ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2013, Vol. 44 ›› Issue (12): 2016-2021.doi: 10.11843/j.issn.0366-6964.2013.12.023

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Efficacy of a Combination of Egg Yolk Immunoglobulins against Staphylococcus aureus Exotoxins and Capsules in the Treatment of Bovine Mastitis

WANG Lin-hui1, LI Xiao-yu1, JIN Li-ji1,2, LI Shu-ying2, XU Yong-ping1,2*   

  1. (1. School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China; 2. MOE (Ministry of Education) Center for Food Safety of Animal Origin, Dalian 116020, China)
  • Received:2013-06-13 Online:2013-12-23 Published:2013-12-23

Abstract:

The objective of this study was to evaluate the efficacy of a combination of egg yolk immunoglobulins (IgYs) specific for exotoxins (IgY-toxins) and serotypes 5, 8 and 336 capsules of Staphylococcus aureus (IgY-T5, IgY-T8, IgY-T336, respectively) in the treatment of bovine mastitis. A lactate dehydrogenase assay indicated that IgY-toxins prevented mammary epithelial cells (MAC-T) from lysing. An internalization assay demonstrated that 5 mg·mL-1 IgY-T336 markedly blocked the invasion of a GFP-expressing S. aureus RN6390 to MAC-T cells, and a combination of 5 mg·mL-1 of IgY-T336 and 0.5 mg·mL-1 of IgY-toxins provided the cells with greater protection and improved growth morphology compared with the IgY-T336 treatment alone. A field trial for clinical mastitis indicated that two doses of a combination of 20 mg each of IgY-T5, IgY-T8 and IgY-T336 plus 20 mg of IgY-toxins daily for six days significantly reduced somatic cell counts (SCC) compared with PBS control (P < 0.001). Treatment with IgY-T5, IgY-T8 and IgY-T336 or IgY-toxins alone produced a slight reduction in SCC compared with PBS control. However, the reduction was much lower than that in IgY combination treatment (P < 0.01). Both surface capsules and secreted exotoxins should be targeted in the treatment of S. aureus-caused bovine mastitis with IgY.

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