International Journal of Aquaculture, 2025, Vol.15, No.1, 11-20 http://www.aquapublisher.com/index.php/ija 18 indicate an adverse effect of the high concentration of açaí, highlighting the need for more detailed analyses to determine the appropriate dosage of this fruit supplementation in fish diets. It was observed that the animals receiving diets supplemented with açaí at concentrations of 1.0% and 1.5% had lower indices of Mononuclear Inflammatory Infiltrates (MI) compared to the control group and the other inclusion levels. The high presence of MI in the control group may be associated with a cellular inflammatory immune response in the hepatic tissue. The same effect may have occurred in the fish fed the 2.0% diet, suggesting that this concentration may be harmful to the organ's integrity. Our results support the findings of Leite et al. (2021), who reported in their trials with tilapia that açaí oil (3% and 6%) stimulates antioxidant effects in the liver, increasing the activity of glutathione peroxidase (GSH-Px) and Superoxide Dismutase (SOD). Meanwhile, in the study by Silva et al. (2023), juveniles of Colossoma macropomum that received 5% açaí in their diet showed positive results related to growth, metabolic biomarkers, and antioxidant capacity. Additionally, cytoplasmic vacuolization was significant in the control group and the group with 2.0% açaí inclusion. This histological change is characterized by the presence of small fat accumulations within the hepatocytes. In the other diets, this effect was minimized, suggesting that açaí at lower concentrations may reduce the accumulation of vacuoles in hepatocytes, while higher concentrations may enhance the presence of these vacuoles. This effect was also observed by Zheng et al. (2017) in tilapia supplemented with rutin, one of the antioxidants found in açaí, at a dosage of 0.3 g/kg in the diet. 5 Conclusion As far as we know, this is the first report on the impact of diets containing freeze-dried açaí on the histopathology of koi carp liver tissue. The results indicate that açaí has considerable potential as a dietary supplement for koi carp, provided it is administered in adequate quantities, taking advantage of its antioxidant benefits, and improving the fish's liver health. In this study, the inclusion of 1.5% açaí showed the best results. However, we stress the need for future studies that analyze oxidative stress in the liver, with the aim of determining the ideal dose of açaí and carrying out experiments with other fish species, to gain a comprehensive understanding of the effects of açaí in the diet of ornamental fish. Authors’ contributions Fernandes M.C. and Costa D.S. contributed to the conceptualization, methodology, software development, validation, formal analysis, investigation, data curation, and the writing of the original manuscript, as well as visualization. Silva A.V. was responsible for designing the experimental trial structure and methodology. Lopes E.M. participated in the investigation and contributed to the original writing. Ventura A.S. and Cardoso C.A.L. were involved in methodology development, conducting chemical analysis of the feed, and reviewing and editing the manuscript. Tedesco M. played a key role in methodology development and performed the histological analysis. Mouriño J.L.P. and Martins M.L. provided support in visualization, supervision, and project administration. Acknowledgments The authors thank the National Council for Scientific and Technological Development (CNPq) for research grants to J.L.P. Mouriño (CNPq 301524/2017-3) and M.L. Martins (CNPq 306635/2018-6, 409821/2021-7). This study was partially funded by CAPES (AUXPE 2722/2023, code 001). References Abbate F., Maugeri A., Laurà R., Levanti M., Navarra M., Cirmi S., and Germanà A., 2021, Zebrafish as a useful model to study oxidative stress-linked disorders: focus on flavonoids, Antioxidants, 10(5): 668. https://doi.org/10.3390/antiox10050668 Akbari B., Baghaei‐Yazdi N., Bahmaie M., and Mahdavi A.F., 2022, The role of plant‐derived natural antioxidants in reduction of oxidative stress, BioFactors, 48(3): 611-633. https://doi.org/10.1002/biof.1831 Capanoglu E., Beekwilder J., Boyacioglu D., Hall R., and Vos R., 2008, Changes in antioxidant and metabolite profiles during production of tomato paste, Journal of Agricultural and Food Chemistry, 56(3): 964-973. https://doi.org/10.1021/jf072990e
RkJQdWJsaXNoZXIy MjQ4ODYzNA==