NUTRITIONAL-EVALUATION OF LINSEED MEALS FROM FLAX WITH YELLOW OR BROWN HULLS, USING MICE AND PIGS

Linseed meals (LM) from two genetic lines of low linolenic acid flax were evaluated in three experiments. Meal from yellow seed (YLM) contained less neutral detergent fibre (NDF) than meal from brown seed (BLM; 24% vs. 29%), less crude fibre (8.7% vs. 11.7%) and more crude protein (CP; 41% vs. 38%) in the dry matter. Amino acids in the CP were similar. In Experiment 1. 120 weanling mice fed 0, 33, 67 and 100% LM replacing soya-bean meal (SBM) in a 2 x 3 x 4 factorial experiment showed better growth and feed efficiency with YLM and commercial LM (CLM) than with BLM. Supplemental lysine was beneficial. In Experiment 2, apparent digestibility of CP by 30-kg pigs was 70% and by 60-kg pigs was 75%, for both YLM and CLM. Fibre was more digestible in YLM (NDF. 39% vs. 30%; acid detergent fibre, 16% vs. 10%) but digestible energy kg-1 dry matter for 30-kg pigs was 11.2 MJ for YLM vs. 12.3 MJ for CLM and for 60-kg pigs was 13.2 MJ and 12.3 MJ. In Experiment 3, a 23-100 kg pig growth trial comparing BLM with CLM, daily gains decreased from 677 to 604 g (P<0.05) as dietary LM level increased from 0 to 18% in the grower period (to 57 kg). The feed:gain ratio increased from 2.52 to 2.69 (P<0.05). Pyridoxine to counteract linatine and supplementary lysine (to 0.85%) were provided. Pigs of 57-100 kg were unaffected by the type or level of LM. Low levels of LM, up to 8 or 10%, may have improved digestibility and the growth rate of pigs (23-57 kg) and mice. Further research on the nutritional implications of flax mucilage may be warranted.