Liver response to diet and estrogen in white Leghorn and Rhode Island Red chickens

Experiments were conducted to compare the response of Rhode Island Reds (RIR) and White Leghorns (WL) to estradiol (E2) administration and diets of different composition. In growing chickens injected with E2 for 7 days, RIR accumulated significantly more hepatic lipid and had significantly less plasma lipid than WL. Both RIR and WL, injected for 4 days with E2, had lower hepatic lipids when fed a diet containing fish meal, alfalfa meal, and torula yeast (FAY) than when fed a corn-soybean meal diet (CS). Plasma glutamic oxaloacetic transaminase activity was significantly lower for RIR. Feeding a FAY diet to laying hens significantly reduced hepatic lipids in WL but not in RIR. Implantation of tubes containing E2 in RIR-laying hens resulted in a significant body weight loss and 25% mortality, while a similar treatment in WL-laying hens caused no body weight loss or mortality. Injecting both RIR and WL-laying hens with E2 caused a marked body weight loss and high mortality in both breeds although WL were less severely affected. The results show that breeds of chickens respond differently to both E2 administration and changes in diet composition.