Effects of dietary energy levels on plasma leptin in sheep
Authors: TOKUDA, Tomomi; DELAVAUD, Carole; CHILLIARD, Yves
Source: Animal Science Journal, Volume 73, Number 6, December 2002 , pp. 471-478(8)
This experiment investigates the changes in the plasma leptin levels of sheep fed a diet of three energy levels (low, moderate and high). Four mature wethers were used for this experiment. For the first 4 weeks, the sheep were fed diets to provide 1.2 times the maintenance metabolizable energy requirements, low energy levels (LE). During the second 4 weeks, the sheep were fed diets to provide 1.5 times the maintenance metabolizable energy requirements, moderate energy levels (ME). During third 4-week period, the sheep were fed a diet to provide 1.8 times the maintenance metabolizable energy requirements, high energy levels (HE). Body weight was determined every week. Blood samples were collected prior to the morning meal at 3 days intervals throughout the experiment, and plasma leptin, insulin and nonesterified fatty acid (NEFA) concentrations were assayed. Body weight decreased in week 1 after the start of the experiment, it continued to decrease during the LE feeding, but it gradually increased until the end of HE period. Similarly, plasma leptin concentration decreased during LE feeding, but increased during the HE feeding. Additionally, positive correlation was obtained between leptin and insulin or glucose concentrations, whereas no clear relationship with circulating NEFA was observed. In conclusion, it was suggested that plasma leptin concentrations were affected by the metabolizable energy in feed.
Document Type: Research Article
Affiliations: Unité de Recherche sur les Herbivores, Equipe Tissu Adipeux et Lipides du Lait, INRA, Theix, 63122 St-Genés-Champanelle, France
Publication date: December 1, 2002