Journal
BRITISH JOURNAL OF NUTRITION
Volume 99, Issue 1, Pages 100-109Publisher
CAMBRIDGE UNIV PRESS
DOI: 10.1017/S0007114507801553
Keywords
antigens; antibodies; rumen protozoa; sheep
Categories
Ask authors/readers for more resources
Two rumen protozoa vaccine formulations containing either whole fixed Entodinium or mixed rumen protozoa cells were tested on Merino sheep with the aim of decreasing the number and/or activity of protozoa in the rumen. Negative control (no antigen) and positive control (Tetrahymena corlissi antigens) treatments were also included in the experiment. Blood and saliva were sampled to measure the specific immune response. Protozoal numbers in the rumen were monitored by microscopic counts. Vaccination with protozoal formulations resulted in the presence of specific IgG in plasma and saliva, but saliva titres were low. Titres after secondary vaccination were higher (P<0.05) than after primary vaccination. There was a moderate (r(2) 0.556) relationship (P<0.05) between plasma and saliva titres for the rumen protozoal vaccine formulations. Rumen protozoa were not decreased (P>0.05) by the vaccination and there was also no difference (P>0.05) between treatments in rumen fluid ammonia-N concentration or wool growth. hi vitro studies investigated the binding ability of the antibodies and estimated the amount of antibody required to reduce cell numbers in the rumen. The studies showed that the antibodies did bind to and reduced protozoa numbers, but the amount of antibody generated by vaccination was not enough to produce results in an in vivo system. It is suggested that the vaccine could be improved if specific protozoal antigens are determined and isolated and that improved understanding of the actions of protozoa antibodies in rumen fluid and the relationships between levels of antibodies and numbers of protozoa in the rumen is needed.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available