Porcine immunoglobulins survival in the intestinal tract of adult dogs and cats fed dry food kibbles containing spray-dried porcine plasma (SDPP) or porcine immunoglobulin concentrate (PIC)

Survival of orally administered porcine immunoglobulins (PIG) was measured in the gastrointestinal tract (GIT) of adult dogs and cats fed diets containing spray-dried porcine plasma (SDPP) or porcine immunoglobulins concentrate (PIC). Nine adult Beagles and 12 mixed breed adult cats were used in a 3 × 3 Latin square design with three and four replicates by diet, respectively. Animals were fed one of three experimental extruded dry kibble diets during 42 days. The control diet was a commercial diet coated with fat and digest, and the two experimental diets were similar to the control diet but they included 10 g of either SDPP or PIC/kg of diet. After a 10-day adaptation period to the diet total faeces were collected for four consecutive days and food and water intake, faecal score and digestibility of dietary components were determined. No significant differences in nutrient digestibility were found in dogs, although crude fiber (CF) (P<0.01) and ash (P<0.05) digestibilities were improved in cats fed the SDPP diet. The presence of dog or cat IgA and porcine IgG was measured in the faeces, and the survival of porcine IgG was calculated. The Fab and Fc fragments of porcine IgG were determined in faeces to identify the proportion of bioactive fragments that resisted the pass through the GIT. The survival of porcine IgG throughout the GIT was 7.6% and 4.9% for dogs and cats, respectively and was independent of the IgG source (SDPP or PIC) used. The porcine bioactive fragment Fab was identified in the faeces of both species fed the two sources of porcine immunoglobulins. The inclusion of porcine immunoglobulins in the diet significantly reduced (P<0.05) the presence of IgA in the faeces of both species. This study demonstrates that dietary porcine IgG partially resists the digestion process in dogs and cats. The identification of bioactive fragment Fab in faeces, which contains the antigen combining site, and the reduction of IgA, indicate that porcine IgG may transfer passive immunity at the intestinal level in both species as it has been suggested for humans and other mammals.