LOW-GLUCOSINOLATE RAPESEEDS AND RAPESEED MEALS - EFFECT OF TECHNOLOGICAL TREATMENTS ON CHEMICAL-COMPOSITION, DIGESTIBLE ENERGY CONTENT AND FEEDING VALUE FOR GROWING PIGS

Twenty-nine samples of rapeseed meal; 8 of the zero normal type (RSM 0), 21 of double zero (RSM 00) low-glucosinolate type, and 1 of the whole rapeseed (RS 00) were tested. Their digestible energy (DE) content and apparent digestibility (AD) of crude protein were measured by the difference procedure. In addition, 370 growing-finishing pigs (30-100 kg liveweight) were used to assess the effect on feeding value of the cultivar and oil extraction process of 15 samples only, included at 10-25% of a diet based on maize or wheat. The DE values (MJ kg-1 dry matter (DM)) and AD (%) of crude protein were 13.4 and 74.3 vs. 14.0 and 80.2 for RSM 0 and RSM 00, respectively; 16.5 and 85.1 for dehulled RSM 00; 17.9 and 84.3, and 15.3 and 87.5 for single and double expeller-extracted RSM 00, respectively, and 22.8 and 83.7 for the whole RS 00. The average performance of animals was lower with RSM 0 or RSM 00 treated with inappropriate technology including overheating. Addition of lysine improved growth performance. Weights of thyroid and liver were linearly (r = +0.75, r = +0.78, respectively) related to the amount of glucosinolate ingested by the pigs. Progress in plant breeding and technological processing indicated a promising future for the utilisation of low-glucosinolate RSM in pig feeding. © 1990.