Fósforo disponível na nutrição e saúde óssea de peixes teleósteos

Abstract

This thesis aimed to investigate the use of available P (AP) in diets of teleost fish species, considering its effects on growth, health, bone development and mineralization of skeletal structures. For this purpose, scientific experiments were conducted to determine the quantitative and qualitative implications of the consumption of diets containing levels of adequate dietary correspondence, below and above the specific nutritional requirements of each species. The results of these studies resulted in the elaboration of two scientific articles, whose approaches and main features are described below. The first article aimed to determine the nutritional requirement of AP for tambaquis (Colossoma macropomum) in the final growth phase (± 400 to 1000 g). The results indicated that AP supplementation did not affect the growth of tambaquis fed plant-based diets, and the diets containing 4.1 g/kg of AP. were sufficient to sustain growth in the evaluated phase. However, for adequate mineralization of the whole body and mineralized structures, the level in the diet of tambaquis is 10.3 g/kg AP. The second article investigated the impacts of AP. deficiency and the effect of restoring the mineral in the diet in three species of teleost fish: tilapia (Oreochromis niloticus), pirapitinga (Piaractus brachypomus) and panga (Pangasius pangasius). The results showed that phosphorus deficiency increased body fat deposition, however, restoring the AP supply was not able to completely reverse this adiposity. The dynamics of mineral deposition in mineralized structures was speciesspecific, with the cephalic bones being the main source of mineral mobilization in situations of deficiency. The findings indicate that reestablishing the AP supply after a long period of deficiency is able to restore the physiological well-being of the fish evaluated in this study. The results obtained highlight the importance of assessing the impacts of phosphorus deficiency at different stages of rearing and the use of appropriate parameters to determine the level of AP in the diets of teleost fish. Although bone abnormalities are visible and relevant indicators, they represent only a part of the consequences of phosphorus deficiency, with the metabolic and physiological effects being less apparent. Therefore, a more comprehensive approach focusing on parameters related to the physiological well-being of teleost fish can contribute to more sustainable and environmentally friendly aquaculture