Addition of Sodium Chloride to Water and Its Effects on Ammonia Toxicity in the Rearing of Juvenile Piaractus mesopotamicus HOLMBERG, 1887Author: Thalline Santos Diniz (Currículo Lattes)
Advisor: Dr. Luciano de Oliveira Garcia
Abstract
The present study aimed to evaluate the relationship between the toxic effects of un-ionized ammonia (NH₃) and sodium chloride (NaCl) in juvenile pacu (Piaractus mesopotamicus), as well as their influence on hematological parameters and zootechnical performance. A total of 180 juvenile pacu (18.15 ± 0.22 g) were used, randomly distributed across 12 tanks of 80 L (with 60 L of useful volume), each containing 15 fish, in a closed recirculating system with constant aeration, for a period of 45 days. During the experimental period, fish were subjected to four treatments: T1: Salinity (6); T2: Ammonia (1.0 mg NH₃ L⁻¹); T3: Salinity (6) plus Ammonia (1.0 mg NH₃ L⁻¹); and T4: Control (salinity 0; ~0 mg NH₃ L⁻¹). At the end of the experiment, final biometric measurements were taken (n = 36 fish per treatment) to assess zootechnical performance. Subsequently, blood samples were collected to determine glucose, hematocrit, hemoglobin, pH, red blood cell count, and hematimetric indices (MCV – Mean Corpuscular Volume, MCH – Mean Corpuscular Hemoglobin, and MCHC – Mean Corpuscular Hemoglobin Concentration). The results showed that both zootechnical and hematological parameters were affected. Based on the findings, it can be concluded that pacu is a species tolerant to ammonia variation, as no mortality was observed. Although salinity increased the fish's tolerance to ammonia exposure, it was not sufficient to prevent the toxic effects of ammonia on zootechnical and hematological parameters.