Abstract

Plasma sulfate concentration is a useful indicator of sulfur amino acid oxidation. Measurement of sulfate in water and other fluids has been made by turbidimetric, ultra-violet (UV) absorption or ion chromatography HPLC methods. The turbidimetric method is variable and suffers from interferences and both turbidimetric and UV methods are less sensitive than ion chromatography. We describe a quick and simple HPLC method, where sample preparation is a centrifugal filtration and the sulfate measurement is by single column HPLC using one buffer at a constant flow rate. Recoveries from spiked samples were 99.5 % (RSD 1.8 %) and the RSD of repeated standards over 6 weeks was 0.7 %. Using this method, we measured plasma sulfate levels in both growing lambs with intestinal parasites and in sheep fed fresh Lotus corniculatus containing condensed tannins (CT) or other fresh forages. The CT in Lotus corniculatus decreased (P < 0.05) plasma sulfate concentration while parasite infection did not (P > 0.05). Our method provided quick and reliable data that could be transferable for measuring sulfate in blood, serum and other biological fluids and could be used as a biomarker of whole body sulfate status under various physiological conditions in farm animals.

BR, Sinclair, MH Tavendale, EN Bermingham, JL Burke, WC McNabb, and NC Roy

Proceedings of the New Zealand Society of Animal Production, Volume 66, Napier, 284-289, 2006