The effect of protein content of wheat grain on its nutritive value in pig diets

Abstract

In two experiments pigs were individually and restrictively fed from approximately 24 to 83 kg liveweight. The diets consisted of wheats of varying protein content supplemented with four levels of soybean meal. In experiment 1, wheats of 19.2 per cent and 11.5 per cent crude protein were compared and in experiment 2, the per cent crude protein content of the wheats was 14.9 and 13.1. Average daily gains, feed conversion ratios and carcase characteristics were not significantly affected by source of wheat in experiment 1, whereas in experiment 2, the 14.9 per cent protein wheat resulted in average daily gains and feed conversion ratios significantly superior to the 13.1 per cent protein wheat. Average daily gains and feed conversion ratios in both experiments and carcase quality in experiment 2 improved with increasing level of soybean meal supplementation. The interaction of wheat source x soybean meal level was significant only for backfat thickness in experiment 2. The level of soybean meal at which backfat thickness significantly increased was 6 per cent and 3 per cent with wheats of 14.9 per cent and 13.1 per cent protein respectively. The observed growth performance and carcase quality between the wheats fed appeared to be unrelated to the determined essential amino acid content of the wheat.