Determination of Time Point and Sensitive Biomarkers of Maternal Zinc Depletion in Broiler Chickens and Pekin Ducks Fed a Zinc Deficient Dietary

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