Effect of extrusion of corn and feed form on feed quality and growth performance of poultry in a tropical environment.
Two experiments were conducted to study the effect of corn extrusion and feed form on feed quality and growth performance of broilers. In experiment 1, whole corn was extruded at a water flow rate of 16, 19, and 22 L/h. The experimental design was a completely randomized design with 3 replications for each treatment. The extrusion process significantly decreased (P < 0.01) ether extract, crude fiber, and moisture content of corn. Increased water flow significantly decreased enzyme susceptibility from 56 to 47% (P < 0.01), but increased the bulk density of extrudate from 134 to 224 g/L (P < 0.01). However, there was a trend for lower total energy consumption (P < 0.01) and extruding production rate (P < 0.05) when corn was processed at the water flow of 22 L/h. In Exp. 2, 1,600 broilers (initially BW of 41 g) were used to determine the effect of extrudate and feed form on the growth performance in poultry during a 42-d growth assay. There were 50 chicks per pen and 8 pens per treatment. Treatments were arranged in a 2 x 2 factorial arrangement with the main effect of feed form and the main effect of 25% processed corn inclusion. Treatments were 1) conventional corn mash, 2) conventional corn pelleted feed, 3) +25% extruded corn mash, and 4) +25% extruded corn pelleted feed. Chicks fed pelleted feed, regardless of processing of corn, had a greater BW and feed conversion than those fed mash feed diet (P < 0.001). Extruded corn mash decreased the growth performance. Results suggested that optimal growth rate and feed conversion of birds raised in a tropical environment given extruded corn might be achieved by steam pelleting.