Effects of expanding wheat by-product containing diets on performance of growing pigs

A growth trial was conducted to study the effectof expanding diets, in which barley was increasingly replaced with wheat bran and wheat middlings (WBM, 2:1), on pig performance. The experiment was carried out in a 2 * 4 factorial arrangement with a total of 160 pair-fed pigs (25-100 kg). The inclusion levels of WBM were 0, 10, 20 and 30 %. The diets were formulated to contain 0.8 % of digestible lysine. On each WBM addition level, one diet was expanded and pelleted (EP) and the other only pelleted (P). All pigs were equally fed (1.25-2.90 g/d) and their feed intake was weekly adjusted according to body weight. The analysis of varianceof the growth and carcass data showed that the processing * WBM level interaction was absent (p<0.30). With the increased inclusion of WBM, the daily weight gain (DG) of the pigs (933, 905, 890 and 845 g) decreased (p<0.001) and the slaughter loss p<0.001) and the meat percentages (p<0.05) increased lineary, but the feed conversion ratio (FCR, MJ NE/kg gain) remained unaffected. The diet expansion had no effect on the DG and the carcass characteristics of the pigs. The FCR of the pigs fed with EP diets, however, tended (p<0.08) to be lower (22.7 MJ/kg EP/23.1 MJ/kg P). It is concluded that the expanding of diets containing WBM does not eliminate the negative effects of dietary fiber content on pig performance.