Reprod. Nutr. Dev. 46 (2006) 9-18
DOI: 10.1051/rnd:2005064

Effect of supplemental calcium propionate on insulin action to blood glucose metabolism in adult sheep

Hiroaki Sano and Tadahisa Fujita

Department of Agro-bioscience, Faculty of Agriculture, Iwate University, Ueda 3-18-8, Morioka 020-8550, Japan

(Received 10 October 2004; accepted 1 June 2005; published online 27 January 2006)

Abstract - An experiment combining a hyperinsulinemic euglycemic clamp procedure of four sequential 2-h periods and an isotope dilution method of [U-¹³C]glucose determined the effect of supplemental calcium propionate on blood glucose metabolism during insulin and glucose infusions in adult sheep. They were fed lucerne hay cubes and commercial concentrate with and without supplementary calcium propionate (Prop and Cont diets, respectively) in a crossover design for each 21-day period. At the preinfusion period, blood glucose turnover rate (GTR) was greater (P < 0.05) for the Prop diet than for the Cont diet. Blood GTR, endogenous glucose production rate (EGPR) and the ratio of EGPR to blood GTR were greater (P < 0.01, P < 0.05 and P < 0.05, respectively) for the Prop diet than for the Cont diet. Blood GTR and glucose infusion rate (GIR) increased (P < 0.001) and the ratio of EGPR to blood GTR was reduced (P < 0.01) with increased insulin infusion rates. The maximal GIR tended to be (P < 0.10) greater for the Prop diet than for the Cont diet but plasma insulin concentration at half maximal GIR did not differ between diets. It is suggested that in adult sheep, dietary propionate supplementation enhances insulin action on glucose metabolism, however, changes in measures of tissue responsiveness and sensitivity were not significant.

Key words: calcium propionate / glucose clamp technique / glucose metabolism / insulin / isotope dilution method / sheep

Corresponding author: Hiroaki Sano sano@iwate-u.ac.jp

© INRA, EDP Sciences 2006