Strain Response of Laying Hens to Varying Dietary Energy Levels With and Without Avizyme Supplementation

The response of 4 strains of laying hens fed diets varying in ME with and without Avizyme 1500 (AVI) supplementation was evaluated in a factorial arrangement study. The strains of laying hens (Hy-Line W-36, Hy-Line Brown, Babcock B300, and Shaver White) were fed 3 diets: moderate ME (2,900 kcal/kg), low ME (2,810 kcal/kg), and low ME with AVI for 28 wk commencing at 22 wk of age. No significant effects of diet, strain, or their interaction on feed intake and BW change were observed. Lack of an effect on feed intake was surprising given the different levels of ME. It is hypothesized that the reduced dietary ME was not low enough to elicit a response. Of course, dietary level of ME did change caloric intake among hens, with hens fed moderate ME consuming more calories than those fed low ME with or without AVI. There was an interesting dietary ME × strain interaction effect on egg production (EP). Babcock B300 hens fed moderate ME and low ME with AVI had greater EP compared with the B300 hens fed low ME, whereas the Shaver White hens had a greater EP when fed a low-ME diet compared with feeding a moderate-ME diet or low-ME diet with AVI. Egg weight and egg mass were significantly affected by strain but not by diet ME. Hy-Line Brown and Babcock B300 hens laid eggs with greater weight and mass in contrast to Hy-Line W-36 or Shaver White. Hy-Line Brown eggs were the largest, whereas Shaver White had greatest egg-specific gravity. Strain significantly affected proportions of albumen vs. yolk in the egg. Across all strains, Hy-Line Brown had more albumen percentage, whereas Hy-Line W-36 had higher wet yolk and yolk solids percentages. The low-ME level fed to laying hens may have been too high to evoke an enzyme response to improve energy utilization by birds. This is important, because to obtain an economic benefit, producers would need to know the proper ME level to feed with the supplemental enzymes.