Ileal nutrient and energy digestibility of steam-exploded canola meal in cannulated grower pigs and total tract nutrient digestibility and growth performance of diets containing steam-exploded canola meal in weaned pigs

Abstract

Canola meal is a relatively highly fibrous protein meal that could benefit from further processing to disrupt its fibre matrix, reduce anti-nutritional factors and increase nutrient availability. Two studies were conducted to determine effects of steam-explosion on digestibility of gross energy (GE), crude protein (CP) and amino acids (AA) in solvent-extracted Brassica napus canola meal in grower pigs and diet nutrient digestibility and growth performance in weaned pigs. Canola meal was steam-exploded at either 0.7 MPa (CM7) or 1.1 MPa (CM11) for 5 min. In study 1, 8 ileal-cannulated barrows (29 kg mean initial body weight) were fed 3 corn starch-based diets including 400 g non-steam-exploded canola meal (CM0), CM7 or CM11/kg and a N-free diet in a replicated 4 × 3 Youden square. The canola meal sample contained 361 g CP/kg and 17.2 g chemically available lysine/kg that was reduced to 14.1 g/kg in CM7 and 14.6 g/kg in CM11. Steam-explosion of canola meal at 0.7 MPa decreased (P < 0.05) the coefficient of apparent ileal digestibility (CAID) of dry matter (DM) and GE. Steam-explosion decreased (P < 0.05) the coefficient of standardised ileal digestibility (CSID) of CP and AA in canola meal except for tryptophan, proline and tyrosine. In study 2, four wheat-based diets were formulated to include 200 g/kg soybean meal (SBM), CM0, CM7 or CM11 and to provide 9.6 MJ net energy/kg and 12 g standardised ileal digestible lysine/kg. In total, 256 weaned pigs (10 kg mean initial body weight) were fed the diets for 4 weeks starting 2 weeks post-weaning. The CM0, CM7, and CM11 diets had lower (P < 0.05) coefficient of apparent total tract digestibility (CATTD) of DM, CP and GE than the SBM diet. Steam-explosion of canola meal reduced (P < 0.05) dietary CATTD of CP. For the 28-day nursery trial, average daily feed intake (ADFI) of pigs fed the CM0 diet was lower (P < 0.05) than of pigs fed the SBM diet. Steam-explosion of canola meal increased (P < 0.05) ADFI. Average daily gain (ADG) did not differ among pigs fed the 4 diets. Finally, gain-to-feed ratio (G:F) was greater (P < 0.05) for pigs fed the 3 canola meal diets than the SBM diet. In conclusion, steam-explosion reduced ileal digestibility of CP, most indispensable AA and GE of canola meal in grower pigs. Dietary inclusion of 200 g canola meal/kg supplemented with crystalline amino acids and canola oil to replace dehulled soybean meal reduced ADFI, but not ADG, and thus increased G:F in weaned pigs. Steam-explosion of canola meal reduced dietary CATTD of CP and increased ADFI, but not ADG or G:F of weaned pigs.