QUANTITATIVE ASSESSMENT OF AERIAL AMMONIA TOXICITY TO THE NASAL-MUCOSA BY USE OF THE NASAL LAVAGE METHOD IN PIGS

Effects of atmospheric ammonia (NH3) on the nasal mucosa and somatic g rowth were investigated in pigs exposed to 4 NH3 concentrations (0; 25 ; 50; and 100 ppm) for 6 days in a specifically designed air-pollutant exposure chamber. Nasal lavage (NAL) was applied to quantify the ammo nia-induced inflammatory response by measuring the number of neutrophi ls and the albumin (porcine serum albumin) concentration in the NAL li quid. In control pigs, these variables remained unchanged throughout t he exposure period. In all other groups, an important ammonia concentr ation-related increase was recorded. The equation of the linear regres sion line established between the mean values of the number of neutrop hils (X 10(3)) per milliliter of NAL liquid OI) recorded at the end of the exposure period and the ammonia concentrations (ppm) was: y = 69. 7 + 3.3 [NH3] (r = 0.979; P < 0.020). The increase in the neutrophil c ount was significant (P < 0.05) at concentrations as low as 25 ppm. Fo r albumin concentration nanograms per milliliter, the corresponding eq uation was: y = 574 + 14.3 [NH3] (r = 0.953; P < 0.045). However, the first significant change (P < 0.05) in this variable was only obtained for the higher concentration (100 ppm). In exposed pigs, a concentrat ion-related depression of somatic growth was observed. The equation of the regression line plotted relating the individual values of the cha nges in body weight gain recorded over the exposure period expressed a s percentage of the initial body weight (y) and the ammonia concentrat ion was: y = 3.507 - 0.203 [NH3] + 0.001 [NH3](2) (r = 0.55; P < 0.010 ). The decrease in the somatic growth was significant (P < 0.05) at co ncentrations as low as 25 ppm. We conclude that biochemical and cytolo gic analysis of NAL fluid is a good tool for quantifying the effects o f atmospheric pollutants in pigs, a 6-day exposure to ammonia induces nasal irritation and depression of somatic growth at concentrations as low as 25 ppm.