DECREASED SERUM APOLIPOPROTEIN-A-I CONCENTRATIONS IN COWS INFECTED WITH SALMONELLA-TYPHIMURIUM

Serum apolipoprotein A-I concentrations in cows infected with Salmonel la Typhimurium were evaluated to assess its relevance in salmonellosis . Apolipoprotein A-I has been shown in rats to be secreted by the inte stine as well as the liver. Clinical symptoms such as diarrhea reveale d an outbreak of salmonellosis in 22 cows on a farm, and sera were obt ained at 6 (acute phase), 16, 28 (convalescent period) and 42 d (postc onvalescent period) after the outbreak. Apolipoprotein A-I concentrati ons (mean +/- SD, mg/mL), determined by ELISA, were 0.598 +/- 0.497 (d ay 6), 0.111 +/- 0.060 (day 16), 0.432 +/- 0.311 (day 28) and 0.727 +/ - 0.516 (day 42), Compared with the concentration at day 42, those at 16 and 28 d were significantly (P < 0.01, P < 0.05) lower, but that at day 6 was not. The serum concentration of apolipoprotein B-100 (of li ver origin in cattle) was unaltered during the course of salmonellosis . The concentration of apolipoprotein A-I was positively correlated wi th those of serum total cholesterol (r = 0.589, P < 0.01) and phosphol ipids (r = 0.590, P < 0.01). These results suggest that apolipoprotein A-I in cattle is in part of intestinal origin, and also that its decr eased serum concentration in salmonellosis can be attributed to the re duced intestinal synthesis or secretion of this apolipoprotein. Moreov er, as a potential carrier for dietary lipids such as cholesterol, det ermination of serum apolipoprotein A-I concentration is suggested to b e useful when assessing the nutritional status of the affected cows.