Dietary Effects on Content of Hepatic Lipid, Plasma Minerals, and Tissue Ascorbic Acid in Hens and Estrogenized Chicks

Abstract

The purpose of this study was to determine if plasma mineral levels and plasma or hepatic ascorbic acid would be affected by the composition of the diet fed to chickens with higher circulating estrogen levels. Three-week-old broiler chicks were implanted with estradiol dipropionate to give estimated release rates of 0, 3.2, and 8.0 μg/bird/day. The chicks were fed a corn-soy diet (CS) or a diet containing 5% fish meal, 5% alfalfa meal and 10% torula yeast (FAY). The FAY diet resulted in significantly lower hepatic lipid and plasma iron, copper, manganese, and zinc in chicks administered the highest level of estrogen. In two experiments laying hens were fed either CS or diets containing fish meal (FM), alfalfa meal (AM), distillers dried grains with solubles (DDGS) or wheat-soy (WS) for 4 weeks. In the first experiment, liver lipid content was not significantly affected by diet composition, but plasma iron was significantly reduced by the AM, DDGS, and WS diets. No significant effects on copper, manganese, and zinc in plasma were observed among the dietary treatments. In the second experiment, relative liver weight was significantly reduced with the AM, DDGS, and WS diets and liver lipid by the AM diet. Plasma iron levels were significantly reduced by feeding all diets compared with the CS diet, but no significant differences in total iron binding capacity were observed. Plasma and hepatic ascorbic acid were significantly increased by the AM, DDGS, and WS diets, but no significant differences in hepatic ascorbic acid were observed when calculated per unit of fat-free dry matter. Significant correlations were observed between plasma iron or ascorbic acid and relative liver fat. These studies show that diet composition influences the plasma iron response to either exogenous (chicks) or endogenous (hens) estrogen and show a correlation of lower plasma ascorbic acid and higher iron levels with higher hepatic lipid accumulation in hens.