Effects of adding barley hulls and linseed meal to wheat and hulless barley diets fed to growing pigs

Abstract

Two high energy basal grains (wheat and hulless barley), three levels of barley hulls derived from hulless barley (0, 4 and 8%), two levels of linseed meal (LM) (0 and 5%) and two sexes of pigs (barrows and gilts) were compared in a factorial experiment involving 72 pigs over the weight range 23 to 100 kg. The animals were housed in groups of four but were fed individually. All diets were nutritionally adequate except for digestible energy (DE) which ranged from 12.6 to 13.5 MJ kg −1; the US National Research Council requirement level is 14.2 MJ kg −1. Average daily gain was unaffected by dietary treatments in either the grower or finisher stages. Efficiency of feed utilisation was improved with wheat diets by addition of hulls but hulls had no effect with hulless barley diets. Linseed meal depressed the efficiency of feed and DE utilization. The carcass dressing percentage declined with increasing hull level but only when LM was also fed. Backfat depth was reduced by adding hulls to hulless barley diets, especially when LM was included. The findings are discussed in relation to the possible effects of different levels and kinds of fibre.