Nitrogen intake was greater in all the treatments than in control. Faecal N excretion was also higher in all treatment groups than in control (Table 3). Urinary N excretion tended to be greater for T3 compared with control, T1 and T2. Total N excretion increased for T3 than for control, but was similar among T1, T2 and T3. Nitrogen retention greatly increased in treatment groups compared with control. N retention expressed in terms of percentage of digested N intake was higher for T1 and T2 than control and T3.