Résumé : [en] This study aims to measure under barn conditions the emissions of NH3, N2O, CH4 and CO2 associated with gestating sows (trial 1) and fattening pigs (trial 2) fed either by a control diet (CTD) based on cereals or a high-fibre diet (HFD) based on sugar beet pulp (SBP). Three successive batches of 10 Belgian Landrace gestating sows were used for trial 1. Two successive batches of 24 Piétrain x Belgian Landrace fattening pigs were used for trial 2. Animals were kept on slatted floor. The gas emissions were measured by infrared photoacoustic detection and expressed per day and per livestock unit (LU, equal to 500 kg body weight). Similar trends were observed for both animal types. With HFD, NH3 emission was reduced (27.2 vs. 36.5 g/LU for the gestating sows, P<0.001; 23.2 vs. 45.0 g/LU for the fattening pigs, P<0.001) whereas CH4 emission was increased (41.5 vs. 21.0 g/LU for gestating sows, P<0.001; 37.9 vs. 27.2 g/LU for fattening pigs, P<0.001). The fibre content of the diet had no significant impact on N2O emission (around 1.4 g/LU for gestating sows and 2.1 g/LU for fattening pigs, P>0.05), and on CO2 emission (around 6.0 kg/LU for gestating sows and 9.1 kg/LU for fattening pigs, P>0.05).