Influence of different dietary levels of zinc on performance, vitamin B12, and blood parameters in lambs.
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.
Wang
Runlian
R
College of Animal Science and Technology, China Agricultural University, Beijing 100094, P R China. wangrunlian2005@yahoo.com.cn
Zhu
Xiaoping
X
Guo
Fucun
F
Zhang
Wei
W
Jia
Zhihai
Z
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*
D001786:Blood Glucose; D006710:Homocysteine; D003035:Cobalt; D008764:Methylmalonic Acid; D005492:Folic Acid; D015032:Zinc; D014805:Vitamin B 12