Energy and nitrogen balance in heavy pigs fed different fibre sources

The aim of the experiment was to investigate the possible differences in the utilization of different fibrous feeds by the heavy fattening pig. Eight LandraceXLarge White barrows of 85 kg BW were paired and fed, in a Latin Square design, four diets containing different dietary fibre sources: 8% coarse soft wheat bran (control, C), 24% milled wheat bran (MB), 24% coarse wheat bran (CB), and 16% dried beet pulp (BP). Compared to C, the MB and CB diets significantly decreased the digestibility of most parameters, while the BP diet lowered the digestibility of N and EE, increased fibre digestibility, and had similar DM, OM and energy digestibility. Compared to BP, diets MB and CB had significantly higher N and EE digestibility, but lower DM, OM, fibre and energy digestibility. CH4 emission was significantly increased by BP compared with C, MB and CB. Compared to C, metabolisable energy was significantly lowered by MB and CB, but not by the BP diet. The BP diet caused significantly ( P < 0.01) greater heat production (47.3% of intake energy) than the MB (45.2%) and CB (45.0%) diets; heat production for diet C was intermediate (46.4%). The retained energy and N retention were similar for all treatments. MB and BP diets had significantly lower NE than the other two diets. The results suggest that, because the heavy pig can use dietary fibre better than younger pigs, wheat bran and beet pulp have a higher energy content than reported from trials on animals of lower bodyweight.