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This Article Full Text (PDF) All Versions of this Article: jas.2008-1184v1 87/5/1722    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Blanch, M. Articles by Wallace, R. J. Search for Related Content PubMed PubMed Citation Articles by Blanch, M. Articles by Wallace, R. J.

Physiological changes in rumen fermentation during acidosis induction and its control using a multivalent polyclonal antibody preparation in heifers

M. Blanch^*, S. Calsamiglia^*, N. DiLorenzo, A. DiCostanzo, S. Muetzel and R. J. Wallace

^* Grup de Recerca en Nutrició, Maneig i Benestar Animal, Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193 - Bellaterra, Spain , Department of Animal Science, University of Minnesota, 55108 - St. Paul, USA Rowett Research Institute, Aberdeen AB21 9SB, UK

Sergio.Calsamiglia{at}uab.es

Abstract

Physiological changes in rumen fermentation during acidosis induction and its control using a multivalent polyclonal antibody preparation (PAP) were studied in a completely randomized experiment using 12 crossbred heifers (452 ± 20 kg BW). Treatments were control (CTR) or PAP. The acidosis induction protocol composed 3 periods: 3 mo of 100% fescue hay fed for ad libitum intake, 10 d (from d 1 to 10 of the experiment) of adaptation to the treatment (100% forage feeding + 10 mL/d of PAP top-dressed to the treatment group), and 5 d (from d 11 to 15 of the experiment) of transition that consisted of increasing concentrate (16.5% CP) 2.5 kg/d up to 12.5 kg/d while maintaining ad libitum intake of fescue and providing 10 mL/d of PAP to the treated heifers. The concentrate feeding level of 12.5 kg/d was maintained until heifers developed acidosis (from d 16 to 22 of the experiment). When an animal was considered acidotic, it was changed to a 50:50 forage:concentrate diet, monitored for 4 d, and taken out of the experiment. Samples of ruminal fluid were collected before and 6 h after feeding to determine pH, VFA, lactate, protozoa counts, and DNA extraction for quantitative real time PCR (qPCR) and denaturing gradient gel electrophoresis analyses. Only samples collected during adaptation to the treatment, 3 and 1 d before acidosis, on the acidosis day, and at 1 and 4 d after acidosis were analyzed. Heifers (83% for CTR and 50% for PAP) entered into acidosis 5.25 ± 0.17 d after the start of transition. The fermentation profile of animals with acidosis was similar between treatments. From 3 d before acidosis to acidosis day, decreases of pH and of acetate to propionate ratio and increases in total VFA, butyrate, and entodiniomorph counts were observed. However, the greatest levels of Streptococcus bovis and Megasphaera elsdenii (79 ± 54 and 104 ± 73 ng DNA/mL ruminal fluid, respectively) and a decrease in DMI (10.6 vs 6.46 kg, respectively) were recorded 1 d after acidosis. Compared with CTR heifers, heifers fed PAP had greater pH before feeding on d 6 (6.70 vs. 6.11), 8 (6.54 vs. 5.95) and 9 (7.26 vs. 6.59) after the start of the feeding challenge. Heifers fed PAP tended to have greater total VFA concentrations than CTR (124 and 114 ± 4.0 mM, respectively). These results indicate that PAP may be effective in controlling acidosis of heifers during a rapid transition to a high-concentrate diet.

Key Words: acidosis • antibody • microbial profile • rumen fermentation