The present study was undertaken to evaluate the effects of faecal collection interval (using a settling column) and the levels of dietary meat and bone meals (MBM) on the apparent digestibility coefficient (ADC) for dry matter, protein, energy and phosphorus in gibe] carp. Six iso-nitrogenous (crude protein: 410 g/kg) and iso-energetic (gross energy: 18 kJ/g) diets were used in which fish meal (FM) protein was gradually replaced by MBM at 0%, 20%, 40%, 60%, 80% and 100%. These diet combinations were fed to juvenile gibel carp for 11 weeks. The faecal samples were collected two weeks after the beginning of the experiment using a settlement column starting 1 min after excretion started, or 4h and 16h after feeding. The results showed that the ADCs of dry matter, protein, energy and phosphorus increased significantly as the time from excretion to faecal collections increased while not being significant for the high MBM inclusion diets. ADCs of dry matter, crude protein, energy and phosphorus decreased linearly or almost linearly with the increase in dietary MBM levels. These findings suggest that faeces should be collected soon after they had settled under the conditions of this study for digestibility determination while rapid leaching is apparently responsible for this false reading of digestibility with increasing sampling interval. It is also apparent that the digestibility is one of the problems affecting the use of MBM in juvenile gibel carp.
Zhang Song; Xie Shou-Qi (email@example.com) ; Zhu Xiao-Ming; Lei Wu; Han Dong; Yang Yun-Xia.Effect of faecal collection interval and dietary meat and bone meal levels on digestibility of nutrients in gibel carp (Carassius auratus gibelio),Acta Hydrobiologica Sinica,2008,32(1):79-90