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.

Fecal moisture in our study ranged from 50 to 77.2% (median, 66.7%), with a negative correlation with fecal scores, which is accordance with previous studies. 10, 30 A negative correlation also was observed between fecal markers and fecal score. The higher IgA and calprotectin concentrations in puppies with liquid or soft feces in this study do not seem to be a direct consequence of stool consistency (dilution) because this negative correlation was observed for fresh feces as well as for concentrations based on fecal dry matter. The negative correlation between fecal score and fecal marker concentration could be explained by the effect of age acting as a confounding factor. Indeed age influence feces quality (lower fecal score in very young puppies) 6 and, at the same time, age influences fecal concentrations of both markers (higher fecal concentrations in very young puppies). 47 Our study indicates that fecal calprotectin concentrations decrease and stabilize with age. This result is in accordance with our longitudinal study performed in young dogs around the age of weaning. 47 In humans, considerably higher fecal calprotectin concentrations also have been observed in infants around the time of birth compared with those in healthy older children and adults. 33, [48] [49] [50] In our study, 17% of puppies had high fecal calprotectin concentrations (>49 lg/g) similar to those observed in adult dogs with inflammatory bowel disease, with large interindividual variations. 19 These high concentrations do not appear to be linked to viral or parasite shedding because this effect of age on fecal calprotectin concentrations was still observed when both variables (age and enteropathogen shedding) were taken into consideration within the same statistical model. Moreover, we previously observed a spontaneous normalization of fecal calprotectin concentrations in healthy puppies during the weaning period. 47 The type of food (eg, natural milk, industrial milk, dry food) may have influenced fecal calprotectin concentrations. Human infants who are exclusively breastfed show significantly higher fecal calprotectin concentrations compared to those receiving a mixed diet. 49, 51 The effect of natural milk may depend on several factors such as hormones (eg, ghrelin, leptin), cytokines and other immunostimulants and growth factors (eg, epidermal growth factor, granulocyte colonystimulating factor), which all contribute to the development of the gastrointestinal immune system. 51 Milk ingestion was not controlled in our study, with puppies having free access to maternal milk. However, from 5 to 8 weeks of age, the proportion of natural maternal milk decreases continuously in a puppie's diet because of physiologic progressive weaning. Developmental processes occurring in the digestive tract during this period of life also could explain the higher fecal calprotectin concentrations. During the first weeks of life, intestinal permeability is higher 52 , which may lead to transepithelial migration of neutrophils, as observed in adults with inflammatory bowel disease. 53 The physiological establishment and stabilization of the gut microbiota also may have an effect on calprotectin release as has been suggested in humans. 54, 55 The higher calprotectin concentrations observed also could be linked to bacterial gastrointestinal infections as described in children. 15, 56