Effect of Propionibacterium acidipropionici P169 on growth performance and rumen metabolism of beef cattle fed a corn- and corn dried distillers’ grains with solubles-based finishing diet

Abstract

Narvaez, N., Alazzeh, A. Y., Wang, Y. and McAllister, T. A. 2014. Effect of Propionibacterium acidipropionici P169 on growth performance and rumen metabolism of beef cattle fed a corn- and corn dried distillers’ grains with solubles-based finishing diet. Can. J. Anim. Sci. 94: 363–369. A growth and metabolism experiment was conducted to evaluate the effect of Propionibacterium acidipropionici P169 on feedlot steers fed a corn- and corn dried distillers' grains with soluble (DDGS)-based finishing diet. Steers (40 non-cannulated and 8 ruminally cannulated) were divided into two groups and administered 10 g head−1 d−1 of maltodextrin containing 1×1011 colony-forming units (CFU) of P169 or the same amount of carrier (Control), top-dressed once daily upon feeding. Feed intake, growth rate and feed efficiency were determined over 115 d. For cannulated steers, ruminal pH was monitored continuously for 5 d during the second week of each month over the entire feeding period with rumen samples collected 3 h after feeding on days 1 and 5. Molar proportions of butyrate, branched-chain volatile fatty acids (VFA) and NH3-N concentration increased (P<0.01) with P169, whereas total VFA, molar proportions of propionate, the acetate:propionate ratio, and lactate concentration did not differ (P>0.05) between treatments. P169 had a limited effect on ruminal pH as duration and area under the curve both at pH 5.5 and 5.2 as well as frequency of acute ruminal acidosis bouts were similar (P>0.05) for both groups. Compared with control steers, steers fed P169 had more (P<0.05) bouts of subacute ruminal acidosis (SARA). All steers had similar (P>0.05) feed intake, growth rate, feed efficiency and carcass characteristics, except for longissiumus muscle area, being less (P<0.05) for P169 steers than controls. Supplementing P169 to beef cattle fed a corn- and corn DDGS-based finishing diet had no effect on growth performance of beef cattle or ruminal pH and increased the bouts of SARA.