The invention relates to a method for the non-therapeutic treatment of animals selected from the group consisting of poultry, pigs and fish. The treatment comprises orally administering at least one ß-alanine compound to the animals in an amount of between 2 and 55 mmol/kg dry weight of said feed for the treatment of poultry and fish and between 2 and 25 mmol/kg dry weight of said feed for the treatment of pigs. These amounts of the ß-alanine compound are used for reducing the conversion ratio or for increasing the bodyweight gain of the animals. The ß-alanine compound is in particular ß-alanine. In prior art methods higher amounts were used resulting also in a reduction of the feed conversion ratio but this to the detriment of the bodyweight gain.