Microsphere uptake by the intestine of White Leghorn chickens

A study was conducted to determine the effective size for latex microsphere uptake in the intestine of white leghorn chickens. Three trials were conducted in which ligated intestinal segments of anesthetized 8-wk-old chickens were injected with 0.2-, 0.5-, 2-, 6-, 10-, or 20-mu diameter fluoresceinated latex microspheres. Microspheres were counted in brush border, epithelium, and lamina propria of each intestinal segment, liver, and spleen. After 1 hr, the 0.2-, 0.5-, and 2-mu microspheres were oriented along the brush border of epithelial cells and microsphere uptake into the epithelium and lamina propria was observed in the duodenum, ileum, cecum, cecal tonsil, and colon. Uptake of microspheres of 6, 10, and 20 mu diameter into epithelium and lamina propria was not observed in any intestinal segment. Also, no microspheres of any diameter were observed in sections of liver and spleen to suggest that there was no appreciable entry of microspheres into the bloodstream within 1 hr after administration. The results indicated that uptake of microspheres by the chicken intestine is a size-dependent process with microspheres < or = 2 mu being taken up to an equal extent by most segments of intestine.