Parasites, metabolic parameters and trophic ecology of Oreochromis niloticus cultivated and wild, from Grande River, Brazil

Abstract

The production of fish from Brazilian aquaculture totaled 507.12 thousand tons in 2016, with Oreochromis niloticus being the main species produced, with 239.09 thousand tons or 47.1% of the total production. Popularly known as the Nile tilapia, O. niloticus, belongs to the family Cichlidae (Perciformes). This species presents rapid growth, late sexual maturity, high prolificacy, omnivorous feeding habits, facilitating feed acceptance, and good adaptation to confinement. However, although tilapia is the target of many studies, due to their large commercial production and consumption, there are some points not yet clarified, such as the environmental effects of the escape of these individuals from the farming systems on the environment. Thus, the present project will concentrate on evaluating three aspects: parasites (endo and ectoparasites), metabolism (lipids, proteins, carbohydrates and fatty acids) and trophic ecology of O. niloticus from cage farms and the wild (from accidental releases). Two samples (rainy/dry periods) were carried out during 2016 and 2017, in a cage farm in the Municipality of Santa Clara D'Oeste - São Paulo State, in the Can-Can distributary. Fifty animals were collected per collection, 25 specimens of cage farms and 25 wild, for diet and parasitology evaluations. Other species of wild fish, which inhabit the vicinity of the cage farm, were also collected for diet analysis. The metabolic analyses were performed with 40 specimens, 20 of which were collected (10 cultivated and 10 from wild). Thus, the main idea of this work is to interpolate all data, diet, metabolism and parasitology with mathematical and statistical assistance, especially using softwares PRIMER + PERMANOVA and RStudio. (AU)