Abstract: The present invention relates to a method for desalting tissue originating from animals. In particular, the present invention provides a method for desalting mucosa tissue, notably mucosa tissue originating from bovine or porcine. The invention also provides a method for preparing animal feed supplement or additive enriched in nutritional elements readily available to the animal, in particular to the young animal, for example young piglets, chickens, calves or aqua species. The invention also provides a low-salt content or a salt-free animal feed supplement and a feeding or growing method using the same.