Morphology and enzymatic activity of the small intestinal mucosa of Iberian pigs as compared with a lean pig strain.

Castrated male Iberian (n = 12) and Landrace × Large White (n = 12) pigs were used to study histological structure and enzymatic activity in the small intestine at 3 points of the productive cycle (BW = 15, 50, and 115 kg). Both strains were fed the same cereal-based diets (DE = 2,799 kcal·kg(-1), and CP = 15%) throughout the entire experimental period. Differences (P < 0.05) in histometrical variables (villus height, width and surface, crypt depth, villus height/crypt depth relationship, mucosal thickness, muscular layer thickness, and number of goblet cells) were found among samples of small intestinal sections (duodenum, jejunum, and ileum) at the 3 productive stages studied. Also, differences (P < 0.05) in histometrical variables of small intestinal samples were found between Iberian and lean pigs at all productive stages, although these differences tended to disappear with age. Differences (P < 0.05) in enzymatic activities (lactase, sucrase, maltase, isomaltase, aminopeptidase, and alkaline phosphatase) of small intestinal samples were found between the different intestinal sections at all productive stages studied. Although differences (P < 0.05) in enzymatic activities of small intestinal samples were found between Iberian and lean pigs at all productive stages, values tended to equalize with pig age. We concluded that differences previously found in dietary nutritional utilization between Iberian and lean strains are likely not due to differences in intestinal absorption or hydrolytic capacity.