Growth and metabolism studies in growing pigs given diets containing a low glucosinolate rapeseed meal

Abstract

SUMMARYTwo growth and two metabolism experiments were made in which a low gluoosinate rapeseed meal (var. Tower; TRSM) was compared with soya-bean meal (SBM) as the sole protein-rich material in simple diets containing barley and a vitamin and mineral supplement only.In the first growth experiment 108 pigs were fed individually and restrictedly SBM and TRSM diets so that digestible energy (DE) and crude-protein intakes were similar. The DE used to promote a unit of growth or a unit of carcass weight was significantly less for the SBM, than for the TRSM, diet. In the second experiment 48 pigs were given, in groups of four, diets similar to those in Expt 1. There were no significant differences in growth rate or in serum thyroxine concentrations, but a significantly higher degree of thyroid hypertrophy was induced in pigs given the TRSM diet.The two metabolism experiments compared the same diets used in the first growth experiment. Apparent digestibility of dry matter, nitrogen and gross energy, and retention of nitrogen relative to intake, were significantly greater for the SBM diet than for the two RSM diets. The addition of synthetic lysine to the TRSM diet significantly improved the apparent digestibility and retention of nitrogen. Pooled DE values (MJ/kg dry matter) calculated for SBM, TRSM and barley were 13·72 (S.E. 0·318), 13·97 (S.E. 0·211) and 14·01 (S.E. 0·080) respectively.