Effects of a high-fibre diet on ammonia and greenhouse gas emissions from gestating sows and fattening pigs François-Xavier Philippe a, * , Martine Laitat b , Jos  e Wavreille c , Baudouin Nicks a , Jean-François Cabaraux a a Department of Animal Production, Faculty of Veterinary Medicine, University of Li ege, B-4000 Li ege, Belgium b Department of Production Animals Clinic, Faculty of Veterinary Medicine, University of Li ege, B-4000 Li ege, Belgium c Production and Sectors Department, Walloon Agricultural Research Centre, B-5030 Gembloux, Belgium highlights  Dietary fibre has significantly lowered NH 3 emissions from fattening pigs and gestating sows.  CH 4 emissions were increased in the case of dietary fibre.  N 2 O and CO 2 emissions were not impacted by the dietary fibre content.  Growth performance of fattening pigs was impaired by high level of fibre inclusion. article info Article history: Received 24 October 2014 Received in revised form 9 March 2015 Accepted 11 March 2015 Available online 11 March 2015 Keywords: Ammonia Carbon dioxide Methane Nitrous oxide Sugar beet pulp Swine production abstract This study aims to measure under barn conditions the emissions of NH 3 ,N 2 O, CH 4 and CO 2 associated with gestating sows (trial 1) and fattening pigs (trial 2) fed either 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 Pi etrain  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, equals to 500 kg body weight. Similar trends were observed for both animal types. With HFD, the NH 3 emissions were reduced (27.2 vs. 36.5 g for the gestating sows, P < 0.001; 23.2 vs. 45.0 g for the fattening pigs, P < 0.001) but the CH 4 emissions were increased (41.5 vs. 21.0 g for gestating sows, P < 0.001; 37.9 vs. 27.2 g for fattening pigs, P < 0.001). The fibre content of the diet had not significant impact on N 2 O emissions (around 1.4 g for gestating sows and 2.1 g for fattening pigs, P > 0.05), and on CO 2 emissions (around 6.0 kg for gestating sows and 9.1 kg for fattening pigs, P > 0.05). Most of manure parameters did not statistically differ regarding the treatment. Reproductive performance and body condition of the sows were not affected by the diet. However, growth performance and carcass traits of the HFD-fed fattening pigs were deteriorated compared to CTD. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction The use of dietary fibre in pig production is known as having beneficial effects on animal health and welfare. With gestating sows, energy dilution due to fibrous feedstuffs avoids excessive weight gain that impairs reproductive performance, and reduces the feeding motivation, that may result in stereotyped and aggressive behaviours (Philippe et al., 2008). With weaned piglets and fattening pigs, it has been proved that dietary fibre improves the gut health by reducing gastric ulcerative lesions and strength- ening the intestine's protective barrier against the invasion of bacterial pathogens (Bruininx et al., 2009; Hermes et al., 2009; Laitat et al., 2015). High fibre diets are also known to decrease ammonia (NH 3 ) emissions. Comparing a fibrous diet based on sugar beet pulp (SBP) with a control diet based on cereals, O'Shea et al. (2009) observed a reduction of NH 3 emissions from slurry samples by 40%. Such a reduction is beneficial for pig health as ammonia is an irritant for * Corresponding author. Boulevard de Colonster, 20 B43a, 4000 Li ege, Belgium. E-mail address: fxphilippe@ulg.ac.be (F.-X. Philippe). Contents lists available at ScienceDirect Atmospheric Environment journal homepage: www.elsevier.com/locate/atmosenv http://dx.doi.org/10.1016/j.atmosenv.2015.03.025 1352-2310/© 2015 Elsevier Ltd. All rights reserved. Atmospheric Environment 109 (2015) 197e204