Yttrium - an initial assessement

Offentlig prosjektsammendrag

Due to the increasing number of raw material sources and the ever changing raw material options, effective inclusion of a new ingredient into a diet involves an initial step of determining its digestibility, there are various ways to do this but practically the best option is often the "indicator method" this is based on using either an internal or external (included as 0,01-2% of diet) indicator. Percentage present in feed and feaeces are then measured and used to estimate the digestibility coefficient. An inert marker for the estimation of digestibility should ideally be: Indigestible Unabsorbable Does not alter organoleptic properties of diet Passage rate similar to rest of digesta Does not interfere with digestive or absorptive processes External markers that have been used previously such as Acid-insoluble ash, Chromium oxide,Cholestane, Crude fibre,yttrium each have pros and cons about them. Currently to the best of our knowledge there is no published data on yttrium oxide (an inert, rare earth metal that is used as a digestibility marker) dispersal within the fish flesh and so this is just an initial assessment to ensure that it is not the case when used in the diet.