Effects of Span Rapeseed on the Performance, Organ Weights and Composition of the Carcass, Heart and Liver of Broiler Chicks

Abstract

Experiments were conducted to study the effects of varying levels of arginine and Span rapeseed (a low erucic acid variety) on the performance, organ weights and composition of the carcass, heart and liver of broiler chicks. Chicks fed rations containing 20% ground raw rapeseed gained weight more slowly, showed increased feed requirement per unit gain and produced leaner carcasses than chicks fed a control ration containing soybean meal or a ration containing 20% ground autoclaved rapeseed. Increasing the level of autoclaved rapeseed beyond 20% in the ration tended to reduce chick performance and produce leaner carcasses. Supplementation of rations with arginine had no significant effect on rate of growth, efficiency of feed conversion or carcass composition.Rations containing raw rapeseed caused thyroid enlargement. Autoclaving the seed for 10 minutes at 120°C. reduced this effect. No appreciable differences in the sizes of the livers and hearts were observed amongst the groups fed the different rations. Inclusion of rapeseed in the ration (either raw or autoclaved) resulted in a lower percentage of fat and a higher percentage of protein in the hearts of chicks than were obtained when the control ration was fed. The dietary treatments employed apparently had no effects on the liver composition. The inclusion of rapeseed in the rations resulted in a lower percentage of carcass fat and a higher percentage of carcass protein than were obtained on the control ration. The use of raw rapeseed gave lower carcass fat levels than when autoclaved rapeseed was used.