Biochemical and immunological changes in chickens experiencing pulmonary hypertension syndrome caused by Enterococcus faecalis

Recent studies have proven that Enterococcus faecalis (1.5x10(7) live bacteria from a tryptic broth culture given s.c. or intra-abdominally (IA) to 5-wk-old broilers) caused pulmonary hypertension syndrome (PHS) in 97% of the birds within 48 h. Definitive diagnosis of PHS was made at necropsy by observing a cavity on the surface of the right ventricular wall and by increased ratio of left ventricular weight to total ventricular weight. A nonlethal method of diagnosing PHS would enhance the study of PHS and alert production poultrymen to the onset of ascites (waterbelly), which is the culminating event of PHS. In the present study, serum hemoglobin, glucose, protein, cholesterol, aspartate amino transferase (AST) and creatine kinase-MB (myocardial in origin) enzymes, differential leukocyte numbers, and specific antibody levels against Ent. faecalis were evaluated as nonlethal diagnostic indicators of PHS. Decreases in serum protein and cholesterol of 3 and 10%, respectively, plus increases in percentages of basophils and monocytes of 18 and 40%, respectively, appear to indicate that PHS has been initiated. An agglutinating antibody, specific against Ent. faecalis, but not against other closely related bacteria, has been developed. Presence of this antibody in a bird means that the bird has previously encountered Ent. faecalis. Thus, this antibody may become a diagnostic for PHS in fast-growing chickens.