Conjugated linoleic acid supplementation during late gestation and lactation of sows affects myofiber type in their litters

• CLA increased the percentage of slow myofiber in pigs.
• CLA changed expression of genes related to muscle ib growth and transformation.
• Not t10, c12-CLA but c9, t11-CLA promoted differentiation of pig muscle cells.

The purpose of this study is to determine the effect of dietary conjugated linoleic acid (CLA) supplementation of pregnant and lactating sows on muscle growth and myofiber type of their piglets. There are thirty healthy, pregnant Rongchang sows with similar body condition and closed expected day of parturition for the experiment in vivo. Three experiment groups carry out with/without CLA (1%, 2% and 0%). The experiment began on 85th day of gestation and ended at 28th day after piglet birth. The results show that (1) piglets from CLA-fed sows had heavier longissimus dorsi and higher percentages of slow myofibers than control piglets (P<0.05); (2) moreover, real-time PCR showed that CLA supplementation induce increasing expression of MyHC 1, MyOG, and MyOD genes while decreasing expression of MyHC 2a, MyHC 2x, and MSTN genes in piglets. We also check the expression of genes which appear in 2 in vitro experiment. c9, t11-CLA acted to induce the differentiation of cultured pig skeletal muscle cells and up-regulates the expression levels of MyHC 1 and MyOG, but t10, c12-CLA strongly inhibited cellular differentiation and down-regulates expression of MyOG. These findings suggest that dietary CLA during early life may affect muscle development and myofiber type in pigs.