The digestibility of DM, OM, CP and NFC was affected by both urea addition level (p = 0.0214; p = 0.0132; p = 0.0002; p = 0.0001, respectively) and the periods of aerobic exposure (p = 0.048; p = 0.049; p = 0.0001; p = 0.028, respectively) (Table 3). This evidence concerns the gene CP and ocular melanoma.