The effects of a protein deficiency on egg composition

Eggs were collected from groups of pullets receiving 9, 14 or 20 per cent dietary protein and the component parts were separated and weighed. The reduction in egg weight associated with protein deficiency was found to be due to reductions in all components, but yolk and shell weight changed proportionately less than total weight and albumen weight proportionately more. The resulting increase in percentage yolk was found to be of similar magnitude to that expected from a consideration of the relationship between egg size and yolk size in birds receiving adequate protein. In a similar way the increased proportion of shell apparently reflected only the relationship between egg size and surface area in eggs collected when the birds were 52 weeks of age but at 67 weeks a real increase in shell thickness on the deficient diet was also indicated.