Feeding Brassica juncea or Brassica napus canola meal at increasing dietary inclusions to growing-finishing gilts and barrows

Novel Brassica (B.) juncea has a thinner seed coat and therefore lower fibre content than conventional B. napus canola meal (CM) and could potentially be fed at greater dietary inclusions to pigs. In a 2×2×3 factorial arrangement, 528 barrows and 528 gilts [33.6kg body weight] housed in 48 pens (22 barrows or gilts) were fed either B. juncea or B. napus CM at 100, 200 or 300g/kg of diet with up to 200g/kg wheat DDGS to slaughter weight (120kg). Compared with B. napus, B. juncea CM had 32g/kg greater CP, 12g/kg lower crude fat, 86g/kg lower ADF, and 91g/kg lower NDF content. However, aliphatic glucosinolate content was 2.7 times greater in B. juncea (11.76μmol/g) than B. napus CM (4.34μmol/g). For the entire trial (d 0–72), daily weight gain (ADG) was not affected by canola species, but feed disappearance (ADFI) was 45g/d lower (P=0.06) and feed efficiency 7g/g greater (P<0.05) for pigs fed B. juncea than B. napus CM. Carcass traits were not affected by canola species except dressing, which was 1% lower (P<0.05) for pigs fed B. juncea than B. napus CM. For the entire trial, increasing CM inclusion from 100 to 300g/kg of diet decreased ADFI (P<0.001) by 184g/d, decreased ADG by 32g/d (P<0.05), but increased feed efficiency (P<0.001) by 14g/g. Dietary CM inclusion level did not affect farm ship live weight to slaughter, carcass backfat thickness, lean yield, or index. Nonetheless, carcass weight was 0.9kg lower (P<0.05), dressing was 1% lower (P<0.001), loin depth was 1.3mm lower (P<0.01), and days to slaughter was 2.3 days greater for pigs fed 300 compared with those fed 100g CM/kg diet. In conclusion, growing-finishing pigs can be fed diets including B. juncea CM the same as conventional B. napus CM without decreasing growth performance or carcass traits. Feeding growing-finishing pigs a diet with 300 vs. 200 or 100g/kg CM with up to 200g/kg of wheat DDGS resulted in decreased weight gain and a minor decrease in carcass weight, dressing and loin depth, but increased feed efficiency.