Propionate is not an important regulator of plasma leptin concentration in dairy cattle.
Propionate was recently shown to increase leptin synthesis in rodents. To determine if a similar effect occurs in ruminants, propionate was administered to lactating dairy cows. In experiment 1, 31 cows were given an intrajugular Na propionate bolus (1,040 micromol/kg body weight), increasing plasma propionate from 160 to 5,680 microM and plasma insulin from 6.8 to 77.8 microIU/mL. Plasma leptin concentration decreased from 2.11 ng/mL before bolus to 1.99 ng/mL after dosing (P<0.05) with no differences in leptin concentrations at 20, 50, and 100 min post-bolus (P>0.10). In experiment 2, 12 cows were used in a duplicated 6 x 6 Latin square experiment to assess the dose-response effect of ruminal propionate infusion on plasma leptin concentration. Sodium propionate was infused at rates of 0, 260, 520, 780, 1040, or 1,300 mmol/h, while total short-chain fatty acid infusion rate was held constant at 1,300 mmol/h by addition of Na acetate to the infusate. Coccygeal blood was sampled following 18 h of infusion. Increasing the rate of propionate infusion linearly increased plasma propionate concentration from 180 to 330 microM (P<0.001) and plasma insulin concentration from 6.7 to 9.1 microIU/mL (P<0.05). There was a quadratic response in plasma leptin concentration (P=0.04) with a maximum at 780 mmol/h propionate, but leptin concentrations increased by no more than 8% relative to the 0 mmol/h propionate infusion. Leptin concentrations were correlated with insulin concentrations but not with propionate concentrations in plasma. Propionate is not a physiological regulator of leptin secretion in lactating dairy cows.
Department of Animal Science, Michigan State University, 2265G Anthony Hall, East Lansing, MI 48824, USA.
Barry J
BJ
Bradford
Masahito
M
Oba
Richard A
RA
Ehrhardt
Yves R
YR
Boisclair
Michael S
MS
Allen
D000818:Animals; D002417:Cattle / Q000097:blood*; D005260:Female; D007275:Injections, Intravenous; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood*; D011422:Propionates / Q000097:blood / Q000494:pharmacology*
D007328:Insulin; D020738:Leptin; D011422:Propionates; C514135:sodium propionate; C029658:propionic acid