title: Effects of dietary vitamin C on neutrophil function and responses to intramammary infusion of lipopolysaccharide in periparturient dairy cows.
abstract: Neutrophil function and the severity and incidence of mastitis in dairy cows is related to the intake of many antioxidant nutrients. Because vitamin C is the major water-soluble antioxidant in mammals, we examined the effect of dietary vitamin C on neutrophil function and responses to intramammary infusion of lipopolysaccahride (LPS) in periparturient dairy cows. At 2 wk before anticipated calving, Holstein cows were fed diets that provided 0 (16 cows) or 30 (15 cows) g/d of supplemental vitamin C (phosphorylated ascorbic acid). Treatments continued until 7 d after cows received an infusion of 10 microg of LPS into one quarter of the mammary gland (on average, this occurred 32 d postcalving). Supplementation of vitamin C increased plasma concentrations of vitamin C at calving, but no differences were observed in samples taken 24 h postinfusion. Concentrations of vitamin C in milk (24 h postinfusion) and in neutrophils (calving and 24 h postinfusion) were not affected by treatment, but vitamin C concentrations in neutrophils isolated from milk were about 3 times greater than concentrations in blood neutrophils. The LPS infusion did not alter concentrations of vitamin C in plasma or milk, suggesting that the LPS model did not produce the same effects as a bacterial infection of the mammary gland with respect to antioxidant effects. Supplemental vitamin C had no effect on neutrophil phagocytosis or bacterial kill. Dietary vitamin C reduced the milk somatic cell count but did not affect the febrile response or milk production following LPS infusion.
authors.affiliation: Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691, USA. weiss.6@osu.edu
authors.forename: W P
authors.initials: WP
authors.lastname: Weiss
authors.forename: J S
authors.initials: JS
authors.lastname: Hogan
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000032:analysis / Q000097:blood; D001770:Blood Bactericidal Activity / Q000187:drug effects; D002417:Cattle; D004032:Diet; D005260:Female; D005334:Fever; D007700:Kinetics; D008070:Lipopolysaccharides / Q000008:administration & dosage*; D008321:Mammary Glands, Animal / Q000187:drug effects*; D008414:Mastitis, Bovine / Q000097:blood / Q000517:prevention & control*; D008892:Milk / Q000737:chemistry / Q000166:cytology; D009504:Neutrophils / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D036801:Parturition; D010587:Phagocytosis; D011247:Pregnancy
chemical_list: D000975:Antioxidants; D008070:Lipopolysaccharides; D001205:Ascorbic Acid