The effect of substitution to DL-methionine with L-methionine and dietary protein levels on Expression Myogenic Genes in Japanese quail

This research was conducted to investigate the effect of different levels of protein (20 and 24%) and the replacement of methionine DL with L methionine on the expression of myogenic genes (atrogin-1 and MYF-5) using the RT-qPCR technique in Japanese quail. This experiment was done in the form of a 2×2 factorial with 4 treatments and 4 repetitions and 15 quail in each replicate. The first treatment included DL-methionine and 20% protein (control group). The second treatment consisted of L methionine and 24% proteins, and the third treatment included L methionine and protein 20% and the fourth treatment included DL-methionine and protein 24%. After 35 days of feeding and keeping the quails, with 8 hours interval of hunger, 2 quails were slaughtered in each replicate, and a piece of their chest has been removed immediately and was transferred to the laboratory with Liquid nitrogen, and froze in -80°c. After extraction of the whole RNA, its quality was measured and was used to generate and synthesis the cDNA. Eventually, the expression of myogenic genes was measured by the real-time PCR method. In this method, 𝜷-actin gene, as the source gene, was used to normalize the data. The results showed that by decreasing the protein level from 24% to 20%, atrogin-1 gene expression increased and the MYF-5 gene expression decreased. Also, the replacement of methionine DL with L-methionine did not have a significant effect on the expression of myogenic genes. The results indicated that DL-methionine could be replaced with L methionine, and a 24% protein level is more suitable than 20% in the Japanese quail diet.