---

This study investigates the effects of dietary β-glucans on the activity of key antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPx)] in the hepatic and cardiac tissues of rainbow trout (Oncorhynchus mykiss Walbaum). Supplementation with β-glucans significantly modulated catalase (CAT) and glutathione peroxidase (GPx) activities in both tissues, suggesting enhanced antioxidant defence mechanisms. In the hepatic tissue, a 264.6% increase in CAT activity (p < 0.05) and a 311% increase in GPx activity (p < 0.05) was observed, indicating enhanced hydrogen peroxide detoxification and oxidative stress resistance. A similar enhancement of antioxidant capacity was observed in the heart, with an increase in cardiac CAT activity of 135.7% (p < 0.05). Although changes in superoxide dismutase (SOD) activity were not statistically significant, a trend of decreased hepatic SOD activity and increased cardiac SOD activity was observed, potentially reflecting tissue-specific oxidative defense strategies. Glutathione reductase (GR) activity decreased in both tissues, albeit not significantly, suggesting possible adaptations in the glutathione cycle. The findings of this study emphasise the tissue-specific modulation of antioxidant pathways by dietary β-glucans and their potential role in enhancing oxidative stress resistance in aquaculture species. The data suggest that dietary β-glucans induce tissue-specific modulations of antioxidant enzyme activities in rainbow trout, potentially enhancing oxidative resilience in liver and heart tissues. These effects are likely to arise from the bioactive properties of β-glucans, which are known to influence immune and oxidative defence pathways. It is recommended that future studies focus on long-term feeding trials and the inclusion of additional biomarkers to facilitate a comprehensive understanding of the physiological effects of β-glucan supplementation.

References

Allameh, A., Niayesh-Mehr, R., Aliarab, A., Sebastiani, G., & Pantopoulos, K. (2023). Oxidative Stress in Liver Pathophysiology and Disease. Antioxidants (Basel, Switzerland), 12(9), 1653. https://doi.org/10.3390/antiox12091653.

Banaee, M., Faraji, J., Amini, M., Multisanti, C. R., & Faggio, C. (2023). Rainbow trout (Oncorhynchus mykiss) physiological response to microplastics and enrofloxacin: Novel pathways to investigate microplastic synergistic effects on pharmaceuticals. Aquatic toxicology (Amsterdam, Netherlands), 261, 106627. https://doi.org/10.1016/j.aquatox.2023.106627.

Bar-Dagan, H., Gover, O., Cohen, N. A., Vetvicka, V., Rozenboim, I., & Schwartz, B. (2023). Beta-glucans induce cellular immune training and changes in intestinal morphology in poultry. Frontiers in veterinary science, 9, 1092812. https://doi.org/10.3389/fvets.2022.1092812.

Barton, C., Vigor, K., Scott, R., Jones, P., Lentfer, H., Bax, H. J., Josephs, D. H., Karagiannis, S. N., & Spicer, J. F. (2016). Beta-glucan contamination of pharmaceutical products: How much should we accept?. Cancer immunology, immunotherapy: CII, 65(11), 1289–1301. https://doi.org/10.1007/s00262-016-1875-9.

Bradford M. M. (1976). A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Analytical biochemistry, 72, 248–254. https://doi.org/10.1016/0003-2697(76)90527-3.

Cichoż-Lach, H., & Michalak, A. (2014). Oxidative stress as a crucial factor in liver diseases. World journal of gastroenterology, 20(25), 8082–8091. https://doi.org/10.3748/wjg.v20.i25.8082.

Colaço, M., Panão Costa, J., & Borges, O. (2022). Glucan Particles: Choosing the Appropriate Size to Use as a Vaccine Adjuvant. Methods in molecular biology (Clifton, N.J.), 2412, 269–280. https://doi.org/10.1007/978-1-0716-1892-9_13.

Glatzle, D., Vuilleumier, J. P., Weber, F., & Decker, K. (1974). Glutathione reductase test with whole blood, a convenient procedure for the assessment of the riboflavin status in humans. Experientia, 30(6), 665–667. https://doi.org/10.1007/BF01921531.

