Effect of flame roasting of dietary grains on the performance of leghorn hens

Abstract

Two experiments examined the effect on the performance of Leghorn hens given diets containing flame-roasted grains from 140 to 490 d of age. In exp. 1, the inclusion of barley, corn and wheat roasted at 121, 119 and 149 °C, respectively, had no significant (P > 0.05) effect on productive performance. Experiment 2 contained a factorial arrangement of treatments that involved two sources of dietary barley (non-roasted or flame-roasted at 154 °C), two methods of milling (hammer or roller) and two dietary protein levels (15 or 18%). Hens given the diets that contained roasted barley had lower (P < 0.01–0.001) 490-d body weights, egg production, early egg weight (196 d) and number of extra large sized eggs, and higher (P < 0.05–0.01) feed conversion, monetary returns, interior egg quality and number of medium sized and grades B and C eggs than those fed the non-roasted barley control diet. Mortality, the number of large-sized eggs and egg weights, feed conversion and the occurrence of blood spots were higher (P < 0.05–0.001) while the number of medium-sized eggs was lower (P < 0.05–0.001) when the hens were fed roller compared with hammer-milled grains. Hens given the 18% protein-containing diets had higher (P < 0.05–0.01) 490 d body weight, egg production, monetary returns and numbers of small sized and grades B and C eggs, but lower (P < 0.05) mortality than those receiving the diets that contained 15% protein. Key words: Flame roasting, dietary grains, Leghorn hens