The use of determining the enzymatic activities in the posterior respiratory tract as a diagnostic tool has already been demonstrated in several species. In this context, this paper aims to determine the activity of alkaline phosphatase (ALP) in the bronchoalveolar lavage (BAL) of horses from the Military Police of the State of Rio de Janeiro, comparing healthy animals with asymptomatic carriers of an inflammatory airway disease (IAD). Twenty-eight adult male animals with no history of respiratory diseases in the last two months prior to the study were studied. Physical exam and blood laboratory test results (ALP, hematocrit, leukogram, total protein and plasma fibrinogen) were within physiological parameters. The equines were separated into two groups according to the results of the bronchoalveolar cytology. The determination of ALP was done by spectrophotometry with aliquots of the supernatant of the BAL preserved in liquid nitrogen. To estimate pulmonary epithelial lining fluid and ALP activity, correction of the dilution caused by the lavage was done. The horses with a cell type differential count compatible with IAD presented a lower ALP activity in BAL when compared to healthy animals, therefore this dosage can be used as a complement in the diagnosis of IAD.
horse; bronchoalveolar lavage; alkaline phosphatase; IAD