Jesus, S., Panão Costa, J., Colaço, M., Lebre, F., Mateus, D., Sebastião, A. I., Cruz, M. T., Alfaro-Moreno, E., & Borges, O. (2024). Exploring the immunomodulatory properties of glucan particles in human primary cells. International journal of pharmaceutics, 655, 123996. https://doi.org/10.1016/j.ijpharm.2024.123996.

Jomova, K., Raptova, R., Alomar, S. Y., Alwasel, S. H., Nepovimova, E., Kuca, K., & Valko, M. (2023). Reactive oxygen species, toxicity, oxidative stress, and antioxidants: chronic diseases and aging. Archives of toxicology, 97(10), 2499–2574. https://doi.org/10.1007/s00204-023-03562-9.

Kofuji, K., Aoki, A., Tsubaki, K., Konishi, M., Isobe, T., & Murata, Y. (2012). Antioxidant Activity of β-Glucan. ISRN pharmaceutics, 2012, 125864. https://doi.org/10.5402/2012/125864.

Koroliuk, M. A., Ivanova, L. I., Maĭorova, I. G., & Tokarev, V. E. (1988). Metod opredeleniia aktivnosti katalazy [A method of determining catalase activity]. Laboratornoe delo, (1), 16–19.

Kostiuk, V. A., Potapovich, A. I., & Kovaleva, Z.hV. (1990). Prostoĭ i chuvstvitel’nyĭ metod opredeleniia aktivnosti superoksid- dismutazy, osnovannyĭ na reaktsii okisleniia kvertsetina [A simple and sensitive method of determination of superoxide dismutase activity based on the reaction of quercetin oxidation]. Voprosy meditsinskoi khimii, 36(2), 88–91.

Liang, X., Zhou, J., Wang, M., Wang, J., Song, H., Xu, Y., & Li, Y. (2024). Progress and prospect of polysaccharides as adjuvants in vaccine development. Virulence, 15(1), 2435373. https://doi.org/10.1080/21505594.2024.2435373.

Liu, Y., Wu, Q., Wu, X., Algharib, S. A., Gong, F., Hu, J., Luo, W., Zhou, M., Pan, Y., Yan, Y., & Wang, Y. (2021). Structure, preparation, modification, and bioactivities of β-glucan and mannan from yeast cell wall: A review. International journal of biological macromolecules, 173, 445–456. https://doi.org/10.1016/j.ijbiomac.2021.01.125.

Mata-Martínez, P., Bergón-Gutiérrez, M., & Del Fresno, C. (2022). Dectin-1 Signaling Update: New Perspectives for Trained Immunity. Frontiers in immunology, 13, 812148. https://doi.org/10.3389/fimmu.2022.812148.

Mirza, Z., Soto, E. R., Dikengil, F., Levitz, S. M., & Ostroff, G. R. (2017). Beta-Glucan Particles as Vaccine Adjuvant Carriers. Methods in molecular biology (Clifton, N.J.), 1625, 143–157. https://doi.org/10.1007/978-1-4939-7104-6_11.

Moin V. M. (1986). Prostoĭ i spetsificheskiĭ metod opredeleniia aktivnosti glutationperoksidazy v éritrotsitakh [A simple and specific method for determining glutathione peroxidase activity in erythrocytes]. Laboratornoe delo, (12), 724–727.

Nakashima, A., Yamada, K., Iwata, O., Sugimoto, R., Atsuji, K., Ogawa, T., Ishibashi-Ohgo, N., & Suzuki, K. (2018). β-Glucan in Foods and Its Physiological Functions. Journal of nutritional science and vitaminology, 64(1), 8–17. https://doi.org/10.3177/jnsv.64.8.

Rodrigues, M. V., Zanuzzo, F. S., Koch, J. F. A., de Oliveira, C. A. F., Sima, P., & Vetvicka, V. (2020). Development of Fish Immunity and the Role of β-Glucan in Immune Responses. Molecules (Basel, Switzerland), 25(22), 5378. https://doi.org/10.3390/molecules25225378.

