Various Blood Parameters in Commercial Hens Acutely and Chronically Infected with Mycoplasma gallisepticum and Mycoplasma synoviae

Abstract

Two trials were conducted to study the effects of acute (Trial 1) and chronic (Trial 2) mycoplasma infections on differential leukocyte counts in chickens. The trials initially included either 20 (Trial 1) or 40 (Trial 2) 6-wk-old commercial leghorn chickens negative for antibodies to Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS). Chickens were inoculated with F strain MG (FMG), MS (WVU 1853), or both. One group of chickens remained uninoculated and served as a negative control for both trials. Chickens were housed in fiberglass isolation units from 6 to 10 wk (Trial 1) or 6 to 70 wk of age (Trial 2). Differential leukocyte counts were examined from 6 to 10 wk (Trial 1) or 66 to 70 wk of age (Trial 2) in all chickens. Also, in Trial 2, packed cell volumes (PCVs) and plasma protein values were examined from 66 to 70 wk of age. In the acute study (Trial 1), differential leukocyte counts revealed statistically significant differences (P < 0.05) in heterophil, lymphocyte, monocyte, eosinophil, and basophil values among treatments. In general, the differential counts of FMG- and MS-infected birds were characterized by heterophilia, lymphopenia, monocytosis, eosinopenia, and basopenia. Histopathologic examination of the spleen, liver, kidney, and bone marrow revealed a high degree of lymphoid foci within the spleen and bone marrow of all infected chickens. In the chronic study (Trial 2), no statistically significant differences (P < 0.05) were observed in differential leukocyte counts, PCV, and plasma protein values among treatments. Histopathologic examination of spleen, liver, kidney, and bone marrow did not reveal any difference among treatments.

Leukocyte Profiles in Wild House Finches with and without Mycoplasmal Conjunctivitis, a Recently Emerged Bacterial Disease

“…Consistent with studies of responses of domestic poultry infected with M. gallisepticum (Branton et al, 1997), the proportions of heterophils and monocytes in wild House Finches showed the most extreme changes as a function of visible signs of mycoplasmal conjunctivitis. Relative levels of heterophils and monocytes were clearly higher among House Finches with clinical signs of MG, and both leukocyte types increased with infection severity (Fig.…”

“…Most conclusions concerning the function of avian leukocytes in innate immunity are based on research conducted with domestic poultry (e.g., Branton et al, 1997;Qureshi, 1998;Zulkifli et al, 1999;Campo et al, 2000;Elston et al, 2000), but a growing number of experimental and descriptive studies have examined leukocytes in wild passerines. Leukocyte profiles have been used in recent empirical studies to assess general stress and immunocompetence in wild birds (e.g., Svensson and Skarstein, 1997;Figuerola et al, 1999;Bortolotti et al, 2002).…”

“…This host-pathogen system also provides a unique opportunity to examine how avian leukocyte differentials are associated with infections in wild birds, and to compare the differentials from wild birds and poultry infected with a similar pathogen. For example, infections with MG in commercial hens have been shown to cause significant increases in the proportions of circulating heterophils and monocytes (Branton et al, 1997). However, it is not known if the innate immune system of House Finches responds similarly to MG infection.…”

Effects of single and combined Mycoplasma gallisepticum vaccinations on blood electrolytes and acid-base balance in commercial egg-laying hens

“…Live MG vaccines reduce the effects of MG clinical signs and have been shown to replace indigenous strains (Evans et al, 2002). Despite the welldocumented reports concerning the effects of MG vaccination on the blood characteristics and chemistry of layer hens (Branton et al, 1997;Burnham et al, 2003;Peebles et al, 2008Peebles et al, , 2009, only a few reports are available concerning the effects of MG vaccination on the physiological blood gas parameters and acid-base balance of layer hens. In addition, MG-induced effects on the physiological and immunological interactions in layer hens are poorly understood.…”

Infection withMycoplasma gallisepticumBuffers the Effects of Acute Stress on Innate Immunity in House Finches

“…Meanwhile, estimated heterophil numbers increased following stress in infected birds, which is in contrast to the decrease seen in uninfected birds (table 1 ). This pattern makes sense given the role of this cell in the immune system; studies of domestic chickens indicate that heterophils, being phagocytic in nature, are important in the host response to MG infection (Branton et al 1997). A previous survey of leukocyte profiles in MG-infected and uninfected house finches also found that infected birds had greater numbers of heterophils (Davis et al 2004).…”