Comparison of Low Glucosinolate-Low Erucic Acid Rapeseed Meal (Cv. Tower), Commercial Rapeseed Meal and Soybean Meal as Sources of Protein for Starting, Growing and Finishing Pigs and Young Rats

Eighty 3- to 4-wk-old crossbred pigs averaging 5.3 kg in weight at allotment were fed experimental diets during starting, growing and finishing phases to compare Tower rapeseed meal (00-RSM) and commercial rapeseed meal (C-RSM) as the sole or partial replacements for soybean meal (SBM). Barley and wheat were the main energy sources with varying amounts of animal tallow to provide isocaloric diets on a digestible energy basis. A 50/50 isonitrogenous combination of 00-RSM + SBM resulted in feed intake, daily gain and feed/gain ratio similar to results with pigs fed SBM as the sole protein supplement during the three phases. Complete substitution of SBM by 00-RSM resulted in reduction (P <.05) of feed intake during the starting phase as well as lower (P <.05) daily gain and inferior (P <.05) feed/gain ratio during the growing phase. Partial substitution of C-RSM for SBM resulted in reduction (P <.05) of feed intake during the starting and finishing phases. Complete replacement of SBM with C-RSM resulted in a depression (P <.05) of daily gain during all three phases of the experiment, inferior feed/gain ratio during the starting and growing phases compared with pigs fed the other four diets and lower (P <.05) feed intake during the starting and finishing phase compared with pigs fed the SBM diet. These findings were confirmed in a rat experiment. Carcass characteristics of pigs were not greatly affected by experimental treatments. A trend of lower digestibility of energy, nitrogen and amino acids was noted by complete replacement of SBM with either source of RSM in the pig and the rat experiments.