscopy (SEM) analyses indicated preservation of gross morphological features, none of the cryopreserved oocytes supported embryonic development, indicating loss of functional viability following cryoprotectant exposure and freezing. For embryos, two low-rate freezing protocols were evaluated: Protocol 1 (P1E), based on gradual cooling to −13 °C, and Protocol 2 (P2E), involving linear cooling to −60 °C followed by storage in liquid nitrogen. In P1E, eight treatments using 3.1 M MeOH combined with different concentrations of polyvinylpyrrolidone (PVP) or sucrose were tested. The highest proportion of morphologically viable embryos (15.3%) was obtained with MeOT + 0.45 M sucrose (SC5), which different significantly from the other treatments. In contrast, no morphologically viable embryos were recovered after P2E, likely due to inadequate dehydration and intracellular ice formation. Overall, high concentrations of permeant cryoprotectants and prolonged equilibration times were detrimental to oocyte and embryo viability, while sucrose showed better cryoprotective performance than PVP. Even though protocols tested were insufficient to ensure consistent post-thaw viability, the partial success observed in P1E under MeOH and sucrose combinations provides a relevant experimental basis for future refinement of conservation strategies and contributes to development of ex situ germoplasm conservation approaches for P. brachypomus and other Neotropical species.
  • Celiotomy to collect spermatogonial stem cells in Brycon orbignyanus for species preservation
    Laís Gonçalves da Silva, Karel Gelina Torres-Lozano, Rômulo Batista Rodrígues, Thaiza Rodrigues de Freitas, Jayme Aparecido Povh, et al.
    Animal Reproduction, 2026
    Surgical techniques in aquatic species are underdeveloped, despite these species comprising a significant superclass among vertebrates. In the context of species preservation, studies involving the use of reproductive tissues typically involve the euthanasia of donors. Thus, in animals at high risk of extinction, the practice of sacrificing them presents a point of contradiction between ex situ conservation efforts. The objective of this study was to compare the viability of spermatogonia stem cells (SSCs) collected from Brycon orbignyanus using conventional methods (euthanasia) versus a surgical procedure. Lateral celiotomy was performed on 27 immatures males to obtain a portion of gonadal tissue. The fish were divided into three groups (n=9), with each group receiving polyglactin 910, polyester, or catgut sutures, respectively, for celiorrhaphy. Dermorraphy was performed using nylon sutures in all groups. A. An additional euthanasia group consisted of nine animals exposed to 20 mg/L of propofol. The survival rate over a 48-hour period was 100% for the polyglactin 910 group and 77.7% for the polyester and catgut groups. Additionally, the viability of SSCs was similar between the euthanasia and surgical procedures. The lateral celiotomy technique is feasible for obtaining SSCs in fish with laterally compressed anatomy, such as B. orbignyanus. Additionally, the technique allows the preservation of SSCs as a model for endangered fish species.
  • First Frozen Repository for Coral Sperm in the Southwestern Atlantic: A Tool to Support Reef Conservation
    Nayara Oliveira da Cruz, Andrea Giannotti Galuppo, Allison Gonçalves Silva, Luciano da Silva Lima, Romulo Batista Rodrigues, et al.
    Aquatic Conservation Marine and Freshwater Ecosystems, 2025
    Coral reefs are among the most biodiverse ecosystems on Earth, yet they are rapidly declining due to climate change and other anthropogenic stressors. Population reductions threaten sexual reproduction in sessile coral species, as increased distances between colonies hinder gamete encounters. Once populations fall below critical density thresholds, natural recovery may become impossible even after stressors are removed. Biobanking of coral germplasm has therefore emerged as a key strategy to preserve genetic diversity and support reef restoration. This study developed and validated a cryopreservation protocol for sperm of the Brazilian endemic reef‐building coral Mussismilia harttii , representing a milestone in coral conservation for the Southwestern Atlantic. Spermatozoa were exposed to dimethyl sulfoxide (DMSO) and methanol (MeOH) at concentrations of 10%, 15% and 20% and subjected to controlled slow freezing and ultra‐rapid freezing. Postthaw analyses assessed motility, mitochondrial activity and viability. The best results were obtained with 20% DMSO and controlled slow freezing, yielding 29.7% ± 0.84% motility and 83.6% ± 2.2% viability. Mitochondrial activity (MTT assay) was higher with 15% MeOH (1.63 ± 0.17) than with DMSO (0.74 ± 0.17). Cryopreserved sperm (20% DMSO + slow freezing) achieved a 100% fertilization rate, statistically equivalent to fresh sperm ( p = 0.4533). This optimized protocol enabled the establishment of the first coral sperm repository in the South Atlantic, currently storing 2.4 billion viable M. harttii spermatozoa. This repository provides a crucial resource to safeguard genetic diversity, strengthen assisted breeding programs and enhance the long‐term conservation and restoration capacity of Brazilian coral reefs.
