EFFECT OF REMOVING TRACE MINERALS FROM THE DIET OF HENS LAYING EGGS WITH HEAVY OR LIGHT SHELL WEIGHT

Hy-Line W36(R) hens, 48-wk-old, were used to study the effect of removing either supplemental Fe, Cu, Zn, Mn, or all of them from the diet of hens laying eggs with heavy shell weight (HSW) or light shell weight (LSW). The experiment was conducted for 10 wk. Egg production (EP), egg mass (EM), feed consumption (FC), feed conversion efficiency (FE, grams feed:gram egg), egg weight (EW), shell weight (SW), percentage shell (PS), specific gravity (SG), percentage fertility, percentage hatchability of fertile eggs (HF), and percentage hatchability of total eggs set (HT) were measured. Removing trace minerals from the diet had no significant effect on EP, EM, FC, FE, EW, PS, SG, HF, or HT with either HSW or LSW hens. However, removing Mn from the diet significantly reduced SW with HSW hens. Diet by shell classes (HSW and LSW) interaction was not significant for any variable measured. The HSW hens had significantly higher EW, SW, PS, SG, and EM and lower EP, HF, and HT. However, there were no significant differences on FC or percentage fertility between the two groups of hens.