The effect of nutrient density of the diet and of a change in nutrient density on the performance of pigs fed ad libitum for bacon

ABSTRACT A total of 56 individually-penned pigs, with equal numbers of boars and gilts, were fed ad libitum in an investigation of the effects of nutrient density in growing (17 to 35 kg) and finishing (35 to 82 kg) periods. Diets of high (H) and medium (M) nutrient density, with 13·8 or 12·6 MJ digestible energy (DE) per kg and 10·0 or 9·1 g lysine per kg, were used. In the growing period, diet H proportionately increased the rates of DE intake and live-weight gain by 0·17 (P < 0·001) and 0·24 (P < 0·001) respectively. While the nutrient density of the diets given in the growing period did not significantly affect the mean performance over the finishing period, carry-over effects were observed for about 4 weeks following the change with evidence of compensation in energy intake. In the finishing period, diet H proportionately increased the rates of consumption of DE and live-weight gain by 0·06 (P < 0·05) and 0·04 (P = 0·18) respectively. The consumption of energy was virtually identical for the two sexes. It is concluded that the change in nutrient density had only transitory effects on energy intake and growth rate and did not affect overall performance in the finishing period.