Relationship between Dietary Fiber and Nutrient Density and Its Effect on Energy Balance, Egg Yolk Cholesterol and Hen Performance

Two experiments were conducted to determine the effect of dietary fiber in rations of varying nutrient density on egg yolk cholesterol, energy balance and reproductive efficiency of laying hens. Initially, four diets arranged in a Latin square design were tested: low, medium and high nutrient density diets and a control diet. The energy-to-protein ratio was 171.8 kcal/% protein for all diets. Significant differences (P < 0.01) were observed between diets for feed intake, feed efficiency and fecal output of the hens. Dietary differences in yolk cholesterol, egg production, egg weight, body weight change and energy balance were not significant, and hence unrelated to dietary fiber level. A significant negative correlation (P < 0.01) was found between yolk cholesterol and egg production (r = -0.45) or egg energy output (r = -0.38). In addition, yolk cholesterol was positively correlated with body weight change (r = 0.23, P < 0.01). In the second experiment, the possible relationship between level of feed intake, body weight change and yolk cholesterol was further investigated. Yolk cholesterol tended to increase when the laying pullets consumed more than 387 kcal ME/day or gained more than 100 g in body weight. When the energy intake was less than 340 kcal ME/day or the birds lost body weight, an increase in yolk cholesterol also was noted but was inversely related to feed intake or body weight change.