title: Influence of vitamin D on fecal shedding of Escherichia coli O157:H7 in naturally colonized cattle.
abstract: Three experiments were conducted to evaluate the influence of vitamin D on fecal shedding of Escherichia coli O157:H7 in cattle. In the first experiment, two groups of cattle (beef and dairy) were assigned to a control treatment or to receive 0.5 × 10(6) IU vitamin  D per day via oral bolus for 10 days. Fecal samples were collected before and throughout the dosing period for culture of E. coli O157:H7. No differences were observed for fecal shedding of E. coli O157:H7 among treatments for either beef or dairy animals. Serum concentrations  of vitamin D were markedly higher (P < 0.0001) in treated beef cattle but only tended to be higher (P = 0.09) in the dairy cattle. In the second experiment, three successive vitamin D dosages (2,400, 4,800, and 9,600 IU/day; 14 days each) were administered to 14 dairy steers  (7 steers served as controls), fecal samples were collected daily, and serum samples were collected weekly throughout the 42-day experimental period. No significant differences in fecal prevalence or serum vitamin D concentrations were observed for any of the vitamin D dosages. A third experiment  sampled feedlot cattle (winter and summer) to determine whether serum vitamin D concentrations were correlated with fecal shedding of E. coli O157:H7. A fecal sample and a blood sample were obtained in each season from 60 randomly selected animals (total of 120 fecal samples and 120  corresponding blood samples). As expected, season was highly correlated (r = 0.66) with serum vitamin D concentration with higher concentrations (P < 0.01) observed in the summer. E. coli O157:H7 prevalence (percentage of positive samples) was not highly correlated  (r = 0.16) with season, although the correlation tended to be significant (P = 0.08). The proportion of cattle shedding E. coli O157:H7 was 16.7 and 6.7% for the summer and winter collections, respectively. Results of this research do not support a correlation between  vitamin D intake and E. coli O157:H7 shedding in cattle.
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, College Station, TX 77845, USA. edrington@ffsru.tamu.edu
authors.forename: Tom S
authors.initials: TS
authors.lastname: Edrington
authors.forename: Russell L
authors.initials: RL
authors.lastname: Farrow
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Mackinnon
authors.forename: Todd R
authors.initials: TR
authors.lastname: Callaway
authors.forename: Robin C
authors.initials: RC
authors.lastname: Anderson
authors.forename: David J
authors.initials: DJ
authors.lastname: Nisbet
mesh_terms: D000818:Animals; D002417:Cattle / Q000097:blood / Q000382:microbiology*; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012621:Seasons; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood
chemical_list: D014807:Vitamin D