Respostas metabólicas e hematológicas de tilápias do nilo, Oreochromis niloticus, alimentadas com ração suplementada com Arthrospira platensis, submetida a diferentes agentes estressores

Abstract

Aquaculture is the world's fastest growing food production sector nowadays. Intensification of aquaculture is mainly due to the increasing demand for animal protein. However, this explosive growth is subject to factors that increase fish susceptibility to disease, causing a high mortality rate. In order to maintain fish homeostasis, stress reduction is fundamental. The objective of this thesis was to evaluate the action of Spirulina platensis microalgae supplementation on the metabolic and hematological characteristics of juveniles of Nile tilapia, facing different challenges stressful. Metabolic responses (blood glucose, lactate and total protein) and haematological (erythrocyte, hematocrit, hemoglobin, mean corpuscular concentration and mean corpuscular hemoglobin concentration) were evaluated on stressful challenges: degradation of water quality, densification, and simulation of transport. Two diets were offered to the fishes: only commercial ration (control); and commercial feed supplemented with A. platensis microalgae. In the first experiment (degradation of water quality), the addition of the microalga in the feed reduced the metabolic stress of fish, which was showed by the lower concentration of glucose and serum lactate, but did not present significant differences in the hematological. In the two other experiments, density and transport simulation, animals fed with a diet supplemented with A. platensis indicating a reduction of stress in relation to the stressors when compared to the control group. In addition to the decrease in glucose and lactate, the animals fed with diet 1 presented higher erythrocyte, hemoglobin and hematocrit values, adapting fishes to a more comfortable condition in the face of adverse situations.