In a study conducted on diarrheic calves, it was ascertained that rectal body temperature increased depending on the infection and inflammation
19. In our study as well, rectal body temperature was determined to be higher in the diarrheic calves compared to the control group. This incident might be related to the fact that the diarrhea result from infections.
It has been reported that serum or plasma Hp concentration has increased in calves after naturally or experimentally generating infection or inflammation14-16,20. A statistical increase in Hp concentration was noted in the study group compared to the control group in our study as well. In our study, while serum Hp concentration was measured as 6.81±0.58 μg/mL in the control group, it was 195.88±32.24 μg/mL in the study group. We believe that the high concentration in the study group arises due to infectious factors. Some researchers reported that serum Hp concentration has increased during infectious and inflammatory diseases21,22.
It has been reported that TNFα, IL-1β and IL-6 play a key role in APR9,23,24. It has been reported that the synthesis of APPs from the liver cells is initiated by the pro-inflammatory cytokines (TNFα, IL-1β and IL-6) released from monocytes and macrophages during inflammation7. In the presented study, serum IL-1β, IL-6 and TNFα concentrations in calves were detected to be statistically higher in the study group (IL-1β: 58.35±5.17, IL-6: 28.75±4.21 TNFα: 0.36±0.05) in comparison to the control group (IL-1β: 19.68±3.98, IL-6: 8.02±1.49, TNFα: 0.14±0.02). Serum IL-1β concentration in calves which Bovine viral diarrhea (BVD) disease generated experimentally was seen to be higher in the study group than in the control group on the 9th day of the disease. In the same study, serum TNFα concentration was determined to decrease in the study group in comparison to the control group on the 9th day of the disease25. In an another study, calves were experimentally administered with intravenous endotoxin, and after the administration; serum IL-1β, IL-6 and TNFα concentrations were seen to be higher in comparison to the control group20. In a previous study, it has been reported that IL-1β concentration in calves diagnosed with pneumonia could increase 6-fold more than the healthy ones26. Risalde et al.19 have determined that IL-1β, TNFα concentrations in diarrheic calves were higher than the control group. In our study, serum IL-1β, IL-6 and TNFα concentrations were determined to be higher in the study group than in the control group. We suggest that this incident resulted from infectious agents which caused diarrhea.
Some researchers have reported an increase in WBC values in the calves with diarrhea27,28. In another study, it has been noted that WBC figures markedly increased in the calves with diarrhea; and leukocytosis stemming from the relative increase of neutrophil granulocytes has occured as a result of the reaction of the body against gastrointestinal infection29. In our study we have also believed that the increase in WBC values in the calves with diarrhea arises from gastrointestinal infection. It has been reported that in calf diarrhea serum Hct and plasma protein levels increase owing to the decrease in extracellular fluid volume30. In our study, Hct concentration was determined to be higher in the study group diagnosed with diarrhea than in the control group, as well. In the study, no statistical difference (P>0.05) was detected between the study and the control groups in terms of RBC and Hb concentrations.
Sing and Sodhi31 have reported that there was an increase in serum ALT and AST levels in the calves with diarrhea. In other studies, it has also been ascertained that an increase in serum ALT and AST concentrations was found in the calves clinically diagnosed with diarrhea comparing to the healthy ones32,33. In this study, even though an increase in serum ALT and AST concentrations was determined in the study group in comparison to the control group, this increase was noted as not statistically significant. In our study, serum GGT concentration was determined to be statistically higher in the study group (34.29±3.59 IU/L) than in the control group (17.62±1.51 IU/L). It has been reported that serum GGT concentration could be higher than 200 IU/L in both diarrheic calves and the healthy ones, and this could result from the amount of colostrum that the calves take34. In the presented study, no statistically significant increase in serum TP and ALB concentrations was detected in the study group compared to the control group.
In conclusion, regarding the results derived from our study, it has been determined that the increase in the serum Hp concentration in the calves with diarrhea has accompanied clinical symptoms of the calves naturally infected with diarrhea. Moreover, it has been detected that the serum Hp in the healthy animals of the control group was at low concentrations. In the light of these results, we suggest that routine measurement of serum Hp IL-1β, IL-6, and TNF-α levels in the serum and are the most valuable parameters to evaluate the course of the disease and prognosis in the field of veterinary medicine.