title: Effect of zinc toxicity in laying white leghorn pullets and hens.
abstract: Two experiments involving 124 Single Comb White Leghorn (Hy-Line) laying pullets and hens were conducted to determine the effect of zinc toxicity on bird performance. Twenty milligrams of zinc per gram of diet fed for 5 days significantly lowered fertility and hatchability of pullet eggs collected 14 to 28 days after the 5-day zinc feeding period. Zinc significantly depressed body weight on the day 5 of zinc feeding and significantly lowered egg poroduction from 0 to 4 weeks of test. Egg production from 4 to 12 weeks, feed conversion from 0 to 12 weeks, final body weight, and livability were not significantly affected. Hens fed the supplemental zinc for five days had depressed egg production from 0 to 4 weeks. Egg production from 4 to 12 weeks, feed conversion, final body weight, and livability were not significantly affected. Compared to their respective controls, 2% supplemental zinc fed for 5 days significantly improved hen but not pullet egg weight. Hen eggs collected 28 days after hens received the zinc diet contained significantly less potassium, copper, and zinc than the controls.
mesh_terms: D000818:Animals; D002645:Chickens / Q000502:physiology*; D005260:Female; D015032:Zinc / Q000009:adverse effects*
chemical_list: D015032:Zinc