The Effects of Zinc Supplementation on Growth, Diarrhea, Antioxidant Capacity, and Immune Function in Holstein Dairy Calves

Abstract

The current study examined the effects of supplementary zinc proteinate (ZnPro) and zinc oxide (ZnO) on growth performance, diarrhea, antioxidant capacity, immune function, and mineral element concentrations of calves aged 1 to 28 days. A total of twenty-four newborn calves were divided randomly into 3 groups (n = 8; 2 males and 6 females per group), and each received: 0 mg/d Zn (CON), 627 mg/d ZnPro (80 mg/d Zn; ZnPro group), and 101 mg/d ZnO (80 mg/d Zn; ZnO group). The calves received the additive in their milk during the first 28 days of life. Compared with the CON group: ZnPro and ZnO improved average daily gain (ADG) and decreased the feed:gain ratio (FGR) between days 1 and 14 (p < 0.05), while the ADG increased and FGR decreased only in the ZnPro group between days 1 and 28 (p < 0.05). The incidence of diarrhea decreased (p < 0.05) in the ZnPro and ZnO groups between days 15 and 28 as well as days 1 and 28, but decreased (p < 0.05) only in the ZnPro group between days 1 and 14. The serum immunoglobulin G (IgG) concentration of the ZnPro and ZnO groups increased on days 14 and 28 (p < 0.05). ZnPro supplementation increased serum IgM concentration during the whole study, while ZnO enhanced serum IgM concentration only on day 14 (p < 0.05). In the ZnO group, the serum concentration of cytokines interleukin (IL)-10 increased on day 14, while that of IL-1β increased on day 28 (p < 0.05). In addition, ZnPro reduced the serum malondialdehyde (MDA) concentration on days 14 and 28 (p < 0.05). Both ZnPro and ZnO increased the serum concentrations of alkaline phosphatase (ALP) and metallothionein (MT) on day 14 (p < 0.05). With zinc supplementation, plasma Zn concentration increased (p < 0.05) on days 14 and 28 of age. We concluded that supplementary ZnPro and ZnO reduced incidences of diarrhea and promoted the immune function, but ZnPro improved the growth performance and antioxidant capacity of Holstein dairy calves to a greater extent.

Zinc about it – zinc and calf immunity

“…Zinc supplementation (80 mg/kg DM, Zn proteinate, and Zn Met) did not influence plasma IL-8 or TGF-b concentrations in preweaning calves (27). However, Zn supplementation (80 mg/kg DM, Zn oxide) increased serum IL-10 concentrations after 14 days in newborn dairy calves, but this effect was temporary and disappeared by 28 days (31). Additionally, Zn supplementation increased IL-2 concentrations with 80 mg/kg DM Zn as an amino acid complex (33), but not 40 mg/kg DM (33) or doses greater than 80 mg/kg DM (i.e., 120 mg/kg DM -300 mg/ kg DM) in preweaning calves (14,33).…”

“…Zinc supplementation increased total immunoglobulin (Ig) in serum and plasma when Zn (30 -32 mg/kg DM) was fed to preweaning calves (29, 30). Increased IgG concentrations were reported when 32-100 mg/kg DM Zn was supplemented to preweaning dairy calves (27,29,31,32). In contrast, 1-month-old beef calves supplemented with a Zn amino acid complex (40, 80, 120 mg/kg DM) showed no difference in IgG concentrations among the treatments (33).…”

“…In contrast, 1-month-old beef calves supplemented with a Zn amino acid complex (40, 80, 120 mg/kg DM) showed no difference in IgG concentrations among the treatments (33). Serum and plasma IgM concentrations increased in preweaning calves when 32-100 mg/kg DM Zn was supplemented (27,(31)(32)(33). However, a threshold of Zn concentration seems to be in place as no further improvement was documented in beef calves supplemented with 120 mg/kg DM (33).…”

“…Zn supplementation (32 mg/kg DM) in the form of nanoparticles increased plasma IgA concentrations (29). However, when Zn was supplemented as Zn oxide (40, 80, 120 mg/kg DM), Zn proteinate (80 mg/kg DM), Zn as an amino acid complex (40, 80, 120 mg/kg DM) or Zn Met (80 mg/kg DM) there were no changes in preweaning calf serum or plasma IgA concentrations (27,29,31,33). It is important to note that IgA is most abundant in external secretions; thus, serum and plasma samples may not be representative of changes in IgA production (44).…”

“…However, there were mixed results regarding which outcomes were most affected. The strongest results were for total Ig and non-specific Ig classes, with unanimous improvement of at least one outcome (27,(29)(30)(31)(32)(33). Results indicate the possibility of a threshold for the beneficial effects of Zn supplementation.…”