Responses in Calcium and Phosphorus Metabolism and Hepatic Lipid Deposition among Estrogenized Chicks Fed Various Dietary Ingredients

Abstract

The purpose of this study was to determine whether diet composition would influence calcium and phosphorus metabolism in chicks administered estrogen. At 1 day of age, broiler chicks were fed either a corn-soybean meal diet (CS), or an isoenergetic and isonitrogenous diet containing 5% fish meal, 5% alfalfa meal and 10% torula yeast (FAY). At 21 days equivalent numbers were implanted with one of two lengths of Silastic tubing containing estradiol dipropionate, while the remaining birds served as nonimplanted controls. Significant increases were observed in liver weight, liver lipid, plasma total calcium and inorganic phosphate in chicks that were implanted, while concomitant declines were seen in body weight. Implanted chicks fed the CS diet had significantly higher liver weight, liver lipid, plasma phosphorus and plasma calcium and lower tibial bone ash than those fed the FAY diet. Furthermore, liver lipid values were very highly correlated with plasma phosphorus and calcium. In an identical study with slower growing White Leghorn chicks, the same trends were observed but were less well defined. These data show that the inclusion of certain ingredients into corn-soybean diets balanced for the major nutrients affects the response of chicks to estrogenization. Liver lipid deposition, calcium and phosphorus metabolism are all subject to diet and estrogen interactions.