Nutritional evaluation of very low glucosinolate canola meal

Abstract

Two very low glucosinolate (VLG) canola meals from crop years 1987 and 1988 (CM; 1.66 and 0.53 μmol g −1 ) and two Tobin CM (B. campestris) (10.71 and 15.62 μmol g −1 ) were evaluated in experiments with pigs. In exp. 1, 1987 Tobin CM, VLG-CM and soybean meal (SBM) were compared in individually fed meal and pelleted diets. Daily gains from 23 to 57 kg were similar for the CMs (VLG-CM 662 g, Tobin CM 645 g) but lower than those obtained with SBM (730 g; P < 0.01). Daily feed intakes of pigs fed CM were lower than for those fed SBM (P < 0.05). Plasma thyroxine (T 4 ) levels were similar for SBM and VLG-CM and were above those from pigs fed Tobin (P < 0.05) CM. Triiodothyronine (T 3 ) levels were lower for VLG-CM than for SBM (P < 0.05) and the T 3 value for Tobin CM was intermediate. Pelleting enhanced T 3 (0.70 vs 0.94 ng mL −1 ) and T 4 (50 vs. 60 ng mL −1 ) levels with all protein supplements (P < 0.01). In exp. 2, similar diets were fed ad libitum. Daily gains for SBM were greater than for Tobin CM (803 vs. 744, P < 0.05) and gains for pigs fed VLG-CM was 774 g. Daily feed intakes were similar (2.01, 1.99 and 1.92 kg). In exp. 3 energy digestibility of 1987 VLG-CM was greater (P < 0.01) than for Tobin CM (75.0 vs 67.4% for 30-kg pigs). Apparent digestibility coefficients of crude protein (CP) were 71.9, 71.2 and 71.6 in 16% CP diets. In exp. 4 Tobin and VLG-CMs from 1987 and 1988 crops were compared with SBM and commercial CM using 96 pigs (48M, 48F). Daily gains and feed intakes were similar for the CMs but T 3 and T 4 values were below those of SBM (P < 0.05). Key words: Canola meal, very low glucosinolate, digestibility, feeding value, pigs