Effect of Replacing Conventional Corn with Corn Containing Thermostable α-Amylase Enzyme (AMY797E) in Standard and Low-Energy Diets in Laying Hens

In laying hens, the undigested starch in conventional corn can reduce the efficiency of their diet. Therefore, the current study evaluated the effects of replacing conventional corn with a corn hybrid expressing thermostable α-amylase (Enogen corn) in standard and energy-deficient diets in laying hens. A total of 320 White Leghorn hens were assigned to four dietary treatments in a 2 × 2 factorial design of corn type (conventional and Enogen) and energy density (standard and 200 kcal/kg reduction) from 18–45 weeks of age. Enogen corn diet improved overall feed efficiency by 8% (p < 0.001) and increased egg production by 6–10% (p < 0.05) during 35–45 weeks compared to conventional corn diet. Yolk weight was also improved by Enogen corn at 35 and 45 weeks (p < 0.05), with no significant effect on body weight and body composition (p > 0.05). Reducing dietary energy led to higher feed intake during 36–45 weeks (p = 0.017), worsened overall feed efficiency (p = 0.030), and decreased cortical bone mineral density (p = 0.035). In conclusion, replacing conventional corn with Enogen corn improved feed efficiency and egg production, whereas a 200 kcal/kg energy reduction triggered compensatory intake and impaired cortical bone quality.