Effects of full fat or defatted rice bran on growth performance and blood characteristics of weanling pigs

The objective of this experiment was to determine the effect of increased concentrations of full fat rice bran (FFRB) or defatted rice bran (DFRB) in diets without or with supplementation of an exogenous xylanase on growth performance and blood characteristics in weanling pigs. A total of 532 pigs (9.3 ± 0.5 kg initial BW) were allotted to 14 diets in 4 blocks and 8 replicate pens per diet in a randomized complete block design. There were 4 or 5 pigs per pen. A basal diet containing corn, soybean meal, and whey powder and 6 diets containing corn, soybean meal, whey powder, and 10, 20, or 30% FFRB or 10, 20, or 30% DFRB were used. Seven additional diets that were similar to the initial 7 diets with the exception that they also contained 16,000 units/kg of microbial xylanase were also formulated. On the last day of the 23-d experiment, 2 blood samples were collected from 1 pig in each pen. Tumor necrosis factor-α (TNF-α), IgA, and peptide YY (PYY) were measured in plasma samples and blood urea nitrogen (BUN), total protein, and albumin were measured in serum samples. Initial and final BW were not affected by the inclusion level of FFRB or DFRB or by the addition of xylanase. The ADFI linearly decreased (P < 0.05) as inclusion of FFRB increased in diets and there was a tendency (P = 0.08) for reduced ADFI as DFRB was increased in the diets. Pigs fed diets containing DFRB had greater ADFI (P < 0.05) than pigs fed diets containing FFRB. The ADG increased and then decreased (quadratic, P < 0.05) with increasing level of FFRB or DFRB in the diets. The G:F linearly and quadratically increased (P < 0.05) as the inclusion of FFRB increased, and the G:F was greater (P < 0.05) in pigs fed diets containing FFRB than in pigs fed diets containing DFRB. The concentration of BUN linearly decreased (P < 0.05) when pigs were fed diets containing increasing levels of FFRB or DFRB. There was a tendency for the concentrations of TNF-α and PYY to linearly decrease (P = 0.09 and P = 0.075, respectively) as the inclusion of FFRB increased in the diet. In conclusion, ADG of weanling pigs was not affected by at least 20% FFRB or DFRB and inclusion of 30% DFRB had no effect on the G:F whereas 30% FFRB increased the G:F. However, microbial xylanase did not influence growth performance under the conditions of this experiment and there was minimal influence of rice coproducts or xylanase on blood characteristics.