Singh, R. P., & Bhardwaj, A. (2023). β-glucans: a potential source for maintaining gut microbiota and the immune system. Frontiers in nutrition, 10, 1143682. https://doi.org/10.3389/fnut.2023.1143682.

Singla, A., Gupta, O. P., Sagwal, V., Kumar, A., Patwa, N., Mohan, N., Ankush, Kumar, D., Vir, O., Singh, J., Kumar, L., Lal, C., & Singh, G. (2024). Beta-Glucan as a Soluble Dietary Fiber Source: Origins, Biosynthesis, Extraction, Purification, Structural Characteristics, Bioavailability, Biofunctional Attributes, Industrial Utilization, and Global Trade. Nutrients, 16(6), 900. https://doi.org/10.3390/nu16060900.

Song, H. S., & Moon, K.-Y. (2006). In Vitro Antioxidant Activity Profiles of β-Glucans Isolated from Yeast Saccharomyces cerevisiae and Mutant Saccharomyces cerevisiae IS2. Food Science and Biotechnology, 15(3), 437-440.

Tkachenko, H., Kurhaluk, N., & Grudniewska, J. (2023). Effects of dietary yeast β-1.3/1.6-glucans on lipid peroxidation in the hepatic and cardiac tissues of rainbow trout (Oncorhynchus mykiss Walbaum), European whitefish (Coregonus lavaretus L.), and grayling (Thymallus thymallus L.). Scientific and Technical Bulletin of the Institute of Animal Science of the National Academy of Agrarian Science of Ukraine, 129, 16-25. https://doi.org/10.32900/2312-8402-2023-129-16-25.

Torres-Maravilla, E., Parra, M., Maisey, K., Vargas, R. A., Cabezas-Cruz, A., Gonzalez, A., Tello, M., & Bermúdez-Humarán, L. G. (2024). Importance of Probiotics in Fish Aquaculture: Towards the Identification and Design of Novel Probiotics. Microorganisms, 12(3), 626. https://doi.org/10.3390/microorganisms12030626.

Tsoni, S. V., & Brown, G. D. (2008). Beta-glucans and dectin-1. Annals of the New York Academy of Sciences, 1143, 45–60. https://doi.org/10.1196/annals.1443.019.

Uiuiu, P., Lațiu, C., Păpuc, T., Craioveanu, C., Ihuț, A., Sava, A., Răducu, C., Șonea, C., Constantinescu, R., Cocan, D., & Mireșan, V. (2021). Multi-Approach Assessment for Stress Evaluation in Rainbow Trout Females, Oncorhynchus mykiss (Walbaum, 1792) from Three Different Farms during the Summer Season. Animals: an open access journal from MDPI, 11(6), 1810. https://doi.org/10.3390/ani11061810.

Vetvicka, V., Vannucci, L., & Sima, P. (2020). β-glucan as a new tool in vaccine development. Scandinavian journal of immunology, 91(2), e12833. https://doi.org/10.1111/sji.12833.

Wu, Y., Li, P., Jiang, Z., Sun, X., He, H., Yan, P., Xu, Y., & Liu, Y. (2023). Bioinspired yeast-based β-glucan system for oral drug delivery. Carbohydrate polymers, 319, 121163. https://doi.org/10.1016/j.carbpol.2023.121163.

Yu, C., Chen, H., Du, D., Lv, W., Li, S., Li, D., Xu, Z., Gao, M., Hu, H., & Liu, D. (2021). β-Glucan from Saccharomyces cerevisiae alleviates oxidative stress in LPS-stimulated RAW264.7 cells via Dectin-1/Nrf2/HO-1 signaling pathway. Cell stress & chaperones, 26(4), 629–637. https://doi.org/10.1007/s12192-021-01205-5.

Zar, J. H. (1999). Biostatistical Analysis. 4^th ed., Prentice Hall Inc., New Jersey.

Zhong, X., Wang, G., Li, F., Fang, S., Zhou, S., Ishiwata, A., Tonevitsky, A. G., Shkurnikov, M., Cai, H., & Ding, F. (2023). Immunomodulatory Effect and Biological Significance of β-Glucans. Pharmaceutics, 15(6), 1615. https://doi.org/10.3390/pharmaceutics15061615.