Effects of dietary protein and energy levels on digestive enzyme activities and electrolyte composition in the small intestinal fluid of geese

The present study was conducted to evaluate the effects of dietary protein and energy levels on digestive enzymes and electrolyte composition in jejunum of geese. A 3x3 factorial and completely randomized design was adopted with three protein levels and three energy levels. The experiment included four replicates for each treatment, and three geese for each replicate. Isovolumetric supernate from centrifugal jejuna fluid were mixed in each replicate. Activities of digestive enzymes and ions were analyzed. The results showed trypsin and chymotrypsin activities were significantly increased with increasing of dietary protein and energy levels (P<0.05). The concentrations of Ca2+ and pH value were significantly decreased by increased dietary protein and energy levels. However, no significant differences were found for the activities of amylase and cellulase, as well as the concentration of Na+ among groups with different protein and energy levels. In conclusion, digesta enzymes and electrolytes in the small intestine adapted to the protein and energy levels. The activities of protease, rather than amylase and cellulase were induced with increasing of protein and energy levels. The imbalance of positive and negative ions was possibly adjusted by the fluctuant concentrations of K+, Cl- and Ca2+ for maintaining normal physiological function.