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 containing7.5%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.