APPARENT DIGESTIBILITY OF STARCH IN DOGS AND CONTRIBUTION TO THE STUDY OF DIGESTIBILITY INVITRO BY ENZYMATIC METHOD

This study verifies the interest of technological treatments on digestibility "in vitro" and "in vivo", of starch-rich feeds for carnivores. Different sources of both raw and cooked starch such as wheat, corn, manioc and potato are used. Two factors related to the degree of digestibility are observed: The vegetable origin: in general the digestibility of root vegetables is less than that of cereals. This difference is related to the structure of the starch; the coefficient of digestive use of wheat and corn starches are respectively 99.7 and 98.3 compared with 93.3 and 73.6 for manioc-tapioca and potato. Industrial treatment: technological treatment greatly increases the digestibility of starch "in vitro" and "in vivo". In effect in raw starches the CUDa is 83.2 and "in vitro" the average of broken down starch in percentage of total starch is 7.6 as compared with gelatinised starch, where the CUDa is 99.3 with an average of broken down starch of 62.4. In conclusion our results show the correlation between digestibility "in vivo" and the break-down "in vitro" (r=0,57 for 14 ddl) and the appreciation of the degree of gelatinisation appears to predict the digestibility of starch "in vitro" with a correlation coefficient of 0.99.