Effect of expanded cottonseed meal on laying performance, egg quality, concentrations of free gossypol in tissue, serum and egg of laying hens

Abstract Three hundred and sixty H y‐ L ine B rown hens, 40 week of age, were allocated to five treatments, each of which included four replicates of 18 hens. After an expanded process of cottonseed meal ( CSM ), free gossypol content in CSM was decreased from 1.24 to 0.40 g/kg. The dietary treatments were corn‐soybean meal based diets including 6% CSM and 6%, 8% and 10% expanded cottonseed meal ( ECSM ). Hens fed 8% ECSM had higher ( P < 0.05) laying rate and average egg weight than those fed 6% CSM . The albumen height and Haugh unit in the control group, 6% and 8% ECSM groups were superior ( P < 0.05) to other treatments. Hens fed 6% CSM resulted in severe ( P < 0.05) egg yolk discoloration. Free gossypol ( FG ) concentrations in yolk and albumen and tissues of the 6% CSM group were greater ( P < 0.05) than those in any ECSM treatments. Hens fed 6% CSM and 10% ECSM had the highest ( P < 0.05) FG concentrations in the liver compared with those in the kidney and muscle, and higher ( P < 0.05) FG residues in yolk than those in albumen. In conclusion, FG in CSM can be reduced by 68% through an expanded process and ECSM can be available in laying hens at up to 10% of the total diet and an appropriate replacement of soybean meal with ECSM may improve performance in laying hens.