Abstract
Fipronil (FIP), a broad-spectrum phenylpyrazole, is extensively used across the globe to control pests and as a veterinary drug. Incorrect use of FIP leads to contamination of soil and water ultimately causes toxic effects in non-target organisms. Therefore, the present experimental study was aimed to determine the deleterious effects of sub-lethal concentrations of FIP in adult cockerels. FIP mixed in corn oil was administered orally in different groups as follows: A = control, B = 1.5 mg/kg, C = 2.5 mg/kg, D = 3.5 mg/kg and E = 4.5 mg/kg body weight for 60 d. Signs of toxicity like anemic comb, tremors, gasping and watery droppings were evident in birds exposed to higher levels. The feed intake, body weight, absolute and the relative weight of different organs were significantly (p ≤ .05) decreased in birds exposed to higher concentrations. Histomorphometric analysis of small intestine in birds exposed to higher levels of FIP showed decreased villus height and crypt depth of duodenum, jejunum and ilium. Histologically, congestion in liver, pyknosis of hepatocytes and congestion in kidneys along with necrosis of tubular epithelial cells and increased urinary spaces were observed in birds. Microscopically, seminiferous tubules exhibited necrotic nuclei of the spermatids, arrest of process of spermatogenesis and admixture of necrotic cells in testes of exposed birds. Moreover, significantly (p ≤ .05) decreased hematological parameters such as erythrocytes counts, hemoglobin concentrations and hematocrit, while increased total leukocyte counts were recorded in birds. Furthermore, significantly (p ≤ .05) increased concentrations of serum urea, creatinine, alanine aminotransferase, aspartate aminotransferase and cardiac isoenzyme (CK-MB), while reduced serum testosterone levels were recorded in birds. Results revealed significantly (p ≤ .05) increased frequency of micronuclei in erythrocyte and bone marrow cells. The findings of our study demonstrated that FIP induces deleterious impacts on multiple tissues in birds even at low doses.