The Effect of Phthalate Administration to Laying Hens on the Shell Thickness, Shell Weight, Egg Weight and Shell lndex

Abstract

The effects of diethylhexyl phthalate (DEHP) administration to laying hens on the shell thickness, shell weight, egg weight, shell index and the concentration of calcium ion in serum were investigated. One gram of DEHP per kg body weight was intubated to Babcock hens by silicon tube every day (Group A), and the DEHP-containing feed (0. 5-1.0g/100g feed) was given to Iwaya hens (Group B) and Babcock hens (Group C) ad libitum. In Group B, the decrease in the value of egg weight, shell weight, shell thickness and shell index was statiscally significant for the first 16 days of DEHP adminstration, but was not observed from the 17th day and on. In Groups A and C, many soft-shelled eggs resulted from the DEHP administration. The concentration of calcium ion in the serum of the DEHP administered hens (Group C) was lower than that of the control hens.