  • A Systematic Review of Brycon Genus Sperm Cryopreservation Protocols: Challenges on Ex-Situ Conservation for Sustainable Aquaculture
    Danilo Pedro Streit, Rômulo Batista Rodrigues, Jhony Lisboa Benato, Gregory Brayan Valdívia‐Gutiérrez, Eduardo Thomé Nicoleti, et al.
    Reviews in Aquaculture, 2025
    This systematic review shows an overview of the history of protocols used for genus Brycon sperm cryopreservation. Relevant studies were identified from Web of Science, Scopus, PubMed, and Scielo databases. Thirty‐four studies published between 2001 and 2021 were included in the systematic review following the eligibility criteria. Selected studies showed cryopreservation protocols of nine species of the genus Brycon, with Brycon orbignyanus being the most studied species. The studies were conducted by Brazilian (76.5%) and Colombian (23.5%) researchers, with the majority (68.6%) carried out in hydroelectric plants promoting fish restocking programs. Two main protocols were extensively investigated across nine studied species: 10% methyl glycol +5% Beltsville Thawing Solution and 10% dimethyl sulfoxide +5% glucose. However, the protocols lacked standardization regarding equilibrium time and temperature, freezing and thawing curves, or sperm‐to‐cryoprotectant solution ratios. Limited collaboration among research groups from the two South American countries was identified as a significant factor in this lack of standardization. In addition, emerging approaches for sperm cryopreservation are necessary, such as developing less toxic alternative cryoprotectants. Implementing advanced cryopreservation methodologies and using artificial intelligence and machine learning can optimize protocols by modeling key parameters and enhancing post‐thaw sperm quality. These findings underscore the need for collaboration between research groups to develop standardized cryopreservation protocols and establish functionally accessible germplasm banks. Such measures are essential for the ex‐situ conservation and long‐term sustainability of aquaculture involving species of the genus Brycon.
  • Methods for greenhouse gas emission accounting in inland aquaculture: a systematic review
    Sharmilla Antonieta Favero Streit, Marco Aurélio Rotta, Jhony Lisboa Benato, Rômulo Batista Rodrigues, Úrsula da Silva Morales, et al.
    Environmental Monitoring and Assessment, 2025
  • Understanding Rigor Mortis Impacts on Zebrafish Gamete Viability
    Renata Villar Dantas, Lis Santos Marques, Thaiza Rodrigues Freitas, Nathalia dos Santos Teixeira, Rômulo Batista Rodrigues, et al.
    Zebrafish, 2025
    This study aimed to evaluate the viability of gametes in zebrafish (Danio rerio), at different rigor mortis stages. Viability assessments were conducted on oocytes at various developmental stages using LIVE/DEAD and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. For sperm evaluation, both kinetic (computer-assisted sperm analysis) and morphological assessments (Rose Bengal staining) were performed. Results demonstrated that rigor mortis progression significantly impacted oocyte viability during post-rigor stages, with the following viability rates: pre-rigor (70.43 ± 12.31%), fresh/control (46.43 ± 12.54%), post-rigor (27.62 ± 22.29%), and rigor mortis (comparable to fresh/control). Conversely, sperm kinetics exhibited nuanced responses to the rigor mortis stages, with specific parameters showing sensitivity, whereas the others remained relatively stable. Sperm motility was higher in the fresh/control (63.23 ± 19.03%) and pre-rigor (58.96 ± 14.38%) compared to the post-rigor group (3.34 ± 4.65%). This study highlights the significance of the pre-rigor for successful gamete collection and preservation. These findings provide valuable insights for conservation efforts and optimization of genetic resource management for endangered fish species. This study aimed to develop effective assistive reproductive techniques by elucidating the interplay between rigor mortis and gamete quality, contributing to the broader goals of species conservation and maintenance of genetic diversity in fish populations.
  • Gelatin capsules for post mortem vitrification of Piracanjuba (Brycon orbignyanus) ovarian tissue as an accessible solution for emergency genetic preservation
    Thaiza Rodrigues de Freitas, Lis Santos Marques, Raquel Santos dos Santos, Renata Villar Dantas, Thales Souza França, et al.
    Animal Reproduction Science, 2025
  • Cryopreservation-Induced Morphological Changes in Freshwater Fish Sperm: A Systematic Review
    Bruna Bitencourt da Costa, Paula Graziela Lassen, Danilo Pedro Streit
    Biopreservation and Biobanking, 2024
    A systematic review was performed to summarize the scientific evidence and critically evaluate the effects of cryopreservation on sperm morphology in freshwater fish, and to assess the methodologies for sperm morphology classification. The search strategy was applied to four electronic databases (CAB Direct, Pub Med, Scopus, and ISI Web of Science). The main inclusion criteria involved studies on semen from freshwater fish subjected to the cryopreservation process and evaluation of sperm quality through morphology. The risk of bias was assessed with respect to randomization, allocation concealment, blinding, incomplete outcome data, and selective reporting. A total of 6 publications reporting sperm cryopreservation from 4 species with a total 74 fish individuals were included in this review. A high methodological variability among the results of the studies was observed due to the species-specific protocols and diversity of freshwater fish species studied. All included studies reported negative effects of cryopreservation on sperm quality, especially morphology, highlighting the increase in incidence of sperm abnormalities. However, only five studies statistically compared abnormalities between groups (fresh and cryopreserved sperm). Our results suggest the need to elaborate on a new morphological classification of fish spermatozoa, by considering the structure and physiology of fish sperm. This classification should be developed based on the sperm characterization and observing damage caused by different cryopreservation protocols.
