Abstract
1. An experiment was conducted to study changes in the expression of the hypothalamic leptin receptor, neuropeptide Y (NPY) and proopiomelanocortin (POMC) with age during the early neonatal period in two different strains of chickens: Beijing-You (BY) and Arbor Acres (AA).
2. Compared with BY chickens, AA chickens ate more, and grew faster. Hypothalamic NPY concentrations of both strains increased with age until d 7 followed by a decline. Hypothalamic NPY of BY chickens on d 7 was lower than in AA chickens at the same age.
3. No difference with age was observed in hypothalamic α-melanocyte-stimulating hormone (α-MSH) of BY chickens, while hypothalamic α-MSH in AA chickens on d 0 was higher than on the other days. Compared with AA chickens, BY chickens showed lower hypothalamic α-MSH on d 0.
4. Similar developmental changes between two strains were observed in the expression of leptin receptor, NPY or POMC genes in the hypothalamus. Hypothalamic mRNA of leptin receptor on d 0 was higher than on d 1 and 7. Unlike NPY, hypothalamic NPY mRNA on d 0 was higher than on the other days.
5. Hypothalamic POMC mRNA decreased gradually with age until 7 d followed by a slight increase.
6. The results showed that the developmental changes of hypothalamic signal molecules varied with age and strain. NPY, α-MSH and leptin receptor might be involved in the early programming of feed intake in newly hatched chickens.
Acknowledgement
This study was supported by the Earmarked Fund for Modern Agro-industry Technology Research System (Beijing, China) and the National Basic Research Program of China (Project Number 2004CB117501; Beijing, China).