Breed and diurnal effects on leptin and glucose concentrations in tropical cattle

Résumé

The effects of breed and time of day was evaluated on plasma leptin and glucose concentrations in four breeds of cattle. The breeds were Muturu, White Fulani, Ndama and Muturu x White Fulani cross. Animals had ad-libitum access to feed and water. Each animal was weighed daily and bled by jugular venipuncture using Vacutainer kits for three consecutive days. Plasma leptin was determined using the Millipore Multi-species radioimmunoassay and plasma glucose was determined using the Wako Autokit Glucose technique. Plasma leptin was significantly (P<0.0001) dependent on breed. The Muturu breed had the lowest amount of leptin (3.9 ± 1.8 ng/ml) while the White Fulani breed had the highest level (8.5 ± 3.2 ng/ml). There was a significant correlation between bodyweight and leptin. Leptin level was not affected by time of day. Mean plasma glucose ranged from 42.7 to 54.7 mg/dL and was significantly (P = 0.019) dependent on cattle breed. Also, time of day had no effect on plasma glucose concentration. These data indicated that significant breed differences exist in leptin concentrations in tropical cattle. These differences may reflect the disparity in muscularity and adiposity in the breeds.