Plasma citrulline, arginine, nitric oxide, and blood ammonia levels in neonatal calves with acute diarrhea

Gultekin, Mehmet; Voyvoda, Huseyin; Ural, Kerem; Erdogan, Hasan; Balikci, Canberk; Gultekin, Gamze

However, our plasma CIT result is in agreement with the findings of several previous reports in humans with enteropathies 10-12,15 and sepsis, 13, 16, 17 as well as in dogs. 22, 42 As previously reported in humans, decreased plasma CIT and ARG in diarrheic calves could be because of impaired intestinal production, different metabolic processes altered in inflammatory conditions, or a combination of both. 9, 11, 13, 33, 42 Infectious diarrhea in neonatal calves results in a low to strong inflammatory response. 1, 4, 43 Approximately 80% of CIT is converted to the amino acid, ARG, in the body to support ARG and NO levels. 6, 8, 9, 44 Conversion of CIT to ARG and converting/recycling ARG to CIT and NO appear to be dependent on the severity of inflammation. 6, 7, 14 Therefore, the decreases in plasma CIT and ARG levels can especially be based on intestinal damage, dysfunction, or both mechanisms, leading to the impaired production of these amino acids. Although small bowel enteroscopy or histopathological examination was not performed in this study, certain enteropathogens, particularly C. parvum, rotavirus, and coronavirus are associated with mucosal injury in calves. 1, 4 Considering all of these factors, low plasma CIT and ARG concentrations in neonatal calves with diarrhea ( Figure 1A,B) . We cannot explain the exact reasons for these results. Perhaps this result stems from the low number of calves with noninfectious diarrhea enrolled in the study.