In vivo phagocytosis and hematology in Astyanax altiparanae, a potential model for surrogate technology

Abstract

<jats:p>Abstract 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 evaluate the immunocompatibility between donor and receptor. Thus, the present study aimed to optimize a methodology to assess in vivo phagocytosis in Astyanax altiparanae using Saccharomyces cerevisiae and to evaluate their hematological response resultant from the inflammatory induction. To this, S. cerevisiae were labeled with Congo red and injected in the coelomic cavity of A. altiparanae at the concentration of 2.5 x 106 cells mL-1. A PBS solution and a non-injected group were kept as control. Fish blood was sampled and the phagocytic capacity and index were determined at 1, 2, 3 and 6 h post-injection (hpi). The yeast injection successfully stimulated phagocytosis, with the best result for phagocytosis assessment after 2 hpi. Moreover, it was achieved a high traceability of phagocytized and non-phagocytized yeast under optic microscopy analysis due to the Congo red labeling. The hematological profile was similar to usually observed in early infections, indicating lymphocyte migration to inflammatory site and increase in number of circulating phagocytes due to natural response to inflammatory stimulus. In conclusion, our method was efficient to assess in vivo phagocytosis in A. altiparanae and will be an important tool to evaluate the efficacy of immunosuppressive drugs in this species. Additionally, these results may serve as support for further studies in fish immunocompetence, both in laboratory and in field conditions.</jats:p>

Phagocytotic activity and gene expression of leukocytes isolated from Astyanax lacustris

“…Moreover, this fish species belongs to the group of Characiform, such as Piaractus mesopotamicus and Colossoma macropomum, which are important fish species for Neotropical aquaculture (FAO, 2022). Recently, our research group conducted studies on the in vivo immune response of diploid and triploid A. lacustris (Levy-Pereira et al, 2020;Levy-Pereira et al, 2021) allowing a better understanding of A. lacustris innate immune response, the development of a new technique to assay in vivo phagocytosis and the evaluation of the expression of immune-related genes.…”

Avaliação do efeito do extrato pirolenhoso sobre parâmetros zootécnicos e na imunomodulação frente à infecção por >i<Streptococcus agalactiae>/i< em tilápias do Nilo (>i<Oreochromis niloticus>/i<)

“…Os neutrófilos e os eosinófilos são granulócitos por O IF considera a quantidade de leveduras encontradas dentro dos macrófagos após terem sido fagocitados por estes (NAKANDAKARE et al, 2013), sendo a fagocitose uma primeira linha de resposta imunológica frente aos patógenos (HAUGLAND et al, 2012;HAN et al, 2021) et al, 2003). A confirmação da infecção foi feita através da observação dos sinais clínicos dos animais infectados, estando presentes a exoftalmia, natação errática e ascite (CHEN et al, 2012;LEIRA et al, 2016). Nesse contexto, o presente estudo contribui para um melhor entendimento dos efeitos do extrato pirolenhoso como um aditivo de ração para peixes e abre perspectivas para novas investigações na prospecção de antimicrobianos naturais que possam ser utilizados com segurança e eficiência na piscicultura.…”