The effect of selenium on the metabolism of rumen bacteria in vitro : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Agricultural Science in the University of Canterbury [Lincoln College]

Abstract

Sodium selenate was added to rumen fluid and artificial saliva mixtures which were incubated with either a hay or starch substrate. Using a starch substrate, selenate up to 0.3mg/l increased bacterial protein synthesis and volatile fatty acid (VFA) production and reduced the pH of incubation mixture. Selenate levels about 0.3mg/l had the opposite effect and also altered the proportions of VFA produced. With a starch substrate the stimulatory effects of selenium on bacterial metabolism were thought to be due to selenium promoting bacterial multiplication. The lack of significant increases in VFA production and protein synthesis with hay substrate may have been a result of much of the selenate being reduced by the bacteria to unavailable forms.