Pancreatic mass, cellularity, and alpha-amylase and trypsin activity in feedlot steers fed diets with increasing corn silage inclusion

摘要

Swanson, K. C., Kelly, N., Wang, Y. J., Fan, M. Z. and McBride, B. W. 2008. Pancreatic mass, cellularity, and alpha-amylase and trypsin activity in feedlot steers fed diets with increasing corn silage inclusion. Can. J. Anim. Sci. 88: 703-709. Twenty-four yearling beef steers (initial BW = 535 +/- 5.0 kg), predominately of Angus breeding, were used in a randomized complete block design to determine the effect of dietary inclusion of corn silage on pancreatic cellularity, mass, and alpha-amylase and trypsin activity. Using calan gates, steers were individually fed diets containing 20, 40, 60, or 80% corn silage (DM basis) with the rest of the diet made up of concentrate. Diets were formulated to maintain a constant CP:ME (g M cal(-1)) and were fed at 2.1 x NEm requirement. After 28 d on treatment, the two heaviest steers from each treatment were slaughtered per week and pancreata collected. Pancreatic weight (g and g kg(-1) BW) and content (kU and U kg(-1) BW) of alpha-amylase activity did not differ among dietary treatments. Concentration (U g(-1)) of pancreatic alpha-amylase decreased (P = 0.03) with increasing corn silage inclusion. Pancreatic DNA and RNA content (g and mg kg(-1) BW) increased linearly (P <= 50.04) with increasing corn silage inclusion. The content of pancreatic trypsin activity responded cubically (P = 0.03). These data indicate that increasing corn silage inclusion does not influence total pancreatic alpha-amylase activity and that cell number may influence pancreatic alpha-amylase concentration.