Effects of Free Gossypol and Cyclopropenoid Fatty Acids Present in the Feed on the Productivity, Quality, Elasticity, and Microstructure of Hens’ Egg

Abstract

BACKGROUND: Free gossypol (FG) and cyclopropenoid fatty acids (CPFAs) are two main natural toxins in cottonseed meal(CSM). The increased yolk elasticity under cold storage conditions is related to the excessive CSM in the feed. However, which toxin caused the increased yolk elasticity is still not clear. RESULTS: Our results show that the addition of FG or CPFA to the diet significantly reduced the egg production and feed conversion ratio. Besides, FG also resulted in a decrease in egg weight. The storage of eggs at 4 °C for four weeks resulted in a significant increase in elasticity and a decrease in the concentration of iron and calcium in the boiled yolks of CPFA and CSM groups when compared to the control. CPFA and CSM supplemented groups also showed an increase in pH and content of water in the yolk. Scanning electron microscopy (SEM) images from the CPFA and CSM groups revealed that the morphology of the vitelline membrane of eggs was characterized by different-sized holes. Furthermore, after four weeks of cold storage, the morphology of the vitelline granules in the CPFA and CSM supplemented groups were damaged; however, there were no significant alterations found in the FG group. CONCLUSION: The main cause of the “sponge-bob egg” effect was the presence of CPFA in cottonseed meal, which causes an increase in permeability of the vitelline membrane in eggs.