Maternal nutrition altered embryonic MYOD1, MYF5, and MYF6 gene expression in genetically fat and lean lines of chickens

Abstract

Objective: The objectives of this study were to evaluate the effects of daily feed intake during the laying period on embryonic myogenic differentiation 1 (<i>MYOD1</i>), myogenic factor 5 (<i>MYF5</i>), and myogenic factor 6 (<i>MYF6</i>) gene expression in genetically fat and lean lines of chickens.Methods: An experiment in a 2×2 factorial design was conducted with two dietary intake levels (100% and 75% of nutrition recommendation) and two broiler chicken lines (fat and lean). Two lines of hens (n = 384 for each line) at 23th week of age were randomly divided into 4 treatments with 12 replicates of 16 birds. The experiment started at 27th week of age (5% egg rate) and ended at 54th week of age. Hatched eggs from the medium laying period were collected. Real time polymerase chain reaction analysis was used to analyse the <i>MYOD1</i>, <i>MYF5</i>, and <i>MYF6</i> mRNA levels of E7, E9, E11, E13, and E15 body tissues and E17, E19, and E21 chest and thigh muscle samples.Results: The results indicated that there were significant effects of line, dietary intake, and interactions between them on <i>MYOD1</i>, <i>MYF5</i>, and <i>MYF6</i> gene mRNA expression levels in embryonic tissues. Low daily feed intake did not change the expression trend of <i>MYOD1</i> mRNA in either line, but changed the peak values, especially in lean line. Low daily feed intake altered the trend in <i>MYF5</i> mRNA expression level in both lines and apparently delayed its onset. There was no apparent effect of low daily feed intake on the trends of <i>MYF6</i> mRNA expression levels in either line, but it significantly changed the values on many embryonic days.Conclusion: Maternal nutrient restriction affects myogenesis and is manifested in the expression of embryonic <i>MYOD1</i>, <i>MYF5</i>, and <i>MYF6</i> genes. Long term selection for fat deposition in broiler chickens changes the pattern and intensity of myogenesis.