Expression of amino acid transporter in porcine skeletal muscles during postnatal development

Amino acids are transported across the plasma membrane by the transporters that often overlap in their substrate specificities. Because quality of meat, taste in particular, is dependent on the concentrations and the composition of amino acids in skeletal muscle (Nishimura and Kato, 1988), we aim to change the concentrations or the proportion of amino acids in skeletal muscle by regulating amino acid transporter (AAT) expression in pigs. However, our knowledge on regulation of expression of the AATs in porcine skeletal muscle is limited (Ai-Min et al., 2010, Garcia-Villalobos et al., 2012, Shi-Geng et al., 2009). Skeletal muscle is comprised of myofibre sub-populations which have different metabolic properties. Moreover, properties of porcine myofibres continue to develop postnatally (Davies, 1972). This led us to hypothesize that the expression of the AATs is muscle specifically regulated and its levels change during postnatal development. Therefore, we determined mRNA expression of amino acid transporters in three distinct skeletal muscles at 5 time points during the first 10 weeks postnatally.