Relationship between plasma ghrelin and leptin concentrations on food intake and feeding frequency in scheduled meal-fed male lambs during long term

Abstract

Ghrelin, a novel acylated peptide is the endogenous ligand for Growth Hormone Secretagogue (GHS) receptor. Ghrelin has been reported to increase feed intake and BW gain. Ghrelin also has been identified in bovine oxyntic glands of the abomasum and in the stomach of nonruminant animals this peptide may also function in the regulation of feedng or energy balance in ruminants. For this reason; the lambs were randomly assigned to the following 4 groups of 4 animals each according to the administration rhythm of the ration and to the ghrelin treatment: in the Group I, animals were fed ad libitum, in the Group II, they were also fed ad libitum and were intravenously injected with the ghrelin twice a week, in the Group III they were fed once a day (09:00) and in the Group IV, the lambs were fed twice a day (09:00 and 16:00). The daily food allowance was adjusted to metabolic energy in each day and an average body weight of 43 kg was maintained. Blood samples collected 30 min before feeding (08:30) and 60 min after feeding (10:00) at were analyzed for plasma ghrelin, growth hormone and leptin levels. Researchers have collected the blood samples 15 days intervals until 45 days. There was the highest peak values of ghrelin and leptin levels at the second period in the whole groups but there was no significant changes between sampling times in the groups. Researchers have obtained feed consumption, weight gain and feed conversion of each lambs and each groups. Researchers determined that systemic (iv) injection of ghrelin might affect feed consumption and body weight but not affect feed conversion rate.