The effect of dietary leucine on blood plasma leptin and adipose leptin mRNA in feeder cattle

The objective of this study was to determine if dietary leucine would increase circulating plasma leptin and adipose leptin mRNA in feeder cattle. It is hypothesized that by supplementing rumen-protected leucine there would be an increase in the amount of circulating leptin in the blood plasma of feeder cattle and an increase of leptin mRNA found in adipose tissue. Two feeding trials were conducted utilizing a control diet and a treatment diet (control diet with ruminally protected leucine to provide 30 g of leucine/hd/d). Trial 1, calves (n = 10) were fed a control diet for 14d followed by 14d on the treatment diet. Trial 2, steers (n = 10) were divided into two pens and subjected to a feeding trial with a cross-over design consisting of two 14d periods. Trial 1 measured leucine, leptin, glucose, and insulin, and trial 2 measured adipose leptin mRNA, glucose, and insulin. Dietary leucine increased (P 0.05) increase leptin mRNA in subcutaneous fat. However, mRNA was negatively correlated (P < 0.05) to plasma glucose