Hematological and histological responses of common carp (Cyprinus carpio) to paraquat and glyphosate under aqueous saffron extract as a mitigating agent

Abstract

In recent years, despite the known detrimental effects of herbicides such as paraquat (PQ) and glyphosate (GLY), their agricultural application has escalated to support a growing global food demand. Bioactive herbal extracts such as aqueous saffron (Crocus sativus) extract may potentially mitigate herbicide-induced adverse effects in non-target aquatic organisms. This study evaluated the comparative efficacy of aqueous saffron extract in attenuating the sublethal toxicity of PQ and GLY, administered individually and in combination, on hemato­ logical parameters, serum biochemical markers, tissue histopathology, and residue accumulation in common carp (Cyprinus carpio). The results demonstrated that exposure to PQ and GLY, both individually and in com­ bination, significantly decreased red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), and he­ matocrit (Ht) percentage compared to the control group (P < 0.05). Co-treatment with aqueous saffron extract significantly improved these hematological parameters, maintaining them toward control levels. Exposure to PQ, GLY, and their combination induced marked reductions in serum total protein and albumin levels, as well as significant elevations in serum hepatic enzyme activities aspartate aminotransferase (AST), alanine amino­ transferase (ALT), and alkaline phosphatase (ALP) (P < 0.05) indicating hepatocellular injury. Saffron cotreatment significantly attenuated these herbicide-induced enzymatic elevations and helped maintain protein levels near baseline values. Histopathological examination revealed that PQ and GLY caused severe tissue al­ terations in the gills, intestine, and liver. Saffron extract supplementation exerted a tissue-specific protective effect, partially mitigating hepatic damage, whereas its ameliorative capacity in branchial and intestinal tissues was less pronounced. HPLC analysis confirmed the bioaccumulation of PQ and GLY residues across tissues, with the liver exhibiting the highest deposition under single-exposure regimes. Notably, saffron supplementation was associated with lower tissue residue levels of both herbicides, particularly under co-exposure conditions. Overall, aqueous saffron extract demonstrates potential as a dietary mitigating agent against herbicide-induced physio­ logical stress and hepatotoxicity in common carp, though its protective efficacy remains tissue-specific.