Selection is the basic tool to exploit and improve the productive potential of
livestock. The objectives of the present study were to evaluate the effect of selecting
Japanese quail at 4-week for high body weight for four successive generations on
the growth traits including body weight (BW) and average daily gain (ADG) and on
the expression level of insulin-like growth factor I (IGF-I), growth hormone
receptor (GHR), adenine nucleotide translocase (ANT), uncoupling protein (UCP)
and Cytochrome C Oxidase subunit III (COX III) genes. Growth traits were
evaluated for the base, 1st, 2nd, 3rd, and 4th generations. Total RNA was extracted
from the liver then cDNA was synthesized. Real-time polymerase chain reactions
were performed using the SYBR Green PCR Master Mix. The 4th generation of this
study recorded the highest and significant values for body weight at zero (hatching),
2
nd, 4th and 6th week of age (BW0 = 9.75, BW2 = 75.16, BW4 = 163.46 and BW6 =
253.13 gm, respectively), and for average daily gain (ADG0-2 = 4.67, ADG2-4 =
6.36 and ADG0-6 = 5.79 gm, respectively). Moreover, the 4th generation recorded
the highest and significant mRNA expression of GHR and IGF-1 genes in the liver
(1.80 and 1.66 fold change, respectively). In contrast, the base generation showed
the highest and significant levels of hepatic mRNA expression of ANT, UCP, COX
III genes (1.08, 1.24 and 1.05 fold change, respectively). We may conclude that
these genes are promising candidate biomarkers for improving growth traits, leading to increased quail marketable meat. |
