EFFECTS OF RAPESEED GUMS ON THE FEEDING VALUE OF DIETS FOR GROWING-FINISHING PIGS

Gums from high and low glucosinolate rapeseed oils were mixed at 1, 2 and 4% levels into Tower rapeseed meal (RSM; low glucosinolate cultivar) and soybean meal (SBM). These meals were fed in grower diets at 15.1 and 12.6% levels, respectively, to 72 pigs from 23 kg initial to 91 kg final weight. Neither the source nor level of gums had any effect on rate of growth or feed consumption. The digestibility of energy was determined by feeding Tower gums at 0, 1.25, 2.50, 5.00 and 10.00% of diets containing 15% of gums-free Tower RSM. Gums had no apparent effect on energy digestibility. All diets were 80% (79.6 ± 0.5) digestible, regardless of dietary level of gums, indicating that gums were similarly well digested. Samples of RSM and SBM containing 8% gums were kept in burlap containers at ambient temperatures over a 7-mo period to determine storage effects. No significant deterioration occurred as indicated by acid values, color or anisidine values. There were some differences in values between RSM and SBM but probably not of nutritional importance.