Effect of age on digestibility of fatty acids in chickens

Effect of age on apparent digestibility of fatty acids was investigated from the 2nd to the 42nd day of age using Ross chickens receiving a commercial feed mixture ad libitum. Digestibility of all fatty acids rapidly decreased from Day 2 to Day 4. This drop was followed by an increase till Day 8. The observed changes can be explained on the basis of excretion of endogenous nutrients originating primarily from the yolk sac. In the period of Days 9 to 42, coefficients of all saturated and monounsaturated fatty acids (with the exception of C20 : 1 n-9) significantly (P < 0.001) decreased with age. Changes in digestibility of linoleic, alpha-linolenic, arachidonic, and docosahexaenoic acid were very small (P > 0.05). Digestibility of eicosapentaenoic acid increased highly significantly; the daily increase was 1.09 per cent. Mean values of polyunsaturated fatty acid digestibility were higher (P < 0.001) than those of saturated and monounsaturated fatty acids.