J. Anim. Sci. 82 (Suppl. 1):244.
The objective of this experiment was to determine the effects of diet and age on gut morphology in healthy dogs. Small intestinal villus width, height, and area, and small intestinal and colonic crypt depth were measured. Twelve senior (age = 12 yr old; 6 M, 6 F) and 12 young adult (age = 1 yr old; 6 M, 6 F) beagles were randomly assigned to one of two dietary treatments: an animal product-based diet (APB) and a plant product-based diet (PPB). The APB diet was primarily composed of highly digestible, animal-derived ingredients and was formulated to contain 30% crude protein and 20% fat. The PPB diet was primarily composed of plant-derived ingredients and was formulated to contain 22% crude protein and 8% fat. In addition to dietary protein and fat differences, total dietary fiber was greater in the PPB diet (15.2%) com- pared to the APB diet (4.8%). Diets were fed for one year. Intestinal sections were collected from the duodenum, jejunum, ileum, and colon and placed in formalin for preservation. Tissues were embedded in paraffin and cut into 3 mm sections, and placed on glass slides. Digital im- ages of tissues were taken using a Nikon Optiphot-2 microscope (Nikon, Melville, NY). Height and width measurements, a minimum of 15 per section, were taken using Image Pro Plus software. Jejunal and ileal villus height, and duodenal villus width were greater (P<0.05) for dogs consuming the PPB diet. Age also affected gut morphology as young dogs had greater (P<0.05) jejunal villus height while senior dogs had greater (P<0.001) colonic crypt depth. Thus, both diet and age affect small intestinal and colonic morphology of the dog. This research was supported by Pyxis Genomics, Inc.