Plasma glucagon-like peptide-1 concentration in non-lactating cows during abomasal infusion of linseed oil and in response to glucose and insulin challenges.

PIRES, J.A.A., A.E. RELLING, C.K. REYNOLDS AND R.R. GRUMMER.

Clermont-Ferrand, France

Simposio; XIth international symposium on ruminant physiology; 2009

ISRP International Scientific Committee,

In nonruminants, the gastrointestinal hormone glucagon-like peptide-1 (GLP-1) increases glucose-stimulated insulin secretion and has multiple (direct and indirect) effects on feed regulation and metabolism (Holst, 1997). In dairy cows, plasma GLP-1 concentration is influenced by physiological state, dietary fat supplementation and fatty acid profile (Relling and Reynolds, 2007a, b). Unsaturated dietary fat increases GLP-1 to a grater extend than saturated sources (Relling and Reynolds, 2007b). Previous experiments have focused on the effects of abomasal infusion of linseed oil (LO), a fat source rich in C18:3 n-3, on whole-body responses to insulin in fed and feed-restricted non-lactating Holstein cows, as assessed by i.v. glucose tolerance test (GTT) and insulin challenge (IC). Abomasal infusion of LO decreased insulin response during GTT in fed cows, compared to tallow (T) (Pires et al., 2008), and we speculated that this effect could have been mediated by differential secretion of GLP-1. The objective was to determine whether LO infusion altered plasma concentration of GLP-1 and assess whether it could explain the pattern of insulin response during GTT in the previously mentioned experiments (Pires et al., 2008).