Copper deficiency in the laying hen.

Copper deficiency in the laying hen resulted in anemia and the production of eggs which were abnormal in size and shape. Many of the eggs had shells which were wrinkled and rough in texture. There was also an increase in the number of shell-less eggs. Examination of malformed egg shells using the scanning electron microscope revealed ultrastructural changes in the mammillary layer of the shell. The effect of copper deficiency on shell formation was attributed to the shell membranes which were altered in color, appearance, and physical consistency. Amino acid analysis of the membranes indicated that the membranes from copper deficient hens were characterized by an increase in lysine content. This suggests that copper is necessary for the formation of lysine derived cross-links in a manner similar to that which occurs in connective tissue. The exact nature of these cross-links is unknown at this time.