Effect of dietary defatted diatom biomass on egg production and quality of laying hens

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： The15% 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.