Blood urea-N content was significantly higher (3.4 as compared to 2.2 mmol l−1)in the High group compared to the Control group on day 21 (Student–Newman–Keuls test, Pb0.01) and higher compared to all other groups on day 42 (Pb0.05). Similarly, PCO2 was significantly different (Pb0.05) between all treatment groups at day 21 and 42, and increased with increasing degree of reuse level through-out the experiment.