  • Catalase and Uric Acid Prevent Morphological Damage to the Sperm Flagella of Colossoma macropomum During 96 Hours at Low Storage Temperatures
    Yugo M. Pastrana, Jaydione L. Marcon, Amanda P. de Amaral, Francisco Bruno P. Santos, Emerson S. Lima, et al.
    Biopreservation and Biobanking, 2024
  • Biodegradable capsules as a sustainable and accessible container for vitrification of gonadal tissue using the zebrafish animal model
    Thaiza Rodrigues de Freitas, Rômulo Batista Rodrigues, Lis Santos Marques, Renata Villar Dantas, Karel Gelina Torres-Lozano, et al.
    Cryobiology, 2024
  • Successful cryopreservation in biodegradable containers of sperm from aquaculture Mediterranean fishes
    T.S. França, W.A. González-López, M.P. Sanchez, L. Ferrão, F. Fernández-García, et al.
    Theriogenology, 2024
  • Use of Powdered Milk in Semen Cryopreservation Protocols for Fish: A Systematic Review
    Iuri Moraes Neyrão, Francisco Bruno Pereira Santos, Rômulo Batista Rodrigues, Danilo Pedro Streit, Leandro Godoy
    Biopreservation and Biobanking, 2024
  • Cryobiology for South American Neotropical Fish Species
    Danilo P. Streit Jr., Tiantian Zhang, Estefania Paredes
    Cryobiology for South American Neotropical Fish Species, 2024
  • Sperm Cryopreservation Protocols for Neotropical South American Species
    Danilo P. Streit, Rômulo Batista Rodrigues, Eduardo Antônio Sanches, Jayme Aparecido Povh, Diógenes Henrique de Siqueira-Silva, et al.
    Cryobiology for South American Neotropical Fish Species, 2024
  • Potential Use of Germplasm Banks of Neotropical South American Species for Fish Farming in Brazil
    Danilo P. Streit, Jayme A. Povh, Darci C. Fornari, Jonhy L. Benato, Fernanda De Mello, et al.
    Cryobiology for South American Neotropical Fish Species, 2024
  • Laboratory Techniques for the Analysis of Cells and Reproductive Tissues of Neotropical Species
    Lauren Dorneles Dipp, Lis Santos Marques, Rômulo Batista Rodrigues, Thales de Souza França, Nathalia dos Santos Teixeira, et al.
    Cryobiology for South American Neotropical Fish Species, 2024
  • Mass synchronization of gonadal maturation in banded knifefish broodstock (Gymnotus cf. carapo)
    Marco Aurélio Rotta, Rômulo Batista Rodrigues, Merlison Figueiredo Pedroso, Luiz Carlos Acorci Filho, Jorge Antonio Ferreira de Lara, et al.
    Aquaculture, 2023
  • Fish sperm cryopreservation using biodegradable containers: New low-cost and environment-friendly methodology
    Thales de Souza França, Itamar Cossina Gomes, Eduardo Antônio Sanches, Maritza Pérez Atehortúa, Nathalia dos Santos Teixeira, et al.
    Reproduction, 2023
  • Morphological organization and ultrastructural evaluation of the oocyte–sperm bundle of the Southwestern Atlantic coral Mussismilia harttii
    Wanderson Valente, Andrea Giannotti Galuppo, Danilo Pedro Streit Jr, Jener Alexandre Sampaio Zuanon, Leandro Godoy
    Coral Reefs, 2023
  • Hydrogel encapsulation as a handling and vitrification tool for zebrafish ovarian tissue
    Thaiza Rodrigues de Freitas, Andrea Giannotti Galuppo, Lis Santos Marques, Rômulo Batista Rodrigues, Maritza Perez Atehortúa, et al.
    Theriogenology, 2023
  • Temperature modulates gonadal development and sex ratio of pirancanjuba Brycon orbignyanus
    Helena Robattini Carvalho, Diógenes Henrique de Siqueira-Silva, Rômulo Batista Rodrigues, Louise Nex Spica, Daniel Antonio Rotili, et al.
    Aquaculture, 2023
  • Pogonias courbina sperm characteristcs in its first reproductive season
    Jhony Lisboa Benato, Danilo Streit Jr, Nathalia Dos Santos Teixeira, Rômulo Batista Rodrigues, Thaiza Rodrigues de Freitas, et al.
    Peerj, 2023
  • Aquaculture Sustainability Assessed by Emergy Synthesis: The Importance of Water Accounting
    Úrsula da Silva Morales, Marco Aurélio Rotta, Darci Carlos Fornari, Danilo Pedro Streit
    Agriculture Switzerland, 2022