The Use of Cottonseed Meal with or without Added Soapstock in Laying Hen Diets

Abstract

Laying hens fed diets containing cottonseed meal (CSM) can produce eggs that have pink albumen discolorations and brown yolks due to the respective presence of cyclopropenoid fatty acids and free gossypol in the CSM. The potential concentration of these two compounds is less in the CSM produced in the modern expander-solvent cottonseed mills, which leave little residual oil in the meal, than in older expeller plants. However, part or all of the possible benefit can be lost if soapstock is added back to the CSM. An experiment was conducted to examine the degree of egg discoloration produced when feeding CSM obtained from an expander-solvent extraction mill. The CSM used in this study contained 4.2% ether extract, indicating a moderate amount of soapstock had been added back to the meal. Egg-yolk discoloration associated with the presence of gossypol was observed when feeding diets containing above 10% CSM (100 ppm free gossypol). In subsequent experiments it was determined that egg-yolk discoloration could be greatly reduced when using a cottonseed meal without soapstock and that some hens were insensitive to the egg discoloration effects of gossypol.