Effects of different heat treatments during processing of soybean meal on nursery and growing pig performance.

Four soybean meals (SBM) were manufactured in a commercial solvent-extraction plant to give a much wider range in heat treatment than is usually found among commercially available SBM. The SBM were designated in ascending order of heat treatment as Under, Normal, Over and Rumen Escape. The nutritive value of the four meals was evaluated in a series of five feeding trials using 458 pigs: two performance and two diet preference trials with pigs weaned at 4 wk of age and one performance trial with growing pigs (17.4 kg initial weight were conducted). In both nursery and grower trials, there were no differences (P greater than .10) in performance of pigs fed the four meals. However, in the nursery trials, the severely heated meal (Rumen Escape) supported slightly lower gains (6.4%) and less desirable feed efficiency (3.5%) than the average of the other three meals. Growing pig performance was essentially the same for all meals. This suggests that older pigs either used the Rumen Escape meal more effectively than nursery pigs, or the Rumen Escape diet contained adequate digestible lysine for 17.4-kg pigs to grow optimally. In the preference studies, pigs selected between Normal- and Rumen Escape-supplemented diets. Pigs consumed 63 and 62% of the Normal diet in preference trials 1 and 2, but these differences were not significant (P greater than .10) due to the large variation among pens. These data suggest that the range of heat treatment normally found among commercially available SBM (Under, Normal and Over meals) has no effect on the nutritive value of the meal for swine.(ABSTRACT TRUNCATED AT 250 WORDS)