Sublethal Effects of Cadmium on the Osmoregulatory and Acid-Base Parameters of Tilapia (Oreochromis niloticus) at Various Times

Agoes Soegianto; Bambang Yulianto; Carolyn Melissa Payus; Moch Affandi; Wildanun Mukholladun; Khudrotul Nisa Indriyasari; Ary Marchellina; Nailul Muthiati Rahmatin

doi:10.1155/2023/2857650

Sublethal Effects of Cadmium on the Osmoregulatory and Acid-Base Parameters of Tilapia (Oreochromis niloticus) at Various Times

J Toxicol. 2023 Feb 27:2023:2857650. doi: 10.1155/2023/2857650. eCollection 2023.

Authors

Agoes Soegianto¹, Bambang Yulianto², Carolyn Melissa Payus³, Moch Affandi¹, Wildanun Mukholladun¹, Khudrotul Nisa Indriyasari¹, Ary Marchellina¹, Nailul Muthiati Rahmatin¹

Affiliations

¹ Department of Biology, Faculty of Science and Technology, Universitas Airlangga, Surabaya, Indonesia.
² Department of Marine Science, Faculty of Fisheries and Marine Science, Diponegoro University, Semarang, Indonesia.
³ Faculty of Science and Natural Resources, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia.

Abstract

Background: Cadmium (Cd) can contaminate aquatic environments as a result of anthropogenic activity. Cd accumulates quickly in the tissues of fish and has the potential to affect their physiology, including osmoregulation and acid-base balance. Therefore, the purpose of this study was to examine the sublethal effects of Cd on the osmoregulation and acid-base balance of tilapia Oreochromis niloticus at different times.

Methods: Fish were exposed to sublethal concentrations of Cd (1 and 2 mg/L) for 4 and 15 days. At the end of the experiment, fish were collected from each treatment to examine the levels of Cd and carbonic anhydrase (CA) in the gills, plasma osmolality, ions, blood pH, pCO₂, pO₂, and hematological parameters.

Results: Cd concentrations in gills rose with increasing Cd concentrations in the medium and exposure time. Cd inhibited respiration by generating metabolic acidosis, decreasing gill CA, reducing pO₂, plasma osmolality, Cl^-, and K⁺, particularly at 2 mg/L for 4 days and 1 and 2 mg/L for 15 days. Red blood cell (RBC), hemoglobin (Hb), and hematocrit (Ht) levels decreased as Cd levels in water and exposure duration increased.

Conclusion: Cd inhibits respiration, lowers RCB, Hb, and Ht levels and decreases ionic and osmotic regulation. All of these impairments can limit a fish's ability to provide appropriate oxygen to its cells, hence diminishing its physical activity and productivity.