The influence of microflora on the breakdown of maize starch granules in the digestive tract of chicken.

Influence of the microflora on the extent of degradation of starch in the chicken digestive tract has been studied by scanning electron microscopy. Axenic (germfree), holoxenic (conventional), and monoxenic (only one germ) chickens inoculated with two strains of lactobacillus (strains 220 and 207) isolated from the crop of the cock were used in these experiments. In vitro starch granules were less hydrolyzed by strain 207 than by strain 220. A more extensive degradation was observed when starch was included in feed. This breakdown resulted in formation of cavities and pin holes in the starch granules. In vivo starch granules in the crop of holoxenic and monoxenic chickens were scarcely damaged and erosion was always superficial. In monoxenic 207 chicken as in holoxenic ones, bacteria were fixed on the crop wall. In feces, the pattern of the breakdown was dependent on the type of animal. These results demonstrated the role of the total microflora in the breakdown of starch and the specific intervention of the two strains of lactobacilli.