The effect of the endotoxemia on the abomasal emptying rate in suckling lambs as shown by acetaminophen absorption test

Abomasal hypomotility and a decreased rate of abomasal emptying are believed to play important roles in the etiopathogenesis of abomasal disorders in ruminants. The abomasal emptying rate is potentially influenced by several factors. Effect of endotoxins on contractility of smooth-muscle preparations from the bovine abomasal antrum has been evaluated, and the results showed that endotoxemia has an inhibitory effect on contractility of abomasal smooth-muscle fibers. To evaluate the effect of the endotoxemia on the abomasal emptying rate in suckling lambs, this study was conducted. This study was done on five suckling lambs in two phases. In phase 1 (control group), the first blood sample was obtained in 7 a.m. (time zero). Then a mixture of milk, barium sulfate 70%, and acetaminophen was administered orally to each lamb. Afterwards, blood samples were obtained each 15 min up to 4 h later. Phase 2 (treatment group) was similar to phase 1, but after the first blood sampling in time zero in 7 a.m., endotoxemia was induced by administration of commercial lipopolysaccharide at dose rate of 2 μg/kg. The rest of the processes of phase 2 were similar to phase 1. C_max, T_max, and area under concentration curve (AUC) of acetaminophen were measured in the control and treatment groups. The abomasal emptying rate was assessed by comparing C_max, T_max, and AUC of acetaminophen between the control and treatment groups. The data from the control and treatment groups were analyzed statistically by SPSS program, using one-way ANOVA. Results indicated that C_max, T_max, and AUC in the endotoxemic (treatment) group were significantly different compared with those in the control group, which means endotoxemia decreased abomasal emptying rate. Results of present study indicated that endotoxemia profoundly decreases the abomasal emptying rate in suckling lambs. Thus, administration of drugs which attenuate endotoxemia could enhance the abomasal emptying rate in endotoxemic animals.