The Effects of Chinese and Argentine Soybeans on Nutrient Digestibility and Organ Morphology in Landrace and Chinese Min Pigs

Abstract

Twenty Landrace and twenty Min piglets, with an average initial body weight of 22.4 kg, were randomly divided into 5 groups with 4 animals per group, within each of the breeds. The piglets were housed in individual concrete pens. Each group of the piglets was fed one of 5 diets. The diets contained either 20% raw Argentine soybeans, 20% processed Argentine soybeans (118°C for 7.5 min.), 20% raw Chinese soybeans, 20% processed Chinese soybeans (118°C for 7.5 min.) or no soybean products (control diet). Faecal samples were collected on days 6, 7 and 8 of the treatment period. Digestibilities of dietary nutrients were determined with AIA (acid insoluble ash) as a marker. After a 17 day treatment, three piglets were killed from each of the groups. Tissue samples of small and large intestine for light and electron microscopy examination were taken immediately after the opening of abdomen. Then, the weight or size of relevant organ sw as measured. The results show that the digestibilities of dry matter (DM), crude protein (CP) and fat were higher in Min piglets than in Landrace piglets (p<0.05). The diets containing processed soybeans had a significant higher CP digestibility than the control diet and the diets containing raw soybeans (p<0.05). Landrace piglets had heavier and longer small intestines, heavier kidneys and a lighter spleen than Min piglets (p<0.05). The pancreas of the animals fed the diets containing processed soybeans was heavier than that of the animals fed control diet (p<0.05) and the diets containing raw soybeans. But, the differences between raw and processed soybean diets were not significant. A significant interaction (p<0.05) between diet and pig breed was observed in weight of the small intestine. The Landrace piglets increased the weight in their small intestine when they were fed the diets containing soybeans. In the light micrographs and electron scanning micrographs, it was found that the villi of small intestinal epithelium of animals (especially Landrace piglets) fed the diets containing raw Chinese soybeans were seriously damaged. The transmission electron micrograph showed that a lot of vesicles were located between the small intestinal microvilli of these piglets. The histological examination also indicated that the proportion of goblet cells in villi and crypts in the piglets consuming the control diet was significantly lower (p<0.01 and p<0.02, respectively) than those of the animals consuming the diets containing raw or processed soybeans. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 4 : 555-564)