Biological Systems: Theory and Innovation

Chronic effect of low urea concentration on the content of carotenoid pigments in Lymnaea stagnalis

Lidiia Muzyka*, Galyna Kyrychuk

lidiya.muzyka@ukr.net

Download article
Abstract

Urea is one of the most common nitrogen-containing pollutants in freshwater ecosystems and, if it enters water bodies for a long time, can disrupt the course of metabolic processes in aquatic organisms. Since carotenoids serve as non-enzymatic antioxidants, changes in their content reflect the development of oxidative stress and serve as sensitive biochemical markers of toxic effects. The purpose of the study was to find out the features of the effect of low urea concentration on the content of β-carotene and xanthophylls in the haemolymph, hepatopancreas, mantle, and foot of Lymnaea stagnalis. The study was conducted on sexually mature uninfected mollusks that were kept in an environment with urea at a concentration equivalent to twice the maximum permissible concentration for water bodies used for fisheries purposes (2 MPCfisheries), for 2, 7, 14, and 21 days. The carotenoid content was determined spectrophotometrically, and the results were processed using two-factor analysis of variance and correlation. It was found that with short-term urea exposure (2 days), the content of β-carotene in the mantle and foot of L. stagnalis increased by 1.93-2.88 times (p < 0.01-0.05). The content of xanthophylls in these organs significantly decreased by 50.73-56.68%, while no significant differences were found in hepatopancreas. An increase in the duration of exposure to 14-21 days was accompanied by a systemic decrease in the content of β-carotene (by 25.94-69.24%; p < 0.001-0.05) and xanthophylls (by 38.89-88.41%) in the hepatopancreas, mantle and foot of L. stagnalis, which is probably conditioned by increased pro-oxidant processes and the use of carotenoids in free radical neutralisation reactions. Correlation analysis revealed a statistically significant negative association between urea exposure and β-carotene and xanthophyll content, which indicates depletion of the carotenoid reserve under toxic load. Consequently, chronic exposure to urea in the studied concentration causes tissue-specific changes in the carotenoid profile of L. stagnalis, which reflect the transition from compensatory-adaptive reactions to depletion of the non-enzymatic link of the antioxidant system. The results obtained can be used by environmental and fisheries organisations for ecotoxicological assessment of the impact of nitrogen-containing pollutants on freshwater ecosystems, and the content of β-carotene and xanthophylls – as an informative biochemical marker of such effects

Keywords

freshwater shellfish; β-carotene; xanthophylls; oxidative stress; nitrogen-containing compounds

