Effects of Dietary Fiber, Fat and Total Energy Upon Plasma Cholesterol and Other Parameters in Chickens

Abstract

To determine possible alterations of ovarian cholesterol synthesis and corresponding effects of fiber, fat, and total dietary energy upon body parameters, laying hens were fed diets containing 50% wheat bran, oat hulls, or alfalfa meal substituted isonitrogenously for part of the corn and soybean meal in the control diet. Additionally, one group of hens received the 50% bran diet plus 19% corn oil so that this diet was also isoenergetic with the control diet; another group received the high bran diet plus copper sulfate (50 ppm added Cu), with the exclusion of zinc. The results of the studies presented in this report indicate no effects of fiber on the nutrition of laying hens and/or their progeny which cannot be accounted for in terms of reduced energy or increased phytic acid or saponin contents of the diets. Energy deficiency in the laying hen results in decreased egg production and sometimes in decreased egg size, but had no effect upon hatchability of the eggs produced. Growth of the progeny tended to parallel initial egg weights and maternal energy consumption. The underweight chicks at hatching did not catch up to controls during a 1-month period of feeding a diet completely adequate for growing chickens. The results of these investigations did not indicate that lignin, present in high amounts in wheat and oat affal, had any effect upon plasma cholesterol, and increasing the dietary copper to zinc ratio had no effect upon either plasma or egg cholesterol levels in adult chickens. The finding that a high dietary level of alfalfa meal reduced plasma cholesterol but had no effect upon egg cholesterol levels indicates that ovarian synthesis of cholesterol may be important in maintaining an essential cholesterol level in the egg.