The energy value of canola meal is considered low because of its relatively higher fibre and depleted oil content. Brassica juncea is a novel canola species with thinner seed coat and reduced fibre, but twice the glucosinolate content of B. napus, which may decrease feed intake of animals and negatively affect thyroid, liver, and kidney functions. However, extrusion prior to expeller pressing may increase fat and protein digestibility and decrease the antinutritive effects of glucosinolates. The objective of this study was to compare the growth performance, dressing, carcass characteristics, and jowl fatty acid profile of growing-finishing pigs fed different percentages of inclusion of extruded B. juncea canola expeller-pressed cake housed in a commercial pig production facility. A total of 880 pigs (38 kg), housed in 40 pens by sex, were fed 0, 5, 10, 15, or 20% extruded B. juncea expeller-pressed cake (EPC) to slaughter weight (120 kg). Diets provided 9.6 MJ net energy (NE) and 1.0, 0.9, 0.8, 0.7, and 0.7 g standardized ileal digestible Lys:MJ NE over five growth phases (days 0-14, 15-35, 36-56, 57-74, day 75 to slaughter weight).
Each 5% EPC inclusion linearly decreased (P<0.05) feed disappearance (ADFI) by 46 g and weight gain (ADG) by 8 g, but did not affect gain:feed. Each 5% EPC inclusion linearly decreased (P<0.01) carcass weight by 440 g, loin depth by 0.6 mm, and increased days on test by 0.43, but did not affect dressing, backfat thickness, lean yield, or carcass index. Each 5% EPC inclusion linearly increased (P<0.001) mono- and polyunsaturated fatty acid content and iodine value by 0.8, 1.0 and 1.4 g/100 g of jowl fat, respectively.
In conclusion, increasing the dietary inclusion of extruded B. juncea canola expeller –pressed cake linearly decreased ADFI, ADG, BW, farm ship weight to slaughter, carcass weight and loin depth. It also increased jowl fat unsaturation but did not compromise jowl fat firmness beyond acceptable levels as assessed by iodine value. It was attributed much of the decrease in feed intake to greater 3-butenyl (9.7 μmol g-1) content in extruded B. juncea canola expeller-pressed cake, a glucosinolate more bitter than others in conventional canola.
Zhou, X., Young, M.G., Zamora, V., Zijlstra, R.T. and Beltranena, E. 2014. Feeding increasing dietary inclusions of extruded Brassica juncea canola expeller-pressed cake on growth performance, carcass characteristics, and jowl fatty acids of growing-finishing pigs. Can. J. Anim. Sci. 94: 331-342. doi:10.4141/CJAS2013-198