Effect of enhanced early life nutrition on the M. longissimus thoracis et lumborum transcriptome of crossbred beef heifer calves.

Enhanced early-life nutrition in calves holds potential for improving economically important traits, including growth rate, milk yield and reproductive development. However, the mechanisms through which these nutritional strategies affect skeletal muscle development remain to be fully elucidated. This study aimed to evaluate the impact of enhanced dietary intake during early calf-hood on the transcriptional profile of skeletal muscle tissue. Angus × Holstein-Friesian heifer dairy-calves were offered either a high (HI, n = 10) or moderate (MOD, n = 10) diet from 3 to 21 weeks of life. At 21 weeks of age, M. longissimus thoracis et lumborum tissue was harvested from all calves and subsequently subjected to mRNA sequencing. Altered early-life nutrition led to the differential expression of 482 genes in the skeletal muscle transcriptome (False discovery rate (FDR) < 0.1; fold change > 1.5) between HI and MOD calves. Differentially expressed genes were involved in processes related to metabolism, energy production and cellular growth and proliferation and included enrichment of the Sirtuin signalling pathway and skeletal muscle system development and function. The results of this study identify novel gene transcripts involved in the molecular regulation of skeletal muscle response to nutritional modulation, offering insights into muscle development and its potential impact on tissue composition.