Effect of gelatinizing dietary starch through feed processing on zero-to three-week broiler performance and metabolism

SUMMARY Feed manufacturing produces physical and chemical changes in ingredients, including the gelatinization of starch. The effect of gelatinized starch on animal metabolism and subsequent performance has been inconsistent in past research. In the current study, corn was processed through different procedures (pelleting and extrusion) and substituted for unprocessed corn at varying levels (one-third, two-thirds, and three-thirds) in complete diets. Complete diets were not further processed. The objective of the study was to evaluate different levels of starch gelatinization produced by different processes on broiler performance through 3 wk of age. Pelleted and extruded corn had analyzed starch gelatinizations of 29 and 92%, respectively. Each of the 6 processed corn diets and a control diet (ground unprocessed corn) was fed to 8 replicate pens of 10 male broilers. A second experiment determined AMEn of each diet. Broilers fed diets containing pelleted corn had lower feed intake (P = 0.0439) and higher gain to feed (G:F, P = 0.0028) than broilers fed diets containing extruded corn. Gain-to-feed ratio was not affected when pelleted or extruded corn was increased in diets. The AMEn of diets increased as pelleted or extruded corn inclusion increased (P = 0.0331 and 0.0009, respectively). Diets containing pelleted or extruded corn pooled by inclusion level did not improve AMEn or G:F compared with the control diet. However, diets containing pelleted or extruded corn pooled by inclusion level increased live weight gain (LWG, P = 0.04 and 0.0038, respectively) compared with the control in part due to increased feed intake.