Dose-specific toxicity of naphthalene (Polycyclic Aromatic Hydrocarbon) and subsequent recovery by humic feed-o-fert on Anabas testudineus (Bloch): Blood biochemical and morphological introspections

Polycyclic aromatic hydrocarbons (PAHs) are pervasive contaminants in aquatic ecosystems, yet their specific effects on blood pathophysiology, including alterations in blood biochemical and morphological introspections, remain largely unexplored. As consequence, the present study is aimed to record the toxicity of naphthalene exposure for 21-d under two selected doses 0.7075 mg/L (T1) and 1.415 mg/L (T2), i.e., 25 and 50 % of LC₅₀ value [2.83 mg/L] respectively and subsequent recovery with one improved organic solid waste, feed-promoter Humic feed-o-fert (HF) of 0.5 g/L for the same duration of 21-d. The results showed significant increment in values in blood biochemical parameters, viz., cholesterol (CHOLES), glucose (GLU), glutamine pyruvic transmission (GPT), calcium (Ca), alkaline phosphatase (ALP), high density lipoprotein (HDL) and low density lipoprotein (LDL), and some displayed decreasing trend like protein (PRO), albumin (ALB) and triglyceride (Trig) under this exposure. During recovery phase with HF, the nature of biochemical changes became reversed showing significant restoration and repairment in comparison to naphthalene treatment. Morphological alterations of blood cells revealed maximum changes and appearance, such as tear drop-like cells (Tr), sickle cells (Sk), swelled cells (Sc) and vacuolated cells (Va) under two doses of exposure in 21-d, but under recovery with HF the cells approached towards regaining the normal contour of leucocytes (L), erythrocytes (Er) and tear drop like cells (Tr). So, it can be inferred that Humic feed-o-fert (HF) here played an important role to resist the haematological impairments in fish against the naphthalene (PAH) exposure. Further, Humic feed-o-fert (HF) may contribute in aquatic ecosystem restoration against the environmental contaminants, especially PAHs in aquaculture.