What is the most economically interesting dietary amino acid level during the fattening period under different conditions of feedstuffs' price and breeding conditions ?

From 104 individual growth curves obtained in experimental station, the InraPorc® software was used to estimate the most interesting level of amino acid supply from both technical and economical points of view. According to calculations, the price of feed is not the most pertinent criteria: decreased amino acid supply induces a reduction of feed cost but simultaneously growth performance are decreased resulting in worse feed efficiency, carcass weight and leanness and thereafter lower margin over feed. When possible with regard to available buildings on farm, this loss is lower when fattening duration can be increased to maintain the carcass weight. As a matter of fact, most interesting level of amino acid supply depends on feedstuffs cost. Under expensive feedstuffs context, feeding strategy that maximise feed efficiency will be preferred, i.e. with supplies 15% above the average requirement calculated from the 104 pigs used.