In-feed emamectin benzoate abuse affects the biological responses and erythrocytes of Nile tilapia Oreochromis niloticus

In aquaculture, drugs are often abused to accomplish disease control without considering the negative effects on fish health. This study aimed at elucidating the pernicious effects of in-feed antiparasitic drug emamectin benzoate (EB) abuse on the haemato-biochemistry and erythro-morphometry of healthy Nile tilapia Oreochromis niloticus. The fish were fed EB at 50 & mu;g (1x) and 150 & mu;g/kg biomass/d (3x) for 14 d as against the recommended 7 d and periodically assessed the blood parameters. A significant dose- and time-dependent reduction in feed intake, survival, total erythrocytes (TEC), monocytes (MC), hemoglobin (Hb), hematocrit (Ht) and mean corpuscular Hb concentration were noted. The total leukocytes (TLC), thrombocytes (TC), lymphocytes (LC) and neutrophils (NC) markedly augmented. The EB-dosing altered the fish physiology by enhancing the glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and creatinine and reducing the calcium, chloride and acetylcholinesterase (AChE) levels dose-dependently. The fish recovered within 4 weeks in the 1x group post-dosing but persevered in the overdosed group. The erythro-cellular and nuclear dimensions were reduced with the increase in dose and normalized after the cessation of dosing, except for nuclear volume. The erythro-morphological alterations were more prominent in the overdosed group. The results implied the pernicious effect of oral EB medication on the biological responses of fish if abused.

Automated summary

This study explores the harmful effects of abusing an antiparasitic drug, emamectin benzoate (EB), on the blood biochemistry and erythro-morphometry of Nile tilapia. Results showed that over-dosing of EB led to a decrease in feed intake, survival rate, erythrocyte count, hemoglobin, hematocrit, and mean corpuscular hemoglobin concentration. On the other hand, it resulted in an increase in leukocytes, thrombocytes, lymphocytes, and neutrophils. In addition, EB abuse altered the fish physiology by affecting various blood parameters and exhibited dose-dependent effects.