Protective, immunologic, and histopathologic effects of garlic extract (Allium sativum) on rainbow trout (Oncorhynchus mykiss) exposed to acute toxicity with copper (Cu2+)

The present study is an attempt to assess the protective and immunity effects of  Allium sativum in Oncorhynchus mykiss to acute exposure to copper .55 rainbow trout fish with an average weight of 51.20 ± 3.73 g were subjected to various densities of copper (0.02, 0.1, 0.3, and 0.4 mg/l). Under stable conditions, the lethal concentration of copper was detected to be 0.40 mg/l. The treatments included a control with no Cu or garlic treatment (T1), feeding with garlic additive and Cu exposure (T2), and exposure to a lethal dose of Cu with no garlic additive (T3).  The blood sample was used to designate hematological indices  such as white blood cell (WBC) and red blood cell (RBC) count, hematocrit (HCT), hemoglobin (HB) mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), neutrophils, lymphocytes, monocytes, eosinophils percent and Immunological indices (glucose, total protein, lysozyme, IgM). The results indicated significant differences among the treatments when the concentration of copper was increased (p < 0.05). According to the results obtained, there were noteworthy differences in MCV, MCHC, and HCT amongst the treatments (p < 0.05). The histopathological results indicated that the main lesions were hyperplasia and necrosis of epithelial cells (in gill), enlargement of Bowman's capsule and tubular degeneration (in kidney), hepatocytes necrosis (in liver) in all the fish. Pathologic severity signs in sampled tissues were increased by increasing in concentration and exposure times of copper sulphate However, the results revealed that the use of garlic in dietary can be beneficial to increasing fish resistance to copper.