The Influence of Wintering on Macronutrients in Fish Meat, in Species from a Wild Habitat

To determine the macronutrient variations in fish meat at the end of the winter period compared to the start of wintering, 7 species from the Danube River were fished (Abramis brama, Ballerus sapa, Barbus barbus, Blicca bjoerkna, Gymnocephalus schraetser, Sander lucioperca, Vimba vimba). Biochemical analyses of fish meat were performed for the winter of 2020-2021 and 2021-2022. The biochemical profile followed the same trends for the 7 fish species as well as the 2 wintering periods considered. At the start of the winter period, in the meat of all analysed species, the percentage of water was lower compared to the end of the winter period. Proteins and lipids varied inversely with the amount of water in the fish meat for both wintering periods. In 2020-2021, the percentages of proteins and lipids were lower than in 2021-2022, for all 7 species analysed. The variations of macronutrients between the start and the end of the winter period are explained by the hibernation behaviour of the fish, which is directly influenced and dependent on temperature variations. The thermal regime recorded higher values in the winter of 2020-2021, interrupting the hibernation of fish, which led to a higher consumption of energy reserves in the meat of the considered species.