Eggshell Quality Research

Khon Kaen University, Thailand This full cycle layer production trial evaluated the effects of adding Availa-Zn and Availa®Mn to the diet of layers. The control diet contained a standard industry level of trace minerals (60 ppm Zn from ZnO and 60 ppm Mn from MnO). The treatment diets contained added zinc and manganese from Availa-Zn and Availa-Mn at levels of 20-20 ppm, 30-30 ppm and 40-40 ppm of zinc and manganese respectively. Data were collected during each of two phases and were combined within phase and for the total period. Phase I represents data from week 18 to 37. Phase II represents data from week 38 to 65.
	Zinpro Corporation
Results of this 47-week experiment demonstrated a positive effect of complexed zinc and manganese for improving eggshell quality. The addition of zinc from Availa-Zn and manganese from Availa-Mn improved eggshell weight and eggshell thickness in Phase II as well as a numerical improvement in Phase I and for the Overall experiment (Table 1 and 2).

Table 1. Effects of Zinc and Manganese Amino Acid Complexes on Eggshell Weight

Table 2. Effects of Zinc and Manganese Amino Acid Complexes on Eggshell Thickness

Figure 6. Common Eggshell Defects (Adapted from: Roche Vitamins; Egg Quality, a Practical Approach):

Break or Toe-Pinch	Internal Crack	Soft Shell

Commercial Field Trial
Recent research conducted with a large layer operation in the Western U.S. further evaluated the effects of Availa-Zn on egg quality. One hundred thirty-five thousand pullets (Isa White) were used to determine the effect of complexed Zn on layer production and egg quality. Pullets were allocated arbitrarily to one of two paired houses at one day of age. Each house was randomly assigned to one of two treatment diets. Treatments included a series of standard commercial diets (66 ppm added Zn from ZnO) and the same commercial diets with 40 ppm added Zn from Availa-Zn. At 18 wk of age, birds were transferred to three lay houses (average of 34,312 layers per house) keeping integrity of treatments within two houses (Control and Availa-Zn) and the third house containing a mixture of the two grow-out treatment groups. Feeding 40 ppm Zn from Availa-Zn commenced with the day-old chick and continued through the entire lay cycle. Egg quality data was determined during the five weeks preceding the molt (61-65 wk). Feeding
Availa-Zn reduced the percentage of undergrade eggs (Table 3).

Table 3. Effects of Zinc Amino Acid Complexes on Egg Quality