Tolerância de lambaris (Bryconops caudomaculatus) submetidos a diferentes concentrações de amônia

Abstract

The diversity of the oscillations in the aquatic environment can be enhanced by the lack of preventive methods in management. The lack of knowledge about the parameters of water quality, such as transparency, alkalinity, hardness, dissolved oxygen, pH, ammonia, nitrite and pollutants cause various problems. The increase in the concentration of ammonia causes toxicity to aquatic organisms as it interacts with the biological parameters and can be intensified by the lack of appropriate management in water. Animals exposed to these contaminants may change in metabolic, immunologic, physiologic, and tissue damage in target organs such as gills and liver processes. The tetra (Bryconops caudomaculatus) is a native species with potential for aquaculture, with great potential for expansion, have high proliferation, short production cycle, accepts artificial food and serves as food for other species. The lack of information and the demand for knowledge about the disturbances caused by these animals increased concentrations of ammonia in the water require more specific studies in these target organs. The objective of this experiment was to evaluate the effects of exposure of un-ionized ammonia (NH3) in juvenile Bryconops caudomaculatus, and morphological and histopathological changes in the gills and liver. 150 juvenile minnows subjected to five treatments in tripicata with concentrations of NH3 (mg L-1) were control 0.003 ± 0.4; 0.15 ± 0.5; 0.30 ± 0.3; 0.50 ± 0.5; 1.00 ± 0.4. After the experimental period, 12 animals from each treatment were collected to obtain the gills and liver. After, target organs passed by fixation, dehydration, and paraffin embedding diafranização processes. The staining technique used was toluidine blue for gills and hematoxylin-eosin for the liver. Analysis of variance was used for parametric data and Kruskal-Wallis test for the descriptive analyzes. Morphological changes were observed in the secondary lamellae in the gills from 0.15 mg L-1 as hyperplasia, hypertrophy, epithelial displacement, lamellar melt, edema, aneurysm rupture lamellar epithelium and increase in width of the lamellae. There was also the presence of liver histopathologies from 0.30 mg L-1 as the capillary congestion, inflammation, pigmentation and endogenous treatment with the highest concentration in hepatocytes showed necrosis. These changes caused by the processes of intoxication impaired vital functions, metabolism, processes of respiration and detoxification of the body, probably in hematopoiesis and osmoregulation.