Validation of the measurement of glucose appearance rate with [6,6-2H2]glucose in lactating dairy cows

Sophie Lemosquet , Jean Thibault , Agnès Thomas , Elisabeth Debras , Catherine Hurtaud

The aim of this study was to validate the measurement of glucose appearance rate using [6,6-2H2]glucose i.v. infusion in lactating dairy cows. Sample enrichments were analysed by gas chromatography/mass spectrometry. Linearity (enriched solutions) and specificity (enriched plasma) were good: for enrichments ranging between 1.6 and 6.3 mol% excess, the slopes were about 1 and the ordinates at the origin were not different from zero. For a plasma enriched at 3.74 mol% excess, repeatability and long term intralaboratory reproducibility coefficients of variation were 1.31 and 1.90%, respectively. The appearance rates were calculated by two models. The values provided by the steady-state model were not different from those provided by the non-steady-state Steele model. Both models can be used because the treatment effects were similarly discriminated regardless of the model. In our experiments analysing the nutritional effects on Ra in mid-lactating cows, the precision of the method (1.90%) was not the limiting factor to detect a significant difference in Ra compared to the statistical precision obtained with the experimental scheme (4 × 4 and 5 × 5 Latin square design). We conclude that in lactating dairy cows, the measurement of glucose fluxes with this method is relevant and minimally invasive for the animals.

Mots clés: dairy cows; glucose metabolism; GC-MS; [6; 6-2H2]glucose; validation

Domaines: Biologie de la reproduction; Alimentation et Nutrition; Biologie du développement

Sophie Lemosquet, Jean Thibault, Agnès Thomas, Elisabeth Debras, Catherine Hurtaud. Validation of the measurement of glucose appearance rate with [6,6-2H2]glucose in lactating dairy cows. Reproduction Nutrition Development, 2004, 44 (1), pp.17-27. ⟨10.1051/rnd:2004012⟩. ⟨hal-00900473⟩