Caracterização da composição centesimal de tambaquis oriundos de diferentes ecossistemas amazônicos

Abstract

Tambaqui, the main native species cultivated in the country, has a series of favorable zootechnical characteristics that justify its growing cultivation, along with the market acceptance of its meat, which is one of the main attractions for national fish farming. Tambaqui meat is characterized by high levels of moisture, mineral matter, protein and lipids; it should be noted that this composition varies within the same species, depending on the time of year, the environment captured, the type and quantity of food available, the quality of the diet consumed, age, farming conditions and the part of the body analyzed. The aim of this study was to characterize the centesimal composition of tambaquis meat obtained from different Amazonian environments. Twenty adult tambaquis were acquired at random from local fishermen, 10 of them during the flood (five from black water and five from white water), and the same number during the drought. Once in the laboratory, morphometric measurements were taken of the fish. Samples of the white, red and belly muscles were taken from each fish to analyze its centesimal composition. The data was analyzed using the SISVAR statistical analysis system with 5% probability, submitted to analysis of variance and the means were compared using the Tukey test. The stomachs were removed and fixed in a 10% formaldehyde solution, and their contents were then analyzed for frequency of occurrence (FO%), percentage volume (VP%) and food index (IAi). The results were submitted to PERMANOVA (Permutational Multivariate Analysis of Variance) with a Bray-Curtis dissimilarity matrix. For the morphometric measurements, there was a significant difference in body height and head size. The highest fillet and belly yields were obtained for white-water tambaquis and, regardless of the type of water, the highest fillet yields were found in the dry season. The most important food items in the diet in the dry season were: stems, leaves and crustaceans (79%, 9.44%, 4.82% IAi) and in the flood season fruits (99.76% IAi). There was a difference in diet when comparing the black and white water environments (p=0.041) and hydrological periods (p=0.015). Lower percentages of moisture were found for the white muscle (78.42±0.64%) in dry season tambaqui; higher protein content for the belly of white water tambaqui (18.48±1.16%) and higher caloric value for the white muscle of dry season tambaqui (86.64±3.42%). For the protein and carbohydrate content of the belly, there was a significant interaction for the water x season factor and for the mineral matter and lipid content of the blood muscle. The white and blood muscles showed higher levels of potassium and manganese during the flood, and there was a significant effect for the water x season interaction in these muscles for the minerals potassium, sulphur, iron, zinc and manganese. The white musculature of the tambaquis showed higher iron (Fe) levels in the dry season. Black-water tambaquis had higher iron levels than white-water tambaquis during the dry season.