Physiological parameters of Piaractus mesopotamicus (Osteichthyes: Characidae) exposed to a biopesticide based on Bacillus thuringiensis

Abstract

This study investigated the physiological effects of a pesticide based on Bacillus thuringiensis (Dipel-WP ®) added in the water and diet of Piaractus mesopotamicus during 24 and 48 h. It was added 0.13 g of de B. thuringiensis per kg of commercial feed; and for the fish subjected to the biopesticide in the water of the tanks, it was added 0.13 g/l of the biopesticide. Plasma levels of sodium, chloride, potassium, cholesterol, glucose, triglycerides, cortisol, total protein, alanine aminotransferase (AlT), aspartate aminotransferase (AST), hematocrit, hemoglobin, erythrocytes number, mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC), number of thrombocytes and leukocytes were determined. Cortisol, lactate, glucose, total protein, cholesterol, triglycerides, AlT, AST, sodium, potassium, hematocrit, hemoglobin, MCV, number of erythrocytes, leukocytes, lymphocytes, eosinophils and PAS-positive granular leukocytes suffered alterations derived from the addition of B. thuringiensis in water and diet of the fish. The toxicity of the concentrations of biopesticide in short-term exposure in water and diet of the fish led to blood alterations (increase or decrease). Therefore, care must be taken to avoid a possible prolonged contamination in the tanks of fish farming by agricultural pollution based on B. thuringiensis.

Avaliação de toxicidade de biopesticida comercial à base de Bacillus thuringiensis em tilapia-do-Nilo, Oreochromis niloticus

“…A concentração utilizada neste estudo não ocasionou toxicidade em O. niloticus, embora, alguns estudos demonstram que este agente biológico pode alterar funções biológicas importantes dos vertebrados (Shaban et al, 2003;Chen et al, 2014;Mariano et al, 2019). No entanto, é necessário considerar a influência da forma de exposição do organismo ao agente, seja às protoxinas, às toxinas ativas, à bactéria ou aos esporos.…”

“…De acordo com Villaverde et al (2014), alguns biopesticidas à base de Bt possuem um espectro relativamente amplo de organismos alvo. Ainda, alguns estudos apontam o Bt como agente nocivo a organismos não alvos como tartarugas (Chen et al, 2014) e peixes (Omoya & Akharaiyi, 2015;Mariano et al, 2019).…”

Dissecting the Environmental Consequences of Bacillus thuringiensis Application for Natural Ecosystems

“…For instance, the intra-abdominal Bt injection (0.2 mL of 1 × 108 spores/mL) caused the increased apoptosis rates in O. niloticus erythrocytes, although no acute toxicity was observed when fishes were placed in an aquarium with Bt solution for 72 h [ 151 ]. Short-term Bt presence both in the surrounding water and diet of Piaractus mesopotamicus altered blood properties and slightly reduced fish appetite without, however, elevated mortality rates [ 159 ].…”