Efeito do stressor moderado sobre o desafio social e o crescimento na tilália-do-nilo

• Ano de defesa: 2015
• Autor(a) principal: Colognesi, Gisele [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Ecologia aquatica; Peixe - Comportamento; Tilapia (Peixe); Confinamento (Animais); Stress (Fisiologia); Isolamento social
• Link de acesso: http://hdl.handle.net/11449/127765; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/01-09-2015/000844649.pdf

In natural environments, animals have to deal with numerous and constant challenges, being exposed to different stressors. Once the stressor is mild and of short duration, the answer to this environmental information is an adaptation that allows the animal immediately respond to a threatening situation. Also, keep the animals in environments that offer lower stress conditions you can improve your growth rate. However, more intense and long lasting stressors may trigger to a physiological condition known as distress. Artificial environments, in other hand, can provide a lack of stimuli and cause monotone, also considered to be detrimental to the animal. Keep the animals under mild stressors conditions are, therefore, to maintain adaptive features of the animal, which is a condition that increases the readiness to social challenge and improve individual's welfare. Thus, our aim in this study was to test the effects of mild stressors on the social challenge and welfare in fish. For this, 34 male adults of the fish Nile tilapia were isolated and subjected to three treatments: a) a situation of monotone (N = 13): absence of new stimuli in the environment; b) a situation of intense stress (N = 12): provided by individual containment; and c) a situation of mild stress (N = 9): disturbance in the environment. Video records of five minutes each were filmed twice a day, (9h and 14h) during the presentation of the stressors to the fish, to quantify the ventilatory rate, the plasma cortisol levels and the specific growth rate. We also evaluated the animal's response to the social challenge, provided by a mirror test, recorded during 10 minutes. Regarding the growth rate, we observed that situation of mild stress increased fish growth, whereas monotone and intense stress situations had decreased their growth rate. Agonistic interactions increased in situations of mild stress, remained stable in conditions of intense stress and decreased in...