Effect of fattening on the Development of Abscess Disease in Sheep and Growth of Staphylococcus aureus subsp. Anaerobius

Abstract

The present study was designed to investigate factors related to fattened sheep that affect the growth of Staphylococcus aureus subsp. anaerobius (Sasa) and enhance its pathogenicity. The pH of sweat, cholesterol levels in sweat and sera of fattened and un-fattened sheep were measured and the effect of sera from fattened sheep on the growth of Sasa was studied. Fattened and un-fattened lambs were subjected to experimental infection using a strain of Sasa. The pH of the sweat of un-fattened group ranged between 5.0 and 6.0, while in fattened group it ranged from 6.2 to 7.6. Serum cholesterol level was significantly higher in fattened group (74.06 ± 5.56 mg/ dl) than in un-fattened group (43.00 ± 6.66 mg/ dl). Serum from fattened sheep promoted the growth of Sasa more than serum from un-fattened sheep. In experimental inoculation of sheep with this bacteria, abscesses developed in parotid lymph nodes and livers of all fattened animals (N = 6) and in 50% (N=3) of un-fattened animals and the size of the abscess positively co-related with the weight of the animal. The study concluded that changes in the blood and skin chemistry of fattened sheep enhance the growth of S. aureus subsp. anaerobius and thus its ability of infection leading to abscess formation.