title: Effect of dietary defatted diatom biomass on egg production and quality of laying hens.
abstract: BACKGROUND
  This study was to determine if feeding laying hens with defatted diatom microalgal biomass (DFA) from biofuel production affected their egg production and health status.
  
  
  METHODS
  Five replicates of 5 individually caged ISA Babcock White leghorn hens were fed 4 diets, including a corn-soybean meal control diet, a diet containing 7.5% DFA substituting for soybean meal, and diets containing 7.5% or 15% DFA substituting for corn and soybean meal. Body weights, feed intake, feed conversion ratio (FCR), rate of egg production, egg size, egg mass, and several characteristics of eggs were determined at 4 and 8 wk. Venous blood was sampled at 4 and 8 wk for measurement of 5 biomarkers of health.
  
  
  RESULTS
  The 15% DFA diet decreased (P < 0.05) feed intake, egg production, and plasma uric acid concentrations as compared with the control diet, but increased (P < 0.05) egg albumen weight and height compared with the 7.5% DFA diets. The two levels of DFA produced dose-dependent (P < 0.05) changes in three color measures of egg yolk, without affecting four hen plasma biochemical indicators of health.
  
  
  CONCLUSIONS
  Feeding laying hens with 7.5% DFA in the corn-soybean meal diet for 8 wk had no adverse effect on their health, egg production, or egg quality, but 15% inclusion reduced feed intake, egg production, and efficiency of feed utilization.
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Leng
authors.forename: Kun-Nan
authors.initials: KN
authors.lastname: Hsu
authors.forename: Richard E
authors.initials: RE
authors.lastname: Austic
authors.affiliation: Department of Animal Science, Cornell University, Ithaca, NY 14853, USA. XL20@cornell.edu.
authors.forename: Xin' Gen
authors.initials: XG
authors.lastname: Lei