Toxicological effect of deltamethrin on enzymatical, apoptosis and immune response, histological morphology in Litopenaeus vannamei

Deltamethrin (DM) use in agricultural production and storage can result in the presence of residues in several feed ingredients, which can then be ingested by aquatic animals, potentially leading to adverse health effects. Although the potential toxicity of the lipophilic deltamethrin has been evaluated in several studies, there is a paucity of comprehensive studies on the negative effects induced by chronic exposure of shrimp to deltamethrin at different dietary lipid levels. A feeding experiment of six weeks was carried out to assess whether alterations in dietary lipid levels have an impact on the toxicity of DM. In a feeding experiment on Litopenaeus vannamei, the effects of dietary fat levels on the toxicity of DM were studied. There were six distinct diets created comprising three levels of DM (0.2 mg⋅kg^–1, 1 mg⋅kg^–1, 5 mg⋅kg^–1), and two lipid levels (6.96 %, 10.88 %). The diets were designated as LF0.2, LF1, LF5, HF0.2, HF1, HF5. The growth performance and whole shrimp body lipid were reduced with the increase of DM addition to the diet, and DM caused abnormal changes in lipoproteins (LDL, HDL, LPS) in shrimp when feeding diets containing high doses of DM. Furthermore, GOT, GPT, AKP, and ACP activities were found to be significantly increased by long-term exposure to DM. Meanwhile, the way that genes linked to the nuclear factor kappa-B immune signaling pathway showed a significant increase in the hepatopancreas (dorsal, imd, pelle, ikkβ), intestine (imd, tube, pelle), and muscle (toll, imd, pelle) of shrimp following exposure to DM. Similarly, cellular autophagy genes in the hepatopancreas (atg9, atg12), muscle (atg3, atg9), and intestine (atg3, atg5, atg9, beclin, atg13) were significantly upregulated in a dose-dependent manner after shrimp chronic exposure to DM. Histopathological damage was also induced in the muscles under DM exposure. In summary, chronic exposure to DM resulted in a slowing of growth performance, disruption of lipoprotein metabolism, impairment of hepatopancreatic, intestinal, and muscle-related immune functions, as well as the promotion of autophagy and damage to shrimp muscle.