Evaluation of the ruminal bacterial diversity of cattle fed diets containing citrus pulp pellets (CPP) using bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP)

Authors: BROADWAY, PAUL - Texas Tech University; Callaway, Todd; Carroll, Jeffery - Jeff Carroll; Sanchez, Nicole; DONALDSON, JANET - Mississippi State University; RATHMANN, RYAN - Texas Tech University; JOHNSON, BRADLEY - Texas Tech University; CRIBBS, JOSH - Texas Tech University; Durso, Lisa; Miller, Daniel; Nisbet, David; SCHMIDT, TY - Mississippi State University

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/8/2012
Publication Date: 6/25/2012
Citation: Broadway, P.R., Callaway, T.R., Carroll, J.A., Sanchez, N.C., Donaldson, J.R., Rathmann, R.J., Johnson, B.J., Cribbs, J.T., Durso, L.M., Miller, D.N., Nisbet, D.J., Schmidt, T.B. 2012. Evaluation of the ruminal bacterial diversity of cattle fed diets containing citrus pulp pellets (CPP) using bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP). Journal of Animal Science. 90:339(E-Suppl. 3).

Interpretive Summary:

Technical Abstract: The rumen microbial ecosystem has been extensively studied, but remains a mystery from a quantitative perspective. Dietary components and changes cause shifts in the ruminal microflora that can affect animal health and productivity, but the majority of these changes remain unknown. The objective of this study was to analyze the diversity of bacterial populations in the rumen of cattle fed various amounts of CPP. Heifers (n=18; 298.7±5.1 kg) were fed a basal feedlot diet and randomly assigned to 1 of 3 diets (n = 6/diet). Diets containing CPP (0, 10, or 20%) were formulated to be exchanged with steam flaked corn on a 1:1 basis. Using bTEFAP, the normal ruminal microbiota was examined to understand how different concentrations of a common by-product feedstuff affect ruminal microbial ecology. Bacteria in the genera of Prevotella and Eubacterium were found to be the predominate bacteria that populated the rumen comprising 34% and 6%, respectively, of the bacterial population. The Firmicutes:Bacteroidetes ratio tended to increase (P=0.07) in animals fed CPP when compared to controls. Also, Butyrivibrio and Carnobacterium populations increased in number with increasing amounts of CPP in the feed ration. In contrast, a decline (P=0.009) in the population of Dialister and Catonella population occurred with increasing CPP. An increase (P=0.04) in the proportion of Bacilli bacteria in the ruminal microflora was associated with increases in dietary CPP. Overall, there were relatively few changes observed in ruminal microbial populations highlighting the functional flexibility of the rumen and demonstrating that feeding CCP at rates up to 20% does not adversely impact ruminal microbial ecology. The lack of major changes in ruminal microflora may possibly be due to a lack of essential oils in the CPP which may play a greater role in the alteration of ruminal microbial populations.