Nutrition V

S OF PAPERS 253 145 Effects of Originial XPC on performance of layers. K. E. Anderson1 and J. Frank*2, 1North Carolina State University, Raleigh, 2Diamond V, Cedar Rapids, IA. Laying hens (11 white and 7 brown strains; approximately 17 weeks of age; n = 9594) were utilized in a 16 week study to determine the effect of Saccharomyces cerevisiae fermentation product (Original XPC) on hen day and hen housed production, egg weight, size, and quality, and feed conversion. Hens were housed at 2 densities (497 or 471 sq cm with 5 or 7 hens/cage) within 2 production houses (approximately 13 replicates per strain x density combination). Treatments were: Control and XPC (0.68 kg/ton feed). Egg weights and sizes were recorded from the previous 24 h production for every 28 d period starting at 119 d of age. Percentages of eggs within each size category, average egg weight, and average egg mass were calculated. Egg shell strength was determined from a subset sample of eggs (6 eggs from 3 replicates per strain per density during each period) using a Texture Technologies TAXT2i texture analyzer. Breaking force was defined as the force in grams required to fracture the shell. Egg quality was determined using USDA grades. Feed was provided ad libitum and was weighed back every 28 d by replicate group. Feed intake, feed cost, feed/dozen eggs, and feed per unit of egg mass were calculated. Data was analyzed separately for white and brown strains using PROC GLM of SAS. LS Means that were significant were separated using PDIFF. For white and brown strains, hen day and hen house production, feed per bird per day, and percentage of extra large eggs was greater (P < 0.05) for hens supplemented with XPC. Percentage of leakers and medium size eggs were lower (P < 0.05) for hens supplemented with XPC. White strains of hens supplemented with XPC had greater (P < 0.05) percentage of grade A eggs and egg albumen concentrations, and lower (P < 0.05) percentage of checks. Brown strains of hens had greater (P < 0.05) shell strength and elasticity. The results indicate that supplementation of XPC can improve egg production and egg quality in white and brown strains of laying hens.