Influence of Breed Size, Age, Fecal Quality, and Enteropathogen Shedding on Fecal Calprotectin and Immunoglobulin A Concentrations in Puppies During the Weaning Period

Grellet, A.; Heilmann, R.M.; Polack, B.; Feugier, A.; Boucraut-Baralon, C.; Grandjean, D.; Grützner, N.; Suchodolski, J. S.; Steiner, J.M.; Chastant-Maillard, S.

Diarrhea is common in puppies around the time of weaning, and may be accompanied by slowed growth of the puppies. 6 Viral and parasitic infections are very common in young puppies and are involved in weanling diarrhea. 5, 6, 14, [41] [42] [43] The early detection of such infections would avoid growth retardation and could decrease the development of more severe forms of the disease. Thus, noninvasive markers of digestive health, the concentrations of which might be modified by the presence of enteropathogens, would be of great utility in these patients. Thus, our study investigated 2 fecal markers, calprotectin and IgA, used in human pediatric gastroenterology for their utility in weanling puppies. In our study, puppies that shed ≥1 enteropathogen had significantly lower fecal IgA concentrations than did puppies without any enteropathogen shedding identified. This lower fecal IgA concentration may be a cause or a consequence of the enteropathogen shedding. Immunoglobulin A can actively bind microrganisms, enterotoxins, and other antigens, and prevent adherence and subsequent penetration of the intestinal wall. Thus, a lower fecal IgA concentration could be caused by IgA being utilized in antigen binding or by enterohepatic recirculation of IgA. After IgA binds an antigen in the intestinal lumen, it is either excreted in the feces or is actively reabsorbed for destruction of the microorganism or virus by hepatic Kuppfer cells. Reabsorption of IgA could have been increased by an infection with an enteropathogen, which could result in decreased fecal concentrations of IgA. Conversely, the lower fecal IgA concentration also could indicate the presence of altered local immunity and thus serve as evidence for a higher risk of infection with an enteropathogen. A positive impact of fecal IgA on protection against infectious diseases already has been described in other species. Mice lacking secretory IgA exhibit a significant delay in clearance of rotavirus infection compared with mice that have secretory IgA. 44 In children, fecal IgA concentrations also were shown to have an influence on protection against rotavirus infection and resulting disease. 45 No significant effect of any viral (CCV or CPV2) or parasite shedding (G. duodenalis, C. ohioensis complex, C. canis, or T. canis) on fecal calprotectin concentration was observed. This lack of difference in calprotectin concentrations between dogs that showed enteropathogen shedding and those that did not could be explained by the population of dogs enrolled in our study (ie, healthy puppies or puppies presenting only with an abnormal fecal quality without any other clinical sign). In humans, the patient's clinical status influences the concentrations of this marker. In children who are clinically healthy but infected by Giardia, no effect on fecal calprotectin concentration was described. 33 However, in human patients with viral gastroenteritis, fecal calprotectin concentrations were reported to be associated with the severity of clinical signs. 46 In our study, 18.9% of puppies were found to be excreting a high load of CPV2 but without any of the typical clinical signs (eg, hemorrhagic diarrhea, vomiting, prostration, dehydration, anorexia). This healthy carrier state could explain the lack of association between shedding of this virus and fecal calprotectin concentrations. Another study comparing fecal calprotectin concentrations among healthy puppies, puppies with an abnormal fecal quality,