Effect of intramammary infusion of tumour necrosis factor-alpha on milk protein composition and induction of acute-phase protein in the lactating cow.
The present study was designed to evaluate the effects of tumour necrosis factor-alpha (TNF-alpha) on lactating bovine mammary functions such as milk protein secretion and the integrity of the milk-blood barrier. The effect on the induction of the systemic inflammatory response was also examined using concentrations of serum haptoglobin (Hp), a major inflammatory acute-phase protein, as an index. One hundred micrograms per mammary gland of recombinant bovine (rBo) TNF-alpha or placebo saline was individually infused into a rear mammary gland of each of four lactating cows, and milk and blood samples were collected before and 4, 8, 24, 32, 48, 96 and 168 h after infusion. In the rBoTNF-alpha-infused gland, increases of somatic cell counts were observed at 4-48 h. Although concentrations of total milk protein were not changed, compositions of milk proteins varied following rBoTNF-alpha infusion. Concentrations of caseins, alpha-lactalbumin and beta-lactoglobulin were significantly decreased at 4 and 8 h. Lactoferrin concentrations were significantly increased at 4 h. Significant infiltrations of serum albumin, immunoglobulin G1 (IgG1) and IgG2 were observed at 4 and 8 h. Elevations of the serum concentration of Hp were detected at 8-32 h, but were very small in comparison with those reported in inflammatory diseases. Changes in rectal temperature and white blood cell counts were not significant. These results show that single rBoTNF-alpha infusion into the lactating mammary gland suppresses the lactogenic function of the gland and influences the function of the milk-blood barrier, with little effect on the generalized inflammatory response.
Watanabe
A
A
Hokkaido Research Station, National Institute of Animal Health, 4 Hitsujigaoka, Sapporo 062-0045, Japan. awata@affrc.go.jp
Yagi
Y
Y
Shiono
H
H
Yokomizo
Y
Y
D000209:Acute-Phase Proteins / Q000187:drug effects*; D000818:Animals; D001772:Blood Cell Count / Q000662:veterinary; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D006242:Haptoglobins / Q000187:drug effects; D007774:Lactation / Q000276:immunology*; D008414:Mastitis, Bovine / Q000276:immunology*; D008894:Milk Proteins / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage / Q000494:pharmacology*
D000209:Acute-Phase Proteins; D006242:Haptoglobins; D008894:Milk Proteins; D014409:Tumor Necrosis Factor-alpha