Fermented liquid feed is well known for its health promoting effects on piglets. High levels of lactic acid are desired in the feed together with low levels of acetic acid and certain biogenic amines. Limits for acetic acid have been suggested to be 30-40 mmol/kg to avoid a decreased palatability of the feed; however, few studies have been performed. The purpose of this trial was therefore to examine which levels of lactic acid and acetic acid that can be accepted in a fermented feed without affecting the feed intake and thus the weight gain of the pig. A total of 60 pigs (Yorkshire/ Hampshire) were used in a trial during two weeks, between 9-11 weeks of age.