Determination of Time Progression and Sensitive Biomarkers of Maternal Zinc Depletion in Broiler Chickens and Pekin Ducks Fed a Zinc-Deficient Diet.

Two experiments were performed to assess maternal zinc (Zn) depletion in broiler chickens and Pekin ducks fed a Zn-deficient diet. The time of Zn depletion was assessed based on growth performance, and sensitive biomarkers were determined based on tissue Zn content via a linear regression model. A total of 200 1-day-old male broiler chickens (experiment 1) and 200 1-day-old male Pekin ducks (experiment 2) were randomly allocated to 2 diets with 10 replicate cages (10 birds/cage). The two diets were a zinc-deficient diet (ZnD, 20.42 mg Zn/kg) and a control zinc diet (CON, 84.77 mg Zn/kg). In experiment 1, compared to CON, ZnD decreased (P < 0.05) the body weight (days 7, 14, and 21), body weight gain, feed intake (days 1-7, 1-14, and 1-21), and the Zn content of plasma (days 7 and 21), pancreas (days 7, 14, and 21), and tibia in broiler chickens. The R of a linear model was greater at day 7 than at day 14 or day 21 for pancreatic Zn content in broiler chickens. In experiment 2, compared to CON, ZnD also decreased (P < 0.05) the body weight (days 7, 14, and 21), body weight gain (days 1-7, 1-14, and 1-21), and feed intake (days 1-14 and 1-21) and increased (P < 0.05) the feed-to-gain ratio (days 1-7 and 1-14) in ducks. Compared with CON, ZnD reduced (P < 0.05) the Zn content of the pancreas (days 7, 14, and 21), tibia (days 7, 14, and 21), and skin (days 14 and 21) and increased (P < 0.05) the Zn content of the plasma (day 21) and skin (day 7) in ducks. The R of a linear model was greater at day 7 than at days 14 or 21 for skin Zn content in ducks. The results indicated that the maternal Zn was depleted by 7 days of age in both birds; the sensitive biomarker for broiler chickens is pancreatic Zn content, and for ducks, it is skin Zn content.