The effects of extrusion processing of carbohydrate sources on weanling pig performance

Three experiments were conducted to study the effects of extrusion processi ng on growth performance of weanling pigs. In Exp. 1, 350 weanling pigs (in itially 4.4 +/- 1.0 kg BW and 10 +/- 2 d of age) were used to study the eff ects of various carbohydrate sources (corn, cornstarch, broken rice, wheat flour, and grain sorghum), with or without moist extrusion processing, on g rowth performance in a 5 x 2 factorial arrangement of treatments. No carboh ydrate source x extrusion processing interactions were observed (P > .10). Growth performance was not affected by extrusion processing; however, pigs fed corn had poorer growth performance (P < .05) than those fed other carbo hydrate sources. In Exp. 2, 360 weanling pigs (initially 5.0 +/- .5 kg BW a nd 10 +/- 2 d of age) were used to determine the interactive effects of ing redient processing and diet complexity on growth performance. Three process ing combinations were used with either a simple or complex diet formulation in a 3 x 2 factorial arrangement of treatments. The three processing condi tions were 1) pelleted only (control); 2) corn that was moist-extruded and then the complete diet was pelleted (extruded); or 3) the complete diet was expanded and then pelleted (expanded). Pigs fed extruded diets had a great er improvement in ADG as diet complexity increased than those fed other die ts (processing x diet complexity interaction, P < .10). Pigs fed moist-extr uded corn had the best growth performance (P < .01). In Exp. 3, 210 weanlin g pigs (initially 6.8 +/- 1.5 kg BW and 21 +/- 2 d of age) were fed pellete d diets containing nonextruded corn (14.5% gelatinization; control) or corn extruded to provide 38.7, 52.7, 64.4, or 89.3% gelatinization. Average dai ly gain and ADFI decreased and then increased (P < .05), but apparent diges tibility of DM, CP, and energy (P < .01) increased and then decreased with increasing gelatinization. These results indicate that;moist extrusion proc essing of carbohydrate sources has variable effects on growth performance o f early-weaned pigs and that the degree of gelatinization does not seem to be a major factor in explaining this variation.