Abstract: The present invention is located in the field of sustainable agriculture, referring to two processes of renewable origin for the production of fertilizer from by-products of animal origin, with two innovative raw materials: whole fish and/or fish waste and/or fish waste of marine or freshwater origin and/or fish waste containing by-catch fauna, and the pre-treatment developed in the process makes it possible to process any fish species to obtain fish concentrate (CPX), an intermediate product in the subsequent obtaining of fertilizer compositions and/or for use as an ingredient in compositions intended for animal feed. Poultry viscera waste. The development aims at making use of raw materials and by-products of poultry viscera to obtain fertilizers with innovative characteristics.