Abstract
Abstract
Background
A leptin-like immunoreactive substance has been found in chicken eggs and has been implicated in serving as a maternal signal to program offspring growth and metabolism. In the present study, we investigated the effects ofin ovoleptin administration on hatch weight, serum and hepatic concentrations of metabolites and hormones, as well as on the expression of genes involved in hepatic lipid metabolism and the predicted microRNAs (miRNAs) targeting the affected genes. To this end we injected fertile eggs with either 0.5 μg of recombinant murine leptin or vehicle (PBS) before incubation.
Results
Prenatally leptin-exposed chicks showed lower hatch weight, but higher liver weight relative to the body weight, compared to the control group.In ovoleptin treatment increased the hepatic content and serum concentration of leptin in newly hatched chickens. The hepatic contents of triglycerides (TG) and total cholesterol (Tch) were decreased, whereas the serum levels of TG, Tch and apolipoprotein B (ApoB) were increased. The hepatic mRNA expression ofsterol regulator element binding protein 1(SREBP-1c),SREBP-2,hydroxy-3-methylglutaryl coenzyme A reductase(HMGCR) andcholesterol 7α-hydroxylase 1(CYP7A1) was significantly up-regulated, as was the protein content of both SREBP-1c and SREBP-2 in hepatic nuclear extracts of leptin-treated chickens. Moreover, out of 12 miRNAs targetingSREBP-1cand/orHMGCR, five were significantly up-regulated in liver of leptin-treated chicks, includinggga-miR-200bandgga-miR-429, which target bothSREBP-1candHMGCR.
Conclusions
These results suggest that leptinin ovodecreases hatch weight, and modifies hepatic leptin secretion and lipid metabolism in newly hatched broiler chickens, possibly via microRNA-mediated gene regulation.