Age-related changes in apparent digestibility in growing kittens.

The ability of the growing kitten to digest protein, fat, carbohydrate, dry-matter and energy were assessed. Kittens were divided into two groups; one group was fed a wet diet, the other a dry diet. Both groups were allowed ad libitum access to food. Apparent digestibility of the two diets, and kitten bodyweights were measured over a 24-week period. There were no significant differences in mean bodyweight between the two groups. Digestible energy intake of the kittens decreased with increased age; regression analysis of the data generated two fitted models which appeared to accurately predict the digestible energy intake between 39 and 41 weeks of age. There was a significant (P < 0.05) effect of diet on the apparent digestibility of protein, organic-matter and dry-matter. Age had a significant (P < 0.05) effect on the apparent digestibility of all the parameters measured. Newman-Keuls multiple range tests showed that apparent digestibility of carbohydrate, organic-matter and total energy significantly (P < 0.05) increased in kittens older than 19 weeks. This suggests that the digestive capacity of the younger cat may be affected by the physiological development of the gut, and dietary induced enzyme modulation.