title: An Optimal Dietary Zinc Level of Brown-Egg Laying Hens Fed a Corn-Soybean Meal Diet.
abstract: An experiment was conducted to estimate the optimal dietary zinc (Zn) level of brown-egg laying hens fed a corn-soybean meal diet from 20 to 40 weeks of age. A total of 120 20-week-old Beijing Red commercial laying hens were randomly allotted by bodyweight to one of five treatments with six replicates of four birds each in a completely randomized design, and fed a Zn-unsupplemented corn-soybean meal basal diet containing 27.95 mg Zn/kg by analysis and the basal diets supplemented with 30, 60, 90, or 120 mg Zn/kg as Zn sulfate (reagent grade ZnSO4·7H2O) for a duration of 20 weeks. Laying performance, egg quality, tissue Zn concentrations, and activities of serum alkaline phosphatase (AKP), and liver copper-Zn superoxide dismutase (CuZnSOD) were measured. Regression analyses were performed to estimate an optimal dietary Zn level whenever a significant quadratic response (P < 0.05) was observed. Tibia Zn concentration (P = 0.002) and serum AKP activity (P = 0.010) showed significant quadratic responses to dietary supplemental Zn levels. The estimates of dietary Zn requirements for brown-egg laying hens from 20 to 40 weeks of age were 71.95 and 64.63 mg/kg for tibia Zn concentration and serum AKP activity, respectively. The results from this study indicate that the tibia Zn might be a more suitable and reliable parameter for Zn requirement estimation, and the optimal dietary Zn level would be about 72 mg/kg for brown-egg laying hens fed a corn-soybean meal diet from 20 to 40 weeks of age.
authors.affiliation: Faculty of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China.|Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China.
authors.forename: Shizhen
authors.initials: S
authors.lastname: Qin
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lu
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China.
authors.forename: Xichun
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China.
authors.forename: Xiudong
authors.initials: X
authors.lastname: Liao
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China.
authors.forename: Liyang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Faculty of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, People's Republic of China. guoyl@gsau.edu.cn.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China. wlysz@263.net.
authors.forename: Xugang
authors.initials: X
authors.lastname: Luo
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002645:Chickens; D019587:Dietary Supplements; D005260:Female; D013025:Glycine max / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry*; D015032:Zinc / Q000008:administration & dosage / Q000032:analysis* / Q000378:metabolism
chemical_list: D015032:Zinc
keywords: Brown-eggshell laying hens; Requirement; Tissue Zn; Zinc; Zn-containing enzymes