Using labelled antifreeze proteins placed in the gut of notothenioid fish to determine the path they take from the gut to the blood

The many fish that live in the waters around Antarctica have a unique set of adaptations to cope with the extremely cold conditions in which they live. They have developed antifreeze proteins (AFP) that prevent the fish from freezing by arresting the growth of ice crystals in their tissues. The AFP are produced in the pancreas and released into the gut. It is unknown how the AFP reach the blood. Labelled AFP (with 14C) were placed in the gut of a notothenioid fish Trematomus bernacchii. A series of blood samples was taken and analysed by biological atomic mass spectroscopy (BAMS). There was little evidence to support absorption of AFP from the gut. Labelled AFP was administered with a meal to determine if that affects absorption from the gut. Blood samples were analysed by BAMS.