Perfil bioquímico sérico de tilápias do Nilo (Oreochromis niloticus) criadas em tanques rede durante as estações do verão e inverno
Rodrigues, Gustavo MoyaNascimento, Fernanda Gatti de OliveiraBizare, AmandaOliveira, Wilson JuniorGuimarães, Ednaldo CarvalhoMundim, Antonio Vicente
Background: The growth of fish farming in Brazil has been noticeable over the past few years, and the Nile tilapia (Oreochromis niloticus) is the most bred species in the country. Studies on the physiology of these animals are necessary so that the production continues to grow and to improve its rates. However, very discrepant data are still found in the area of blood biochemistry. The aim of this study was to evaluate the physiological variations in serum concentrations of proteins, metabolites, electrolytes and serum enzymes in Nile tilapias bred in net cages in Cachoeira Dourada, state of Minas Gerais, Brazil, during summer and winter. Materials, Methods & Results: During the year of 2016, samples from 100 Nile tilapias were collected during summer (January and February) and samples from 100 Nile tilapias were also collected during winter (July and August). Only one blood sample was collected by caudal venipuncture of each fish, just before the slaughter, always in the morning. The serum samples obtained were then analyzed for serum concentrations of proteins, metabolites, electrolytes, lipids and serum enzymes. Serum concentrations of total proteins, globulins, triglycerides, high density lipoprotein (HDL), alkaline phosphatase, sodium and chloride were significantly higher during winter in comparison to summer, while the serum concentration of uric acid was significantly lower during winter in comparison to summer. Discussion: Due to the lower temperature of water during winter, tilapias reduced food intake and became more susceptible to diseases, which led to an increase in circulating globulins. In that same season, there was an increase in serum concentrations of sodium and chloride as a result of adding sodium chloride to the water in order to stimulate mucus secretion on the fishes skin and gills to prevent pathologies. Triglycerides, HDL, and uric acid are considered indicators of nutritional status of animals.[...](AU)
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