Biomarkers of Gastrointestinal Nematodes in Beef Cattle Raised in a Tropical Area

Abstract

Biomarkers are specific molecular, histological or physiological characteristics of normal or pathogenic biological processes and are promising in the diagnosis of gastrointestinal nematodes (GINs). Although some biomarkers have been validated for infection by Ostertagia sp. in cattle raised in temperate regions, there is a lack of information for tropical regions. The aim of this project was to assess potential biomarkers and validate the most promising. In the first study, 36 bovines (Nelore breed) naturally infected by GINs were distributed into two groups: CON-A (control, not treated with anthelmintic) and TREAT-A (treated with fenbendazole on Days 0, 7, 14, 21, 28, 42 and 56). The variables of interest were live weight, fecal egg count, hemogram, serum biochemical markers, phosphorus, gastrin and pepsinogen. In the second step, pepsinogen was assessed in cattle of the Nelore breed distributed among three groups: CON-BC (control, not treated with anthelmintic), TREAT-B (treated with moxidectin) and TREAT-C (treated with ivermectin + albendazole). In the first study, no difference between groups were found for weight, albumin, hematocrit (corpuscular volume [CV]), erythrocytes or hemoglobin. Negative correlations were found between pepsinogen and both CV and albumin, and albumin was negatively correlated with the percentage of Haemonchus sp. in the fecal culture. Among the biomarkers, only pepsinogen differentiated TREAT-A and CON-A (beginning with the 28th day of the study). In the second study, a reduction in pepsinogen was found after anthelmintic treatment. Therefore, pepsinogen is a promising biomarker of worms in cattle naturally infected by the genera Haemonchus and Cooperia in tropical areas.