title: Influence of different dietary levels of zinc on performance, vitamin B12, and blood parameters in lambs.
abstract: This experiment was conducted to investigate the influence of different dietary levels of zinc (Zn) on performance, vitamin B12, and blood parameters in lambs. Thirty six cannulated Poll Dorset x Small-tailed Han wether lambs were assigned randomly to four treatment groups: The control group, which was supplemented with 0.30 mg Co/kg dry matter (DM) to the basal diet; and the low-, medium- and high-Zn supplemented groups, supplementation of 50, 100, and 150 mg Zn/kg DM to the control diet, respectively. Lambs were housed in individual pens and the experiment lasted for 70 days. There was no significant difference in body weight gain and feed/gain between different treatment groups. The high-Zn supplemented lambs showed lower vitamin B12 concentrations in both ruminal fluid and plasma, and higher methylmalonic acid and homocysteine concentrations in plasma compared with the control and low-Zn supplemented groups (p < 0.05). No significant difference was observed in these biochemical values between the control, the low-, and the medium-Zn supplemented groups (p > 0.05). Plasma folate concentration, glucose, and heme-dependent blood parameters were not influenced by dietary zinc level. It was concluded that the higher level of zinc supplementation had a negative effect on vitamin B12 in lambs. Higher inclusion level of dietary zinc could inhibit vitamin B12 synthesis in the rumen of lambs.
authors.affiliation: College of Animal Science and Technology, China Agricultural University, Beijing 100094, P R China. wangrunlian2005@yahoo.com.cn
authors.forename: Runlian
authors.initials: R
authors.lastname: Wang
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Zhu
authors.forename: Fucun
authors.initials: F
authors.lastname: Guo
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Zhihai
authors.initials: Z
authors.lastname: Jia
mesh_terms: D000821:Animal Feed; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects*; D003035:Cobalt / Q000008:administration & dosage; D004032:Diet / Q000379:methods*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005492:Folic Acid / Q000097:blood / Q000187:drug effects; D006710:Homocysteine / Q000097:blood / Q000187:drug effects; D008764:Methylmalonic Acid / Q000097:blood; D012417:Rumen / Q000187:drug effects / Q000378:metabolism; D012756:Sheep; D014805:Vitamin B 12 / Q000097:blood / Q000378:metabolism*; D015032:Zinc / Q000009:adverse effects / Q000494:pharmacology*
chemical_list: D001786:Blood Glucose; D006710:Homocysteine; D003035:Cobalt; D008764:Methylmalonic Acid; D005492:Folic Acid; D015032:Zinc; D014805:Vitamin B 12