The present work was planned to test the effects of 2 protein-oil rich ingredients which replaced an important part of classical soybean meal, on nitrogen (N) metabolism indicators. Simultaneous we aimed to assess performances, enteric methane (CH4) and carbon dioxide (CO2) emitted through manure. A balance test was conducted with 15 barrows, 36 ± 0.24 Kg initial body weight, assigned in three groups in metabolism cages: 1. SC diet based on a classical diet (soybean meal, 13%); 2. SP diet based on peas Tudor variety 16% that replace 49% of SM; 3. SPF diet containing 8% soybean meal, 12% peas and 4% linseed Lirina variety. Faecal and urine were quantitatively collected in two balance periods. A semiautomatic Kjeldahl method was used for assessing the N. The Spotchem EZ SP-4430 was used for determining plasma protein and urea nitrogen (BUN). The regression equations were used to determine N metabolism indicators, CO2 emitted and enteric CH4. An increase of 1.16 times of feed intake was noticed in the SP group compared to SC. The lipid intake was slightly higher in the SP fed group which contributed to an increase of energy intake compared to SC group (>1.17 times) and vs SPL fed group (>1.2 times). The average daily gain (ADG) decreased highly significant in the SP diet compared to the SC diet. Linseed adds in SPL diet contributed to obtaining performances closed to SC group. SP diets increased the N level slightly in faeces and urine. BUN concentration has a linear relation with urinary N. CO2 emitted represent 28-32% of CO2 exhalation. CO2 increased in the SP diet (P<0.10) due to the fact that HP value increased as well. No significant influence was noticed for CH4 estimated value, although a slight increase was observed in the SP diet. In conclusion, although certain N metabolism indicator was affected by peas diet, only a little part was significantly modified. An oil-rich ingredient such as linseed could successfully complement peas by diminishing its adverse effects.
