Are fish really waterproof? Storing and thawing losses in fish fed in zoos

Whole fish is an important feedstuff in zoo animal nutrition. However, the knowledge on its nutritional composition is limited in Europe. The existing European data are based on fish muscle meat for human consumption, which does not reflect the composition of whole fish. Freezing, storing and thawing has a negative effect on vitamin and mineral concentrations through losses in water and losses during storage [1]. Especially the storage time has a negative effect on certain nutrients like vitamin A or E [2, 3]. However, the exact degree of these losses is unknown. The aim of this study is to conduct nutritional analysis of whole fish of one catch and its changes with storage time and different thawing methods. Thus, this study provides data on the composition of whole fish and gives insights into nutrient losses.