Suggested citation
Muzyka, L., & Kyrychuk, G. (2026). Chronic effect of low urea concentration on the content of carotenoid pigments in Lymnaea stagnalis. Biological Systems: Theory and Innovation, 17(3), 94-105. https://doi.org/10.31548/biologiya/3.2026.94
References
  1. Arandia-Gorostidi, N., Jaffe, A.L., Parada, A.E., Kapili, B.J., Casciotti, K.L., Salcedo, R.S.R., Baumas, C.M.J., & Dekas, A.E. (2024). Urea assimilation and oxidation support activity of phylogenetically diverse microbial communities of the dark ocean. The ISME Journal, 18(1), article number wrae230. doi: 10.1093/ismejo/wrae230.
  2. Cong, M., Li, Y., Xu, H., Lv, J., Wu, H., & Zhao, Y. (2021). Ammonia nitrogen exposure caused structural damages to gill mitochondria of clam Ruditapes philippinarum. Ecotoxicology and Environmental Safety, 222, article number 112528. doi: 10.1016/j.ecoenv.2021.112528.
  3. Convention on Biological Diversity. (1992, June). Retrieved from https://www.cbd.int/doc/legal/cbd-en.pdf.
  4. Convention on the Trade in Endangered Species of Wild Fauna and Flora. (1973, March). Retrieved from https://treaties.un.org/doc/publication/unts/volume%20993/volume-993-i-14537-english.pdf.
  5. Ge, H., Liang, X., Liu, J., Cui, Z., Guo, L., Li, L., Sun, Y., Dong, Z., & Wei, M. (2021). Effects of acute ammonia exposure on antioxidant and detoxification metabolism in clam Cyclina sinensis. Ecotoxicology and Environmental Safety, 211, article number 111895. doi: 10.1016/j.ecoenv.2021.111895.
  6. Gruszecki, W.I., & Strzałka, K. (2005). Carotenoids as modulators of lipid membrane physical properties. Biochimica et Biophysica Acta (BBA) – Molecular Basis of Disease, 1740(2), 108-115. doi: 10.1016/j.bbadis.2004.11.015.
  7. Hu, X., Ma, W., Zhang, D., Tian, Z., Yang, Y., Huang, Y., & Hong, Y. (2025). Application of natural antioxidants as feed additives in aquaculture: A review. Biology, 14(1), article number 87. doi: 10.3390/biology14010087.
  8. Jia, R. (2025). Natural antioxidants and aquatic animal health. Antioxidants, 14(2), article number 185. doi: 10.3390/antiox14020185.
  9. Kyrychuk, G.Ye. (2022). Proceedings of the XIII all-Ukrainian scientific and practical conference “biological research – 2022”. Zhytomyr: PE “Euro-Volyn”.
  10. Liao, Y., Zhang, B., Wang, D., Jiang, D., Zhu, C., Deng, S., Chen, H., Li, G., & Shi, H. (2025). Metabolism, function, molecular mechanism, and application of carotenoids in coloration of aquatic animals. Reviews in Aquaculture, 17(2), article number e70016. doi: 10.1111/raq.70016.
  11. Lim, K.C., Yusoff, F., Karim, M., & Natrah, F.M.I. (2023). Carotenoids modulate stress tolerance and immune responses in aquatic animals. Reviews in Aquaculture, 15(2), 872-894. doi: 10.1111/raq.12767.
  12. Ma, W., Zeng, W., Zhang, D., Zhou, Y., Huang, Y., & Hong, Y. (2025). Oxidative stress in aquaculture: Pathogenic mechanisms and preventive strategies in farmed aquatic animals. Current Issues in Molecular Biology, 47(11), article number 873. doi: 10.3390/cimb47110873.
  13. Ojha, A., Manna, T., Kumar, A., Shit, P., Mete, M., Das, D., & Bandyopadhyay, T.K. (2025). Urease: Kinetic and thermodynamic mechanisms and their diverse applications. Exon, 2(3), 224-242. doi: 10.69936/en14y0025.
  14. Pasenkiewicz-Gierula, M., Hryc, J., & Markiewicz, M. (2024). Dynamic and energetic aspects of carotenoids in-and-around model lipid membranes revealed in molecular modelling. International Journal of Molecular Sciences, 25(15), article number 8217. doi: 10.3390/ijms25158217.
  15. Shah, F.I., Imran, H., Akram, F., Khalid, T., & Shehzadi, S. (2026). Marine carotenoids: Unlocking advanced antioxidant mechanisms and therapeutic applications for oxidative stress. Molecular Biotechnology, 68, 969-986. doi: 10.1007/s12033-025-01420-w.
  16. Song, J., Maurelli, O.V.J., Yeats, M.S., Thompson, N.F., Banks, M.A., & Calla, B. (2025). Sex-specific transcriptome signatures in Pacific oyster hemolymph. Genes, 16(9), article number 1033. doi: 10.3390/genes16091033.
  17. Yun, S.C., Jeong, H., Lee, J.-S., Kim, J.-H., Kim, I.-C., Maszczyk, P., Yang, Z., Hagiwara, A., & Lee, J.-S. (2026). A review of ammonia toxicity on aquatic organisms: Species-specific responses, microbial shifts, and environmental interactions. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 300, article number 110388. doi: 10.1016/j.cbpc.2025.110388.
  18. Zbyradowski, M., Duda, M., Wisniewska-Becker, A., Heriyanto, Rajwa, W., Fiedor, J., Cvetkovic, D., Pilch, M., & Fiedor, L. (2022). Triplet-driven chemical reactivity of β-carotene and its biological implications. Nature Communications, 13, article number 2474. doi: 10.1038/s41467-022-30095-z.
  19. Zhang, L., Wang, G., Huang, S., Gong, X., & Wang, Y. (2023). Research progress on the mechanism of carotenoid absorption, metabolism and deposition in animals in aquature: A review. Journal of Dalian Fisheries University, 38(6), 1072-1082. doi: 10.16535/j.cnki.dlhyxb.2023-053.
  20. Zhang, T., Xu, D., Zhou, Y., Ma, X., & Wen, H. (2024). Acute ammonia stress affects the immune response, oxidative stress, ammonia transport and detoxication in the hepatopancreas of freshwater mollusk Solenaia oleivora. Toxicology and Applied Pharmacology, 493, article number 117138. doi: 10.1016/j.taap.2024.117138.
  21. Zhuang, C., Yuan, J., Du, Y., Zeng, J., Sun, Y., Wu, Y., Gao, X.-H., & Chen, H.-D. (2022). Effects of oral carotenoids on oxidative stress: A systematic review and meta-analysis of studies in the recent 20 years. Frontiers in Nutrition, 9, article number 754707. doi: 10.3389/fnut.2022.754707.
  22. Zou, Y., Chen, W., Xia, B., Xiang, Y., Shen, Z., Han, Y., & Xue, S. (2023). Ammonia toxicity in the bighead carp (Aristichthys nobilis): Hematology, antioxidation, immunity, inflammation and stress. Toxics, 11(3), article number 243. doi: 10.3390/toxics11030243.