title: Source of supplemental dietary copper, zinc, and manganese affects fecal microbial relative abundance in lactating dairy cows.
abstract: Appropriate trace mineral supplementation can improve immune response and hoof health in cattle and at much higher rates of supplementation to swine and poultry can alter microbial colonization of the gut, resulting in improved gut health. Diet can influence fecal microbial excretion in cattle, and the fecal microbiome may serve as a means for assessing gastrointestinal microbial changes. We hypothesized that feeding diets that differed in source of supplemental Cu, Zn, or Mn would alter the relative abundance of fecal microbes in lactating dairy cattle and that organic Zn would have the greatest effect. Twenty-four cows were fed diets devoid of supplemental Cu, Zn, and Mn for a 16-d preliminary phase (basal diet provided 9, 29, and 32 mg/kg of Cu, Zn, and Mn, respectively), and then were randomly assigned to 1 of 3 treatment diets (n = 8 cows/treatment): one group of cows was fed supplemental Cu, Zn, and Mn from sulfate minerals; the second group was fed glycinate minerals; and the third group was fed Cu and Mn sulfate with glycinate Zn. Assayed total dietary concentrations were approximately 21, 73, and 72 mg/kg for Cu, Zn, and Mn, respectively. Milk production (averaged 38.8 kg/d), DMI (averaged 25.8 kg/d), and milk components were not affected by treatment. Fecal DNA was extracted, amplified using a universal primer targeting the V4-V5 hypervariable region of the 16S rRNA gene, and sequenced to compare microbial community composition between treatments. Relative abundances of Treponema species-level operational taxonomic units (OTU) were less for animals fed Cu and Mn sulfate with glycinate Zn compared with sulfates alone, but were similar to animals fed glycinate mineral sources. Relative abundances for exclusive glycinate mineral and sulfate mineral treatments were similar. Treponema OTU and cultured representatives are often associated with bovine digital dermatitis. These data may provide an additional link between organic Zn supplementation and improved hoof health. To our knowledge this is the first report of a dietary treatment decreasing the relative abundance of Treponema OTU in cattle feces; however, the potential benefits of this response on overall animal health and the mechanism for the observed responses are unknown and warrant further investigation.
authors.affiliation: Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691.
authors.forename: M J
authors.initials: MJ
authors.lastname: Faulkner
authors.affiliation: Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691.
authors.forename: B A
authors.initials: BA
authors.lastname: Wenner
authors.affiliation: Wrighton Microbiome Laboratory, Department of Microbiology, The Ohio State University, Columbus 43210.
authors.forename: L M
authors.initials: LM
authors.lastname: Solden
authors.affiliation: Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691. Electronic address: weiss.6@osu.edu.
authors.forename: W P
authors.initials: WP
authors.lastname: Weiss
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle; D003300:Copper; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D005243:Feces / Q000382:microbiology*; D005260:Female; D007774:Lactation; D008345:Manganese; D012336:RNA, Ribosomal, 16S; D013552:Swine; D015032:Zinc
chemical_list: D012336:RNA, Ribosomal, 16S; D008345:Manganese; D003300:Copper; D015032:Zinc
keywords: digital dermatitis; fecal microbiome; trace minerals