Application of Optical Coherence Tomography (OCT) to Evaluate the Adverse Effects of 2,4-D Dimethylammonium on Morphological Changes in Riceland Prawn (Macrobrachium lanchesteri).

2,4-D dimethylammonium, a widely used herbicide, accumulates in aquatic animals, posing risks to both their populations and human consumers. This study evaluated the effects of 2,4-D on Riceland prawn (Macrobrachium lanchesteri) using Optical Coherence Tomography (OCT) to assess morphological changes. The activity of acetylcholinesterase (AChE), catalase (CAT), and glutathione S-transferase (GST) was also measured. Toxicity increased with both concentration and exposure duration. OCT revealed swelling in the gill region, tissue abnormalities, and muscle damage in the abdominal somite, telson, and uropod, along with tissue separation and degradation. Histological analysis confirmed muscle degeneration, hemocyte infiltration, and swelling. AChE expression was undetectable at 400 and 450µL/L after 96hours, with a molecular weight of 71kDa. CAT and GST activities decreased at higher herbicide concentrations, further demonstrating the harmful effects of 2,4-D on prawn health.